# Time dilation | Special relativity | Physics | Khan Academy | Summary and Q&A

90.3K views
February 11, 2016
by
Time dilation | Special relativity | Physics | Khan Academy

## TL;DR

Space-time diagrams illustrate the phenomenon of time dilation in different frames of reference.

## Install to Summarize YouTube Videos and Get Transcripts

### Q: What is time dilation?

Time dilation is the phenomenon where time appears to move at different rates depending on the relative velocities of two observers. It is a key concept in the theory of relativity.

### Q: How does time dilation occur in the example of spaceships A and B?

In the example, as observed from spaceship A's frame of reference, events appear to occur simultaneously. However, when observed from spaceship B's frame, these events are perceived as happening at different times due to the effects of velocity.

### Q: What is a neutral frame of reference?

A neutral frame of reference is a frame where two observers, in this case, spaceships A and B, appear to be moving outward from a stationary observer at equal speeds. In this frame, the time dilation is symmetrical for both spaceships.

### Q: How does the Lorentz factor relate to time dilation?

The Lorentz factor, denoted as gamma, is a mathematical term that represents the relationship between time dilation and relative velocities. It is responsible for the scaling and dilations observed in different frames of reference.

## Summary & Key Takeaways

• The video discusses the concept of time dilation in the context of two spaceships, A and B, traveling at different velocities.

• The change in time between events in one frame of reference appears different in another frame of reference due to the effects of velocity.

• By using Lorentz transformations and a neutral frame of reference, the video demonstrates how time appears to dilate in different frames.