## What is Time Dilation?

According to the theory of relativity, time dilation is a difference in the elapsed time measured by two observers, either due to a velocity difference relative to each other, or by being differently situated relative to a gravitational field. As a result of the nature of spacetime, a clock that is moving relative to an observer will be measured to tick slower than a clock that is at rest in the observer's own frame of reference. A clock that is under the influence of a stronger gravitational field than an observer's will also be measured to tick slower than the observer's own clock.

## What is Travel Time?

Travel time is the time spent by the astronaut or spaceship in space after leaving the earth. Enter the travel time in years only.

## What is the velocity?

Velocity in here is the speed of the spaceship or the object. Note that the time dilation is negligible at normal speeds. It can be observed only at the speed of the light. In here you have to enter the velocity in accordance to the percentage of speed of light. For example, if the spaceship is travelling at the 30 percent of the speed of the light, you have to enter 30 in the velocity section.