Physicist Kip Thorne On the Physics of "Interstellar"

A review of Interstellar at Scientific American that was not entirely flattering of the film's scientific aspects caught the eye of Cal Tech physicist Kip Thorne, who served as a consultant on the movie, and has actually written a book on the physics depicted. He and SciAm writer Lee Billings ended up having a conversation about how the film deals with time travel, black holes, and more. A slice: I think the laws of physics very probably forbid warp drives and traversable wormholes. The research that has gone on over the past 25 years trying to determine whether its possible all point in negative directions, but it’s not a firmly closed door. So there are two issues here. One is that the laws of physics probably forbid it, but, gee, if they don’t, it would be great to have! The other is that the technology required to make a warp drive or a traversable wormhole is so far, far, far beyond the technology needed for a laser sail or a nuclear-pulse rocket that I would not be in favor of putting any significant resources into trying to develop it. Now, you may have small amounts of money—tens or hundreds of thousands of dollars—spent on this, but nothing is wrong with that. Peer-review, at least in the United States and in Europe, is too strong for there to be any danger of millions or billions of dollars being spent on these things. The technology required for wormholes is so far removed from our current and plausible near-future capabilities that to throw lots of money at it would almost certainly be a total boondoggle.

Comments

Total Boondoggle

[XxtraLarGe]

The technology required for wormholes is so far removed from our current and plausible near-future capabilities that to throw lots of money at it would almost certainly be a total boondoggle.

So basically what he's saying is we might as well dump the money into a black hole. Sounds like most government programs.

Re:Total Boondoggle

[Feral Nerd]

The technology required for wormholes is so far removed from our current and plausible near-future capabilities that to throw lots of money at it would almost certainly be a total boondoggle.

So basically what he's saying is we might as well dump the money into a black hole. Sounds like most government programs.

Does that cover the government projects where they bail to private companies that are to big to fail?

Re:Total Boondoggle

[Anonymous Coward]

He's not commenting on the big picture here. It doesn't matter if you spend 10 billion now to receive a technology, or wait 40 years for people to 'accidentally' develop it. In the end you spend much more money on waiting. Therefore it wouldn't be a 'boondoggle'.

Re:Total Boondoggle

[XxtraLarGe]

Does that cover the government projects where they bail to private companies that are to big to fail?

Yes. They should have let them fail, but then they wouldn't have gotten the golden parachutes.

Re:Total Boondoggle

[rogoshen1]

yes, too big to fail.. infinite mass, wormhole.. singularity.. and we're right back where we started with this discussion.

Re:Total Boondoggle

[angelopaglialonga]

Well, consider that not everything is explainable with today's knowledge and so everything to invest on is pretty much a more or less well informed.... bet.

Re:Total Boondoggle

[joh]

Just be happy to get not all the government you pay for.

Re:Total Boondoggle

[sphealey]

So basically what he's saying is we might as well dump the money into a black hole. Sounds like most government programs.

Such as the government program that created the Internet, thus making it possible to post the quoted comment on Slashdot.

Re:Total Boondoggle

[plopez]

Well just merge it under the f-35 program

Re:Total Boondoggle

[Immerman]

Sure he is. He's saying there's no realistic chance of "receiving" the technology today, no matter how much you spend, this isn't a video game tech tree. In a few centuries or millenia our science and technology may have advanced enough that we might at least have an idea how to start chasing the dream; or maybe not - at present the evidence slightly suggests that such technologies are impossible for anyone in the universe, regardless of their level of technology or how many resources they're willing to dedicate to developing them.

Re:Total Boondoggle

[rogoshen1]

yes but how would your theory explain regulatory capture? would it require a grand unifying theory, like the one that has eluded physicists for decades?

Re:Total Boondoggle

[blue trane]

The mortgages themselves weren't the problem. The problem was the inflation of the mortgages into many times their original value, using financial derivatives and insurance. Because the derivatives were rated AAA, shadow banks didn't take out enough insurance. And insurance companies didn't really insure the derivatives, because they were rated so high they couldn't fail.

Then a few RMBSes failed, and market groupthink took over. Suddenly no one wanted these derivatives, not because they had no value, but because the market became paranoid and emotionally panicked. No private party wanted to roll over funding using the derivatives as collateral anymore. The private parties all wanted T-bills, because they were much much safer.

The government stepped in to take the instruments off the banks' balance sheets.

The government didn't make banks create financial derivatives. The government didn't rate those derivatives AAA. The government didn't fail to insure them adequately. In fact, the government became the insurer when the ostensible insurers (i.e., AIG) failed.

Righties like to quote Kenneth Rogoff. Here's a quote from him:

Without question the best and most effective approach to the problem would have been to bail
out the subprime homeowners directly, forcing banks to take losses but keeping them manageable.
For an investment of perhaps a few hundred billion dollars, the US Treasury could have saved
itself from a financial crisis whose cumulative cost, counting lost output, already runs into many,
many trillions of dollars. Instead of âoesaving Wall Street,â a subprime bailout would have been
targeted, almost by definition, at lower-income households. But unfortunately, this approach too
would have been politically impossible prior to the crisis.

Why don't righties quote that passage from Rogoff? Why wasn't bailing out individuals politically feasible? Because of the ignorance of the Tea Party, that's why.

Re:Total Boondoggle

[fustakrakich]

Sounds like most government programs.

Cui bono... The government is merely a snake oil middleman skimming off some of the profits. Who are the people that actively lobby for this with a bit more than three martinis?

Re:Total Boondoggle

[Hoi Polloi]

Or corporate subsidies or allowing them to dodge taxes?

Re:Total Boondoggle

[davester666]

I believe the US military is interested in developing a wormhole to transit from their bases in the US to anywhere else on the planet near-instantaneously. Any companies with a market valuation of over $1B are encouraged to bid on the project immediately.

Re:Total Boondoggle

[blue trane]

Quoting from http://www.milkeninstitute.org...:

The total value of housing units in the United
States amounts to $19.3 trillion, with $10.6 trillion
in mortgage debt and the remaining $8.7 trillion
representing equity in those units as of June 2008.

Of the approximately 80 million houses in the
United States, 27 million are paid off, while the
remaining 53 million have mortgages. Of those
households with mortgages, 5 million (or 9 percent)
were behind in their payments and roughly 3
percent were in foreclosure as of mid-2008.

So, say 10% of $10.6 trillion was at risk of default, or $1 trillion.

The notional amount of CDS
increased from less than $1 trillion in 2001 to slightly
more than $62 trillion in 2007, before declining to
$47 trillion on October 31, 2008.

So the derivative market inflated the real value of the mortgages by about a factor of 6, and then magnified the size of the possible default problem by a factor of 15.

I'm reminded of a sentence from John Lanchester's book, I.O.U.:

"Even once it's explained, however, it still seems wholly contrary to common sense that the market for products that derive from real things should be unimaginably vaster than the market for the things themselves."

Re:Total Boondoggle

[gordo3000]

rogoff, smart economist, not very good with the law.

The reason you could not bail out homeowners is it was unfeasible in expense. Banks didn't carry a large portion of the mortgages, it was end investors. This means the government would either have to violate standing contract law (you know, what the home owner signed before getting the money) or get EVERY SINGLE INVESTOR to agree. There were no provisions for changes in payouts based on 90 or 95% agreement. You would need everyone to agree to take a loss.

And as the mortgages were stacked in structured bonds, this would mean that the higher risk tranches would get beaten for 100% to protect the AAA tranches as much as possible. good luck getting ANY of those groups to agree to this without first restructuring the payout profile of the bonds, and you would have to do this with EVERY SINGLE DEAL.

Rogoff doesn't realize what he was basically asking for was the government to go in and, one at a time, renegotiate every single mortgage when the lender was a large, diverse group of investors. It's a nice idea, and would have worked if the mortgages were all kept on a bank's balance sheet. But in fact the banks kept almost none of the mortgages and instead just joined investors in owning bonds.

His method would have taken YEARS during a crisis that needed a solution in weeks.

Re:Total Boondoggle

[flappinbooger]

The technology required for wormholes is so far removed from our current and plausible near-future capabilities that to throw lots of money at it would almost certainly be a total boondoggle.

So basically what he's saying is we might as well dump the money into a black hole. Sounds like most government programs.

or green energy

Re:Total Boondoggle

[nine-times]

I kind of love how crazy the internet is. Suddenly a discussion about whether Interstellar's depiction of wormholes is accurate turns into a a contentious argument about the 2008 bailout. What a country.

Re:Total Boondoggle

[nine-times]

You're right in that it makes no sense to spend money trying to develop this technology. It'd make more sense to spend money on various kinds of scientific research, and see where the scientific advancements take us. If it's possible to travel through wormholes, studying physics should eventually lead us to the groundwork for doing that, but it makes no sense to spend money on trying to advance a particular scifi technology when the groundwork isn't there.

But was anyone (other than some AC) actually suggesting that we spend money on wormhole technology? That's the part that confuses me. You have a science fiction movie where people discover an existing wormhole, a scientists with his panties in a bunch because he feels like that's unrealistic, and then the scientific adviser on the script agreeing that it's not realistic.

Re:Total Boondoggle

[Immerman]

You may well be right, assuming the "gravity nut" can in fact be cracked - there's never any guarantee. But unless it opens a *huge* loophole there will probably still be a *lot* of work to do on enabling technologies to actually unlock FTL. For example as I recall the original Alcubierre warp bubble requires energy comparable to the total mass-energy conversion of Jupiter to create, though later revisions managed to reduce the energy requirements to something like only requiring the total energy conversion of the Moon, at the expense of likely running into problems with the plank-length limits interfering with the external geometry

  But the fact remains that when we look out at the universe we see no evidence of *anything* occurring at FTL speeds, which would suggest that any FTL technologies are accomplishing something not seen in nature. Contrast that to electricity that simply allowed us to more readily harness and transport energy in interesting ways to recreate simplistic versions of things already seen in he world. Information processing, mechanical work, etc. There's precious little being done with electricity that wasn't already happening in the world by other means.

Re:Total Boondoggle

[tehcyder]

faster than light travel will be no problem at all once we start to crack the gravity nut.

Yeah, never mind that it would abolish causality and permit time travel paradoxes, clearly it's just another engineering problem.

Re:Total Boondoggle

[TheTurtlesMoves]

Current evidence is not "slightly suggest", it is more like very nearly certainly impossible.

Re:Total Boondoggle

[hinckeljn]

The technology required for wormholes is so far removed from our current and plausible near-future capabilities that to throw lots of money at it would almost certainly be a total boondoggle.

So basically what he's saying is we might as well dump the money into a black hole. Sounds like most government programs.

"warp drive or a traversable wormhole is so far, far, far beyond the technology needed for a laser sail or a nuclear-pulse rocket that I would not be in favor of putting any significant resources into trying to develop it." Hmmm. But a wormhole might get us interstellar, while laser sail or nuclear-pulsed rocket , certainly not. Reaction engines, whatever the source of energy are inherently limited.. Damn Tsyolkowsky!

Re:Total Boondoggle

[Immerman]

And? We still have only the vaguest untested hypotheses as to why time only seems to flow in one direction. Just because we're accustomed to thinking of causality flowing in a nice sequential manner doesn't mean there's any inherent reason why it should do so. And in fact there are several theories of time in which "back propagation" of causality is actually a common occurrence, at least at the subatomic level.

Re:Total Boondoggle

[Immerman]

You are right, I should have used only one of vague or hypotheses. The point though, is that we have no frigging idea why time only seems to flow in one direction, and are not altogether certain that the apparent flow isn't it isn't simply an observer phenomena.

beware of breakthroughs

[iggymanz]

breakthroughs and follow-on tech arising in decades (example of invention of SR and GR and their use in present everyday life) means such cautions about "boondongles" might be nonsense.

We already know the "Standard Model" and "General Relativity" both are incomplete and have mutual contradiction where their realms overlap; something better is needed

Re:beware of breakthroughs

[Impy the Impiuos Imp]

He's talking needing energies that would make Doctor Who's Tardis, powered by an exploding supernova, gasp in disbelief.

