New antigravity solution will enable space travel near speed of light

[molitov bankroll]

Check out this article.

http://www.physorg.com/news10789.html

[LadyWrestler]

[ QUOTE ]
Check out this article.

http://www.physorg.com/news10789.html

[/ QUOTE ]

If this is proven, all I can say is <font color="red">OH WOW!</font> /images/graemlins/tongue.gif

[Metric]

Here is a link to a preprint of his paper.

http://xxx.lanl.gov/abs/gr-qc/0505099

I did a search, and this is apparently the second physics paper he has written (and posted to the preprint archives) -- both are related to antigravity.

I briefly took a look at this paper and nothing struck me as blatantly wrong -- in fact, the basic idea seemed to make sense on the face of it. However, I don't understand the "breakthrough" technological implications. He seems to be saying that a large mass can effectively transmit some of its momentum to a stationary mass, if the large mass is moving toward the small one. This is not surprising, though -- something like this would be expected in any scattering experiment (gravitational or not). So I think he is trying to say something a bit deeper, but I don't have the energy to sift through the details of all his mathematical manipulations.

If one of you is really interested enough, you could email him (email address is listed in his paper) and point blank ask him some question. As it's not an "edu" address, he might enjoy the attention...

[purnell]

Heh. Made me think of that old song that goes, "Would you like to swing on a star..."

[PokerPadawan]

Metric, I just skimmed the article, but is this something like a relativistic gravitational assist? Like what we do with space probes around planets? Or is he saying there is a repulsive gravitational field generated in front of the moving object?

[Darryl_P]

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Or is he saying there is a repulsive gravitational field generated in front of the moving object?

[/ QUOTE ]

I'd say this is the one. I'd be curious how the ship would get to such a body in the first place, and if it did, how it would get back -- something rather important in the case of manned missions.

[wacki]

*cough*1 month ago *cough*

http://forumserver.twoplustwo.com/showfl...rue#Post4379096 (http://forumserver.twoplustwo.com/showflat.php?Cat=0&amp;Board=scimathphil&amp;Number=437909 6&amp;Searchpage=1&amp;Main=4379096&amp;Words=+wacki&amp;topic=&amp;Se arch=true#Post4379096)

[jman220]

[ QUOTE ]
"These antigravity solutions of Einstein's theory can change our view of our ability to travel to the far reaches of our universe."



[/ QUOTE ]

This statement is just wrong. Even at 99 percent of the speed of light, Intestellar travel to all but the nearest star systems would be impossible.

[TStoneMBD]

how is that impossible? i cant understand you people who say that traveling to other stars is impossible. even david sklansky once said that there is probably intelligent life in other parts of the universe but it is very unlikely that any of them would have ever been able to travel to earth. let me build a model for you to understand how one might travel to the far planets of the universe:

1) send a spaceship out on a journey to find intelligent life
2a) occupy that spaceship with a hibernating lifeform that can be revived at any time
2b) send a spaceship large enough to carry a family of lifeforms that continually reproduce so that the offspring will be the ones to travel to the far parts of the universe
2c) find a wormhole
2d) put a warp drive on the spaceship (run by artificial intelligence) that produces a lifeform whenever theyd like so that when the spaceship reaches a destination they can immediately create a lifeform by altering subatomic particles. the warp drive system could create a race of lifeforms to inhabit a planet.
2e) live forever

however, the dilemna now becomes transporting the information back to their home destination since any signals can only travel at the speed of light;

3a) wormhole
3b) travel back in time
3c) transport your entire race of lifeforms on the spaceship

im sure there are many other ways to travel to the ends of the universe. i dont even know anything about science but i know that a 3 step model like the one above will work. traveling the universe isnt such a difficult thing as long as you can take the theoretical concepts that we are not sure if are even capable and impliment them into reality. for all we know, a race of beings that were created 50 billion years ago traveled to our galaxy and have their mothership filled with the race of their beings nearby. from there, smaller alien spaceships could travel to earth. im not trying to argue that alien life has reached earth, but to say that its almost impossible is insane imo.

[Matt R.]

[ QUOTE ]
[ QUOTE ]
"These antigravity solutions of Einstein's theory can change our view of our ability to travel to the far reaches of our universe."



[/ QUOTE ]

This statement is just wrong. Even at 99 percent of the speed of light, Intestellar travel to all but the nearest star systems would be impossible.

[/ QUOTE ]

I don't have time to do the calculations at the moment, but I believe if you include the effects of time dilation when traveling at .99c it is possible to travel to star systems that are reasonably far away (farther than the nearest ones, I mean). I haven't looked up the distances nor done the transformations, so I could be wrong -- but if you somehow can bump the speed up to .999c or .9999c I'm pretty certain it becomes feasible.

