Question related to Mass and the Speed of light.?

Question

It takes infinate amounts of energy to travel at the speed of light.

If you are travelling faster than the speed of light however, does it require infinate energy to maintain this speed. Or would it require infinate energy to travel slower than the speed of light.

Just to clarify. This is supposing you are goign faster than the speed of light in the first place and the question is theoretical.

Answer 1

You can't travel faster than the speed of light in a vacuum, so it's a moot point.

Answer 2

As you say, let's look at the theoretical aspect of this. There is a formula in the Special Theory of Relativity regarding how mass behaves as it gains speed. You are correct, you need more and more energy to move more and more mass, but let's stick with the mass part of it. The formula is:

m=m(o)/sq root (1-v^2/c^2) where:
m = the "new" mass amount
m(o) = the original mass
v = velocity
c = the speed of light

As you increase velocity (from below the speed of light), mass increases, to the point that at the speed of light, mass becomes infinite (and requires infinite energy to accelerate it).

There have been some hypotheses that particles exist which can only travel faster than the speed of light, and never slower, though I don't think many scientists believe they exist.

If you work the formula for a particle traveling at, say, 1.5 times the speed of light (we'll assume a mass of 1), we get:

m = 1/sq root (1-1.5c^2/c^2). The "c^2"s cancel out, leaving:
m = 1/sq root (1-2.25),
m = 1/sq root (-1.25), or m = 1/1.12i (where i = the square root of -1, known as an imaginary unit). This leaves us with:
m = 1 x 0.89 = 0.89

If we do this again for 1.1c, m = 0.46i
For 1.01c, m = .142i

What happens is, as we get closer and closer to the speed of light (by slowing down from a faster speed above the speed of light), mass actually gets smaller and smaller (we're also ignoring the imaginary units, this is all theoretical anyway). What happens is that at the speed of light, mass is infinite, which means infinitely high (if coming from below the speed of light), then drops to infinitely low at the same time (we are talking about infinity, after all, and I realize it doesn't make sense), then begins to increase again. At twice the speed of light (2c), m = 1i.

This all sounds kind of strange, but looking at the formula, that's what it says.

Answer 3

Without the math...........

Mass and energy are equivalent. This is the single most important concept to remember.

It takes an enormous amount of energy to propel an object to a significant percentage to that of light speed. As the object approaches the speed of light, it's mass increases dramatically - thus requiring even more energy to accelerate it further - the speed of light will never be attained because, at the speed of light, the mass will be infinite - and, obviously, an infinite amount of energy would be required to accelerate and infinite amount of mass. In reality, this is, of course, impossible. This is why the speed of light is often referred to as the universal speed limit.

As a side note - the enormous distances involved in the notion of exploring the universe and the fact that we will never travel at light speed is what gives rise to worm holes and tears in the space fabric when science fiction writers visit different galaxies.

Answer 4

Your question may be hypothetical, but it's also meaningless. The speed of light is an ultimate speed limit. Or is it?Recent experiments show some indication of particles exceeding light speed under very esoteric conditions. Such particles would require an infinite amount of energy to slow down to light speed. Such particles, by the way, have been given the name "tachyons" from the root tachy- meaning fast.

Answer 5

It would take an infinite amount of energy to travel at the speed of light, thus, we can only approach it but we will never reach it! As for what is the smallest speed we can travel at in which it will not take an infinite amount of every, i don't really know.

Answer 6

Once you reach infinity, you cannot make any further calculations. The system breaks down. As soon as you reach the speed of light, your mass becomes infinite. You cannot apply any of the known laws of physics or mathematics to find any further consequences. Example, our physical laws cannot tell you what happens if you apply another 10N force to your already infinite mass.

That is why science says our laws break down in black holes, because if has infinite density and zero size.

Answer 7

if u want to travel in the speed of light and beyond it,u will need the energy source similar to that in the explosion of the super nova,but to my knoweledge i heared that they invited an ingine that can travel and go in the speed of light,but infortuanently they have not discovered a metel strong enough to be used in the making of the space ship which the engine will be putted to use in it,since no known metel can sustain and indure the unimaginable amount of friction and acceleration which will occur during the speed of light and beyond.