I'm all for breakthroughs, but geeze.

Re:beware of breakthroughs

[iggymanz]

those are estimations based on current models that may be *wrong*

Re:beware of breakthroughs

[__aaltlg1547]

... but have huge amounts of evidence that indicae they're not THAT wrong.

Re:beware of breakthroughs

[iggymanz]

we have no working quantum gravity theory to explain what would really happen; so no real or theorectical evidence that wormholes could either be created or sustained. introducing a basic part of quantum mechanics into wormholes leads to out-of-control creation and flow of virtual particles without limit

Re:beware of breakthroughs

[Will.Woodhull]

Beware of breakthroughs... [that] have huge amounts of evidence that indicate they're not THAT wrong.

Well, they are good enough for everyday work. Today's everyday work. We'll be looking for something better tomorrow, since what we got now will not get us the flying cars we want.

But remember kids, it all starts with imagination. Which is not at all scientific. Which most definitely is not "real", even though all our technology and all the things good and bad that we do with that technology could never have come into existence without someone first imagining a thing.

To use the language of grandparent post, science and technology are dependent on the magic of imagination. Therefore magic rules. Science comes afterward, and only in certain corner conditions. Most of what we experience as the universe is magical. Which may or may not explain dark matter and dark energy (in an entirely unscientific way).

Re:beware of breakthroughs

[david_thornley]

Similarly, with the exception of black-body radiation, we had huge amounts of evidence that 1900 physics wasn't that far wrong. (We still do, in fact, in areas where it can be applied.)

So it is not an accurate Documentary Film?

[microcars]

I am so disappointed.

Re:So it is not an accurate Documentary Film?

[nine-times]

Yeah, the blog post seems a little insane to me. I get it when Neil deGrasse Tyson complains about things like, in some movie the Earth spins the wrong way, or if the constellations are wrong for the time that the movie takes place. He's nit-picking and he knows it. He's pointing out interesting scientific inconsistencies. It might possibly be educational, and he's showing off his knowledge and attention to detail, and whatever, that's fine.

But this guy is actually complaining that the movie depicts a stable wormhole that we can travel through. His problem with it is, scientifically, we have no reason to think that it's possible, though we don't strictly know. Did he think that either Christopher Nolan or the audience was not aware that we can't create wormholes?

Even in the movie, it's not depicted as something that's easy to create. But that's beside the point, really, since it's a science fiction movie that is just positing that such a thing is possible for the sake of building a plot around that supposition. It's like complaining about Jurassic Park on the grounds that, "It's unlikely that we'll ever be able to clone dinosaurs from ancient mosquitoes formed in amber." Or complaining about the movie E.T. because, "We've never been visited by extra-terrestrial life forms-- at least not so far, not as far as we know..."

Re:So it is not an accurate Documentary Film?

[sconeu]

OBDISCLAIMER: I'm a nitpicker. I'm even a member of a movie nitpicking site.

That said, I'm with nine-times. There is a thing in fiction, particularly in film, called "willing suspension of disbelief". Yes, the wormhole may not be possible, but it's plausible, and it moves the plot. You suspend your disbelief and go along for the ride.

Re:So it is not an accurate Documentary Film?

[fahrbot-bot]

I get it when Neil deGrasse Tyson complains about things like, in some movie the Earth spins the wrong way,

It spins the wrong way in the opening sequence of The Daily Show and he has previously remarked about this to Jon Stewart.

Re: So it is not an accurate Documentary Film?

[dreamchaser]

I read recently that the half life of DNA is a few hundred years. No matter how many flies trapped in amber we find, we will never be able to recover enough dinosaur DNA to make Jurassic Park happen.

Not to mention that making a dinosaur out of fly DNA would be quite a feat in itself ;)

Re:So it is not an accurate Documentary Film?

[nine-times]

Just to clarify, I believe Kip Thorne is the physicist who was a consultant on Interstellar, who made efforts to make the move more scientifically accurate than what Nolan could do on his own, and he's defending the movie to some extent. It's Lee Billings who is complaining that it's not scientifically accurate.

Re:So it is not an accurate Documentary Film?

[denzacar]

He is also one of the two people who came up with the idea for the movie.

 

The premise for Interstellar was conceived by film producer Lynda Obst and theoretical physicist Kip Thorne, who collaborated on the 1997 film Contact and had known each other since Carl Sagan once set them up on a blind date.[8][9] Based on Thorne's work, the two conceived a scenario about "the most exotic events in the universe suddenly becoming accessible to humans," and attracted filmmaker Steven Spielberg's interest in directing.[10]
The film began development in June 2006 when Spielberg and Paramount Pictures announced plans for a science fiction film based on an eight-page treatment written by Obst and Thorne. Obst was attached to produce the film, which Variety said would "take several years to come together" before Spielberg directed it.[11][12] By March 2007, Jonathan Nolan was hired to write a screenplay for Interstellar.[13]

Re: So it is not an accurate Documentary Film?

[ColdWetDog]

I read recently that the half life of DNA is a few hundred years. No matter how many flies trapped in amber we find, we will never be able to recover enough dinosaur DNA to make Jurassic Park happen.

Not quite. Half life is really not a particularly useful descriptor of how DNA degrades since it is not an 'all or nothing' sort of thing. We're getting better at sequencing DNA from organism tens of thousands of years old. Probably won't be able to get much beyond that, but it is possible than an exceptionally well preserved specimen could be found pushing the date back.

Re:So it is not an accurate Documentary Film?

[Oligonicella]

No we don't, not it isn't and no it isn't. Where do you get your information?

Re:So it is not an accurate Documentary Film?

[bill_mcgonigle]

[SPOILERS]

It's the wild inconsistency that was really a drag on the story. It was cool when they lost seven years by wasting a few minutes' time on a rescue attempt by getting a little bit close to a supermassive black hole.

But then later, we have a man in a ship skimming the event horizon and the person up in a much higher orbit is talking to him in realtime by radio.

It's like, why even bother with the pretext of being scientific if the whole damn thing is going to be thrown out when the plot holes demand it? The "sufficiently advanced technology" parts can all be forgiven, but that's not what made the film bad.

Of course,TARS awesomeness makes up for 40% of the bad stuff, but not the soundtrack from hell (I await the torrent with the unauthorized new soundtrack and 40 minutes of relentless editing applied). My eight-year-old said, "it was like they made it loud instead of interesting".

Re:So it is not an accurate Documentary Film?

[CaptainLard]

Thats how I approach movies/tv. I'll allow one giant off the wall liberty (i.e. zombies, warp drive, super powers, senator all of a sudden turns evil and becomes a murderer because he wasn't given majority leader, etc) but everything else has to follow along somewhat logically. Moderate wiggle room is sometimes allowed if I remain entertained cause thats the whole point of course. But if too many plot devices are required to keep the story going I'll give up on it pretty quick.

Re:So it is not an accurate Documentary Film?

[will.perdikakis]

You got him!!! He is a comedian, he was definitely not joking about this.

Re:So it is not an accurate Documentary Film?

[RubberDogBone]

The movie has enough plot problems for several movies. Most of the first half of the movie is pointless and adds nothing, NASA apparently built their meeting room UNDER the nozzles of a rocket motor (ala James Bond Moonraker where they use a similar set to try to KILL Bond), and despite tons of contractors working there, nobody knows about this NASA base.

Then there is the preexisting spaceship (huh?) and the wormhole we blindly trust even though nobody knows how it got there. Going through said wormhole it inexplicably has the same "clanking boat winch" sound effect used in every other Hollywood movie -who knew wormholes sounded like cheap clanking?

And once they find Dr. Mann, he's (golly gee) gone nutso and of course has a sabotaged base waiting. Nobody but Hollywood would do this. An unstable astronaut like that would never get into space. And despite being in space alone for decades he somehow knows how to fly the lander ship and attempt to dock.

But that's OK, later on the hero steals a ship from the far future and somehow knows how to fly it, too. Alone. Back into the wormhole where nobody else in the future has apparently bothered to look, not even once. Huh?

Anyway, the soundtrack is actually fantastic. It holds a huge amount of the angst of the movie, and listened to alone, it stuck me that the film is held together by the moodiness of the music. All the somber, grim bleakness comes from the music because frankly the plot and acting can't hold it together alone. I would not go see the movie again -it is pretty but not worth a second viewing. However the music is going to be on my favorite lists for a long time, but ONLY when I am already in a good mood. Some of the tracks are just so depressing and hopeless.... it takes courage to listen.

Re: So it is not an accurate Documentary Film?

[dbIII]

We need a new movie.
A fly and a dinosaur go into a teleport device ...

Re:So it is not an accurate Documentary Film?

[TropicalCoder]

I kept thinking about all those corn stalks they were trampling - such a waste.

Re:So it is not an accurate Documentary Film?

[russotto]

And once they find Dr. Mann, he's (golly gee) gone nutso and of course has a sabotaged base waiting. Nobody but Hollywood would do this. An unstable astronaut like that would never get into space.

Yeah, never.

But that's OK, later on the hero steals a ship from the far future and somehow knows how to fly it, too.

Did you actually watch the movie?

Re:So it is not an accurate Documentary Film?

[ShakaUVM]

>Just to clarify, I believe Kip Thorne is the physicist who was a consultant on Interstellar, who made efforts to make the move more scientifically accurate than what Nolan could do on his own

And failed utterly. There are so many horribly bad manglings of physics in the movie that he's trying to salvage himself by saying on just one of the two dozen serious errors it's maybe sorta possible that it could be that way.

He should be ashamed of himself for granting the movie his imprimatur.

Re:So it is not an accurate Documentary Film?

[RivenAleem]

I remember a recent Episode of Bones, where they totally misquoted Heisenberg's Uncertainty Principle. This really annoyed me. It's one thing to have your wonder computer zoom and enhance, but there's suspending belief and propagating a complete falsehood.

There have been similar instances in this year's season of Dr Who, where they use a blanket of oxygen to protect the earth from burning up to a massive solar flare, when we all know the exact opposite would happen, or the hatchling from the moon immediately laying a moon sized egg.

Re: So it is not an accurate Documentary Film?

[dreamchaser]

Just imagine a giant fly with a T-Rex head 8-0

Re:So it is not an accurate Documentary Film?

[nine-times]

to make the move more scientifically accurate than what Nolan could do on his own

Not completely scientifically accurate-- certainly not completely within the bounds of what we currently know about science-- but more than it would have otherwise been. It's not clear to me that he failed at all, especially since scientific accuracy doesn't seem to be Nolan's general goal in film-making. Or are we to believe that you can invade people's dreams, and that Tesla invented an electrical matter duplication machine?

Re:So it is not an accurate Documentary Film?

[ardor]

> I think Stewart's gone senile.

Nah, he's just lazy :)

Re:So it is not an accurate Documentary Film?

[sconeu]

Agreed, but those are of a completely different order than the wormhole.

Those are blatant *ERRORS*. The wormhole is at the edge of physics, and may or may not be possible (most likely not possible), but it is plausible. I am therefore willing to go along with it.

The others are flat out "nits" or "errors", depending upon how charitable you want to be.

Re:So it is not an accurate Documentary Film?

[TheTurtlesMoves]

The thing that is not plausible, is that relocating a substantial part of humanity off planet is easier than building a lot of green houses with hydroponics or areo poinics.. or just plane old green houses.

Re:So it is not an accurate Documentary Film?

[meta-monkey]

Also, most movies that require suspension of disbelief don't bill themselves as "taking science seriously." I haven't seen Interstellar, but I've read spoiler-laden reviews and discussions, and I've seen ads or clickbait fluff pieces talking about "the science of Interstellar." No. Nothing like the traversable wormhole depicted in the film is remotely possible given our current understanding of physics. And it's not a "well but 120 years ago heavier-than-air flight was 'impossible.'" That's a completely different thing. Most scientists and engineers didn't think that. Birds are heavier than air. It's obviously possible. They just didn't know how to make it happen for men. Those are engineering challenges. Same thing with going to the moon. We knew space exists. We knew things like planets and comets travel through space. We didn't know how to build a machine to do it.