[BluffTHIS!]

Question about that article where it says this:

In the 'antigravity beam' of a speeding star, a payload would draw its energy from the antigravity force of the much more massive star. In effect, the payload would be hitching a ride on a star.


So, is our own sun a "speedy" star or a slow one? Where is its antigravity beam and what observable effects of same can we see? I'd hate to think we were hitched to a slow star with a bum leg.

[Metric]

[ QUOTE ]
Metric, I just skimmed the article, but is this something like a relativistic gravitational assist? Like what we do with space probes around planets? Or is he saying there is a repulsive gravitational field generated in front of the moving object?

[/ QUOTE ]
I took it to be both. On the one hand, he's saying that there is a kind of "repulsive" effect of gravity if the velocity is high enough (this seems to be the "new" part, but it's not really shocking -- this is a fully sane thing for a relativist to think about, and one sees real papers on "gravimagnetic effects" from time to time). However, it seems that he picks a "reference frame" out in the asymptotically flat region -- this is how he justifies making lorentz transformations. But if you're out in the "flat" region, things like energy and momentum conservation are going to be in effect -- thus any momentum you want to transmit to your "cargo" are going to have to come from the large mass, which as you point out is effectively what we do already today with space probes and planets. As I said before, I may be missing something crucial, but this is what I see on a first pass.

I should also point out that this came out last May -- it may be that he's got some new stuff to present on top of this, hence the press release hype.

[Metric]

[ QUOTE ]
This statement is just wrong. Even at 99 percent of the speed of light, Intestellar travel to all but the nearest star systems would be impossible.

[/ QUOTE ]
Two things, here. Time dilation means that things would be all right from an "ageing" point of view -- you could go anywhere in the galaxy. However, other effects become very important. For example, the cosmic background radiation becomes blue-shifted in front of the space ship, meaning that the ship is either in a very hot thermal bath (at one velocity), or worse, under constant bombardment by high-energy x-rays (at another velocity). Technological details, yes, but very sticky ones.

[Borodog]

[ QUOTE ]
[ QUOTE ]
This statement is just wrong. Even at 99 percent of the speed of light, Intestellar travel to all but the nearest star systems would be impossible.

[/ QUOTE ]
Two things, here. Time dilation means that things would be all right from an "ageing" point of view -- you could go anywhere in the galaxy. However, other effects become very important. For example, the cosmic background radiation becomes blue-shifted in front of the space ship, meaning that the ship is either in a very hot thermal bath (at one velocity), or worse, under constant bombardment by high-energy x-rays (at another velocity). Technological details, yes, but very sticky ones.

[/ QUOTE ]

Luckily, if you can easily accelerate heavy payloads, you can just line the whole craft with a yard of lead. /images/graemlins/wink.gif

[Metric]

[ QUOTE ]
[ QUOTE ]
[ QUOTE ]
This statement is just wrong. Even at 99 percent of the speed of light, Intestellar travel to all but the nearest star systems would be impossible.

[/ QUOTE ]
Two things, here. Time dilation means that things would be all right from an "ageing" point of view -- you could go anywhere in the galaxy. However, other effects become very important. For example, the cosmic background radiation becomes blue-shifted in front of the space ship, meaning that the ship is either in a very hot thermal bath (at one velocity), or worse, under constant bombardment by high-energy x-rays (at another velocity). Technological details, yes, but very sticky ones.

[/ QUOTE ]

Luckily, if you can easily accelerate heavy payloads, you can just line the whole craft with a yard of lead. /images/graemlins/wink.gif

[/ QUOTE ]
Yeah, that's a good point...

[BruceZ]

[ QUOTE ]
[ QUOTE ]
[ QUOTE ]
"These antigravity solutions of Einstein's theory can change our view of our ability to travel to the far reaches of our universe."



[/ QUOTE ]

This statement is just wrong. Even at 99 percent of the speed of light, Intestellar travel to all but the nearest star systems would be impossible.

[/ QUOTE ]

I don't have time to do the calculations at the moment, but I believe if you include the effects of time dilation when traveling at .99c it is possible to travel to star systems that are reasonably far away (farther than the nearest ones, I mean). I haven't looked up the distances nor done the transformations, so I could be wrong -- but if you somehow can bump the speed up to .999c or .9999c I'm pretty certain it becomes feasible.

