# Approching lightspeed with a nuclear reactor?

• June 2nd, 2010, 03:54 AM
roflwaffle123
Approching lightspeed with a nuclear reactor?
http://chiefio.wordpress.com/2010/06...t-speed-drive/

does this make sense?
pretty much hes saying as the ship gains mass as it approaches C, so does the nuclear fuel. So even at near C speeds the proportion to potential energy in the fuel to the mass of the ship stays the same.

is this correct?
• June 2nd, 2010, 04:19 AM
MagiMaster
I'll say that that doesn't really make sense to me, since it'd seem to imply that it'd continue to gain potential energy without bound. Of course, I don't know enough about the subject to say anything definitive, so perhaps DrRocket or someone else can either confirm or deny my initial guess.
• June 2nd, 2010, 04:32 AM
Magnet
If I'm moving at the speed of light and throw a magnet in front of me, is the magnet moving faster than light?
• June 2nd, 2010, 05:19 AM
MagiMaster
If you're moving at the speed of light, you are light and can't have a magnet to throw. If you are moving any slower, then no, the magnet will be moving faster than you, but slower than light. (That also has little to do with the OP.)
• June 2nd, 2010, 07:35 AM
Janus
Re: Approching lightspeed with a nuclear reactor?
Quote:

Originally Posted by roflwaffle123
http://chiefio.wordpress.com/2010/06/01/near-light-speed-drive/

does this make sense?
pretty much hes saying as the ship gains mass as it approaches C, so does the nuclear fuel. So even at near C speeds the proportion to potential energy in the fuel to the mass of the ship stays the same.

is this correct?

No, it is not. There are a couple of ways of pointing out the flaw in this argument:

As the ship accelerates, time aboard the ship slows down and the ship contracts along its length as viewed by our "stay at home" observer. This means also that the exhaust velocity of the rocket decreases as the ship nears light. Since the speed of the the exhaust factors into the rate of acceleration of the ship, and this drop in velocity more than compensates for any gain in its mass, the ship's acceleration rate drops off towards zero as it nears the speed of light.

another way is to recognize that the "increase in mass" is just an expression of how the ship's inertia increases with the ship's kinetic energy. And just like you can't tap the kinetic energy of a moving body to make that same body go faster, you can't tap this "increase in mass" to drive the ship.

But the thing you really have to ask yourself is this: Is it really possible that countless scientists working in Relativity would have missed such an obvious solution to the speed of light limit if it had any validity?
• June 2nd, 2010, 07:18 PM
Topalk
There is one BIG problem in that nucleur power doesn't covert mass into energy it either combines (it doesn't make molecules)two atoms or it splits two atoms more mass doesn't mean more atoms just means heivier more unstable atoms most likely. I think what that guy needs or means is a zero point battery but I don't knowmuch about one myself so I could be wrong.
• June 2nd, 2010, 07:45 PM
roflwaffle123
Quote:

Originally Posted by Topalk
There is one BIG problem in that nucleur power doesn't covert mass into energy it either combines (it doesn't make molecules)two atoms or it splits two atoms more mass doesn't mean more atoms just means heivier more unstable atoms most likely. I think what that guy needs or means is a zero point battery but I don't knowmuch about one myself so I could be wrong.

he was definitely not describing a zero point battery....
• June 2nd, 2010, 08:23 PM
Arcane_Mathematician
Quote:

Originally Posted by Topalk
There is one BIG problem in that nucleur power doesn't covert mass into energy it either combines (it doesn't make molecules)two atoms or it splits two atoms more mass doesn't mean more atoms just means heivier more unstable atoms most likely. I think what that guy needs or means is a zero point battery but I don't knowmuch about one myself so I could be wrong.

Nuclear fusion produces heavier atoms that weigh less than the . That's where the energy comes from. In fission, again, it makes two smaller nuclei that weigh less combined than the original atom, which is what gives you your energy from mass