But FTL travel is almost certainly impossible as demonstrated by everything we know about physics. Every theory we've got, and our theories of relativity and quantum mechanics are very, very well tested, says it can't happen. If we're wrong about that, we would have to be massively, massively wrong.

I can absolutely suspend my disbelief about FTL travel to enjoy Star Wars or Star Trek, but they don't take pains to say they're "based on real science." Interstellar does.

And, I think the message is dangerous. The public has this idea that we need to "get off this rock." That the environmental degradation we've caused on Earth can be side-stepped by moving someplace else, and that's dangerous bullshit. First, as we've said, FTL and interstellar travel (of any meaningful quantity of people in any reasonable time frame) is not going to happen. In system, there's nowhere to go. Mars? The moon? With the no magnetic field to block the solar wind, or the air pressure or any resources or anything to eat? Imagine the most inhospitable places on Earth. The Gobi Desert. Antarctica. Now imagine them irradiated by nuclear fallout. It would still be easier to eek out an existence in one of those places than it would be to live on the moon or Mars. At least there's an atmosphere. A magnetic field and an ozone layer to block solar radiation. The existence of infrastructure to use/scavenge from on the same planet. No where else in the solar system is remotely as hospitable as irradiated Antarctica. There's nowhere to go. Telling people "naw it's cool we can just leave and go fuck up someplace else" is a foolish and dangerous idea. Like it or not, we are stuck on this rock, so we have to take care of it. It's the only one we've got.

No worries there

[Anonymous Coward]

USA doesn't care about space exploration anymore, we're more interested in Keeping Up With the Khardshians.

Re:No worries there

[buddyglass]

Whereas in the 1960s the U.S. was more interested in "Keeping Up With The Kruschevs".

What would you even spend the money on?

[SuricouRaven]

It's all theory work. Money isn't the limiting factor there, it's just that very few people have the required intellect and level of education to advance the field. There's nothing to spend money on until some of them propose an experiment to test their latest theory. Even the particle physics people can ask for new accelerators, and cosmologists always have some new instrument on their wish-list.

The only hope for fundamentally new space travel tech right now is the quantum vacuum thruster, and that only because the experimental evidence so far has too many flaws to say anything more than 'something funny going on here.'

Re:What would you even spend the money on?

[__aaltlg1547]

A quantum vacuum thruster has never been tested in a vacuum, or anywhere else it couldn't produce its micronewton thrust by plain old fashioned electromagnetism.

Re:What would you even spend the money on?

[angel'o'sphere]

I would not call it theory work, if the question is which 'machine' might be able to create a worm hole.
But well, thinking about machines not built yet, might be considered theoretical work.
However we are so far away from stuff like worm holes that thinking about technologies regarding them is IMHO more a 'philosophical work' than a theoretical one.
I mean you can theoretice about a new type of transistor ... because we know how they work and that they exist.

Re:What would you even spend the money on?

[fahrbot-bot]

I would not call it theory work, if the question is which 'machine' might be able to create a worm hole.

Machine? Farscape 1 of course.

Re:What would you even spend the money on?

[Illserve]

It's all theory work. Money isn't the limiting factor there...

Exactly! Theory is essentially free. You just sit down and stare at a wall and maybe write some damn equations on it. There's no need to test those theories, or to even pay the utility bills for the scientists who create them. The best scientists work on a pro-bono basis because they have transcended the need to eat, sleep, or pay their staff a living wage.

Re:What would you even spend the money on?

[SuricouRaven]

It isn't free, but it's cheap compared to high-energy experimental work. How many theorists can you hire for the cost of building the LHC, or launching a space instrument?

"Physics"

[Anonymous Coward]

The research that has gone on over the past 25 years trying to determine whether its possible all point in negative directions..

..but, gee, if they don’t, it would be great to have!

I think this Physicists sums up the problems pretty clearly. Keep it real folks. Applied Science and Engineering only. It's a movie, and any"Physics" it contains should be taken with more than a pinch of salt.

Re:"Physics"

[rogoshen1]

Well, think of it like this.. with limiting factors such as the speed of light, or planck length, those tend to be rather concrete 'limits' to technology. So unless our understanding of those limits is 'wrong', it's not like they can just be removed by some handwaving and dilithium crystals.

Your comparison to electronics 50 years ago was purely a lack of understanding of materials science. To create a transistor there's nothing in the fundamental physical laws that preclude its construction, thus requiring a workaround to construct.

Re:"Physics"

[Anonymous Coward]

No, 50 years ago the primary limitations blocking cell phones were in the engineering, not so much in the theoretical physics.

You will have to reach back a few hundred years before cell phones were a theoretical impossibility.

Which means, unless you expect to live another several hundred years, there is no way you will see warp drive in your lifetime.

Re:"Physics"

[__aaltlg1547]

"I would imagine that the human understanding of physics 50 years ago would have forbid the creation of the kind of microelectronics/transmitters/battery technology that are commonplace in most of our pockets today."

There have been very few advancements in basic physics in the past 50 years that have made their way into products and most of the cutting edge stuff we have today was foreseen decades ago.

Re:"Physics"

[the gnat]

I'd even say there has been very little fundamentally new stuff for the last 100 years.

Depends on what area of technology, and what you consider "new" as opposed to a "technical refinement" or "manufacturing advance". Does the transistor count, or is that just an incremental improvement on vacuum tubes? The physics required to build, say, an iPhone were mostly understood by the 1920s, and I don't think there was any theoretical work suggesting that it was impossible. On the other hand, the concept of ubiquitous handheld multi-functional computing and communication devices connected by a global network containing nearly all human knowledge required levels of technology that couldn't even be guessed at.

If you consider the life sciences instead, our background knowledge is as far beyond 1920s biology as the iPhone is beyond the telegraph, and revolutionary discoveries and technical advances are still being made.

Re:"Physics"

[Dereck1701]

Few advancements? Dark mater/energy (assuming that it even exists) wasn't even theoretical 50 years ago, the presiding theories of the day said that the universe was slowing (current theories say it is accelerating), the Higgs Boson (still not proven) was just beginning to be theorized and I don't know if it qualifies as physics but it was assumed that the solar system was swept clean of asteroids millions of years ago, then Shoemaker-Levy Nine slammed into Jupiter, the resulting search eventually led to the discover of tens of thousands of asteroids and a number of "dwarf planet".

Re:"Physics"

[Kjella]

Of course the universe is impossible given our current understand of physics. Big bang created energy. Big bang created an imbalance between normal matter and anti-matter. Big bang created a singularity with zero entropy and it's been growing ever since. None of those things are possible with physics as we know it, yet it all apparently happened. The only thing we can be quite sure of is that we don't know everything.

Re:"Physics"

[Immerman]

Actually the whole point is that we have several theoretical constructs that should allow travel from A to B at speeds greater than lightspeed. All rely on the fact that special relativity only imposes a local speed limit: i.e. you can't travel faster than light *through space*. Nothing in it forbids the existence of short cuts (wormholes) that connect distant parts of the universe with drastically shorter paths. Nor does it forbid things like an Alcubierre warp drive, where you don't move at all through the space you're in, but instead move an isolated bubble of flat space through the surrounding space at arbitrary speeds, while leaving the contents of that bubble of space in free fall (Relativity imposes no speed limit on space itself.)

Both constructs have their weak spots, but so far every time someone comes up with something showing them to be "impossible" somoeone else comes up with a modified construct that removes the impossibility. And of course there's the little issue that if Special Relativity is correct then any method of getting between A and B faster than light can also be used to send information into your own past, which would wreak havoc with our understanding of causality. But then the whole "time passes in only one direction" thing is a serious weak spot in our current understanding of the universe as well, so it may be that it's only us that would have an objection to causality loops, and not the universe itself.

Where every construct falls flat on it's face is that we have absolutely no idea how to actually create such a thing - we're mathematically modeling the things we might be able to do if we had nuclear reactors while still living in the stone age. But then that's what our species does, we tell ourselves stories of things that have never existed, and then try to figure out how to make them exist. We did it when our ancestors imagined how useful a killing-stone with a long, light handle would be, and we do it today on a million different fronts. Only difference is today we do our imaginings with a level of mathematical precision that guarantees that, if our starting assumptions are true, then the thing we imagine can in principle be built, even if we don't know how to do so at present.

Re:"Physics"

[Immerman]

Wormholes and Alcubierre warp drives are both constructs within the framework of the currently-accepted physical theories - if our theories are correct, these things should be possible to build. They don't need any sort of new physics to enable their existence, we just don't have the foggiest idea how to actually build them. And that's hardly a criticism against their existence - we haven't the foggiest idea how to actually build a tree from raw elements either, but nobody questions their existence.

Of course we also know there are some fundamental contradictions within our current model of the universe, but there's no more reason to assume that filling in those gaps will render wormholes impossible than there is to assume that it will grant us the ability to ride moonbeams across the galaxy.

Re:"Physics"

[__aaltlg1547]

'Few advancements? Dark mater/energy (assuming that it even exists) wasn't even theoretical 50 years ago, the presiding theories of the day said that the universe was slowing (current theories say it is accelerating), the Higgs Boson (still not proven) was just beginning to be theorized'

and neither of those resulted in any technology at all. And you're wrong about dark matter. It was hypothesized 80 years ago to explain orbital velocities of stars in the galaxy and confirmed by more recent and precise measurements.

'and I don't know if it qualifies as physics but it was assumed that the solar system was swept clean of asteroids millions of years ago, then Shoemaker-Levy Nine slammed into Jupiter, the resulting search eventually led to the discover of tens of thousands of asteroids and a number of "dwarf planet".'

I know, and it doesn't qualify as basic physics that would alter our understanding of what is and isn't possible, nor is it possible to base any technology on those facts.

Everything science has discovered over the last 80 years has led to the same conclusion: faster than light travel is almost certainly impossible in practical terms. The only thing that holds out any hope at all is the fact that superluminal expansion seems to have happened in the first 10^-32 sec of the universe's existence. As far as we can know, it hasn't happened since.

Re:"Physics"

[CaptainLard]

50 years ago? The diode was invented in 1906, bro. Binary logic was well established by the 60's and Li-Ion batteries weren't far behind in the 70's. Most everything we're using today was floating around in some form in the 60's, just a hell of a lot bigger. Even the discovery of the Higgs was a minor disappointment to physicists because it turned out to behave almost exactly as predicted.

I agree there is a long long way to go but to say we're still pre-infantile is shitting on all the great achievements humanity has accomplished. They're close to confirming exomoons orbiting on exoplanets! We're at least toddlers standing up in our high chair, throwing spaghetti around, and reaching for the cookie jar. We can see a lot of whats around us but haven't put all the details together yet.

Re:"Physics"

[__aaltlg1547]

But we were talking about basic physics and what is or isn't possible. Take a starship to another star in a human lifetime? There is nothing we know or that is even seriously entertained by physicists that suggests this is possible.

Re:"Physics"

[dbIII]

One of the biggest hurdles had been solved by Heddy Lamar and some US Navy radio technicians in the 1940s - that's why we don't have one phone tower per ten people.

Re:"Physics"

[tehcyder]

But then the whole "time passes in only one direction" thing is a serious weak spot in our current understanding of the universe

I believe the conventional counter-argument is "if time travel were possible, why don't we have any time travelling visitors?"

Similar to the Fermi Paradox about alien life.

Re:"Physics"

[TheTurtlesMoves]

Wormholes and Alcubierre warp drives are both constructs within the framework of the currently-accepted physical theories

Err no they are not. First of all the all violate energy principals widely accepted to hold. Second they need *negative mass* that has *zero* theoretical underpinnings. That is, withing the currently accepted physical theories they are quite impossible. Then add the fact that the basic Alcubierre drive needs more energy than the visible universe and is causally disconnected from the rest of the universe....

We find maths that describes reality, not the other way round. A good example is how high will a ball go when thrown upwards at a given speed. One of the solutions can give a complex number. We just ignore it as physically impossible.

