Stephen Hawking Service: Possibility of Time Travellers 'Can't Be Excluded' (bbc.com)

Organisers of Prof Stephen Hawking's memorial service have seemingly left the door open for time travellers to attend. From a report: Those wishing to honour the theoretical physicist, who died in March aged 76, can apply via a public ballot. Applicants need to give their birth date - which can be any day up to 31 December 2038. Prof Hawking's foundation said the possibility of time travel had not been disproven and could not be excluded. It was London travel blogger IanVisits who noticed that those born from 2019 to 2038 were theoretically permitted to attend the service at Westminster Abbey. He said: "Professor Hawking once threw a party for time travellers, to see if any would turn up if he posted the invite after the party. None did, but it seems perfect that the memorial website allows people born in the future to attend the service. Look out for time travellers at the Abbey."

Comments

Everybody is a time traveller.

[OpenSourced]

At the breakneck speed of 60 minutes per hour.

Re:Everybody is a time traveller.

[Anonymous Coward]

Well, so we are interstellar space travelers also, at the breakneck speed of the universe expansion.

So silly.

Re:Everybody is a time traveller.

[Anonymous Coward]

At the breakneck speed of 60 minutes per hour.

Bah.

I do 3600 seconds per hour.

So there.

Re:Everybody is a time traveller.

[tinkerton]

I can assure you it's always 'now'. You just think you're travelling in time.

Re:Everybody is a time traveller.

[Anonymous Coward]

Your now is different to everyone else's now. Sure, the difference is extremely small for people that are in close proximity. There is always a difference though.

Re:Everybody is a time traveller.

[Anonymous Coward]

At the breakneck speed of 60 minutes per hour.

Yes... unless you happen to be an astronaut travelling in space.

Re:Everybody is a time traveller.

[Anonymous Coward]

Wrong; even for astronauts. All reference frames are equivalent.

Re: Everybody is a time traveller.

[Anonymous Coward]

"That means time should also slow down for the astronauts relative to people on the surface. You'd think that might even out, but actually their velocity time dilation has a bigger effect than their gravitational time dilation, so astronauts end up aging slower than people on Earth."

http://www.businessinsider.com/do-astronauts-age-slower-than-people-on-earth-2015-8

Re: Everybody is a time traveller.

[Anonymous Coward]

Time is an illusion caused by a closed loop of space.

And 9-11 was an inside job. ae911truth dot org

Re:Everybody is a time traveller.

[Anonymous Coward]

But only to an outside observer. From his own frame of reference, he's still traveling through time at 60 minutes per hour.

Re: Everybody is a time traveller.

[Anonymous Coward]

Time is an illusion, lunchtime doubly so.

Also, Towel day is just around the corner!

Re: Everybody is a time traveller.

[Anonymous Coward]

No, their bodies age slower because of lack of gravity and the lower air pressure

Re:Everybody is a time traveller.

[Anonymous Coward]

Well, so we are interstellar space travelers also, at the breakneck speed of the universe expansion.

So silly.

And because we are travelling so fast through the universe if you were to time travel 5 minutes forward or backwards you would find yourself in the vacuum of space millions of miles from Earth.

Re: Everybody is a time traveller.

[arth1]

"That means time should also slow down for the astronauts relative to people on the surface. You'd think that might even out, but actually their velocity time dilation has a bigger effect than their gravitational time dilation, so astronauts end up aging slower than people on Earth."

That's drawing the wrong conclusion. They age at the same speed; it's time itself that is elastic and dependent on the observer. If ten years passed on an astronaut's clock while your clock shows twelve years, he didn't age slower.

Being able to grasp how time is a local phenomenon only with no universal clock ticking time away for everyone is the great hurdle that separates those who understand relativity from those who don't. Use of words like "slower", "before" and "ago" in relativistic or big bang contexts should always be viewed with suspicion that someone is imposing a particular reference frame when they shouldn't.

Re:Everybody is a time traveller.

[Impy the Impiuos Imp]

You're all traveling through the 4-dimensional spacetime continuum at c.

Re:Everybody is a time traveller.

[Anonymous Coward]

Heinlein declared decades ago that any probable time machine must also be a spaceship.
Time travel occurs in the depths of space and then you travel to where you want to go.

Re:Everybody is a time traveller.

[Anonymous Coward]

Heinlein declared decades ago that any probable time machine must also be a spaceship.
Time travel occurs in the depths of space and then you travel to where you want to go.

And not only would it have to be a spaceship- it would have to have a mechanism to defy the laws of thermodynamics. (since it would be creating mass and energy at the destination time and destroying mass and energy in the source time).

Re: Everybody is a time traveller.

[Anonymous Coward]

And when you go back those millions of miles, you'll find a vacant space. Because all of the particles that make up Earth are still five minutes in the future.

Re:Everybody is a time traveller.

[trg83]

If you move your car from one side of town to the other, did you destroy mass in the one side of town in favor of the other? What if time is truly just a 4th dimension in every sense of the phrase? If the universe can handle me moving my car across town, it may make no difference if we simply move it across time.

Re:Everybody is a time traveller.

[HideyoshiJP]

I have this time machine I lie down on. When I close my eyes, time jumps forward 6-8 hours.

Re: Everybody is a time traveller.

[sexconker]

There is a universal clock. It's the speed of light.

Re: Everybody is a time traveller.

[Anonymous Coward]

The Earth is not moving at 24 million mph (2+ million mph in 5 mins) relative to any reasonable reference frame. About the best you can do is 1.2 million mph relative to the CMB. But seeing how there is no "rest" reference frame, how would your time traveller know which way he was supposed to move?

Re: Everybody is a time traveller.

[Anonymous Coward]

What lower air pressure? ISS maintains a ground normal 14.7 psi.

Re: Everybody is a time traveller.

[Anonymous Coward]

Nope, while two people in different frames of reference will agree on how fast a light beam is moving, they will disagree on how far it has travelled and how long it took to get there.

Re:Everybody is a time traveller.

[Marxist Hacker 42]

But only as long as you are within the Windows CE 1.0 Microsoft Standard Century, apparently.

Could they not afford 4 digit years for their database?

Re: Everybody is a time traveller.

[arth1]

There is a universal clock. It's the speed of light.

That is not a clock.
The speed of light in vacuum is 299,792,458 m/s for all reference frames, but that's a ratio. As distance (m) shortens, time (s) contracts so the ratio remains the same. But time changes.

If you travel at 99.5% of light speed, you might insist that you travelled one light year in a little over a year, yet someone watching your travel from the sideline might say you travelled ten light years in over ten years. Both of you are correct, because both distance and time changes depending on viewpoint.

Re: Everybody is a time traveller.

[Anonymous Coward]

How soon is now?
-The Smiths

Re:Everybody is a time traveller.

[BoogieChile]

that's why all the real time machines navigate Time, And the Relative Dimension In Space

Re: Everybody is a time traveller.

[Armonk]

Time is an illusion, lunchtime doubly so.

Also, Towel day is just around the corner!

Well as long as you... DON'T PANIC! while I read you my epic Vogon poem.... Oh garbled rattlecage of disturbed eons of accellerated particles. How you have forsaken me and my towels. My planet dweller of tea sippers wears slippers on days with green earwax of the ages of camelot. Go now and may be gold of a hearth of a blue whale of yesterday gaurd your track from flies. Despite my pudding I gave to you my spoon with nose. Danger from gone is now at bay from the other galaxy at night. My ear as soft as steel while eating pudding with bread, My pudding hard as wood while looking at you, See if I don't (I might)

Once

[JustOK]

Once it happens, it will have happened.

Re:Once

[Bite The Pillow]

We have to live through the timeline without time travel until it is invented.

Then it is invented, they go to the party and the memorial and shit gets weird. But it hasn't been invented in the future so it doesn't exist as a possibility now.

Re:Once

[JustOK]

Unless they will have already invented anti-time travel, probably on a Tuesday.

2038?

[Anonymous Coward]

Why the year 2038? Did they go a bit overboard with the time traveling gag and get a cheapskate 32-bit nix server? They will be surprised when the first "time traveler" tries to enter a date after 19 Jan 20138....

Re:2038?

[Anonymous Coward]

ooooops ... 2038 obviously.

Re:2038?

[Anonymous Coward]

That is when the world is destroyed by the paradoxes caused by the time traveling device :(

Those of us here are trying to undo the damage.

Re:2038?

[NicknameUnavailable]

Why the year 2038?