[/ QUOTE ]

Time dilation factor for velocity v: 1/sqrt(1 - v^2/c^2)

v = 0.99c: 7.1
v = 0.999c: 22.4
v = 0.9999c: 70.7

So we would age about a year traveling to a star 70.7 light years away if we could travel at 0.9999c the whole way. We must also account for time spent accelerating and decelerating. The nearest star besides the sun is about 4 light years away.

[BluffTHIS!]

[ QUOTE ]
Question about that article where it says this:

In the 'antigravity beam' of a speeding star, a payload would draw its energy from the antigravity force of the much more massive star. In effect, the payload would be hitching a ride on a star.


So, is our own sun a "speedy" star or a slow one? Where is its antigravity beam and what observable effects of same can we see? I'd hate to think we were hitched to a slow star with a bum leg.

[/ QUOTE ]



Someone touting this research please attempt to answer my above question which I state again.

Where is the observable evidence of our own sun's antigravity beam as it moves, or is it in fact too slow for such an effect?

[Metric]

[ QUOTE ]
Question about that article where it says this:

In the 'antigravity beam' of a speeding star, a payload would draw its energy from the antigravity force of the much more massive star. In effect, the payload would be hitching a ride on a star.


So, is our own sun a "speedy" star or a slow one? Where is its antigravity beam and what observable effects of same can we see? I'd hate to think we were hitched to a slow star with a bum leg.

[/ QUOTE ]
It is far too slow to see the effect. Apparently, the star would have to be moving at relativistic speeds to see this effect. The problem, of course, is that no stars in our galaxy are moving at relativistic speeds with respect to us. Hence my skepticism of this approach as a "breakthrough" for practical purposes. But of course it is possible that there is some essential point that I have missed.

[BluffTHIS!]

Thanks, that's what I thought, with the same conclusion.

[Borodog]

Am I the only one who noticed the tidbit about the cosmological implications? I think this dude may have just explained the source of the "cosmological constant."

[Metric]

[ QUOTE ]
Am I the only one who noticed the tidbit about the cosmological implications? I think this dude may have just explained the source of the "cosmological constant."

[/ QUOTE ]
Yes, I certainly noticed that (the cosmological constant is an interest of mine) -- however, I don't think this explains the cosmological constant. His stuff is based on relativistic particle trajectories in the so-called Schwarzschild solution. In the Friedmann-Robertson-Walker solution (the "standard cosmology"), the trajectories of galaxies are essentially trivial -- they more or less just sit there, while space expands. In addition, this guy's effect (or at least, his analysis) requires asymptotically flat spacetime -- while this is a property of the Schwarzschild solution, it does not look like our universe has this property.

[Borodog]

Damn you. Way to kill the buzz.

[Metric]

[ QUOTE ]
Damn you. Way to kill the buzz.

[/ QUOTE ]
Well this is one of the biggest problems in all of science -- it's very easy to get that buzz back. Here's a neat intro that emphasizes the currently very muddled state of understanding.

http://math.ucr.edu/home/baez/vacuum.html

[Metric]

Note: Thinking a bit more about it, I think my previous line concerning asymptotically flat spacetime is not really a valid argument. However, the other part (about galaxy trajectories being easily calculable and known) seems very sufficient.

[AEKDBet]

[ QUOTE ]
[ QUOTE ]
[ QUOTE ]
[ QUOTE ]
"These antigravity solutions of Einstein's theory can change our view of our ability to travel to the far reaches of our universe."



[/ QUOTE ]

This statement is just wrong. Even at 99 percent of the speed of light, Intestellar travel to all but the nearest star systems would be impossible.

[/ QUOTE ]

I don't have time to do the calculations at the moment, but I believe if you include the effects of time dilation when traveling at .99c it is possible to travel to star systems that are reasonably far away (farther than the nearest ones, I mean). I haven't looked up the distances nor done the transformations, so I could be wrong -- but if you somehow can bump the speed up to .999c or .9999c I'm pretty certain it becomes feasible.

[/ QUOTE ]

Time dilation factor for velocity v: 1/sqrt(1 - v^2/c^2)

v = 0.99c: 7.1
v = 0.999c: 22.4
v = 0.9999c: 70.7

So we would age about a year traveling to a star 70.7 light years away if we could travel at 0.9999c the whole way. We must also account for time spent accelerating and decelerating. The nearest star besides the sun is about 4 light years away.

[/ QUOTE ]

Yes, the way to find out what the world will be like in 2206

[jman220]

Tstone,
All those scenarios you have described utilize technology that does not yet exist. The person being interviewed implied that the technology he was talking about would make travel to the "farthest reachse of the universe" possible. It does not.