Astronomy Question: First Question
“What is redshift?”
Red Shift is a similar concept to the changing pitch of a car or train as it passes (Doppler effect).
Astronomically, the light radiation from an object can be “stretched” when it is moving away from an observer.
The light itself is stretched into longer/redder wavelengths.
Red shifting is can also be a result of the universe expanding, in the case of the object and observer not moving.