They want someone with a primitive enough time machine they can reverse engineer after beating the time traveler to death for it.

Re:2038?

[Actually, I do RTFA]

They don't want refuges from the post-2038 hellscape.

Re:2038?

[Anonymous Coward]

Pff, obviously not a time traveler. Also, it works either way.

Who is coming

[shayd2]

Watch for new phone booths near the Abbey

Re:Who is coming

[Anonymous Coward]

Don't you mean Blue Police Boxes?

Re: Who is coming

[Anonymous Coward]

Bill and Ted arriving would explain much about the universe.

Dr. Hawking's final joke...

[MrKevvy]

He had quite a sense of humor, and use it to cope with his condition. In 2009 when the threw a Time Traveller's Party and no one attended, he indicated that this was confirmation that time travel was not possible.

And as far as we can tell, it isn't, to the point of ridiculousness, and our physics is validated and complete enough on this to be almost certain. Time travel introduces unresolvable paradoxes (ie sending a single particle backwards far enough in time would completely change future atmospheric patterns, weather events and thus affect who was born, including those doing the sending) and and would require unfathomable physics to carry out (on the order of constraining the energy of a hydrogen bomb in the volume occupied by a human such that no damage or radiation occurred.)

Not going to happen. If it ever did, being time travel, it already would have.

Re:Dr. Hawking's final joke...

[91degrees]

Well I would have gone, but I heard it was a bit of a bust. Nobody turned up.

Re:Dr. Hawking's final joke...

[TheDarkMaster]

well if I were a time traveler I would never show up at a "party for time travelers". Just think about the problems I would have as soon as I proved to be a time traveler, at minimum I would end up locked in some secret government facility or worse.

Re:Dr. Hawking's final joke...

[LordHighExecutioner]

The reason why no time traveller attended dr. Hawking's party is because all of them were busy at the simultaneous (in the Einstein-Minkowsly sense) party organized by dr. Fermi.

Re:Dr. Hawking's final joke...

[UnknownSoldier]

> Time travel introduces unresolvable paradoxes

No it doesn't. Paradox is just another name for when men are not smart enough to understand a 3rd choice due to failing to understand fundamental concepts.

e.g.
* Is Light a Particle exclusive-or Wave? Answer: Both.
* Zeno's Paradox: In theory you can infinitely sub-divide space, in application you can't. Answer: Both time and space are quantized. (analog)

Going back in time and killing your ancestor, an alleged paradox, isn't. You can't violate the Law of Causality no matter how hard you try. It would _instantly_ cause you to cease to exist. Ergo, there is no paradox.

Thankfully humans aren't smart enough to figure out space-time is relative and thus teleportation/time travel are intimately linked ... for now. Just one more technology we'll probably abuse as well, if it isn't weaponized first. Hopefully the species will have grown up a little by the time it gets (re)invented. First Contact in the next decade is going to force us to re-examine a lot of "sacred cows", aka, dogma in Physics (among other things.)

Re:Dr. Hawking's final joke...

[Anonymous Coward]

Or, you know, time travellers just didn't want him to prove that time travellers actually exist.

What kind of host invites people after the event passed?

Re: Dr. Hawking's final joke...

[reanjr]

You don't need quantization to solve Zeno's paradox. You just need limits and a basic understanding of how infinity works in algebra.

Re:Dr. Hawking's final joke...

[Roger W Moore]

Zeno's Paradox: In theory you can infinitely sub-divide space, in application you can't. Answer: Both time and space are quantized.

We do not know that. It's certainly plausible but unless you have a working theory of quantum gravity that you have been keeping to yourself, with experimental evidence to back it up, we have literally no idea how space-time works on incredibly small scales.

You can't violate the Law of Causality no matter how hard you try. It would _instantly_ cause you to cease to exist. Ergo, there is no paradox.

By its very nature, a time machine violates the law of causality so, if one exists clearly the law of causality can be broken and how to resolve paradoxes is then a legitimate question. If you believe the law of causality to be unbroken then you have to believe that it is impossible to build a time machine.

Re:Dr. Hawking's final joke...

[Anonymous Coward]

> Time travel introduces unresolvable paradoxes

No it doesn't. Paradox is just another name for when men are not smart enough to understand a 3rd choice due to failing to understand fundamental concepts.

It violates laws of thermodynamics; as it would cause mass and energy to be created in the new time period and mass and energy to be removed from the exiting time period.

The amount of mass and energy in the universe would fluctuate with time if time travel occurred.

As far as killing your ancestor goes, you couldn't kill your ancestor if you didn't exist; and there is a lot more complexity than just killing yourself, everything would change, chemical reacions, physical reactions, human being responses to one another. It's not that you would just poof out of existence if you travelled back and killed an ancestor; you would poof out of existence by your theory if you went back AT ALL- because changing any minor thing would change YOU in some way. Any minor change would mean the molecules in your body would not be what they are now.

Then there's the whole: I'm pretty sure we would have observed time travelers by now. Human's (barring being wiped out first) would almost certainly have visited us if they could. They almost certainly would have changed certain events (if they could).

Time travel is great for fiction; but the reality is, it almost certainly will always be only fiction.

Re:Dr. Hawking's final joke...

[Anonymous Coward]

(ie sending a single particle backwards far enough in time would completely change future atmospheric patterns, weather events and thus affect who was born, including those doing the sending)

The biggest bogus "understanding" of time travel. No, said particle would be lost in the haze of other particles. Just like it is now.

Re:Dr. Hawking's final joke...

[Anonymous Coward]

By its very nature, a time machine violates the law of causality so

No it doesn't. Now, let's debate why.

Re:Dr. Hawking's final joke...

[arth1]

Going back in time and killing your ancestor, an alleged paradox, isn't. You can't violate the Law of Causality no matter how hard you try. It would _instantly_ cause you to cease to exist. Ergo, there is no paradox.

You're assuming a single universe and the Copenhagen interpretation. If, as some think, the universe branches at every possible probability because they're all true, there's nothing that logically prevents you from going back in time to kill your grandfather without violating the law of causality, because there will be countless universe branches where you didn't.

Re:Dr. Hawking's final joke...

[Anonymous Coward]

That's not true, I've been told countless times on /. that anything is possible because we have computers and things that improve over time.

The fact that things improved in the past is proof that it happens to everything, again this has been told to me countless times on here whether it's wormholes not existing, black holes being unspecial masses of stuff absolutely useless unless you wish to throw oneself and die (but this won't kill you according to people on /. and has magical human-centric effects), long term space travel being idiotic and having insurmountable issues

Now you're saying all these people were lying and this maxim doesn't apply to absolutely everything including time travel and useful worm holes?

Re:Dr. Hawking's final joke...

[smooth wombat]

as it would cause mass and energy to be created in the new time period and mass and energy to be removed from the exiting time period.

Not necessarily. Depending on how the device used to enable time travel is created, energy could be used in our time to create the portal to the past while not sending energy to the past. Think wormhole. It's simply an opening.

As to the mass, the person going back in time would be the mass but they would eventually return (assuming they weren't killed in the past.)

It's not that you would just poof out of existence if you travelled back and killed an ancestor; you would poof out of existence by your theory if you went back AT ALL

Again, not necessarily. In the Many Worlds interpretation, changing something in the past would create another line of Time which would prevent you from going poof. You may have killed your ancestor in the past, but because you come from a different line of Time, you still exist. Your ancestor was killed in a different timeline which doesn't affect you.

They almost certainly would have changed certain events (if they could).

Not unless they were instructed not to change anything but only be an observer. If we somehow are able to enable time travel to be possible, do you think we would let every Tom, Dick, and Harry go gallivanting through Time? Most likely it would be limited to those in the scientific fields who would be trained and instructed what not to do when going to the past.

Further, since there would most likely not be a way for us to determine if a multiverse exists, or if any changes we made in the past affect our future, we wouldn't be able to determine if what anyone did in the past has affected our present. To us, history is history.

Re:Dr. Hawking's final joke...

[Anonymous Coward]

and would require unfathomable physics

What's unfathomable to a Dachshund can be easily understood by a human. What's unfathomable to a human does not mean it's not true or possible. Our assumption is that our mind can understand the reality of the universe. Might not be true.

Re:Dr. Hawking's final joke...

[Anonymous Coward]

Well I would have gone, but I heard it was a bit of a bust. Nobody turned up.

I went, but then a rival timetraveller went and killed my father before I was born so I ceased to exist any more. (I wrote this before he did that).

