Why can't we overtake the speed of light

Hmm.. we can if we cheat!
I've forgotten the explanation of the "light speed limit" but you'll find it on Wikipedia.

It is possible to get around the speed of light by various methods, the simplest (and perhaps most improbable) example is building a spacecraft of enormous proportions and accelerating it close to the speed of light, then send a tiny craft flying from one end of the mothership to the other - ie; 99% light speed + an extra 2%... hardly a practical solution, but to an observer outside the ship, the tiny craft inside would be travelling at a total of 101% the speed of light.

Lorddarklaw, you're forgetting that the tiny spaceship would have a nearly infinite mass, and so would need an infinite energy to break the speed of light.

It's not surpassable by the method you put forward.

This is why it is a speed limit, as you approach the speed of light, your mass becomes greater and so more energy is needed to accelerate you further. As you reach the speed of light, you need an infinite energy to accelerate you further, this is currently unphysical and impossible.

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Originally Posted by ashishhawking

why can't we overtake the speed of light

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Hello ash:

We can. We used to think nothing can go faster than light. We were wrong.

excon

Capuchin, it's just an example - you could theoretically use hundreds of ships one inside another like a Russian doll. Other methods of beating the speed of light involve using worm-holes, or bending the laws of physics (way beyond anything I can think about).

Yes, and it cannot be used to beat the speed of light - your last ship will have infinite mass.

Wormholes are just "shortcuts" through spacetime, you might be able to beat a photon in a race, but you will never travel faster than light.

For example, I put a mirror on the moon and I race the photon from where I am standing to a point 1 meter away from me. I shoot the photon towards the mirror and then run for the finish line, the photon takes several seconds to get there, and I beat it.

Does this means I've travelled faster than the speed of light? No. The same is true with worm holes, the light will obey the curves of space-time, but by using intelligence, we can beat it by using shortcuts.

Excon I would like to hear about your schemata for faster-than-light travel

Hello Cap:

I was hoping you wouldn't ask. However, I recall falling asleep in front of my TV watching the Science Channel, and I heard (in the netherworld just before sleep) that they now can go faster than the speed of light.

I don't know who "they" are, and I don't know how they do it. But, I believe they are doing it.

excon

Should we be worried?

Regularly happens in Star Trek. Ask them!

Hello Cap:

Nahh. The only thing that worries me, is the science that I was taught as a kid. I was told things that aren't true, and I was taught them as though they were.

I was taught that the speed limit in the universe is the speed of light. I think that's as true as any statement is, before it's proven untrue.

excon

Oh yes, there are a number of phenomena that do propagate faster than light (and I'm surprised nobody has brought them up yet), but nothing that (as the OP asked) means "we" can travel faster than light. Taking "we" to mean humans on the macro scale.

Dumbing down of science is one of the essential evils of science education, you just cannot comprehend the truth at that age without better mathematical knowledge.

Hello again:

I don't know if it had to do with dumbing down. I just think I was taught what they knew at the time, but that what they know changes pretty fast these days.

Specifically, I'm speaking of plate tectonics. Of course, South America looks like it fits into Africa, but my teacher said it didn't. Whoa, ho ho on her.

excon

I know that a lot in physics changes as you reach the different levels of education.

Now plate tectonics I have no idea of the history of :) (or how old you are) ;)

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Originally Posted by excon

Specifically, I'm speaking of plate tectonics. Of course, South America looks like it fits into Africa, but my teacher said it didn't. Whoa, ho ho on her.

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Hey I'm almost finished reading A Short History of Nearly Everything by Bill Bryson and he speaks directly to this issue. Great book if you love science.

The ABZ of Relativity

Also an interesting sience book :)

How about a ship powered by Hawking radiation, the only thing that can escape a Black Hole?
Even light can't do this!!

Hawking radiation is produced from outsied the event horizon - light CAN escape from points outside the event horizon.

Hawking radiation is just thermal radiation, but it's created by means other than black body spectra. Thermal radiation = photons = light. THerefore it moves at the speed of light.

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Originally Posted by Capuchin

Oh yes, there are a number of phenomena that do propogate faster than light (and i'm suprised nobody has brought them up yet),

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Hello again, Cap:

Ok, what are they? Something to do with strings? Or things that happen in a particle accelerator?

excon

excon, I missed that bit from Cap.
Well I have one.
How about Tachyons??

Oh now this is good reading Faster-than-Light.