relativity observations: what would you see?

Question

Imagine an observer (O) and two space-ships (A and B) move away from him in opposite directions at a speed greater than 50% of the speed of light? What would the observers in each space-ship see each of the other points (i.e how would A see O and B)?

Now imagine that space-ships A and B each launched a shuttle craft that from their frame of reference was moving in the opposite direction from O but at >50% of the speed of light. If these are D and E what would O see of D and E, and what would D see of A, O, B and E?

A diagram taking O as the starting point:

D <-- A <- O -> B --> E

Answer 1

Favorite Answer

Here is how you add velocities:

http://www.physics.adelaide.edu.au/~dkoks/Faq/Rela...

This is what a relativistic traveler sees:

http://www.physics.adelaide.edu.au/~dkoks/Faq/Rela...

Let's say that the magnitude of these velocities are roughly the same... And lets say the speeds are all 0.866c (this makes gamma = 2).

Before the shuttle

A sees O receding at 0.866c, A sees B receding at less than c, but greater than 0.866c (use the math).

Shuttles

O sees D and E departing at the same value you get for A of B above... greater than 0.866c, but less than c.

Answer 2

To your first one no one would observe anything as traveling 50% greater than the speed of light let alone the speed of light would cause an instantaneous nuclear reaction and it would probably kill and destroy (almost all matter) in about a 6000km circumference.

O would not be able to see A,B,D or E because the human brain cannot process that much "information" nor can the optical nerve.