Re: Dr. Hawking's final joke...

[lgw]

You've completely misunderstood Zeno's paradox. You've merely stated one of his premises. The question at hand was whether an infinite count of events can be packed into a finite time. The answer is still unclear.

Re:Dr. Hawking's final joke...

[Anonymous Coward]

Yeah, a party for time travelers thrown in a time before time when time travel was thought to be physically impossible has to sound about as shady as the prince if Nigeria wanting your help in a money laundering scheme.

Re:Dr. Hawking's final joke...

[Anonymous Coward]

as it would cause mass and energy to be created in the new time period and mass and energy to be removed from the exiting time period.
Not necessarily. Depending on how the device used to enable time travel is created, energy could be used in our time to create the portal to the past while not sending energy to the past. Think wormhole. It's simply an opening.

You can't transport something back in time with out sending it's mass and energy. If you send a peanut back in time- the mass of the peanut and the energy stored in the chemical bonds of the peanut (and it's heat energy) are all sent back in time. You are removing mass and energy from our time, and adding mass and energy in the destination time. You can't create or destroy mass and energy.

As to the mass, the person going back in time would be the mass but they would eventually return (assuming they weren't killed in the past.)

So then when they return they break the laws of thermodynamics again. What if they eat a bunch of cheesecake whilst time travelling and gain 20lbs?

 

It's not that you would just poof out of existence if you travelled back and killed an ancestor; you would poof out of existence by your theory if you went back AT ALL

Again, not necessarily. In the Many Worlds interpretation, changing something in the past would create another line of Time which would prevent you from going poof. You may have killed your ancestor in the past, but because you come from a different line of Time, you still exist. Your ancestor was killed in a different timeline which doesn't affect you.

So now we're not adding the mass and energy from one person- we're adding their mass and energy - we're creating out of thin air: their mass and energy PLUS the sum energy of the entire known universe to create a separate time line.

They almost certainly would have changed certain events (if they could).

Not unless they were instructed not to change anything but only be an observer. If we somehow are able to enable time travel to be possible, do you think we would let every Tom, Dick, and Harry go gallivanting through Time? Most likely it would be limited to those in the scientific fields who would be trained and instructed what not to do when going to the past.

Just being there breathing the air would change the universe. Charles Dickens walks down a street corner and accidentally bumps into Chip McDoodle, time traveler who is quietly observing Victorian England. Dickens gets delayed, doesn't see an orphan who would have inspired him to write Oliver Twist. He goes home and writes a story about bumping into people instead.

OK- so it's not Charles Dickens; it's a simple bar wench. And she doesn't bump into him, she seems him from across the street, thinks Chip McDoodle is kinda hot... when asked out by Joe Bloggins at the pub that night she turns him down because he isn't as hot as the guy she saw on the street. A whole ancestry line wiped out- and everyone they would have ever met or seen has their history changed.

It could be something simple like a footprint Chip leaves that alters where a pothole will form, or a bug he stepped on, that would have saved a bird from starving and everything that dominos down from having an extra bird in the world. Might seem minor- but that bird might eat a bug that is the ancestor of one that later forms DDT resistance.

You can't OBSERVE history without impacting it.

Re: Dr. Hawking's final joke...

[Anonymous Coward]

Unclear how? Does 0.9 bar equal 1 or not? (It does).

Re:Dr. Hawking's final joke...

[Anonymous Coward]

Where is the mass of these other universes?

Re:Dr. Hawking's final joke...

[arth1]

Where is the mass of these other universes?

Your question does not make sense.
It's like thinking that the Schroedinger's cat box would have twice the mass because there would be one instance with a live cat and one with a dead cat. That's the case for neither the Copenhagen nor the Everett interpretation.

Re:Dr. Hawking's final joke...

[Anonymous Coward]

We don't live in a universe. We live in a multiverse. "Time" is an illusion, just consciousness stringing together its journey through different states of matter. Everything that can happen does happen. Each point in "time" is just a different set of eventualities partially Alpha events determined by consciousness (move the coffee cup to the other side of the desk) and partially Omega events (the Earth orbiting the sun). Killing your father happens in another timeline from the one you left in your time machine, therefore, no paradox. You just don't exist in the other timeline.

Re:Dr. Hawking's final joke...

[Anonymous Coward]

Zeno's Paradox: In theory you can infinitely sub-divide space, in application you can't. Answer: Both time and space are quantized.

We do not know that. It's certainly plausible but unless you have a working theory of quantum gravity that you have been keeping to yourself, with experimental evidence to back it up, we have literally no idea how space-time works on incredibly small scales.

You can't violate the Law of Causality no matter how hard you try. It would _instantly_ cause you to cease to exist. Ergo, there is no paradox.

By its very nature, a time machine violates the law of causality so, if one exists clearly the law of causality can be broken and how to resolve paradoxes is then a legitimate question. If you believe the law of causality to be unbroken then you have to believe that it is impossible to build a time machine.

No, a time machine does not violate causality any more than a car does. The "many worlds" interpretation of quantum mechanics provides sufficient leeway to resolve the paradox (if time travel is possible than an infinite subset of the infinitely many universes in which you don't exist are that way because you killed your own grandfather, but for obvious reason those aren't the ones you inhabit so no one able to observe them can tell you about them).

However that's called an "interpretation" because it's more of a way to describe something a lot more complex. Which is that the quantum wave function appears to be a multidimensional structure in which time is just another dimension, containing more states than the ones we observe all of which are "real" in in a way that really doesn't fit human intuition at all.

By all appearances time travel is theoretically possible, but charting a course through time would require an understanding of time that largely makes doing it unappealing (you can't change anything because the multiverse already contains all the outcomes of your doing it (as well as not doing it) whether you decide to do it or not). Also the engineering requirements are such that it's unlikely to be possible to build a time machine, and if it is possible the opportunity cost would be staggering, I mean we're talking "we could have built a Dyson sphere if Fry hadn't decided to bone his grandma to luls". So while it probably does happen in infinitely many universes those universes still manage to make up almost none of the multiverse from simply being low probability "branches".

Re:Dr. Hawking's final joke...

[tehcyder]

Going back in time and killing your ancestor, an alleged paradox, isn't. You can't violate the Law of Causality no matter how hard you try. It would _instantly_ cause you to cease to exist. Ergo, there is no paradox.

You're missing the point of the paradox, which is that by killing your ancestor you would never have existed at all, so therefore you couldn't have gone back in time to kill your ancestor, so therefore your ancestor must still be alive, so therefore you can go back in time to kill him and so on in an infinite loop.

Re:Dr. Hawking's final joke...

[Anonymous Coward]

Maybe the "laws" of thermodynamics need some tweaking.

Re:Dr. Hawking's final joke...

[bobby]

IIRC, college relativistic physics said that as you approach the speed of light, time slows down- in your reference frame. So if you took a trip far away near the speed of light and came back, you would have aged less, which makes it seem, to you, like you went forward in time.

Also, IIRC, to go backward in time you have to exceed the speed of light, which as far as we know, is not possible.

Re:Dr. Hawking's final joke...

[citylivin]

"In 2009 when the threw a Time Traveller's Party and no one attended, he indicated that this was confirmation that time travel was not possible."

Or he partied hard, tripped to the future and the past with the time traveler that showed up and then couldn't possibly report any of that for fears of messing up the timeline. This is a smart guy we are talking about here.

Re: Dr. Hawking's final joke...

[painandgreed]

You've completely misunderstood Zeno's paradox. You've merely stated one of his premises. The question at hand was whether an infinite count of events can be packed into a finite time. The answer is still unclear.

Unless you've taken calculus and have been show that the limit of a sum of an infinite count of events as the time each one takes goes to zero, equals a constant.

Re: Dr. Hawking's final joke...

[sexconker]

It does not.

SUM[i = -1, -inf] 9*(10^i) would be represented in decimal notation by 0.999... or similar.
That infinite series has a LIMIT of 1. It will NEVER reach one. It is NOT EQUAL to 1. Understanding the difference is fundamental to understanding calculus.

1/3 has can be represented in decimal notation by 0.333... or similar. Multiplying that decimal result by 3 will result in 0.999... or similar.
This is NOT EQUAL to 1. The representation 0.333... is indeterminate. Every single "proof" attempting to show that 0.999... is equal to 1 is abusing the fact that the infinite decimal representation is indeterminate.