Just because the math has a solution in some abstract mathematical sense does not mean is represents anything to do with reality.

Re:"Physics"

[Immerman]

And as with the Fermi Paradox, there are so many, many plausible answers to that question that it's not really worth discussing except over cocktails.

Interstellar is a work of - get this - fiction

[Anonymous Coward]

Why is Scientific American even running such an article?

What's next? Supposedly-serious newspapers "fact-checking" a comedy sketch?

Re:Interstellar is a work of - get this - fiction

[Anonymous Coward]

It's an ad. There's a movie out, and you know how it is with the movie industry: They're starving.

Re:Interstellar is a work of - get this - fiction

[Anonymous Coward]

Why is Scientific American even running such an article?

What's next? Supposedly-serious newspapers "fact-checking" a comedy sketch?

Scientific American stopped being about Science at least 15 years ago. If you want to see how much it has gone downhill compare the scientific quality of the articles of the 1950/60/70/80s and those of the 90/00/10s. And weep in dispair.

s/Khardshians/Kardashian

[mmell]

s/Kardashian/Cardassian

FTFY.

gravity fields will rip you to shreds

[RichMan]

Tidal forces. This is the biggy, If you are in orbit deep in a gravity well with a steep gradient then the orbital velocities of things 1m up/down from each other are significantly different. The material stength of any object extending over that 1m has to resist that force.
Those forces will rip materials to shreds.

Think of your hands being pulled up, while your feet are pulled down. The further into the gravity well you get the more up and the more down the two pulls get.

The only way to avoid the tidal forces are a straight in drop. But you can't do that as all around the well is a swirling gas field that will push you into an orbit.

Re:gravity fields will rip you to shreds

[Anonymous Coward]

"Shreds?" The correct term, which was developed by Italian physicists but what it describes is actually of ancient Chinese origin, is 'spaghetti;' i.e. If you get anywhere within proximity of a Black Hole, you and your crew and craft will become spaghetti.

Re:gravity fields will rip you to shreds

[angel'o'sphere]

Of you go straight to the center of a gravitational body, you still have the problem that the force closer thr the center is higher than at the opposite site. I have no idea where you got your wrecked idea about phisics from, and what exactly is a 'gas field' that is pishing you outwards? And atmosphere that is 'breaking' your decent?

Re:gravity fields will rip you to shreds

[sconeu]

Gargantua was a Kerr object. I seem to recall [DISCLAIMER: I may be wrong] that in that case the event horizon is stretched into a disk, and if you approach it perpendicular to the disk, it's possible to survive the tidal forces.

Re:gravity fields will rip you to shreds

[ChromaticDragon]

My intepretation of their comment is that you point directly towards the center of mass and then ACCELERATE (not "drop") "down". Then there is the two-fold assumption that #1 there is an accretion disk and #2 for some odd reason you've decided to go through it. The idea is that it would be rather difficult to maintain your orientation with the accretion disk material pressing against you laterally (not "outwards"... but "sideways" - the gas is orbiting and you're trying not to).

First, I'm curious about the math here. The "intuition" here seems to be that you can push down on your head hard enough so that force downwards on your head matches the mass pulling on your feet and therefore you don't get ripped apart. Even if this works, wouldn't you have to have constantly increasing acceleration/thrust to maintain this balance?

Second, if you've decided to plow through an accretion disk, I'd be more worried about burning up. In any case, if you've got the ability/power to maintain infinitely increasing thrust downwards, I imagine a bit of control laterally would be trivial.

Re:gravity fields will rip you to shreds

[Jamu]

The exact term is spaghettification.

Re:gravity fields will rip you to shreds

[Immerman]

> Even if this works, ...
Absolutely. As you travel deeper into a gravity well the difference between the acceleration of your head and feet is increasing super-linearly - gravity falls off with 1/r^2 after all, and the difference would be:

difference in acceleration (using h as height and r as your average distance for the center of the gravity well)
= 1/(r-h/2) - 1/(r+h/2)
= [(r+h/2) - (r-h/2)] / (r-h/2)(r+h/2)
= h/(r^2 + h^2/4)
~= h/r^2 -- since h will be a negligible component of the denominator

So anyway, yes, to avoid being pulled apart you will have to accelerate at an ever greater speed as you plunge headfirst into an intense gravity well. And it doesn't actually improve things much: where before your head was being ripped off as it accelerated 100g's faster than your feet, now your feet are being crushed into pulp as they try to transfer 100g's of acceleration to your legs.

You wouldn't need infinite acceleration though, just enough to carry you to the event horizon, at which point in a black hole physics as we know it can no longer connect your head and feet and all bets are off. Or, in the case of a classic SF wormhole, once you reach the edge of the "tube" at the center things probably stabilize and you're good to go, and you still haven't reached zero radius or infinite acceleration.

So, depending on the size of the "boundary sphere" at the center, and the tricks you play to minimize your acceleration delta, it just might be possible to reach it alive.

Re:gravity fields will rip you to shreds

[Trogre]

The movie explained that away by making it a supermassive black hole, where tidal forces are (supposedly!) much less.

Re:gravity fields will rip you to shreds

[Jimbob The Mighty]

So why travel feet-first or head-first? If you enter it facing it then you have front-back, which is a much smaller difference than head-feet.

Re:gravity fields will rip you to shreds

[RivenAleem]

This can be easily observed by anyone with a water faucet. A small trickle of water can bee seen to draw into a thinner strand and eventually break into droplets as the leading flow accelerates towards the earth.

Re:gravity fields will rip you to shreds

[angel'o'sphere]

I talked more about the mass/force ideas of our parents :)
They should have mentioned in the movie that it was a 'Kerr' object. However Kerr only implies the black hole is not charged, it does not really imply a flat disk like event horizon.

The event horizon is not that interesting anyway ... the gravitational forces there are not necessarily a problem ... you just can not get out anymore.

There are other black hole types, like electric charged ones, or combination of magnetic active and electric charged ones, where there are mathematical pathways with zero forces to the center. I assume you should also be able to get out of it bia such a path. Reissner and Nordstroem worked on that ...

Here is a simple link with further links: http://en.wikipedia.org/wiki/R...

"Physics"

[Dereck1701]

"physics very probably forbid warp drives and traversable wormholes."

I would imagine that the human understanding of physics 50 years ago would have forbid the creation of the kind of microelectronics/transmitters/battery technology that are commonplace in most of our pockets today. Admittedly the physics of FTL (or any interstellar travel method) are far more difficult than what we have done in the electronics field over the past few decades, but believing that our pre infantile understanding of the universe makes us in any way knowledgeable of what is and is not possible is hubris of the highest degree.

Confession - I didn't like Interstellar

[GreatDrok]

I can't be alone in not liking this film. It wasn't the science (there was obviously a lot of work done there) that bothered me, and besides which with Sci Fi you always get a 'gimme' or two (warp drive, transporters, technobabble etc) but I really didn't feel anything with the story. It didn't draw me in, it just dragged. This wasn't what I was expecting as I had been looking forward to this film since I saw the first teaser. I see so many people going on about who great this film was but I can't help but wonder what it was that I missed?

Re:Confession - I didn't like Interstellar

[microcars]

I see so many people going on about who great this film was but I can't help but wonder what it was that I missed?

The film is about Love. Everything else is window dressing.

If you try and make the film to be about something else, you will be disappointed.

Re:Confession - I didn't like Interstellar

[brxndxn]

I loved this movie.. It wasn't perfect - but no science-based sci-fi movie is. It's up to us to figure out how to make the impossible possible. No one needs another engineer or scientist telling us what we cannot do. We need more people like Elon Musk saying what we can do - and going out and proving it. The laws of physics are there to be broken. Defy them. Prove them wrong. Einstein broke Newton's laws.. Someone needs to break Einstein's laws.

I'll take Interstellar over any one of the normal Hollywood we get fed to us.. (ie.. XMen, Random war movies, save-the-world CIA shit). So please tell me you think this movie was at least better than the typical Hollywood movie.

If engineers and scientists tended to be optimistic rather than pessimistic, engineers and scientists would be running the world. Obama didn't get elected by telling us what mankind cannot do.

Re:Confession - I didn't like Interstellar

[Feral Nerd]

I can't be alone in not liking this film. It wasn't the science (there was obviously a lot of work done there) that bothered me, and besides which with Sci Fi you always get a 'gimme' or two (warp drive, transporters, technobabble etc) but I really didn't feel anything with the story. It didn't draw me in, it just dragged. This wasn't what I was expecting as I had been looking forward to this film since I saw the first teaser. I see so many people going on about who great this film was but I can't help but wonder what it was that I missed?

The first thing (of many) in that movie that I didn't get was why do they choose to land on (IIRC) a super-earth that orbits a black hole and where the time dilation is so severe that a hour long visit translates into, what was it? 8 earth years? ... when they have two other promising prospects to check out that are approximately earth sized, time dilation free and not orbiting a black hole? Plus you'd think that scientists would be able to predict those massive tides. And having said that I'm for the moment willing to overlook the fact that to get that kind of time dilation you have to be practically skimming the surface/event-horizon of the black hole (poetic license, need to create drama, yada, yada, yada....). I would have skipped that first planet and gone for the other two (which they had the fuel to do) and then possibly, if I had enough fuel left, to whatever planet was option number four but that got dropped off their list.

Re:Confession - I didn't like Interstellar

[ElitistWhiner]

The movie is about " What if it were the case that we really don't know what is true?".

At the end of the movie, it boils down to the power of human's capacity to imagine, believe and transcend man's madeup limitations. The subtext of the movie uses the twin human weaknesses of Abandonment and Engulfment to demonstrate what we know to be true is what we " feel is true".

Identity is otherside of Engulfment. The movie narrative struggles substituting enmeshment / engulfment as though they were equivalents. The setup juxtaposes two instances to demonstrate that man's Identity ( what he feels) is more important than saving humanity.

In the earthbound instance the professor's enmeshment with humanity requires that he will take to his grave the secret that it is doomed, except there's a twist - with his last dying breath he reveals he knew the grand hoax of his scientific evidence to the contrary upon which the hopes of the planet were placed in the recolonization mission. His Identity ( id) released by his imminent death, he inflicts pain and suffering to relieve dying with a guilty conscience. His last breaths are an act in saving his Identity as the Professor.

In the interstellar instance the marooned astronaut survived an illusion of engulfment in wrapping his life into the pursuit of a mission he is told cannot succeed. A virtual outlier and existential outsider faced with perpetrating the Professor's grand hoax or pertetuating his own life, his (id) rises to the occasion voting to save man, himself, his Identity over humanity.

In neither instance does the truth save you nor does what they feel.

Except the other side of Abandonment is Love or Hollywood Happy Endings...to wit: Interstellar where Love (what we feel) conquers all.

Re:Confession - I didn't like Interstellar

[TropicalCoder]

I didn't like it either. It left me flat, like I had wasted my time watching it. It somehow reminded me of Contact, and after reading the comments, I now understand there was some cross-fertilization from people involved in that. I didn't like the way Contact turned out either. Been a SciFi fan all my life. We had two great topics with these films - first contact, and time travel. I have read many great stories that employed these themes, but the movies had to turn them into some kind of supernatural, quasi-religious experience - something like Ghost, I suppose. I was very disappointed in these movies.

Re:Confession - I didn't like Interstellar

[TheTurtlesMoves]

I got a better plan. Build green houses with lights. Much easier than moving humanity around. Seriously sci fi misses the most obvious stuff.

Bootstrapping and time travel

[Frans Faase]

Spoiler alert for the movie Interstellar

It seems he did not get the main idea of the movie. The whole movie rests on the idea that it is possible to manipulate gravity in the past. The traversable wormhole was created by some humans in the far future and allowed the main character to communicate with the past, causing himself to join a space program, which would lead him to the place to communicate with the past, and by this save human kind from some disaster and in the far future allow to develop the technology to create the wormhole and a black hole with strange properties. So, it also involves a form of bootstrapping. Which makes even less sense, if indead traversable wormholes could be made at all.

