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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.'"
Theres no point in travelling at close to light speed if your have no way of stopping.
Mind that planet!
What planet?
SPLAT
liqbase
Can't
Can
Can't
Can
Can't
Wake me when someone actually accomplishes something. I'm sick and tired or the back and forth debate over ethereal concepts that can neither be proven or disproven in our lifetime.
What was making impossible near-lightspeed travel? Only FTL was prohibited. Problems like engines, fuel, shielding etc. are only technological problems.
For more information, see Dr. Felber's recent works on arXiv.org:
Weak 'Antigravity' Fields in General Relativity
Exact Relativistic 'Antigravity' Propulsion
Personally I'm a bit skeptical about his claims, however energy appears to be conserved. This method uses gravitationally-mediated kinetic energy exchange - this is the same principle that allows gravitational slingshot to work.
"The White House is not an intelligence-gathering agency," -- Scott McClellan, Whitehouse spokesman.
This guy seems to be saying that if you have an anti-gravity machine, you could counteract that.
.577c is another question.)
Nonono: he's saying that a mass travelling near the speed of light creates an "antigravity beam" in front of it. This sounds hokey, but it's not unprecedented - frame dragging is a similar situation where general relativity basically says that a moving body can "push" others nearby. So in this case the near-light-speed object is "dragging" its frame forward. Calling it an "antigravity beam" sounds wacko, but it's probably quite straightforward. It's almost like the objects would be riding the "wake" of the NLS object, caused by the fact that the object is moving faster than space can respond.
He's essentially saying that you can pretty much effortlessly accelerate something to really high velocities with little effort by hitching a ride on a bigger object.
(Where to find a star moving at greater than
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?
Buick? You mean the size of a dust mote. If a dust particle weighs 1/100 of a gram, and you are going roughly the speed of light, the kinetic energy of the dust particle relative to you (assuming that the dust particle is roughtly standing still) is
.00001kg x (2.998 x 10^8 m/s)^2
898800400000 Newtons
9806 or so Newtons Per Ton
1,000,000 tons per MegaTon
20 Megatons per Hydrogen bomb
Thats 4.6 Hydrogen Bombs of energy that the dust particle has relative to you. Do you want to collide with 4.6 Hydrogen Bombs? I don't think that NLST is practicle, even if it turns out to be possible. What we need is a way to simultaniously transport stuff.
No, we have reduced to the problem of how to accelerate only part of the ship, while the other parts can hitch a ride on the first. I suspect the sweet spot would be the first part at 2/3 of the total mass.
If you're correct, then we're done:
--MarkusQ
Oh wait, I almost forgot:
The density of interstellar space is about one atom per cubic centimeter. If the spaceship were going near the speed of light (3 x 10^10 cm/sec), it would be hit by 3 x 10^10 relativistic particles per cm^2/sec. This is about the equivalent of one Curie per cm^2, which would kill a human and cripple any electronics on board
A very heavy magnet could deflect the protons, but the neutral atoms would be unaffected by the magnetic field.
> One thing I have often wondered is if an object moves fast enough, could its relativistic mass become so large that it
> would look like a black hole relative to a laboratory frame?
No.
Moving faster than 57.7% of c? Relative to what?
Right now, the earth is moving through space at a speed greater than 57.7% relative to something. No, I don't know what, or where, but rest assured there's some body out there somewhere in whose frame of reference the Earth is moving at greater than 57.7% of c. And there's some other body in whose frame of reference the Earth is moving at greater than 10% of c, and another body where Earth is moving at 95% of c, and another body where Earth isn't moving at all (Hey, like me!).
So why isn't the Earth emitting such an antigravity beam, repelling masses in its path? Rest assured that if it were, we'd be seeing its effect, like ferinstance as it played havoc with GPS satellites.
Or, heck, there are cosmic rays which occasionally smack into the Earth's atmosphere at a speed that's only infinitesimally smaller than c in Earth's FOR. They should *definitely* be emitting some sort of antigravity, if this guy's correct. Should be trivial to observe, but we haven't seen it.
This smells like bullshit.
You make the assumption that the dust mote would actually stop, only then would the bulk of the KE go into the target space ship. More likely is that since the KE of each atom in the dust mote is so much larger than the atomic bond energy holding the grain together, the dust mote to the spacecraft really behaves like a very densely packed bundle of cosmic rays. If the spacecraft walls don't stop individual particles of that energy (ie like cosmic ray protons) then it won't stop the dust particle. The atoms would go in one side, out the other radiating a small fraction of their relative energy as gamma rays as cherenkov radiation and compton radiation. The dust would go out the other side as a diverging cone shaped spray of plasma.
I've often felt the same way about 2+2 never getting up to 5. Come on science, you can put a man on the moon but you can't get 2+2 even a decimal place past goddamn 4?
"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.