If you think 0.999... is equal to 1, what do you think 999... is? Infinity? 1000... ?
The ellipsis or bar notation represents a repeating series (of digits or terms). For digits, that series may represent a rational number (such as 1/3), but you cannot know that from the ellipsis or bar representation alone.

Re:Dr. Hawking's final joke...

[Anonymous Coward]

If only there were some way you could have been warned.

Re: Dr. Hawking's final joke...

[samkass]

Nope. It equals 1.

Re:Dr. Hawking's final joke...

[HiThere]

You're making the presumption that the quantum state collapses, but if it doesn't, then time travel doesn't cause any paradox. We are just living within a portion of the state space where it hasn't been significantly noticed. We may have diverged recently from a portion where it was noticed. No paradox, both exist.

This is one of the consistent solutions. The thing is, the ways predicted for inducing time-travel are sufficiently extreme that it's not really surprising that we haven't seen any, so absence of evidence can't be used as evidence of absence. It's what you'd normally expect to see. This does, however, require that the multi-world interpretation be the correct one. (I don't *think* any of the other interpretations would allow that.)

Re:Dr. Hawking's final joke...

[samkass]

The easiest data set I can think of to mine for evidence of time travelers is 23andme. In theory, with enough data points you should be able to detect a discontinuity in the gene patterns such that you could detect someone going back in time and having children. It wouldn't even be that hard of a query... I have to believe someone there has tried it...

Re:Dr. Hawking's final joke...

[Anonymous Coward]

well if I were a time traveler I would never show up at a "party for time travelers". Just think about the problems I would have as soon as I proved to be a time traveler, at minimum I would end up locked in some secret government facility or worse.

You're right. Stephen Hawking is an idiot and we should burn all of his books and notes.

Re:Dr. Hawking's final joke...

[magarity]

well if I were a time traveler I would never show up at a "party for time travelers". Just think about the problems I would have as soon as I proved to be a time traveler, at minimum I would end up locked in some secret government facility or worse.

Except the guy hosting the party was in no shape whatsoever to try to lock anyone up.

Re: Dr. Hawking's final joke...

[lgw]

How do you complete an infinite number of action in finite time? That's the question. Zeno started with the premise that the sum converged to 1.

Re: Dr. Hawking's final joke...

[kumanopuusan]

That's neat, except that you can construct the real numbers as equivalence classes of convergent sequences of rational numbers, where two sequences are equivalent if and only if their difference converges to zero.

Re:Dr. Hawking's final joke...

[maestroX]

well if I were a time traveler I would never show up at a "party for time travelers". Just think about the problems I would have as soon as I proved to be a time traveler, at minimum I would end up locked in some secret government facility or worse.

Pretty moot as you can go back in time and set the clock one hour back.
This is what I usually do anyhow for continuing use of the limited timelines I visit.
Now, if only my interstellar cloud calendar (tm) syncs correctly. .

P.S. time travellers are really easy to spot, they only use present tense.

Re: Dr. Hawking's final joke...

[UnknownSoldier]

> It is NOT EQUAL to 1.

*facepalm*

False.

You are confusing presentation and representation.

Proof:

1/3 = 0.3333... (By Definition)
 
3*1/3 = 3*0.333... (Multiply both sides by 3x)
 
1 = 0.999... (Simply)
 
QED.

Q. Why?
Q. The same way there are TWO different way to present 1/3 (integer fraction) and 0.333 (repeating decimal) which represent the SAME value there are ALSO two different way to present 1 and 0.999.... which represent the SAME value.

1/3 IS EQUAL to 0.333...
1 IS EQUAL to 0.999...

It may appear counter-intuitive but rules of Math are consistent. It appears you failed Calculus.

Re:Dr. Hawking's final joke...

[JohnStock]

The many worlds interpretation avoids all of that crap. As the original article says, it's not been completely proven that TT is impossible.

Re:Dr. Hawking's final joke...

[Anonymous Coward]

And as far as we can tell, it isn't, to the point of ridiculousness, and our physics is validated and complete enough on this to be almost certain.

The only reason it is even remotely "uncertain" is become some physicists can't avoid staying out of the esoteric mental masturbation lime light. Those types are attention whores -- Hawking was definitely one of them -- and the situation worsens when armchair scientists and idiots start parroting them.

What we refer to as time is merely our perception across distinct moments that we can remember. Mathematically, we can treat time as another dimension, and plot things against that axis. Every so often, someone forgets that it is merely an abstraction -- a tool -- and plays around with the axis as if the number line was mutable.

When people mistakenly think you can reverse time like rewinding a film strip, remind them that the film strip is merely their memory of events, not reality.

Re: Dr. Hawking's final joke...

[painandgreed]

How do you complete an infinite number of action in finite time? That's the question. Zeno started with the premise that the sum converged to 1.

He should have talked to Leibnitz

Re: Dr. Hawking's final joke...

[lgw]

Again, that merely restates Zeno's assumptions when stating the problem. The question is: how do you complete an infinite number of actions in a finite time.

What your saying is "I ignore the question and blindly assume it's possible, and having done so, I know how long it takes". Yeah, that's not the interesting bit.

Re:Dr. Hawking's final joke...

[Anonymous Coward]

"And as far as we can tell, it isn't, to the point of ridiculousness, and our physics is validated and complete enough on this to be almost certain. Time travel introduces unresolvable paradoxes "

Not necessarily. Just because we don't know how the universe would 'resolve' such apparent paradoxes doesn't mean they are actually paradoxes. One possible resolution is the Novikov Self-Consistency Principle.

Close timelike curves (aka time travel) are a valid part of General Relativity. In fact, Kurt Godel showed that if the universe was rotating that time travel would be possible according to General Relativity. Without that, you would need something extremely massive arranged in a precise way, like cosmic strings or wormholes.

The problem with all of that is that we don't have a theory of quantum gravity, so we don't know whether that would rule out closed timelike curves. Hawking thought that quantum gravity would prevent time travel, he called it the Chronology Protection Conjecture.

Can't be excluded

[stealth_finger]

It can't be excluded that a T-rex will walk in, morph into a creature with the head of a crocodile, body of a lion, and limbs of a crab with big, big, titties that lays out in perfect english (with subtitles) everywhere that hawking went wrong and fill out some details. Doesn't mean it's going to happen though.

Re:Can't be excluded

[110010001000]

Exactly. To say that Time Travelers might exist opens the door to a lot of stupidity. Then people will say that Jesus might have existed, or the Earth might be flat, or any other lunatic thing. Hawkings opinions on time travel and AI really left a lot to be desired.

Re:Can't be excluded

[Anonymous Coward]

Jesus most certainly existed. There is plenty of documented proof of that. Now, whether He was the omnipotent Son of God, that is what is usually the subject of debate.

Re:Can't be excluded

[Sique]

There is not much evidence outside of Christian history. You could read Iosephus Flavius as some type of proof, but it's quite inconclusive, as he describes it as hearsay himself.

Re: Can't be excluded

[tysonedwards]

There I thought that there was undeniable proof via the genealogy and taxation records of the Roman Empire that Yeshua bar-Yosef existed, and it was Paulos who first referred to him as Yeshua bar Jehovah.

Re:Can't be excluded

[dcollins117]

Jesus exists. He's the Mexican fellow that mows my lawn.

Re:Can't be excluded

[jawtheshark]

A physicist walks into a bar and he orders a beer and turns to the stool next to him and offers it a beer. He finishes his drink and then leaves.

The next day he returns to the bar, orders a beer, and offers a beer to the stool next to him before finishing his drink and leaving.

This continues on for a week before the bartender finally asks, " Why in the world do you keep offering that stool a beer?"

The physicist replies " The laws of physics dictate that there is a slight possibility that at some point the matter above this stool could reform into a beautiful woman, who would then accept the drink."

The bartender is puzzled for a second before replying " The bar is full of beautiful women. Why not see if they will accept your drink?"

The physicist quickly laughs before saying " Yeah, but what are the odds of that happening?"

Re: Can't be excluded

[110010001000]

There isn't. He didn't even have a MySpace account.

Re: Can't be excluded

[drinkypoo]

There I thought that there was undeniable proof via the genealogy and taxation records of the Roman Empire that Yeshua bar-Yosef existed,

"Jesus is not mentioned in any Roman sources of his day". (Article then goes on to make numerous highly specious arguments in favor of the existence of Jesus Christ, like this one:

The earliest followers of Jesus declared that he was a crucified messiah. But prior to Christianity, there were no Jews at all, of any kind whatsoever, who thought that there would be a future crucified messiah.

