by Brian Koberlein | 10 April 2018 | post
There’s a limit to how far into the cosmos we can see. One of the biggest limiting factors is simply the brightness of an object. The more distant an object, the dimmer the object will appear. Even if there is no gas or dust in the way, the brightness decreases proportional to the square of its distance. For example, if two stars are equally bright, and one is twice as far away as the other, we will observe four times the light from the closer star than we see from the distant star. Because of this, main sequence stars such as our Sun can only be observed out to a few hundred million light years. Galaxies can be seen from billions of light years away, as can brilliant supernovae, but not a simple star.
This is a companion discussion topic for the original entry at https://blog.briankoberlein.com/the-invisible-star/