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Near Light Speed Travel Possible After All?
DrStrabismus writes "PhysOrg has a story about research that may indicate that close to light speed travel is possible. From the article: 'New antigravity solution will enable space travel near speed of light by the end of this century, he predicts. On Tuesday, Feb. 14, noted physicist Dr. Franklin Felber will present his new exact solution of Einstein's 90-year-old gravitational field equation to the Space Technology and Applications International Forum (STAIF) in Albuquerque. The solution is the first that accounts for masses moving near the speed of light.'"
Weapons don't need to stop..
I am a viral sig. Please copy me and help me spread. Thank you.
What was making impossible near-lightspeed travel? Only FTL was prohibited. Problems like engines, fuel, shielding etc. are only technological problems.
I honestly don't know, but the idea of stopping a meteor from hitting earth came to mind.
Theres no point in travelling at close to light speed if your have no way of stopping....SPLAT
Well, considering that the nearest star systems are greater than 4.3 light years away, you do not have to worry about it, as you would be dead from starvation.
It's the same reason that Nuclear subs are not limited by how much time they can stay underwater, but how much food they can carry. The need for food makes such long distances impractical, if not intolerable. "Growing" food along the way would mean a very limited diet for eight years (assuming you want to come home), something else that is intolerable.
The first use of this could be unmanned probes - but a four year wait time for signals to travel means that it would be impossible controlling it, and would have to have it's own artificial inteligence.
Of course, if you just wanted to visit the Mars and breath its clean fresh air and gaze upon its deep green pastures then this...oh wait...Mars doesn't have that.
I think the best way to travel long distances is by using a stargate. Mondays on the sci-fi channel.
Take the cheese to sickbay, the doctor should see it as soon as possible - B'Elanna Torres, "Learning Curve"
Bussard ramjets are just cool and fine, and i liked the idea, too.
But the physics dont work out.
You get at most 2% or so of the mass converted into energy by the fusion process, even if you could fuse everything together perfectly efficient. But once your spaceship is moving quite fast (more than 10% or so of the speed of light), you will need to use more energy to move and collect the particles in your flightpath than you could possibly get by fusing them together.
It just doesnt work out if you look at the big picture.
HI O WISE PRINCE. WHT TOOK U SO DAM LONG?
I think you need to reevaluate that.
h tml
For a traveller on the ship it would only seem like months. For the people left behind it would be years.
Look here. http://members.tripod.com/wmhxbigguy/Theory/time.
You are completely missing the point even though I was at great pains to spell it out. He claims his deductions are from Einstein's equations. This is impossible. Therefore he has made up new physics. Anyone can make up new equations. Absolutely anyone. This isn't new science at all. Look, I can do it. I think I'll say F=ma^1.0002 and show how I can use this to violate conservation of energy and generate free power for all. You can't just make up new equations to solve an engineering problem unless you have something motivating them besides an attention grabbing headline. Maxwell didn't wake up one day and say that electromagnetism satisfied his equations. Einstein didn't just make up E=mc^2. People who make up new physics without any kind of data to motivate it are crackpot, especially when they go on to claim they have invented the warp drive etc. Anti-science? You make me laugh!
"The White House is not an intelligence-gathering agency," -- Scott McClellan, Whitehouse spokesman.
I think you have good reason to be skeptical, I'm not convinced this guy isn't a crank. Anybody can post a paper on a preprint server. Does he have any papers on this subject that have actually made it into a peer reviewed journal?
Also this story is basically based on a press release from Starmark, the company that this so-called "noted scientist" founded himself, so basically he wrote the press release I'm guessing.
Also the fact that he's giving a talk at a conference means nothing, I've been to plenty of conferences where they let a few cranks give talks. I sat through a talk on Creation and the Big Bang at a Astrophysics conference once and the guy was a loon.
That said the biggest proof that this guy could be a crank is the fact that this story got posted on Slashdot, where something like 90% of the science stories are crap.
Ok, I've worked in gravity for a while, but unfortunately I haven't time right now to go through this guy's paper. Several things are setting off my B.S. detector, though.
First, this guy is not a "noted" physicist, let alone a noted gravitational physicist, as far as I can tell. He published some papers in accelerator physics while affiliated with the Naval Research Lab. He has no publications, or as far as I can tell, training in general relativity. He's now affiliated with some company ("Starmark, Inc.") in San Diego. Furthermore, gravitational physicists generally give talks at gravity conferences (or at least physics conferences), not space engineering conferences (which have drastically lower standards when it comes to gravity, since the organizers of the conference typically have no GR background).
Second, I skimmed the preprint of his (unpublished) "antigravity" paper. He claims that a distant observer watching a particle fall into a black hole, in the (initial, local) rest frame of the particle, will see the black hole to approach the particle, and then cause the particle to accelerate away from the black hole. This is not in any weird "warp drive" spacetime, but in ordinary Schwarzschild spacetime — such as the spacetime outside of a star or a planet (!). Yes, you read that right, according to him, even planets create antigravity (if you're traveling fast enough). This bears no relation to anything I know about orbits of particles in Schwarzschild spacetime.