This is the usual level of thinking involved in trying to prove the existence of Jesus. It's pathetic. What does that have to do with anything? Nothing. Jews were regularly being crucified at the time, so it makes all the sense in the world that they would invent a crucified messiah.

and it was Paulos who first referred to him as Yeshua bar Jehovah.

Who is Paulos? Did you mean Saul of Tarsus? He's the obviously fake author. His writings are super different from everyone else's and they're the only place Jesus claims Godhood.

Re:Can't be excluded

[stealth_finger]

Jesus most certainly existed. There is plenty of documented proof of that. Now, whether He was the omnipotent Son of God, that is what is usually the subject of debate.

You're right, Jesus does exist, has existed for a long time and will continue to exist way past man but, surprise ending. Jesus isn't the son of god, he's the sun god. As in, literally the sun. Look it up.

Re:Can't be excluded

[thomst]

dcollins117 confided:

Jesus exists. He's the Mexican fellow that mows my lawn.

Man. I wish I had mod points ...

Re:Can't be excluded

[phantomfive]

and is very obviously tainted -- either comes from Christians themselves or is a copy of their works.

Not really, there is stuff that is generally considered reliable.

If a preacher leading a popular movement of anything of the scale postulated in the Bible happened,

You might want to reconsider that the scale mentioned in the bible mostly isn't very big, at least until later when they came to the attention of Nero.

Re:Can't be excluded

[Anonymous Coward]

Just how big do you think the Bible says Christianity was. There are no numbers mentioned in the New Testament, but records collected from various churches that survived the fall of the Roman Empire indicate that the total number of Christians in existence at the time was extremely small, perhaps not more than 3-5% of the total population of the Empire. (FWIW I am a forensic anthropologist specializing in ancient Greek and Roman government records)

(PS, there is neither historical nor biblical support for exempting churches from taxation)

Captcha: Sinned... wow..

Re:Can't be excluded

[crunchygranola]

Any documentation comes from 2nd century, and is very obviously tainted -- either comes from Christians themselves or is a copy of their works. If a preacher leading a popular movement of anything of the scale postulated in the Bible happened, it would be mentioned in secular sources, which have quite detailed records of those times. Yet, any such mentions are conspicuously absent.

Convincing forgery is tricky to do. Most would be scribe-forgers altering documents they copy to insert things they would like to be there rarely, if ever, sophisticated at who do construct forged passages that would state out from sophisticated textual analysis (consideration of context and textual flow, writing style, word choice, etc.). So modern scholars have a pretty good handle on when passages in ancient texts by one author are altered by insertions of others.

We have Antiquities of the Jews written by the Jewish historian Josephus about 60 years after the death of Jesus, i.e. written in the First (not Second) Century. There are two passages in this that refer to Jesus that do appear and seem to be originally authentic references from Josephus's hand. They have been altered by Christian scribes to make them more affirmative of Christian claims, but do not appear to be wholesale fabrications inserted later. On the bare question of Jesus's existence the mere fact that any mentions would appear in Josephus's writing supports the historical existence of Jesus.

This reference meets the demands you make for there to be external surviving references of Jesus's existence. So they are "conspicuously absent" only if you ignore the references that do indeed exist.

Also, you have a very exaggerated sense for how detailed and thorough the surviving records about the First Century Roman Empire really are, and accounts of happenings in the provinces are nearly non-existent. We did not have a single contemporary piece of evidence of the existence of Pontius Pilate who ruled Judea for 10 years under his name appeared on an inscription found in 1963. Before that the only evidence of his existence were Christian literature and three mentions in non-Christian sources (Josephus was one). There many important Roman documents from that era we know of that have been entirely lost. One example: the last Testament of Augustus Caesar, we did not have a single copy of until fragments of it inscribed on plaques were found in Turkey about 100 years ago.

On the other hand, there was a lot of religious kooks (this particular thing hasn't changed...), thus it's possible the story has some basis in truth, but has been mangled beyond recognition.

So, it's like that old Russian joke: "Did you hear that in Moscow they give Volga cars for free?" "Sure, they do, you just got three details wrong. First, not in Moscow but in Leningrad. Second, not Volga cars but Zavmash bikes. Third, they don't give but take away.". Thus, Jesus might indeed have existed, save for some little details...

All this is absolutely true. We do not have any reliable accounts of really anything about Jesus and in keeping with what one expects from oral accounts, the later things were written down the more extravagant and fanciful (or imaginative) they become. But if we restrict the question to the most basic one - whether there was such a person as Jesus - then we have pretty good evident that it is yes.

The earliest evidence is best, and that would be the authentic letters of Paul (there are fake ones in the New Testament also) which were written within 20 years of the death of Jesus by a man who had become an adherent within 10 years of his death, and knew several people who had followed Jesus and knew Jesus personally including his brother James (who is also mentioned in Josephus). This documentation at least to existence is as good or better than most people we know of from ancient times who who were not leading members of society or else authors themselves. It is t

Re:Can't be excluded

[Cajun Hell]

It can't be excluded that monkeys will fly out of my butt.

Re:Can't be excluded

[KiloByte]

Tacitus' work was written AD 116; he himself wasn't even born decades after Jesus' alleged death. The passage in question reads:

Consequently, to get rid of the report, Nero fastened the guilt and inflicted the most exquisite tortures on a class hated for their abominations, called Christians by the populace. Christus, from whom the name had its origin, suffered the extreme penalty during the reign of Tiberius at the hands of one of our procurators, Pontius Pilatus, and a most mischievous superstition, thus checked for the moment, again broke out not only in Judæa, the first source of the evil, but even in Rome, where all things hideous and shameful from every part of the world find their centre and become popular. Accordingly, an arrest was first made of all who pleaded guilty; then, upon their information, an immense multitude was convicted, not so much of the crime of firing the city, as of hatred against mankind.

Show me a mention of "Jesus", "Jehoshuah" or anything of the kind. All that Tacitus reports is that, during the great fire of Rome, a group popularly referred to as "Christians" did exist and that their name was tied to a person named "Christus", a common biblical term that means "anointed one" -- which required far less chutzpah to claim than "messiah" (which, at the time, would bring a torches-and-pitchforks mob of their jewish neighbours who haven't been expelled yet).

Re: Can't be excluded

[Dragonslicer]

This is the usual level of thinking involved in trying to prove the existence of Jesus. It's pathetic. What does that have to do with anything? Nothing. Jews were regularly being crucified at the time, so it makes all the sense in the world that they would invent a crucified messiah.

No, it doesn't really make any sense at all. The messiah (Hebrew mashiach, "anointed") was simply the descendant of King David who would be anointed king of Israel. Kinda tough to do that if you're dead.

Re:Can't be excluded

[Dragonslicer]

"Christus", a common biblical term that means "anointed one" -- which required far less chutzpah to claim than "messiah"

"Anointed one" is exactly what the Hebrew mashiach means.

Re: Can't be excluded

[phantomfive]

You are disagreeing with most historians. When did you get your PhD?

Re: Can't be excluded

[KiloByte]

You are disagreeing with most historians. When did you get your PhD?

You mean, the vast majority of Bible scholars are Christians and thus have a strong belief Jesus existed?

Note my words earlier in this thread: "Any documentation comes from 2nd century, and is very obviously tainted -- either comes from Christians themselves or is a copy of their works.". To which, the answer was Tacitus... who wrote in AD 116, had no knowledge about Jesus at all -- merely about some "Christus" whose name obviously came from the group itself. Additionally, the only surviving copy is medieval, and has suspicious details like Pilate's rank which suggest an ignorant tamperer.

Re: Can't be excluded

[phantomfive]

The experts largely agree, and you disagree with them.

Any documentation comes from 2nd century, and is very obviously tainted

That's a judgment call, isn't it? What qualifications do you have?

Re: Can't be excluded

[KiloByte]

My qualifications here are not any higher than those of an average Slashdot reader -- ie, basic reading comprehension -- but that already puts us above the vast majority of humankind.

What I'm claiming here, is that Bible scholars who are Christians are about as authoritative as cancer scientists who are sponsored by a tobacco company. The vast majority of available literature is produced by such scholars, and additionally, there's no mark of of the author's belief -- nor of who really paid for a given cancer study -- and even if there was, a Christian is capable of being honest, thus any arguments must be judged solely on their own merit rather on who says them. Ie, appeal to authority nor appeal against authority don't apply here.

