# The Naked Scientists Forum

### Author Topic: Faster than the speed of light?  (Read 21828 times)

• Jr. Member
• Posts: 35
##### Re: Faster than the speed of light?
« Reply #50 on: 07/10/2006 00:54:31 »
quote:
Originally posted by simeonie

I am wondering though..... you probably could move faster than the speed of light but whatever is moving that fast you wouldn't be able to see because the light wouldn't reflect off it because it couldn't keep up. Plus I really doubt we will be able to go the speed of light.... EVER. Also does anybody know what "warp speed" is from Star Treck? Is that supposed to be the speed of light or something?

Simon
Trust me I am a doctor!

Warp is the bending of space so that two distant points are forced closer to one another making the trip shorter. Take a piece of paper and place a grasshopper on one edge. The time it takes for it to leap from one edge to other is-let's say, one-second.  Now bend the paper so that its edges are now closer together. You have just warped the paper and the grasshopper can now traverse the distance quicker.
That's what is meant by warp when applied to space travel.

#### M

• First timers
• Posts: 5
##### Re: Faster than the speed of light?
« Reply #51 on: 12/10/2006 07:37:45 »
When traveling faster than the speed of light, an object behind you will appear to recede in time then "disappear" when you outrun the first light reflected or emitted by the object. Conversely, objects in front of you will appear to move forward in time until you reach them. This is not "time travel," however.

#### lightarrow

• Neilep Level Member
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##### Re: Faster than the speed of light?
« Reply #52 on: 12/10/2006 15:47:19 »
quote:
Originally posted by simeonie

why is the speed of light infinite energy?
A body with non zero rest mass (rest mass = the mass it have when it's still) requires an infinite amount of energy to be accelerated to the speed of light, because: E = m*c^2/SQRT[1-(v/c)^2]

E is the total energy of the body
m is its rest mass
v is its speed
c is the speed of light

As you can see, when v approaches c, v/c approaches 1 (and (v/c)^2 too) so the term inside the square root approaches zero (and the square root too), so E approaches infinity (the less the number under a fraction, the greater the result).

Now, where this infinity comes from?

The fact is that in practice the speed of light is infinite. What I mean: when a body's speed is not much, our definition of speed: v = space/time is a good definition, but when the body's speed is very high (that is, near the speed of light) our definition is not good anylonger, because space and time are not (enough) independent each other anylonger.

If you were inside a space-ship moving faster and faster, you would see planets, stars, approaching you in greater and greater amount, without any limit, that is, the number of stars you would see passing by you in one second, e.g., would approach infinity.

Of course we are assuming the average number of stars in a volume of space is constant, but this doesn't change the essence of the concept.
« Last Edit: 12/10/2006 16:23:17 by lightarrow »

#### Zeig

• Jr. Member
• Posts: 12
##### Re: Faster than the speed of light?
« Reply #53 on: 13/10/2006 00:45:51 »
IFyou go faster than light i'm pretty sure you would go back intime. when they tested E=MC2 they droped a bomb from a plane at normal flight speed and another at a much much more rapid speed and the faster bomb acuay went off eighther1. somthign seconds later or.0 somthing seconds later. but the point is they were made to go off after so long after being droped and the faster oen was late. This atleast is what i can remember from hearing it or where ever i found out about it.

#### M

• First timers
• Posts: 5
##### Re: Faster than the speed of light?
« Reply #54 on: 13/10/2006 04:18:52 »
No, and it's relative: fixed receding objects would appear younger (as if we or they were moving back in time) and fixed approaching objects would appear older (as if we or they were moving forward in time).  Neither we nor the objects under consideration would actually move in time, however.  Only objects newly occurring before we reach them would cause an apparent increase in the numbers of objects ahead (and we would see them only when we encounter the leading edges of their respective light waves).  Objects behind us would appear to decrease in number only as we travel beyond the leading edges of their respective light waves.  As an aside, in this simple model, the possibility of leading objects appearing to decrease in number is self-evident and self-explanatory.  As far as I can see, however, lagging objects remaining fixed behind us would never appear to increase in number so long as we travel away from them at greater than light speed.

#### simeonie

• Sr. Member
• Posts: 351
##### Re: Faster than the speed of light?
« Reply #55 on: 06/11/2006 23:15:53 »
one guy who was up in space or something for too long apparently went through time travel for like a fraction of a second or something, it in guiness book of records and can find out more exact if i go get book

#### The Naked Scientists Forum

##### Re: Faster than the speed of light?
« Reply #55 on: 06/11/2006 23:15:53 »