Re:Bootstrapping and time travel

[Anonymous Coward]

Yeah. In philosophical circles the term is "reverse causality." It means that something you do today causes something to have happened several days ago.

Though our mathematical models of subatomic particles suggest that something like this can happen, there hasn't been any demonstration that such a visualization of microscopic behavior can result in the logical equivalent in macroscopic scales (meaning, even if electrons seem to do this, humans still can't and never will).

Few things excite me as much as the prospect of having a belief this foundational be completely overturned by solid evidence. However, that is no excuse for confusing fantasy with reality. Until the solid evidence is produced, I will insist that reverse causality is not only impossible, but nonsensical as well.

Re:Bootstrapping and time travel

[jonnythan]

Dr. Thorne was the primary scientific consultant on the movie. For this article he's stepping away from the movie and talking about how possible or plausible some of the ideas presented in it actually are.

Re:Bootstrapping and time travel

[Immerman]

Well, as the saying goes: "Special Relativity, FTL, and causality: pick any two". If SR is correct then any ability to transfer information between two points faster than light automatically implies the ability to send information into your own past. And honestly, as weak as our theory is as to why we *can't* send information back in time, I think causality is a little shaky.

So, at least in the context of an science geek watching science fiction: if you're suspending your disbelief to allow FTL travel, you get time travel as a free bonus.

Re:Bootstrapping and time travel

[painandgreed]

Well, as the saying goes: "Special Relativity, FTL, and causality: pick any two". If SR is correct then any ability to transfer information between two points faster than light automatically implies the ability to send information into your own past. And honestly, as weak as our theory is as to why we *can't* send information back in time, I think causality is a little shaky.

So, at least in the context of an science geek watching science fiction: if you're suspending your disbelief to allow FTL travel, you get time travel as a free bonus.

Well, we can get rid of special relativity right off the bat because that only works in Minkoski space and we don't live there. We can approximate it really well, but things get weird just as Newtonian physics broke down in certain situations. If we're talking about wormholes or warp drives, we are not in Minkoski space by definition. To figure out stuff by General Relativity, you'll need to know the topology of the space you are in and crunch the math. If something goes outside of normal space, then all rules are off because that space, in fiction, can have whatever rules we want it to, so FTL travel via hyperspace is certainly possible according to whatever transform you want to use. As for causality, Tippler showed that physics doesn't care about that in 1974 as far as general relativity is concerned.

Re:Bootstrapping and time travel

[Immerman]

Sure, all bets are off if we discover hyperspace or some such. As for Minowski space - I'll admit my higher mathematics is rusty, and Wikipedia's explanataion wasn't immediately slear as to the defining qualities beyond four-dimensionality. But as I understand it all the "realistic" warp drive theories though posit only normal GR spacetime folded in improbable ways. And as I understand it, while wormholes must by necessity traverse some sort of "superspace" between points in our universe, anything passing through them will simply traverse a tube of "normal" spacetime with certain fairly well-defined limits on its properties.

Re:Bootstrapping and time travel

[painandgreed]

Well sure. In a lot of these things, like Tippler's time machine, space gets folded in improbably ways, but as Frank Lloyd Wright said when asked how his mile high tower he designed would be built, 'That's a problem for the engineers'. A lot of it requires either exotic materials or structures that might simply not be able to be constructed, but technically, they don't violate the known laws of physics. So they're all based on exploratory physics like string theory, loop quantum gravity, or MOND. Neat ideas that might work and the math is at least partially there, but can't be tested or figured out exactly.

Travel through a wormhole would be through normal space time although highly curved, but things get weird when such things happen. A thought experiment with a black hole and various lightlike paths around it can easily come up with two light like paths that have different distances between the same points. Hell, it's basically happening in every case of gravitational lensing. People mistake things like wormholes as being FTL when they are not really as the path taken through the hole is not FTL, but may be seen as such by observers that can't see the wormhole, although the actual relationship is determined by the properties of the wormhole. This can be taken in extreme with teleportation. If it's possible to teleport between point A and point C, then they must be connected somehow, either either through something like a wormhole, hyperspace, or a transform of some type or every point would be equal to every other point. The typical FTL travel is time travel doesn't hold for such cases because while it might be if it was FTL through Minkowski space using the Lorentz Transform, the actual relationship and qualities of such travel are determined by the qualities of that space or transform that is actually transversed, not of the flat space time between the two points made by a separate observer.

Re:Bootstrapping and time travel

[Immerman]

Sure, you can always find a longer path. Even without a black hole you could send a beam of light on a long circuitous journey through multiple gravitational lenses to eventually end up back across the room from you. But there's always at least one well-defined minimum distance path through normal-geometry space. Wormholes seem to fundamentally break that by creating an anomalous path through spacetime. And in fact the mathematics suggest such a structure could as easily connect two different points in time as in space, and I recall an example a decade or two ago where someone had worked out a wormhole geometry such that you could fly through it, then return through normal space with plenty of time to stop yourself from entering it in the first place. That's one of the big reasons many physicists believe that they're not actually possible - they inherently wreak havoc on all sorts of our fundamental assumptions about the universe.

And I don't believe "FTL is time travel reasoning" cares how you get from A to B: if you can get a signal from A to B faster than you could through normal-geometry space, then you can use that ability to send a signal into your own past. Doesn't matter if you're harnessing worm holes, warp drives, or fairy dust. Took me a long time studying the diagrams to really accept that, and I still can't explain it well, but that's the theory.

Re:Bootstrapping and time travel

[painandgreed]

That's one of the big reasons many physicists believe that they're not actually possible - they inherently wreak havoc on all sorts of our fundamental assumptions about the universe.

Well, if they're really physicists and not just playing philosophers, they'll show us the math.

Re:Bootstrapping and time travel

[Immerman]

They have. Just because most of us didn't understand it doesn't mean it wasn't solidly reasoned. After all physicists are under no obligation to dumb down their findings far enough that we can all understand them - in fact in many cases they *can't*: in order to dumb it down sufficiently they would have to introduce so many inaccuracies that it would become a lie.

Just to be clear though - the problem is not that they have any evidence that it's not possible - it's just that if it *is* possible, much of what we think we know starts breaking down in the corner-cases. Starting with sequential causality - something which we don't actually have any solid evidence of existing in the first place, but certainly *seems* to be the case.

Re:Wtf

[Noah Haders]

its that other movie playing when you go see hunger games

Magic Powers and Interstellar

[Yergle143]

The Newtonian Physics was far more compelling than the Einsteinian Physics in that film. For example the space station link up scene and of course the part where Matt Damon punches Matthew McConaughey in the face. I only wish they could have had it that Matt Damon was punching Matthew McConaugheyin the face near the Event Horizon so it could last forever to an outside observer.

Re:Sounds like the modem problem ...

[Anonymous Coward]

I think you fail to comprehend quite a bit about modems.

Re:Sounds like the modem problem ...

[jonnythan]

I don't believe I've ever seen a modem break 56 Kbps over a phone line.

Hay Professor Kip

[LifesABeach]

So just because you can't figure it out, the rest of humanity should wait? On you?

Re:Sounds like the modem problem ...

[sconeu]

Apples and Oranges.

That's not a modem. That's completely different technology from a modem.

A modem converts binary to analog acoustical data. Based on the infrastructure of the telephone systems, 56K (actually 53K or so, if I remember correctly) was the limit.

What you have is a pure digital connection, on an infrastructure designed to carry pure digital data.

Re:Sounds like the modem problem ...

[CaptainDork]

DSL?

Re:Sounds like the modem problem ...

[CaptainDork]

Too better explain: We were trapped in a dial-up technology with no foreseeable options.

Re:Sounds like the modem problem ...

[jonnythan]

DSL uses a different technology. It piggybacks a different signal on preexisting wiring, but has totally different hardware at each end.

You will not go to wormhole today.

[Tenebrousedge]

This kind of comment is deeply ignorant and anti-science. Relativity is a description of the geometry of the universe. If you would rather believe in your own personal fantasies instead of one of the most well-supported theories in science, congratulations, you are yet another variety of religious loon.

Look, it's pretty simple. Science is not magic, and there is shit that it says that is for real-real not for play-play. We don't know what the future will look like in 2050 or 2100, but we can be completely sure of three things:

1) There will be no violation of the Laws of Thermodynamics.
2) Nothing (for all important values of nothing) will travel faster than the speed of light.
3) Commercial fusion power will still be 20 years out.

The first two are immutable laws of physics, the final one was proven by a Dr. M. T. Budget. Humor aside, relativity and thermodynamics have been proven at both the largest and smallest scales that humans have been able to observe, and at every level in between. They are not perfect theories, but they do place very hard and very real constraints on what kind of rabbits you can pull out of a given hat. You will not go to intergalactic space today, nor tomorrow, nor while anything recognizable as human exists.

Re:You will not go to wormhole today.

[Baloroth]

Humor aside, relativity and thermodynamics have been proven at both the largest and smallest scales that humans have been able to observe, and at every level in between.

This is half completely wrong. Thermodynamics by definition does not apply to small scales, only to bulk systems. Hell, a small system of particles can (and in fact quite often will) easily violate the laws of thermodynamics. They're almost meaningless at small (i.e. a few dozen atoms) scales, because they're purely statistical laws. Even a large system can, in principle, violate the laws of thermodynamics, but only for extremely brief periods of time, and with a likelihood that approaches zero for macroscopic (order of 10^23 particles) systems.

Secondly, the behavior of relativity at very small scales is currently unknown. Reconciling general relativity with quantum mechanics requires quantized gravity, and all current attempts to describe that mathematically have failed. This is a problem in either very small scales (i.e. Planck lengths, which to be fair haven't been observed and probably won't for quite some time), or in extremely large gravitational fields, such as that created by black holes, which we have (indirectly) observed. Both relativity and thermodynamics work great in their relative domains, but both of them have known domains where they collapse. For thermodynamics that doesn't really matter (it's constructed to only be true for bulk systems), but it's a pretty big issue for relativity, and suggests there is a significant gap in our knowledge.

Re:You will not go to wormhole today.

[Tenebrousedge]

No, I was not wrong, I am well aware that certain effects propagate faster than the speed of light. Note that gravity waves have not been directly observed. There are other quantum effects which propagate faster than c, but the fundamental constraint is that nothing can accelerate to or past c, and classical information cannot propagate faster than c. There are solutions to GR equations which allow for spacetime to be bent to the point where something that *looks* like FTL to fall out, but they tend to require exotic matter, and there's no evidence to suggest that said matter exists.

Finally, one must keep in mind that any form of FTL allows for reference frames in which effects precede their causes. You may feel happy living in a universe where causality isn't a thing, but that to me would put unpleasant limits on what is knowable about our universe.

Re:You will not go to wormhole today.

[Tenebrousedge]

When you can drive a starship through the holes in either theory, get back to me. I don't think we're actually in disagreement; I realize I was speaking imprecisely. I hope that you can forgive me a little hyperbole, and I will totally pick you to double-check my physics papers in the future.

Re:You will not go to wormhole today.

[Will.Woodhull]

The truly scientific mind recognizes that even things like the laws of thermodynamics are merely mental models that do not necessarily reflect objective reality, but do seem close enough to true to be incredibly useful ways of looking at the problems we face today. For one thing, there is no objective reality. The most anyone can do with the scientific method is make better models of some parts of the human experience.

Other parts that science cannot handle includes the capacity to imagine, as used by artists of all types, including those involved in making the Interstellar movie. This kind of imagination obviously exists in the universe, and definitely has an influence on other parts of the universe. If that were not so, the toaster in your kitchen would be nothing more than a bunch of ores embedded in rocks somewhere. So imagination is a dominate force in humankind's world, but is totally outside the kinds of things that the scientific method can deal with. Thus I refute parent post's logic.