Thus, the best I can do is to take the arguments and use my, very weak and unqualified, understanding, and try to make sense of them. It might be enlightening to take a look at a less controversial topic first.

Re: Can't be excluded

[phantomfive]

The vast majority of available literature is produced by such scholars, and additionally, there's no mark of of the author's belief -- nor of who really paid for a given cancer study -- and even if there was, a Christian is capable of being honest,

Then link to your expert who is not a Christian.

Re: Can't be excluded

[phantomfive]

A more respectful explanation follows:

In the 1800s it became popular to question the authenticity of ancient historical characters, naturally the Bible was a prime target, but also people like Bodhidarma, or King Ashoka seemed to legendary to be real (and of course, there are many legends about him, so it seemed natural to consider him as unreal as the great flood). Over time however, a lot of the bible turned out to be real. We found external corroboration of many events. For example, there was a war mentioned in the bible where Assyria put Jerusalem to siege, and then the Lord cursed the Assyrian soldiers with sickness, so they left. Eventually a stone pillar was found commemorating that event, but from the point of view of the king of Assyria, who said he had won the battle (the pillar is now on view to the public at the Oriental Museum at the University of Chicago.....I highly recommend visiting it, and the library which has the biggest multi-volume dictionary you will ever see). Later we found an account from the Greek point of view, which said the Assyrians lost and left because mice invaded their camp. Now, which of these stories is true, that is still a historical mystery, but after the 600BC-900BC range, the record gets more and more reliable. Hezekiah's tunnel has been found.

So what we see around the world, as more evidence has been collected, is that the weight of evidence suggests that most of these people actually were real, that the legends accreted around a core historical event. As another example, not long ago, there were questions of whether Pontius Pilate was a real person or not, since there was no mention of him in contemporary historical records. Since that time, of course, we've found the Pilate stone.

There was clearly a movement centered around Jesus Christ in Jerusalem. Based on the evidence that shows how it spread to the East and the West and the South, dating the start of the movement to the fourth decade AD seems reasonable. There is also no reason to believe that it wasn't centered around an actual person. That kind of thing happens fairly often.

A more interesting question is, "Why did Christianity spread so quickly? What was it that seemed so convincing to the Romans and others who heard it?" I don't really have an answer for that.

Re: Can't be excluded

[KiloByte]

The Old Testament is a very diverse mixture of many types of books: mythology, historic records, poetry and even porn (yes, this is how the ancients described sex, even when writing on the wall of a brothel). So tales of Moses and Abraham are 100% invented (heck, even Jah himself was adopted only in Kanaan), while parts from 1000BC get at least names of kings and major facts right. It's still greatly tampered by current wishes of priests of the day: for example, according to the Bible, the kings got the cult of Asherah completely eradicated by 1000BC while it's only by 800BC when we really get stelas dedicated to "Jahveh and his Asherah" (both deities were worshipped elsewhere much earlier). Dating of monotheism is disputed, but it hasn't even been introduced earlier than 500BC and hasn't been universal among Jews until around 100BC.

But that's the Old Testament, where people at least had some interest in tales of the past. Whoever invented Christianity and wanted to give it a veneer of legitimacy by picking a preacher of days past didn't bother to do even the most basic fact checking. An ordinary believer of the turn of 1st/2nd century did not care nor have the means to check a census of a hundred years past, the rules of that census, records of who governed the province by then, whether they did order any mass-scale atrocities such as murder of first-borns in a large area, etc. These tales were pretty tall but people were not used to fact checking (and, judging by spread of faux news, are not used to today).

A more interesting question is, "Why did Christianity spread so quickly? What was it that seemed so convincing to the Romans and others who heard it?" I don't really have an answer for that.

Because the new religion plagiarized elements of pretty much every popular cult of the day. Monotheism started to be in fashion (see Mithraism), the educated were all about platonism, the poor wanted a promise a paradise, etc. The new religion was masterfully engineered for the then-current audience.

Thus, for Jesus, it seems he wasn't a complete Comrade Ogilvy, but whoever designed Christianity didn't care -- or perhaps even know -- about Jesus' life nor what he preached. Plato-like philosophy in particular would be especially unlikely for an illiterate Jewish laborer.

Re: Can't be excluded

[phantomfive]

Whoever invented Christianity and wanted to give it a veneer of legitimacy by picking a preacher of days past didn't bother to do even the most basic fact checking.

Oh, so you think it was created around an actual preacher? In what year approximately do you think the movement started?

Re: Can't be excluded

[KiloByte]

I think it was a multi-stage process. Religious movements, usually limited to a single preacher and his followers, were about as abundant as bugs in Windows. People were more religious than they are today, and we're not exactly lacking in this department even by present day.

Thus, it is quite likely one was indeed run by a guy named Jehoshuah son of Pantera (perhaps even of that particular Tiberius Julius Abdes Pantera).

What I'm putting in doubt is the relationship between this itinerant preacher and the new cult. First, no verifiable facts about his life match -- everything we can check (the census, its rules, who governed, etc) is false; it looks to me as if it was just a ploy by a new group of demagogues to take over a bunch of vulnerable followers who just lost their guru. Heck, it's possible they got even the name wrong! Second, any doctrinal relationship looks too unlikely to me: a cult an illiterate laborer comes up with looks completely different from one designed by people with good knowledge of cults from far regions of the Empire.

Re: Can't be excluded

[phantomfive]

First, no verifiable facts about his life match -- everything we can check (the census, its rules, who governed, etc) is false;

The facts of his life are largely correct, the worst you can say is that some of the dates are slightly inaccurate, which isn't surprising for a document written decades after the event.

Second, any doctrinal relationship looks too unlikely to me: a cult an illiterate laborer comes up with looks completely different from one designed by people with good knowledge of cults from far regions of the Empire.

So you see the Gospel of Thomas to be more accurate in terms of what an actual Jesus would have taught?

I can not do that.

[houghi]

There is a reasson I can not do what they ask : GDPR. And they are lucky. I just saved them 20.000.000 EUR in fines. And if you say that by then Brexit will have been completed and/or the GDPR will not apply, just you wait and see what happens. You are clearly not one of us.
Also do not ask to change the past. We did that once. Now Trump is POSTUS. Well, could have been worse. No, not Clinton. We change history, not politics.

Re: I can not do that.

[Anonymous Coward]

The GDPR is gay as hell. Europe wants its laws to apply to the rest of the world. From here in South Africa: FUCK YOU!

Re:I can not do that.

[omnichad]

It's not called POSTUS in this timeline.

Re:I can not do that.

[houghi]

Sorry. Stuped typo: POSOTUS. I assume the OTOS still means Of The United States.

Imagine when Hawking himself shows up!

[ChunderDownunder]

Didn't Hawking send a message to himself on his deathbed back to the point in time he created time travel?

"Dear Steve, they'll have a memorial service for us in a couple of months. Love Steve"

Seems more like an inside joke to me..

[toonces33]

2038 is when a 32-bit time_t overflows.

Or maybe the software they wrote for the application process is just buggy. Wouldn't be the first time that ever happened.

Re:Seems more like an inside joke to me..

[complete loony]

Yeah, but that's the 19th of January. Maybe if you attempted to enter a date after that, it would revert to 1970....

Re:Seems more like an inside joke to me..

[argStyopa]

32 bits is all any universe will ever need.

Re:Seems more like an inside joke to me..

[houghi]

Perhaps we ALL revert to 1970. For all we know this is the millionth time we are doing that and we have no way of knowing if we are in a loop.

That means we ALL timtravel back to 1920 and the universe goes back to that state.

I mean, in "Hedgehog day" 1 person became aware that he was in a loop. Imagine that nobody was aware of that and that over the period of about a human life instead of 1 day.

Re:Seems more like an inside joke to me..

[Anonymous Coward]

Does this mean I have to start wearing bell-bottoms again?

E. C. George Sudarshan passed away today

[Anonymous Coward]

E. C. George Sudarshan passed away just today.

So, tachyons won't mind since no many know him.

But when

[Anonymous Coward]

I can assure you it's always 'now'. You just think you're travelling in time.

But, when will then be now? Is now then?

And then is when now?

