Astronomy Questions & Answers

How Many Galaxies Are There in the Universe?

Astronomers determine the number of galaxies in the universe by counting up the number visible in a tiny portion of the sky, and then accounting for all the regions of the observable universe. A 2013 study estimates that there are 225 billion galaxies in the observable universe.

Planck temperature map of universe

Science-based Q&A

What is the age of the universe?

Determining the age of the universe requires a knowledge of the universe's expansion rate, as well as its density and composition. Cosmologists currently set the age of the universe at about 13.77 billion years.

Science-based Q&A

The End of the Universe: What is our ultimate fate?

During the latter half of the 20th century, cosmologists narrowed the universe’s fate to three possibilities, and they all depend on its density.