I do agree that science is not magic. Whatever magic is, even if it is "only" imaginary, it is not bounded by the "laws" of thermodynamics or any other limitation of science. Yet magic sometimes has a very powerful effect on us, and on the things around us. It is not science that has mainly shaped our lives. It is instead magical things like the rule of law, systems of ethics and morals, and myths like Star Trek, Avatar, Lord of the Rings, Star Wars, and other fantasies. These are what people live by; these are the things that shape our lives. They are not scientific and have nothing to do with the materials that science works with.

Science has its place. It can assist in realizing the magic, by providing guidelines for the engineers who actually make things happen. That is science's primary role: to be handmaiden to the engineers.

Re:You will not go to wormhole today.

[blue trane]

"Science is not magic"

Remember Clarke's three laws?

1. When a distinguished but elderly scientist states that ... something is impossible, he is very probably wrong.

2. The only way of discovering the limits of the possible is to venture a little way past them into the impossible.

3. Any sufficiently advanced technology is indistinguishable from magic.

Re:You will not go to wormhole today.

[ljw1004]

Relativity is a description of the geometry of the universe. If you would rather believe in your own personal fantasies instead of one of the most well-supported theories in science, congratulations, you are yet another variety of religious loon.

There are lots of spacetimes that satisfy general relativity and are still pretty goofy. Malament-Hogarth spacetimes, for instance, are ones where you can jump into someone's infinite future. (or more precisely: they're ones with two paths through spacetime, one of which has an infinite duration, the other a finite duration, so if you travel down the "finite" one and your friend travels down the "infinite" one then you'll still be arrive while he's been dead for an eternity).

Re:You will not go to wormhole today.

[Anonymous Coward]

Thermodynamics doesn't apply at large scales. Relativity doesn't necessarily conserve energy, for example; where does the energy from red-shifted photons go?

Well that's just wrong. Red-shifting is a matter of frame of reference, it's not a process which the photon undergoes. From the source of the photon's frame of reference, the photon is not red-shifted. In every inertial frame of reference the total energy of the system stays the same over time.

How does emergence of dark energy violate the laws of thermodynamics? Thermodynamics is statistical, so I suppose in principle it is possible for a spontaneous decrease in the entropy of a bulk system to occur, although the probability of that occurring will be negligible in anything greater than microscopic scales. Thermodynamics certainly applies to more than steam engines.

Re:You will not go to wormhole today.

[Will.Woodhull]

I sometimes make exceptions and respond to AC posts. This is an instance. Since I am procrastinating on some other thing.

Objective reality is in the mind of the beholder. And nowhere else.

I could offer a book list for you to read up about this, but I won't, because it would be very long and I doubt very much that you would bother to do the work. Since it would only deprive you of the comfort of your 19th century world view.

Instead I would suggest that you google on the difference between science and philosophy, and on the limitations of the scientific method. But I doubt that many with your point of view will do that either. That's okay: for every great thinker, we also need a multitude of lab techs, code monkeys, and admin assistants who can have perfectly comfortable lives using a pre-twentieth century mental framework.

BTW, whatever an imagined thing is, it is as independent of the instrument that produced it as the sound of music is independent of the chorus that is singing it. Learning something about the underlying physiology will be interesting, but at most that will be like learning how a violin is put together, and will say nothing at all about how the fiddle is played (or the music produced).

Re:You will not go to wormhole today.

[tlambert]

Well, you're wrong with #2

Gravity waves travel faster than light, quantum mechanics/physics have things happening faster than light (ie, something affects particle A, it's clone, particle B, far away, is also affected). I may not have the terminology right, so don't jump on that.

Gravity waves are something some string theorists would like to observe so their pet theories don't get flushed down the toilet, but which have yet to actually be observed, despite the building of expensive observatories to try and find them. When someone disproves Lorentz covariance with an actual experiment, we can perhaps talk.

The only experimental setup that would seem to work would be a tetrahedral mass array with laser interferometry between the masses out in space somewhere (i.e. instruments like LIGO are not sufficient), and then slingshot a projectile mass to accelerate it to a significant fraction of the speed of light (e.g. 0.1C) and aim it through the tetrahedron on a non-face-normal trajectory at a rough offset. This would have the net effect of having the mass apparently "be not there"/"appear"/"disappear again" from the point of view of the instrument, thus establishing, once and for all, the propagation rate of gravitation. If it's actually an artifact of a curvature of space time rather than something with a particulate carrier, the "instantaneous" appearance and disappearance of the mass will be seen by the detector symmetrically, otherwise not.

It would cost quite a bundle to run the experiment, just to make some string theorists and other non-relativistic model believers very happy (or very unhappy). Then they can all go looking for their Goldstone bosons and loop quantum gravity and privileged local inertial frames.

Re:You will not go to wormhole today.

[Anonymous Coward]

This kind of comment is deeply ignorant and anti-science. RelativWe have started using the properties of the EM spectrum for the bity is a description of the geometry of the universe. If you would rather believe in your own personal fantasies instead of one of the most well-supported theories in science, congratulations, you are yet another variety of religious loon.

Look, it's pretty simple. Science is not magic, and there is shit that it says that is for real-real not for play-play. We don't know what the future will look like in 2050 or 2100, but we can be completely sure of three things:

1) There will be no violation of the Laws of Thermodynamics.
2) Nothing (for all important values of nothing) will travel faster than the speed of light.
3) Commercial fusion power will still be 20 years out.

The first two are immutable laws of physics, the final one was proven by a Dr. M. T. Budget. Humor aside, relativity and thermodynamics have been proven at both the largest and smallest scales that humans have been able to observe, and at every level in between. They are not perfect theories, but they do place very hard and very real constraints on what kind of rabbits you can pull out of a given hat. You will not go to intergalactic space today, nor tomorrow, nor while anything recognizable as human exists.

Today's technology would look like magic for anyone living 300+ years ago. Most of the physics describing the universe today are theories and postulations supported by mathematical models that are theoretical in nature themselves. That is not the stablest platform from which to categorically rule out what is possible and what is not possible. The entirety of human existence is tiny and insignificant when compared to the age of the universe surrounding us. Human existence is tiny and just as insignificant when compared to the age of the planet we live on. It's a little early to start making definitive statements on what is possible and what is not impossible.

Re:You will not go to wormhole today.

[TropicalCoder]

"Gravity waves travel faster than light." Interesting - hadn't heard of that. If they do, it must be by cheating - warping SpaceTime, to do it. As far as entangled particles communicating with each other faster than the speed of light goes, we cannot take advantage of that phenomenon, so we are safe from violating Causality.

Re:You will not go to wormhole today.

[joe_frisch]

Depends on what you mean by "small scales". Relativity works to the length scales accessible by accelerators (1 TeV, or something like 1e-18M - and probably extrapolated a lot further). There are issues with quantum gravity but they only become significant at energy scales approaching plank energy - far beyond any conceivable technology. There are also possible issues with relativity at cosmological scales.

The problem is that relativity seems completely under all technologically reachable conditions. Star drives just don't seem possible.

We *could* be missing something, but it is very difficult to imagine a set of rules that allow FTL or other fun stuff, but which would not have been noticed in present day measurements that range for accelerator scales to cosmological scales.

Re:You will not go to wormhole today.

[ardor]

> There are solutions to GR equations which allow for spacetime to be bent to the point where something that *looks* like FTL to fall out, but they tend to require exotic matter, and there's no evidence to suggest that said matter exists.

This is the big one. Alcubierre's metric has been heavily optimized over time to require energy amounts that could be feasible one day, but the exotic matter bit is the second problem. We can only hope that (a) exotic matter exists (b) an alternate solution can be found (perhaps something based on dark energy once it is understood).

As for the frame of reference, perhaps this isn't such a big deal. If for example the many worlds interpretation is valid, and a causality violation leads to some sort of breakdown of a universe, then you simply would never notice them, since the universes where the violation did happen just cease to exist. So, if a spaceship FTL-flies from A to B, B is a planet in movement relative to A, and the ship FTL-flies back to A, perhaps in the "surviving" universes it flies to A slower for example.

It's all hypothetical of course, but it shows that the causality problem could be circumvented.

Then again, we shouldn't be talking about FTL if we don't event have (relatively) cheap and commercial mass transportation to LEO and beyond yet. The sun won't increase its luminosity to lethal levels for the next 700 million years or so, so we have time.

Re:You will not go to wormhole today.

[gordo3000]

gravitational waves are NOT a prediction of string theory. they are a prediction of General Relativity. The question (kind of) remains whether it is just a mathematical fluke or real, but there is circumstantial evidence they are not just mathematical weirdness.

Re:You will not go to wormhole today.

[nine-times]

Relativity is a description of the geometry of the universe. If you would rather believe in your own personal fantasies instead of one of the most well-supported theories in science, congratulations, you are yet another variety of religious loon.

I don't quite agree. There's a mistake in your viewpoint, I think, which is to assume that the progress of science consist in the development of a final theory which bears no modification, and then people disproving that theory because it's wrong, and using evidence to develop the correct theory which also bears no modification, and then you're done. Like, well... we've developed relativity, and that's working really well, so there's nothing else to do there.

It's a very common idea, but it's not quite how things have traditionally worked. People talk about "the theory of evolution" and "the theory of relativity", but in reality there are a lot of sub-theories which continue to develop. We know that somehow life forms evolve and change, and Darwin had a theory about exactly how that happened, and there have been many additions and modifications since that time. We now have a set of currently accepted theories about how various mechanisms in evolution work, and many of those may well be shown to be false, and many more may need modification. But more than that, sometimes there are other ways of looking at things which result in subtly different theories, which are neither quite "true" or "false", but just different ways of looking at things. You can look at a person as an individual organism, or you can look at it as a colony of cells, or you can look at it as a component of a "pack" or a "gene pool". These are all modifications and sub-theories of "evolution". And this is why I object when people argue with creationists by claiming that "the theory of evolution has been proven to be true, and there's no more arguing to be done." No, that's not quite right. We can say with a very high level of certainty that life began as simple forms a very long time ago and evolved to provide the diversity and complexity that we see today, but the exact path and timing is still disputable, and the theory for exactly how that happened is constantly being revised. The exact scientific "theory of evolution" is not set in stone, but the overall concept of evolution is undoubtedly true.

Now that may seem like a tangent, and I'm sorry for that, but I found it easier to describe the idea using evolution rather than physics. It's important, though, since the theory of General Relativity is similar. When Newton developed his theories about the motion of celestial bodies, people saw how clearly this lined up with what we see, and said, "Yes, this is obviously true. No doubting it." And essentially, Newton was right. Unless you have read prior writings on the subject, it might be difficult to understand just how groundbreaking his ideas were, but now we take his physics for granted because they're so fundamental to our current understanding of the world. However, in the time since his work, we've found that his model of the universe doesn't quite work. Einstein seized on one of the ways that it doesn't work, and he made some major changes in the way we view space and time. Those changes, again, made us say, "Yes, this is obviously true. No doubting it." because of how clearly they lined up with the discrepancies with Newton's theories, but ultimately the discrepancies are so mild that we rarely calculate things using Einstein's work. It overturned our Newtonian theory about how and why things work the way that they do, but it didn't quite overturn Newton's work. Most of Newtonian physics still work under most of the circumstances we encounter, and we only bother with relativity when dealing with specialized circumstances.

And so the same might happen with Einstein's work. Someone might pick apart some discrepancy and provide a different explanation for time and space in a way that allows Newton's and Einstein's

Re:You will not go to wormhole today.

[ardor]

To be exact, a scientific theory is not just an idea, it is a rigid and solid mathematical framework that has been demonstrated to hold up scrutiny.

Re:You will not go to wormhole today.

[TheTurtlesMoves]

Gravity waves travel at the speed of light. Not faster. Quantum entanglement does not affect anything. It is a mathematical construct to derive the outcomes of measurements. It has been proven many many times that no information or anything else for that matter is "transmitted", let alone faster than light.

Re:You will not go to wormhole today.

[TheTurtlesMoves]

Thermodynamics doesn't apply at large scales. Relativity doesn't necessarily conserve energy, for example; where does the energy from red-shifted photons go?