Re:But when

[ACalcutt]

Colonel Sandurz: Try here. Stop.
Dark Helmet: What the hell am I looking at? When does this happen in the movie?
Colonel Sandurz: Now. You're looking at now, sir. Everything that happens now, is happening now.
Dark Helmet: What happened to then?
Colonel Sandurz: We passed then.
Dark Helmet: When?
Colonel Sandurz: Just now. We're at now now.
Dark Helmet: Go back to then.
Colonel Sandurz: When?
Dark Helmet: Now.
Colonel Sandurz: Now?
Dark Helmet: Now.
Colonel Sandurz: I can't.
Dark Helmet: Why?
Colonel Sandurz: We missed it.
Dark Helmet: When?
Colonel Sandurz: Just now.
Dark Helmet: When will then be now?
Colonel Sandurz: Soon.
Dark Helmet: How soon?

Re:But when

[yodleboy]

Whatever... My wife didn't make coffee this morning. Now I can't watch radar. Time to play with my dolls.

Re:But when

[Anonymous Coward]

Even a thousand years ago is now. "Time" is just consciousness moving through different states of matter. Those states never change. Everything that ever was still is as is everything that ever will be.

Re:But when

[antdude]

http://www.youtube.com/watch?v... for its video.

Also, Rick voice acted in last week's Goldbergs S5E21: https://www.yahoo.com/lifestyl... ...

What about -invisible- time travelers?

[mccalli]

Hmm? Can that be ruled out? Or remote viewers watching their time travelling nanobot cameras broadcasting through the subetha....

Not so complicated

[sjbe]

he indicated that this was confirmation that time travel was not possible.

All that would prove is that time travelers didn't come to the party.

Re:Not so complicated

[CSMoran]

he indicated that this was confirmation that time travel was not possible.

All that would prove is that observable time travelers didn't come to the party.

FTFY

Re:Not so complicated

[bobbied]

he indicated that this was confirmation that time travel was not possible.

All that would prove is that observable time travelers didn't come to the party.

Heisenberg showed up but it wasn't certain if he was observed there.

Re:Not so complicated

[Anonymous Coward]

Heisenberg showed up but it wasn't certain if he was observed there.

Descartes showed up but thought he didn't.

Re:Not so complicated

[David_Hart]

he indicated that this was confirmation that time travel was not possible.

All that would prove is that time travelers didn't come to the party.

everyone knows that Time Travelers only attend the good parties...

Re:Not so complicated

[maestroX]

he indicated that this was confirmation that time travel was not possible.

All that would prove is that observable time travelers didn't come to the party.

FTFY

It's really bad taste to make jokes about Hawking's blind spot.

Re:Not so complicated

[Anonymous Coward]

All that would prove is that Hawking lied that time travelers didn't come to the party in order to prevent a paradox.

Re:Not so complicated

[EnsilZah]

So you're saying that on top of navigating the currents of time these fuckers are fucking ninjas as well?

Re: Not so complicated

[Anonymous Coward]

Maybe Hawking had the wrong phone number and the time travelers arrived at the wrong location in time and space based on finite probability. They just didnâ(TM)t have an infinite improbably drive.
Towel day is coming on May 25!

Re:Not so complicated

[someoneOtherThanMe]

...because as soon they realize that the party they are currently attending is not a good one, they go back to before it started and unattend it. It is one of the time travel paradoxes that they miss all the parties that could be good but were spoilt by their presence.

If it were possible to time travel

[Chrisq]

If it were possible to time travel then surely someone would have gone beck in time and killed Muhammad. Since islam exists time travel clearly has not been achieved

Re:If it were possible to time travel

[Sique]

If it were possible to time travel then surely someone would have gone back in time and killed everyone trying to kill Muhammad. Since Islam exists, time travel clearly has been achieved.

Re: If it were possible to time travel

[Chrisq]

Should say "has not been"

Re:If it were possible to time travel

[Anonymous Coward]

Maybe there was someone worse than Muhammad that was killed, and we are already left with the better option.

Re:If it were possible to time travel

[Anonymous Coward]

No need to kill them. Just outwit them with spiders:
https://islam.stackexchange.com/questions/42643/how-authentic-is-the-story-of-the-spider-web-at-the-cave-of-thawr

Re:If it were possible to time travel

[Anonymous Coward]

Maybe it means that all religions have died out and become as mythological as the Greek gods. That no one believes in that nonsense anymore and so are far more enlightened. And they use history as an example of what not to do. Why go back in time when their present and future are better than the past. They could screw it up.

Re:If it were possible to time travel

[Actually, I do RTFA]

Maybe time travelers went back in time and saw him performing various miracles and now Islam is recognized as objective fact?

Possibility of werewolves and vampires...

[DeplorableCodeMonkey]

If someone went back in time and changed history, you wouldn't even know it. It's pretty much an impossible to falsify argument. So yeah, it could be true, but then Big Foot could be real along with werewolves, vampires, the Loch Ness Monster, etc. Or how about those sightings of pterodactyls in Papua New Guinea? I mean FFS, if you're going to seriously entertain the time traveler hypothesis, knowing it probably can't be falsified, you can't dismiss things like cryptids either.

Re:Possibility of werewolves and vampires...

[shess]

If someone went back in time and changed history, you wouldn't even know it. It's pretty much an impossible to falsify argument. So yeah, it could be true, but then Big Foot could be real along with werewolves, vampires, the Loch Ness Monster, etc. Or how about those sightings of pterodactyls in Papua New Guinea? I mean FFS, if you're going to seriously entertain the time traveler hypothesis, knowing it probably can't be falsified, you can't dismiss things like cryptids either.

So you're saying that Nessie was a time traveler? OMG! It explains so much!

Re:Possibility of werewolves and vampires...

[Anonymous Coward]

If someone went back in time and changed history, you wouldn't even know it. It's pretty much an impossible to falsify argument. So yeah, it could be true, but then Big Foot could be real along with werewolves, vampires, the Loch Ness Monster, etc. Or how about those sightings of pterodactyls in Papua New Guinea? I mean FFS, if you're going to seriously entertain the time traveler hypothesis, knowing it probably can't be falsified, you can't dismiss things like cryptids either.

God dammit! The Loch Ness monster is real.

He just asked me for tree fiddy yesterday.

we have all been here before?

[Anonymous Coward]

likely show up again from time to time? what a mess? cease fire, stand down. there are originals & 'reprints' in every town.. thanks again..

I couldn't attend,

[Martin S.]

My assistance dino, was excluded from the venue.

Space Balls

[Anonymous Coward]

Oh please! Oh please have Mel Brooks make a Space Balls II before he goes!

Re:Space Balls

[Anonymous Coward]

Oh please! Oh please have Mel Brooks make a Space Balls II before he goes!

Or perhaps "Spaceballs 3: The Search for Spaceballs 2."

First Post!

[Anonymous Coward]

#Trump2020

They're busy elsewhere

[sabbede]

Drinking at a small bar on Long Island.

Re:They're busy elsewhere

[Anonymous Coward]

I don't get it.

Re:They're busy elsewhere

[thomst]

sabbede explained:

Drinking at a small bar on Long Island.

Where it's policy that they don't get to run a tab ...

Despicable him

[Anonymous Coward]

Hawking was a despicable atheist. He believed in everything but God.

His mind was open to everything, to every idea, to every weird concept. But he did not believe in God.

Now that he's in his grave (or was he burned?) maybe he can see God more clearly.

Re:Despicable him

[crunchygranola]

I don't know why people would vote down such a devoted follower of Thor.

I recommend everyone to have attended

[mrbester]

I can assure you all it was a lovely service and a fitting send-off. Not enough vol-au-vents at the wake, however. Maybe because some greedy gits went twice.

Not possible!! Otherwise Known As Slashdotted!!

[Anonymous Coward]

"Come back." Kill parents!! Or their parents!! Or ...!! Not possible!!

pseudo science

[sdinfoserv]

“time travel had not been disproven” – um, Professor, that’s not how science works and you knew it.. Those who make a claim (ie: time travel exists), bear the burden of proof to demonstrate that possibility.

Re:pseudo science

[will_die]

No they don't. If they did then the person making the claim that time travels did not exist would bear the burden of proof to show that is a possibility. As it is right now the reason we don't take time travel as real is because all those that have said they are have been ignored or classified as having mental problems; that is not a scientific proof.
Until either side can formulate a series of observations or tests they can perform, they have not really progressed more then asking a simple question. Neither side is really at a hypothesis stage because of the lack of knowledge in this subject and ideas on how to test for it.

Re:pseudo science

[sdinfoserv]

sorry, remember Hitchen's razor: "What can be asserted without evidence can be dismissed without evidence".