Then he mentions performing a Lorentz transformation of a particle trajectory into the frame of a distant observer. This is impossible. You can only apply a global Lorentz transformation to a flat (Minkowski) spacetime, not a curved spacetime (such as Schwarzschild). Well, you can apply a transformation to a flat tangent space at a point in a curved spacetime, but you can only transform a vector in the tangent space at that point, not an entire trajectory that spans a continuum of points. It is true that Schwarzschild geometry is asymptotically flat for "distant" observers, and he's speaking of transforming into the frame of a distant observer, but the fact remains that you cannot Lorentz transform a worldline that is not entirely within an approximately flat region of spacetime (and his trajectories definitely aren't always far from the gravitating body).
Now, you're free not to buy my suspicions, because as I said I haven't the time to go through all his calculations and see what's up (general relativity calculations are a pain in the ass). My bet, however, is that he's simply misinterpreting a coordinate quantity as having physical meaning. This is a common error for GR beginners (and you can see a prime example of it in the crackpot A. Mitra, who claims that black holes contradict the Einstein field equations based on his misinterpretation of coordinate derivatives in Schwarzschild spacetime). The thing about GR is that you can write solutions in any coordinate system you want, and you have to make sure that the quantities you're calculating are physically meaningful, and not just an artifact of whatever coordinates you happened to choose. Anyway, that's my guess based on what this guy has written so far and the kind of errors I see people make when making "wild" claims in GR. But it's also possible he simply made a math error. I am not betting, however, that he has suddenly discovered antigravity lurking within the ordinary Schwarzschild metric.
No. No, no, no, no, no, no.
... well, actually, nothing - you just seem to think it applies to all parties, which is not the case.
If you were headed right at someone at the speed of light, you would just seem INCREDIBLY blue-shifted (more energetic). You would not, ever, at any time, seem to be moving faster than light.
If a person is travelling at substantial portions of light speed they will experience time dilation. People moving at near the speed of light would experience, say, a 4.3 LY trip at high speed as, perhaps, several months, but an outside observer would, from whatever position they were standing, see the trip as taking at a minimum 4.3 years + whatever extra time was needed because the ship was slower than light.
You seem to be confusing time dilation (an effect on those moving at high speed) with
Since I can't tell them apart, I treat all ACs as the same person.
Time Dilation doesn't actually help much here. You have to accelerate to high speed and deccelerate at the end of the journey. Human beans can handle high accelerations for brief times with few ill affects, but we're talking months here. I suppose if you remain strapped into a squishy chair without having to move around too much then two or three g's might be more reasonable, but I'm pretty sure noone's done the studies.
Anyhoo, I typed "relativistic acceleration" into google, and two clicks later I was here.
It's a little disappointing. A traveller would only get up to 95% of the speed of light before it was time to start deccelerating. For longer trips, however, the effect would be greater.
Those people who think they know everything are a great annoyance to those of us who do. (Isaac Asimov)
Are you comfotable with the notion of time travel?
"The White House is not an intelligence-gathering agency," -- Scott McClellan, Whitehouse spokesman.
"Everthing else [in science] is simply theory. Which is based on some authority and never allowed to be questioned."
Wrong, wrong, wrong, and a thousand times wrong!
The whole basis of science is that everything is open to question. There are few things more prestigious in science than to refute a previously accepted theory. Ever heard of a guy named Albert Einstein? Yeah, thought you might have. Used to be that Newton's theories were the accepted way in which the universe worked, but Einstein showed differently.
The main reason it seems like some theories are "unquestionable" is simply because most of the ways in which people choose to challenge them have been shown time and time and time again to be false.
If you get 100 people a day proposing a design for a perpetual motion machine using a series of cogs, wheels, and magnets, you're not going to take the time to explain to each and every one why their design won't work, instead, you're just going to tell them to bugger off and leave you alone.
Of course, scientists are human, and at times they will reject things inadvertently which they shouldn't. However, if you think you have a good explanation as to how/why we can, in fact, travel faster than the speed of light, instead of whining to Slashdot about how stuck in the mud scientists are, why not publish it? You'd be the next Einstein!
Curiosity was framed. Ignorance killed the cat.
Replying to my own post, as I forgot to mention something else, and Slashdot's "edit post" button has undergone a total existence failure...
The parent also mentioned that scientific theory is based on authority. This is utter nonsense. Authority counts for nothing in science.
We accept Einstein's theories as being correct. Why? Because he was a really smart guy, and therefore must have been right? No. Because he showed exactly how and why his theories were correct.
If I tell you that water turns to ice or steam sometimes, and that's the way it is, because I say so, and because I'm smarter than you, then you'd probably tell me to get stuffed (and rightly so)
On the other hand, if I tell you that cooling water to 0C causes it to freeze into ice, and heating it to 100C causes it to boil, giving off steam, then you can try for yourself in your own kitchen. It doesn't matter if you think I'm a genius or a raving lunatic - it doesn't even matter if I actually AM a raving lunatic. The only thing that counts is whether it works or not. And the things we accept in science are those that work - and if we don't know, we run with our best current explanation based on the avaliable data until a better one comes along.
That's the wonderful thing about science. It's perfectly possible for some unknown, uneducated nobody with a bright idea to overturn hundreds of years of accepted science.
(of course, it's also rather unlikely, as the simple fact is the vast amount of unknown, uneducated nobodies who try to do that are completely off the mark, and don't have the first clue what they're talking about... doesn't mean it can't happen though.)
Curiosity was framed. Ignorance killed the cat.