# Thread: Special Relativety

1. ## Special Relativety

The typical lifetime of a person on Earth is 70yr. In the frame of reference of a galxy moving away from Earth with a speed of 0.75c, what is the lifetime of a person on Earth?

2. bump

3. Originally Posted by Mtl
The typical lifetime of a person on Earth is 70yr. In the frame of reference of a galxy moving away from Earth with a speed of 0.75c, what is the lifetime of a person on Earth?
From the given data, $\Delta t^{'} = 2 \Delta t$.
Answer: 35 years.

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