Re:pseudo science

[Anonymous Coward]

The burden of proof is always on someone making the extraordinary claim. Ordinary, in this case, is that there are no time travelers since they're not a general part of the observed universe. Extra-ordinary is that time travelers exist. There's no need to prove the claim that time travelers don't exist, because it's not an extraordinary claim.

As for testing it, there's no evidence people exist that have certain knowledge of the future. If such were to come forward, such as when Hawking published the date of a party only after the party, it would be potential evidence of time travel. That is how Hawking tested the hypothesis. The test did not reveal any time travelers, no more than any other test has. No one has successfully demonstrated the extraordinary claim, and until they do we accept the ordinary claim. That's how science works.

Re:pseudo science

[arth1]

According to the common accepted theories, the laws of physics work in both directions. That's the null hypothesis. That the arrow of time can only point one way is the anomaly here, and the extraordinary claim.

It may be that we can only observe in one direction, but as of yet, there's really not much except subjective observations that support the claim that time and entropy can only work in one direction. Measuring data objectively might be impossible without begging the question.

That doesn't mean we cannot safely assume that we won't be able to travel backwards in time, just like we can safely assume there was no "before" the universe. At present levels of understanding, it can neither be proven nor disproven, but what we observe tells us that from our point of view, it's a safe assumption that we can't. That doesn't imply that our point of view is the only valid one. If anything, the null hypothesis should be that it isn't. But it's our point of view, and seems valid for us.

Re:pseudo science

[will_die]

That has no basis in the scientific process but thanks for backing up what I wrote, from that quote you cannot dismiss time travel because you don't have any evidence it does not exist.

Re:pseudo science

[sdinfoserv]

It is exactly the basis. There is no evidence for time travel. Therefore it's notion shall be dismissed till such time as evidence exists. ..

Great choice

[Anonymous Coward]

So time travellers have a choice between going to meet with the alive Hawkins at his Time Travellers party, or going to his wake?

Why not both?

There's no need to hold a second Time Travellers welcome event: it has been done, nobody came.

To do this AGAIN is an insult to Hawking.

It was a great memorial service

[Anonymous Coward]

I hope to go again last year.

Time travel just an Engineering Problem

[Roger W Moore]

...and would require unfathomable physics to carry out (on the order of constraining the energy of a hydrogen bomb in the volume occupied by a human such that no damage or radiation occurred.)

...which means that it is not "unfathomable physics" since you claim to have just "fathomed" what is needed. Indeed there is a theoretical time machine consisting of two, linked Black Holes. If you can create that then you accelerate one of the holes up to very close to the speed of light and then passage through them would take you back in time. However, apart from constructing the two, linked Black Holes you also need something with negative mass to open the singularity to allow objects to pass through.

If this even is possible it requires unbelievable energy densities - far, far greater than an H-bomb since you need enough to create a singularity and then hold it "open". We also know of nothing with negative mass (gravitationally repulsive) but, if it is ever possible to build such a thing, it does solve the problem of time travellers from the distant future because it is only possible to travel back in time to the point where the machine was constructed and not before.

So the physics of time travel might have just have been "fathomed" and, if so, it's now just an engineering problem.

Maybe we are just not very interesting

[raxtich]

It's a bit selfish to think a time traveler would even be interested in visiting this exact period in history. What if time travel is discovered 250,000 years from now? Our little blip in that amount of accumulated history might simply be too boring and insignificant to be bothered with.

Windows Service

[Anonymous Coward]

The title made me think for a few seconds that someone made a Windows Service (background server process) called Stephen Hawking Service and that it is still churning out good new work. That would have been impressive...

Going back in time changes polarity

[ITRambo]

I'll take a pass on traveling back in time, since I believe I'll simply become anti-particles during the transit. That might be an unpleasant experience.

Re:Going back in time changes polarity

[RKThoadan]

Is it worse than being drunk?

Stupid is as stupid does

[sjbe]

To say that Time Travelers might exist opens the door to a lot of stupidity.

Only to those already likely to be stupid. No lack of those no matter what anyone actually says.

Then people will say that Jesus might have existed

It's almost certain Jesus existed or at least someone who filled the role. What is in doubt is that Jesus was anything more than an unusually successful cult leader who convinced people he was a deity. Happens all the time even today. See Joseph Smith or L Ron Hubbard for modern day examples of cult leaders founding churches. Christianity and Islam are just examples of the same thing several centuries earlier.

Other Possibilities that Can't Be Excluded

[Anonymous Coward]

Asteroid Collisions
Alien Abductions
Outbreak of Nuclear War
Rampage Shootings
Rapture
Gamma Ray Burst
Passing Singularity
Blackout
Rain
Tornado
Earthquake
Supervolcano Eruption
Nearby Reactor Meltdown
Chunnel Collapses
Trump Wins Nobel Peace Prize
Hawking's Death is Misdiagnosed
Tsunami

I don't buy it

[p51d007]

I love the what if so and so went back in time and killed what's his name. Sorry...I haven't ever, nor will ever believe in time travel. Even IF someone came up with a flux capacitor LOL.

Re:Reporters: Dumb as Nails Again!

[jellomizer]

Well it was a stupid article anyways, because a lot of systems don't bother checking if Date of Birth is before today date.

Also to note Javascript (normally the first line of data validation) Ints are 32 bit

Time is one way....

[bobbied]

It's pretty clear that time is a vector that can only go one way...

You can "slow" time, maybe even "stop" time for a specific observation of events, but it doesn't go backwards, always forward, always advancing. So you cannot go BACK in time, only forward at varying speeds.

I look at time as being the same concept as entropy which is always increasing, always going one direction...

The only fly in this ointment is from Hawking himself. Black Holes emit Hawking radiation... Which is not easily explained with time going but one way.

Re:Time is one way....

[Anonymous Coward]

Time is an illusion. We think that because our meat suits have a beginning, middle, and end, so must the multiverse.

Everything that has ever been or will ever be just IS. Your limited consciousness fabricates "time" to make sense of its three-dimensional experience.

"Time travel" is a mathematical certainty, no matter what your delusion tells you.

We have a few

[hcs_$reboot]

We have a few born in 2019, unfortunately they’re too young to realize they’re time travellers.

Comment removed

[account_deleted]

Comment removed based on user account deletion

non-disclosure

[Anonymous Coward]

Time travelers are forbidden to speak about their time traveling whilst traveling in time.. meh.

The Doctor

[Anonymous Coward]

Well we know the doctor will be there!

so much hipe for the Unix time limitation?

[AlwinBarni]

The future birth date seems to me totally not intentional and just related to Unix time limitation.
If truly time travelers were expected, wouln't the time go much into the future and not just till 2038?

Re:so much hipe for the Unix time limitation?

[HiThere]

Well, that's only a Unix time limitation on a 32 bit machine. But perhaps it's an old box, or perhaps they're using an old framework. More likely it's a joke based on that traditional limit.

If time travel exists

[Anonymous Coward]

Why would you show up to his funeral? If you admire the man so much why not go back to when he was alive and offer a cure for his condition.

Not just when, but 'where'?

[Anonymous Coward]

Space is always expanding. The Milky Way does not sit still, but is constantly rotating. As such, the arms are moving through space. The sun and the solar system travel with them. The solar system travels at an average speed of 515,000 mph (828,000 km/h). https://www.space.com/19915-milky-way-galaxy.html

So to time travel you need to know exactly where that place in space Earth was/is when you time travel. Complicates basic movie plots a bit.

Need to understand causality

[Roger W Moore]

No, a time machine does not violate causality any more than a car does.

Unless that car can travel _really_ fast, faster than light in fact, that's not true. Causality in physics simply stated is that if event A causes event B then A must always occur before event B. If event A is the time machine departing and event B is the time machine arriving at its destination then, unless you have a really boring one directional time machine that only travels to the future (like a car!), the moment the time machine travels to the past it has violated causality. No fancy temporal paradoxes are required: simply having a cause occur after the effect is sufficient.

Causality Violated even in a Multiverse

[Roger W Moore]

We don't live in a universe. We live in a multiverse.

Firstly, there is absolutely zero evidence of this. It might be true, and some theoretical physicists (including a colleague) have suggested this but that in no way makes it true.

Secondly, even if this is true the fact that the time machine departing for the past occurs after the time machine arrives is sufficient to violate causality which, simply put, is just the requirement that if event A causes event B that event A occurs before event B. The multiverse conjecture may be a way to solve all the paradoxes of time travel but it still does not stop causality from being broken.