We will never know the exact number of galaxies in the universe, but astronomers have ways of coming up with pretty good estimates. The current estimate for the number of galaxies in the observable region of the cosmos is about two trillion, but this number is likely to increase as our tools improve. So how do astronomers count the number of galaxies? And, what sort of tools do they use?

Via – SciShow Space
Further Readings And References @ NASA, Gizmodo, The Astrophysical Journal