Chapter 15, Problem 25A

To determine

To Explain: Whether an astronaut can travel more slowly than the speed of light and yet travel the same distance in 10-year trip.

Explanation of Solution

Introduction:

The relation between space and time was first understood by the Albert Einstein. In special theory of relativity, it is described that the time can be affected by the uniform velocity of the moving object. Motion of object through space can affect the motion in time.These conceptswere described by the Einstein under the Time Dilation.

It is known that the speed of light is the limit for the moving matter. Light travel through space with 300000 km/s which is independent on the speed of observer and speed of the source.It is given that light travels some distance in 10000 years as seen by the stationary observer on the earth. According the postulate of special theory of relativity, when person starts his journey with speed less than the speed of light and travel a distance for10000 years, the time measured by the person in the space shift is very less as compared to the time measured by the person on the earth. The difference in the time measured by the astronaut and the person on the earth is because of concept of time dilation. According to concept of time dilation, time observed by the moving object passes slowly as compared to the stationary observer.

Conclusion:

Therefore, astronaut can travel more slowly than the speed of light and can travel more than 10000 years distancein 10-year trip.