Question

A space probe is sent to the vicinity of the star Capella, which is 42.2 light-years from the earth. (A light-year is the distance light travels in a year.) The probe travels with a speed of 0.9960 c relative to the earth. An astronaut recruit on board is 19 years old when the probe leaves the earth.What is her biological age when the probe reaches Capella, as measured by the astronaut?What is her biological age when the probe reaches Capella, as measured by someone on earth?

Answer 1

Using equation of relativistic constant,

by plugging the values we get

which gives us

Measuring the time taken from the Earth is

Time dilation is

or

which gives us

Now,

The biological age measure by astronaut is

When measure by someone on earth is