That is a fairly easy undergrad problem. It is very easy to show thermodynamics, conversation of energy, conservation of momentum and everything else is *not* violated in *all* frames of reference.

Re:You will not go to wormhole today.

[david_thornley]

Your example (that causality violations can't occur) violates Special Relativity in a big way, by saying that certain things can't happen in certain reference frames. Special Relativity is a simple theory that makes a lot of sense and has oodles of evidence, so I'm not really keen on throwing it out, even in speculation.

Re:You will not go to wormhole today.

[cwsumner]

Ya'll are probably right.

But all this does remind me of the arguments back in the 1800's about "heavier than air" flying machines not being possible.

Or the arguments in the early 1900's about distribution of Electric Power being impossible.
I've been through the math on that one, and the calculations are correct !!?!
Of course the framing of the problem was a little "off"... 8-)

Re:You will not go to wormhole today.

[ardor]

No, they *can* happen, but when they happen, the universes cease to exist. The many worlds interpretation then implies that only those universes where these things *didn't* happen survive. It's not about forbidding certain events, its about how precisely these events prune universes.

Re:You will not go to wormhole today.

[david_thornley]

No, because what it comes down to is that we can observe some FTL travel and not some other equivalent FTL travel. There's no practical difference between "it's impossible" and "it's possible, but all such universes vanish".

Re:You will not go to wormhole today.

[ardor]

No, we can observe this other FTL travel as well, but *then*, the universe in which it is observed ends. "It is impossible to observe", on the other hand, would mean that it cannot happen in *any* universe. From the point of view of our universe, you are right, it does appear as if some types of FTL travel are disallowed. But this is solved by allowing them to happen in general, and just the ones where it didn't happen "survive". So, these other types of FTL travel only appear to be disallowed, they aren't really disallowed.

Another example would be a spontaneous transition to a lower quantum vacuum state. It is highly unlikely, but could happen. With the many worlds interpretation, it spontaneusly happens in some universes, which then end, or at least we aren't around to observe it. In others, it doesn't happen, and we are still around to observe these universes.

Re:You will not go to wormhole today.

[david_thornley]

No, we can't have observed all FTL travel. This means that, having done various sorts of FTL travel, we can look over our records and find that we have been able to do some and not do some, so we wind up with a preferred frame of reference, violating Special Relativity.

Also, how are you applying the many worlds theory? Aside from the fact that it's not universally accepted, and the fact that I don't have a clue how to falsify it, it applies to phenomena that could go more than one way. When I measure the spin on an electron, there are two possible values. The many worlds theory says that there are now twice as many universes, half with spin one way and half with spin the other way. Are you claiming that, when I drop a banana, there are universes where it falls and universes where it doesn't?

What we're dealing with is FTL travel, which is macroscopic and effectively determinate. If we use it for time travel, and deliberately violate one-way causality, there won't be universes in which we observe a causality paradox and universes in which we don't. Either no universes will see a paradox or all will, so by your reasoning we could bring the universe to an end.

Re:You will not go to wormhole today.

[ardor]

> Also, how are you applying the many worlds theory? Aside from the fact that it's not universally accepted, and the fact that I don't have a clue how to falsify it, it applies to phenomena that could go more than one way. When I measure the spin on an electron, there are two possible values. The many worlds theory says that there are now twice as many universes, half with spin one way and half with spin the other way. Are you claiming that, when I drop a banana, there are universes where it falls and universes where it doesn't?

This is correct. Note that Many Worlds is not a theory, but a QM interpretation. But you correctly described how it would be applied. What can happen, will happen, in one of the infinite number of universes. The trick is to see all frames of reference over all universes. This way, there really are no preferred ones (in other universes, you do the FTL travel, so you enter these frames of reference, and then a causality violation happens in these universes). If you just look at the frames of reference of your universe, then yes, there would be a preferred one.

The actual problem is that Many Worlds is an interpretation of quantum mechanics, and nobody has ever actually attempted to combine it with special and general relativity, both because Many Worlds is (currently at least) not falsifiable, and because QM and relativity have fundamental incompatibilities, which need to be resolved anyway. So it's all speculation at this point. For instance, "all frames of reference", does this extend to all frames of all universes or not? It is unclear without merging.

Re:Sounds like the modem problem ...

[Bite The Pillow]

A modem modulates and demodulates. Voiceband modem, what POTS was intended to carry, was the 56k limit.

DSL appears to be an acoustic signal carried over POTS, not a digital signal. It is just as digital as voiceband, I should say, by which I mean it is digital, but clearly not in the way you mean it.

If we are talking about cable modems, which are modems as well, the signal I believe is RF. Analog cable TV and digital cable TV are both possible, and I believe cable internet over both is likewise possible, meaning that it may or may not be a pure digital connection and it may or may not carry pure digital data.

As I understand it, fiber is pure digital all the way.

What you meant to say is that the 56k limit was based on the infrastructure which was intended to carry the characteristics of speech and considered frequency loss acceptable. DSL is interesting because it sits on top of all but the most antiquated of the existing POTS infrastructure, but it is distance limited because frequency loss is not allowed.

I skimmed over some details, but in your rush to be pedantic you just kind of ignored a whole mess of important distinction, and you ended with a completely untrue statement.

TARS

[PPH]

A workable robot with a humor setting anywhere near 75%? Not going to happen IRL. That was investigated with the Bender character in Futurama and look at the mess that turned out to be.

Re:Sounds like the modem problem ...

[Livius]

It uses a different technology with the same phone line.

Re:Recommend Replacements for the "Old" SA

[ColdWetDog]

I seem to have slipped in keeping up with science from the standpoint of an educated layman and a big reason is my distaste for what Scientific American has become. What are some recommendations for websites that have the scientific quality of the "old" Scientific American? Thanks!

It'll cost you, but subscriptions for both Science and Nature should keep you rather busy for the rest of your lifetime.

Caltech

[juancnuno]

It's "Caltech." Not "Cal Tech." http://www.caltech.edu/

Re:LOL money won't be spent on maybe science

[blue trane]

Did you know that worldwide OTC derivatives total $710 trillion, according to the Bank for Internatiional Settlements?

The private sector created some $76 trillion in one year alone.

There is plenty of room for the government to create money to spend on projects the private sector considers too long-term to invest in. Government debt is a complete distraction. There is an artificial scarcity of money.

We should be spending money on research. Using economics as an excuse not to do research is silly, since the private sector wouldn't exist without money creation and debt being rolled over or forgiven.

"It's all theory work." Even theoretical

[jpellino]

physicist have to eat. And raise families and live like civilized people who have actual lives. This of course is incomprehensible to some US TV viewers who suspect that Big Bang Theory is just slightly not a documentary. People are as amazed watching Tyson and Hawking hold their own on Colbert or Oliver a if they had just seen a talking squirrel. So it'll be an uphill slog for a while here. It takes money for faculty positions and the time to do the work. Einstein's work was pure theory until it was tested, but you never get to test it unless someone has the theory. So yes. Pay for it. Just as you pay coders to come up with new models for how things can work - also completely useless until they see the inside of a machine that actually does something with the code.

Re:Sounds like the modem problem ...

[Immerman]

Except DSL isn't a phone line, it's a Digital Subscriber Line, nor does the "modem" actually modulate or demodulate anything. Yeah, it's the same copper wires, but nobody ever said you couldn't send a faster signal over copper wires. To deliver DSL the phone company had to replace all the switches, etc. along the connection path with completely new technology specifically designed to carry a high-speed digital signal.

No publication matches the old SciAm.

[jpellino]

They had a particular mix of hitting a HS reading level (most mass market periodicals are 6th grade) and picking the right people to re-explain the essence of things. Just engaging and challenging enough, with Gardner thrown in to remind you to be human about it all. Think Atlantic Monthly for STEM. For me, WIRED comes the closest, if you can ignore the occasional hipster-cool slant and vertigo-inducing layout.

^^^ This. Thanks.

[jpellino]

Well put. (Already commented so no mods at hand)

Inconsistent fuel?

[pmontra]

*Warming: (mild) spoilers follow*

They leave Earth with a Saturn V like rocket and they take 2 years to go to Saturn. That contrasts Cassini's and Pioneer 11's 6.5 years to get there and the 3 years for the two Voyager probes. Let's say that 2 years is within the bounds of what we could achieve with our technology if we really have to hurry up.

On the other side of the wormhole they do all sort of manouvres landing on (easy) and leaving planets (difficult) with only a small craft (the Ranger). One would expect you need at least a large rocket to lift off from a planet with 80% of Earth's gravity (the ice world).

It seems they burnt normal fuel in the Solar system and used some very energetic fuel later on. Anyway, who cares, it's only fiction :-)

By the way, does anybody know what kind of rocket would be required to leave Mars and fly back to Earth?

Re:Inconsistent fuel?

[dunkindave]

*Warning: (mild) spoilers follow*

They leave Earth with a Saturn V like rocket and they take 2 years to go to Saturn. ... On the other side of the wormhole they do all sort of maneuvers landing on (easy) and leaving planets (difficult) with only a small craft (the Ranger).

I noticed that. They needed a multi-stage rocket to leave Earth, but the crafts alone could land on then leave the water planet (130% Earth gravity) and the ice planet (80% Earth gravity), and the main vessel could pull away from orbiting a black hole.

A couple other things also bothered me.

1) If the water planet was that close to the black hole I am pretty sure it would be ripped apart by tidal forces. Also, if it is so close to the hole, where is the star that it is getting light from? And as someone else mentioned, shouldn't the radio transmissions have been Doppler frequency shifted and dramatically slowed? And since they are reading the radio transmissions from the probe, wouldn't they have known that it had only seen a few minutes of ground time since that is all it would have (Doppler shifted) reported? The only other explanation is they chose to go to a planet that they had lost all contact from which is contrary to what the plot is.

2) And for going into the black hole, if we buy his statement about how not to get torn apart, I didn't get how they were planning on sending info out from the black hole. Once you are in, you are in, and they said they needed data from inside it, not from just outside it.

3) And how did he get out of the black hole at the end? No explanation. Just boom, there he is, along with his robot.

4) Why did the wormhole suddenly become unable to communicate back? They already had info from the first people so it was working then, and they spoke about being able to see things in the wormhole as they approached, so why the change?

5) His statement that the wormhole and the inside-the-black-hole constructs were made by far future humans is a theory, but isn't based on any evidence what so ever. Maybe it was, or maybe it is some other species. I guess it keeps them out of hot water with those who insist man is alone in the universe. But if it was future humans, why all the roundabout maneuvers? If they wanted to send a message, and they can manipulate gravity like is stated, then just send it. Big document inscribed in the desert sands. No need for subtleties. Yeah, yeah, I know, then no movie plot. ;)

I know you need to suspend some beliefs when watching movies, especially science fiction, but there has to be a limit to the amount you need to suspend. OK, feel better now.

Re:Inconsistent fuel?

[pmontra]

Point 1 was explained in TFA. They calculated that if the black hole was spinning fast enough and the planet was tidal locked to it, it could survive. They also explain how those huge waves work and why the sea was so shallow there. Furthermore, they say that the light comes from the accretion disk, which is cooling down and not falling in to the black hole at the moment. If it did it would produce X rays and zap the astronauts to death.

Points 2 and 3. I agree with you. Let's say that the pentadimensional aliens/humans found a way to get out of there. Anyway you can look at http://en.wikipedia.org/wiki/N... and there was an article about that subject on Scientific American in February 2009. Gargantua's singularity wasn't naked but I remember a paper about how to remove an event horizon (adding more spin to the black hole) and another paper with a rebuttal of the technique. I can't find them again now.

Point 4. I don't understand that too. After all the light gets out. Why not radio waves?

Point 5. Agreed, it's a theory without a proof. Let's say it's an intuition. There might also be a casuality/time paradox there (Norad's coordinates being known because they've been sent after being known) but who knows how time really works.

Finally, to be pedantic, the main vessel didn't escape from Gargantua (it didn't have to). It just changed orbit to an higher aphelion with a slingshot manoeuvre to reach Edmunds' planet. Not different than getting from Earth to Jupiter with a sligshot around the sun. It takes less fuel than having to reach escape velocity.

