Galaxies are indeed incredibly far away, with the nearest major galaxy, the Andromeda Galaxy, located about 2.5 million light-years from Earth. So, how is it possible to see them with our own eyes?
The light we see from distant galaxies has traveled a vast distance through space to reach us. Light travels at a finite speed, which is about 299,792 kilometers per second (186,282 miles per second) in a vacuum. This means that light from distant objects takes time to reach us.
When we look at a galaxy, we are actually seeing the light emitted by the stars and other celestial objects within that galaxy many years ago. For example, if a galaxy is located 10 million light-years away, the light we see from it today left the galaxy 10 million years ago. So, in a sense, we are observing the galaxy as it was 10 million years ago.
The reason we can see these distant galaxies is because light is incredibly persistent. It continues to travel through space until it encounters an object or is absorbed by something. As a result, the light emitted by distant galaxies has had more than enough time to reach us, allowing us to observe them.
It's important to note that our ability to see distant galaxies is greatly aided by telescopes. Telescopes gather and focus light, allowing us to see fainter and more distant objects than we can with the naked eye. Telescopes can collect light over extended periods, enabling us to capture even fainter signals from incredibly distant galaxies.