"The speed of light depends on the material that the light moves through - for example: light moves slower in water, glass and through the atmosphere than in a vacuum. The ratio whereby light is slowed down is called the 'refractive index' of that medium. In general, the difference in the speed of light in other mediums is ignored. "

so that's being very generalized about where you are and what you are travelling through... and with what figure you are using for the speed of light...

"The scientists would say that mass increases with velocity.

It's an increase whose rate itself increases as you approach the speed of light, designated in formulas as "C," and which to you and me is energy going more than 186,000 miles (about seven times around the Earth) per second. This mass gain exists in anything that is not at rest, and since nothing anywhere in the universe is ever at rest, is part of all matter to one degree or another. If you kick the speed of a chunk of matter up a bit, its mass goes up. Not much for most of the time you have your foot on the accelerator, but when you get up close to the velocity of light, the mass gain takes off like a rocket. Your spaceship gets heavier fast.

At 99.9999% of the speed of light, your ship has almost infinite mass. It has become humongously heavy. Since it takes a lot of rocket juice to make something like that speed up, you eventually reach the point where it would take an infinite amount of power to make it go one mile per hour faster. No gas station offers fuel of infinite octane rating, so it can't be done. Nothing made of ordinary matter can attain lightspeed while remaining in the state we call ordinary matter. (And, perhaps, nothing whose characteristics fit the description of an electromagnetic field can drop below lightspeed without becoming what we call matter.)..."

help any? :P

. ..-={Arramon}=-.. .
(this sure is helping me refresh myself some =)

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