# True/False relativity question.

1. May 2, 2012

### bayan

1. The problem statement, all variables and given/known data

The star alpha centauri is 4.25 light years from us, so it takes its light 4.25 years to reach earth. It is impossible, in principle, for any rocket from earth ever to reach this star in less than 4.25 light years.

2. Relevant equations

3. The attempt at a solution

My first answer was that the statement was false as length contraction would make the journey distance shorter for rockets F.O.R and the accepted answer is true, which leads me to the conclusion that they must mean 4.25years in earth's F.O.R

I would like to know how I could identify in which frame they requested the answer in the problem above.

2. May 2, 2012

### tiny-tim

hi bayan!
the facts given in the question are clearly written in the earth frame, so you should assume that the question itself is also

3. May 2, 2012

### bayan

Thanks for your reply, so unless there is a specified frame I should just use the one with respect to which data is given? Also is my answer of saying that statement is "false" wrong?

4. May 2, 2012

### tiny-tim

yes! … don't make the questions more difficult than they already are!!

(and you "false" was wrong)