Travelling at speed of light

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DAVMARS
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Travelling at speed of light

Post by DAVMARS »

Hi

Please could someone give me an explanation on something.

I heard someone saying on TV 'If you were in a space ship, travelling away from earth at the speed of light for one minute, one minute of your time would of course have passed. On earth however, 4 years would have passed in that same single minute of your time on the ship'.

Is this true? If so, please explain how etc.

Thanks in advance.

David.
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nas76
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Post by nas76 »

It's calculated by using the Lorrentz transformation:

T(Earth) = T(Rocket) / [sqr root(1 - [V(Rocket)/V(Light)]^2)]

However if V(Rocket) was impossibly going at the speed of light, the equation would return infinity.

So if the rocket travelled at 99% of c, then T(Earth) would be about 7 times that of T(Rocket), i.e. in the same experiment 7 minutes would have passed on Earth for the rocket's 1.

To get a difference of 4 years, or 2,103,840 minutes, you find that V(Rocket) would have to be 99.99999999998% of c.

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Post by gyro »

Take a look here for more on time dialation and Einsteins Relativity.
http://www.pbs.org/wgbh/nova/einstein/hotsciencetwin/

and/or listen to this....
http://365daysofastronomy.org/2010/01/0 ... arp-drive/
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Re: Travelling at speed of light

Post by Eclipse »

DAVMARS wrote:Hi

Please could someone give me an explanation on something.

I heard someone saying on TV 'If you were in a space ship, travelling away from earth at the speed of light for one minute, one minute of your time would of course have passed. On earth however, 4 years would have passed in that same single minute of your time on the ship'.

Is this true? If so, please explain how etc.

Thanks in advance.

David.
Brush up on your mathematics and read Einstein´s special theory of relativity. Some things cannot be accurately explained verbally.
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Deimos
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Post by Deimos »

Travel at the speed of light through space or space-time - because the latter is "easier".

Because, when you think of the distance between two events for a object that is not moving in x, y and z, then the object actually moves sqrt((ct)^2) in Minkowskian space-time (as -x^2 becomes zero) . :D

Ian
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Post by astro_dt »

Hi David
Here's a stab at a verbal explanation, I'm always nervous about trying this because some members are quick to jump on any over simplification with derision, but here goes anyway.

To make it simple lets work in a 2 dimensional world. Imagine your speed is limited no matter what direction you travel (North, South, East and West). The faster you travel in the N-S direction, the slower you can travel E to W and vice versa.

I like this because I can demonstrate it with a toy car on a piece of paper.
Hopefully it makes sense so far but here comes the difficult bit.

Now add time as a fourth dimension to the three spacial dimensions we are familiar with and set the speed limit to the speed of light.
As you travel closer to the speed of light in the spatial dimensions, you have to travel slower in the time dimension.
So time slows down as you approach the speed of light.

This mental picture should be borne out by the mathematics. It get's confusing because our concept of speed involves time and that's where the language complicates matters. But I hope the explanation helps.

Cheers
Danny
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