Re:Inconsistent fuel?

[QuantumPion]

The Endurance itself was large and heavy and full of fuel, requiring a large rocket to get to orbit.

The Ranger was a small, lightweight spaceplane which probably used something like a SABRE engine.

Here is a delta-V map of the solar system. According to it, you would need 6300 m/s delta-V to return to Earth from Mars. Which is about 2/3 the delta-V required to get to Earth orbit.

Well, thanks a lot.

[jpellino]

I had just entered an extended period of relative calm in dealing with the concept of regular old blame, and then you have to plant the mindworm of "It means that something you do today causes something to have happened several days ago." Great. All hands - brace for therapy bills.

Re:Sounds like the modem problem ...

[ceoyoyo]

It's not quite that simple. POTS+modem sent your signal all the way to its destination as an acoustical signal carried on a POTS phone line. Those were limited to 3.4 kHz by the switching and other hardware. The speed with which you can transfer data in that bandwidth is limited by Shannon's theorems.

DSL uses a higher frequency (> 3.4 kHz) signal on the line from the local station to your house that also has more than 3 kHz of bandwidth, so can transfer data much more quickly. That signal doesn't go all the way to the destination, it's stripped off the line, re-encoded, and sent on via a packet switched digital network.

The DSL signal is using the same wire as the POTS service to your house, but it's purposely *not* POTS so that it can do so without interfering.

Re:Sounds like the modem problem ...

[CaptainDork]

We're both correct.

Just as we both know what a "floppy disk" is, we also know that since the inception of the 3.5" disk, there's nothing floppy about it and yet, modern computers still use that term.

And so it is with "modem."

While the words may be inaccurate, both are in common use.

To repeat, my modem is handling speeds at 52mbps down and 5mbps up.

So, my worries about hitting the wall at (theoretically) 56kbps, while supported by science, were premature, eh?

Worst physics in Interstellar

[russotto]

The worst physics didn't involve strong gravity fields or high velocities or accelerations. Just Newton's Third Law and an energy argument. The second-worst bit of science was biological, but also involved an energy argument.

Spoilers:
1) Matt Damon's spaceship just would have been gently pushed away when he opened the airlock. Maybe gently pushed to one side or another depending on the partial seal. It certainly would NOT have set the entire Endurance vehicle spinning like mad.

2) The blight was better adapted because it utilized nitrogen from the air instead of oxygen? Yeah I don't think so; what do you combine with N2 that yields energy instead of spending it?

Re:Worst physics in Interstellar

[TomR teh Pirate]

Totally agree with both points. The part I HATED was when our intrepid astronauts were doing much hand-wringing over which two of three planets they should be looking at. The dialog goes on for a painfully long time, and then the big reveal that one of the astronauts in the discussion is voting in favor of one of the planets specifically because she's in love with the guy on the probe ship. At this point, she makes an impassioned argument that "love" must play some role in the physics of how things work. It was an utter load of crap that mocked rather than strained credulity.

So here's my review: I went in with high expectations for Interstellar and came out deeply disappointed. The whole part with Matt Damon's cameo could have been skipped completely and only served to add unnecessary time and drama to a movie that already felt too long. If our primary crew had merely found him dead, the movie could have moved on with far less effort. By contrast I took my son to see Mockingjay with only moderate expectations and came away somewhat pleasantly surprised. Go see that if you have a tween / teen-aged kid who needs an escort.

Blight?

[PPH]

So we can enginer our way out into space and through wormholes. But we can't cure* a crop blight?

*OK. So the resulting food would probably lose its organic certification. And hipsters would rather die than eat GMO.

Re:Blight?

[russotto]

So we can enginer our way out into space and through wormholes. But we can't cure* a crop blight?

Of course we could. But we didn't, so we won't. Typical SF causality loop.

Much bigger problems than this

[thisisauniqueid]

There are much bigger problems with the physics in Interstellar, which Kip Thorne is not willing to address now that he has his name on a book claiming that the movie is unusually scientifically grounded. He should have run the plot past some colleagues.

"Science" of Interstellar=Calvinball

[jodido]

The "science" in Interstellar is all invented for the film. It has much more in common with Calvinball than astrophysics.

You're using that word incorrectly.

[tlambert]

Maybe I've been away too long, but last I heard was that Relativity is still a theory.

It's a Scientific theory: http://en.wikipedia.org/wiki/S...

"A scientific theory is a well-substantiated explanation of some aspect of the natural world that is acquired through the scientific method and repeatedly tested and confirmed through observation and experimentation." ...unless you live in Texas or Oklahoma.

Re:Sounds like the modem problem ...

[dbIII]

Yes and the beige box is the hard drive while the LCD thing on the desk is the computer. That's common usage but you can't really expect any respect for using it in some situations.

Woodward

[miquels]

Well, professor Jim Woodward has been working on his Mach/Lorentz thruster for a while now and has a working setup in the lab, and multiple publications in peer-reviewed journals. With his theory it is in fact possible to build startrek-style impuls engines, warpdrives and wormholes. And it all fits in our existing theoretical knowledge. He has a book out, published by Springer-Verlag (they don't publish nonsense):

http://www.springer.com/engineering/mechanical+engineering/book/978-1-4614-5622-3

Making Starships and Stargates
The Science of Interstellar Transport and Absurdly Benign Wormholes

Series: Springer Praxis Books Subseries: Space Exploration

Woodward, James F.

2013, XXVI, 279 p. 92 illus., 85 illus. in color.

Re:Woodward

[HuguesT]

Thanks, I've read the book. The first part is a introduction to Mach effects. The second part reads like a lab book to a great extent (description of experiments, matching of theory to seen results, etc), leading to experimental descriptions to demonstrate the existence of these effects. The authors makes some interesting benchtop experiments. He sees some new physics happening, including very small reactionless thrust effect, in the order of a few microNewtons, that he cannot explain away with obvious side effects, like heating, varying electromagnetic fields, and so on. He has the theory for it, but not fully developed. It seems a little ad-hoc. This is still great, but this is not yet new real physics, and this is not yet useful. Someone else needs to redo the experiments and confirm them. We need to see if the effects can scale to something not so tiny.

The last part of the book is speculative with wormholes and so on. The authors is careful to draw attention to the work of others, well-respected physicists like K. Thorne. It is fun to read.

In summary, with the author's theory, if it were correct, and if it scaled, it *would* be possible to build Startrek-style engines. We are not *quite* there yet.

English language

[codeButcher]

I think this thread is a good demonstration why I do not like the English language's deviation from how other Germanic languages write a single word for a single idea. Hint: the "science" part in "science fiction" is simply an adjective that describes the noun "fiction". It is the noun that is the important part.

OK, I won't make the mistake again of asking which part of "science fiction" don't you understand....

Re:Sounds like the modem problem ...

[CaptainDork]

Apparently I can't expect respect in some situations.

Re:Sounds like the modem problem ...

[fnj]

Except for the little detail that it is NOT A GODDAM MODEM. Misusing terms does not change their meaning.

BTW the actual disc inside a 3.5" floppy disk cartridge IS floppy. Ever take one apart?

In an industry where ...

[Rambo Tribble]

... a flesh wound from a .22 causes gallons of blood to splash across the surround, you expect realism? How realistic is that?

Re:In an industry where ...

[Areyoukiddingme]

In an industry where a flesh wound from a .22 causes gallons of blood to splash across the surround, you expect realism? How realistic is that?

That depends on the rating. If it's rated R, you get gallons of blood. If it's rated PG-13, even a wound from a .45 won't bleed appreciably, let alone have any sort of torn flesh. Obviously you, as a Rambo Tribble, only watch movies rated R, so you couldn't be expected to know this.

Re:In an industry where ...

[Rambo Tribble]

Seriously, there's a rating lower than "X"?

alumni - please up vote

[drerwk]

Maybe when the editors are finally fully automated we could get the Cal Tech ==> Caltech rule running.

forest/trees, tries to get big stuff right, utterl

[neurocutie]

Nice that Nolan tried to get the big science in Interstellar right (although I didn't buy the depiction of the giant tidal waves), but so many logic and other science errors made the film. The most ridiculous is why 12 humans were sent to scope out tiny patches of promising planets when they clearly had the technology to send out hundreds of smart probes to do the scouting work and report back accurate, untainted data. Even Coop could have first sent out TARS to explore the planets before risking human landings. Other silliness like the solid clouds, or the manner of liftoff from the water planet (with the huge gravitational waves), or the presence of so much free oxygen on a lifeless planet, or the logic of even consideration the viability of choosing a planet with such large time dilation issues just ruined the film...

Re:Sounds like the modem problem ...

[Immerman]

Well said.

Re:Faith based Order

[ardor]

> That's the scary thing about people with some education but not enough, they think they know FAR more than they really do and are more than happy to attack anything they think the people "above them" don't agree with even if they aren't qualified to do so..

Yep. That's the Dunning-Kruger effect in action.

Re:Sounds like the modem problem ...

[Immerman]

Others have described just how wrong you are, so I'll just say this:

When someone says a snowman can't last outside on a hot summer day, redefining "snowman" to mean "rock statue" doesn't undermine the original claim in any way - when considering the original claim you *must* use the same definitions as the claimant, or else you're just constructing an unrelated claim.

Re:Sounds like the modem problem ...

[CaptainDork]

Take up your fucking problem with the goddam Internet. It's a fucking modem whether it modulates/demodulates or stuff.

I've taken 3.5 disks apart but the goddam thing is still a fucking floppy disk.

Bite me.

Re:Sounds like the modem problem ...

[CaptainDork]

My unicorns are not amused.

Re:Recommend Replacements for the "Old" SA

[tehcyder]

I seem to have slipped in keeping up with science from the standpoint of an educated layman and a big reason is my distaste for what Scientific American has become. What are some recommendations for websites that have the scientific quality of the "old" Scientific American? Thanks!

You're posting on that website now!

More basic problem before you even get to that ...

[notpaul]

First of all, in spite of some scientific & other issues, I really liked the movie, and I especially thought the several bits of 'homage' were well-handled.

HOWEVER -

If you are going to nitpick the science, you really don't need to get into the quantum physics at all. They clearly have the technology (and had it developed quite a few years before the time in which the film is set) to make use of re-usable single-stage-to-orbit (SSTO) space craft. I don't understand why the initial launch required a large booster rocket, either ... because mater the Ranger craft is able to achieve orbit from a planet with 90% Earth-gravity without any such assist.

So - if you have a fast, obviously re-usable SSTO craft that can hurl a bunch of mass into orbit over & over, you really don't need the dang wormhole. As anyone who really understands these things can tell you, if you have affordable, reliable, RE-USABLE SSTO craft, you can do all kinds of neat-o things which involve getting lots of mass off this rock (including starting a colony in space, on the moon, or even Mars).

With decades in which to work, and a presumably well-motivated civilization, they would never have reached this point of desperation in the first place. If you can throw enough mass (materials, fuel, equipment, people) into low-earth orbit with a fleet of re-usable SSTO craft (the Rangers) ... and do it thousands of times over perhaps decades of time, you will have no problem expanding the reach of your civilization beyond a single planet.

Problem solved.

Re:Sounds like the modem problem ...

[david_thornley]

Data transmissions through POTS lines are limited by the restricted bandwidth and the signal-to-noise ratio. 56kb/s was, I believe, slightly faster than Shannon's Theorem allows for that. Switching to a scheme that allows a much larger band of frequencies allows faster information transfer. Who'd have thunk it?

Similarly, a modern car will go a lot faster through mostly empty highways than through a traffic jam.

Such hypocrisy

[Y.A.A.F.O.M.I.]

This coming from a guy that together with a couple others like him, got a bunch of people and government agencies to shell out over 350$ million for an 8 year long project that was supposed to detect gravity waves but instead was closed down because it detected absolutely nothing. For 8 years it detected shit all. Over 350$ million in federal funds that could have been put to good use somewhere else.