8. Defining Redshifts
In physics, a redshift is commonly known as an increase in wavelength and a decrease in frequency and photon energy. This downshift is sometimes called a negative redshift, or more commonly, a blueshift.
There are three main causes of redshifts. The first is because of radiation traveling between objects that are moving apart and is known as a relativistic Doppler effect.
The second cause is due to the same radiation traveling towards objects that have weaker gravitational potential, and more specifically, if these objects have a curved gravitational redshift.
The last cause of redshifts could be how they are affected by radiation traveling freely through the ever-expanding space, and can sometimes correspond to objects’ distance from earth.