How many alien civilizations exist?

This number of civilizations is specific to our galaxy, the Milky Way, which has approximately 200 billion stars. The diameter of its disk is estimated to be between 100,000 and 200,000 light-years. That’s how many years it would take for light to make its way across the disk, from one end to the other, traveling at a speed of 186,000 mi/s. Our galaxy is about half the size of our neighbor, Andromeda, which may contain up to 1 trillion stars.

Like some sixty other galaxies, the Milky Way and Andromeda are located in the Local Group. This vast group of galaxies, yet tiny compared to the Local Supercluster in which it is located, is a structure that connects 10,000 galaxies within a diameter of 200 million light-years.

This Local Supercluster is part of an even larger structure called Laniakea, which comprises 100,000 galaxies spread across a diameter of 520 million light-years.

The Laniakea Supercluster is just one of the 6 million superclusters that exist in the observable Universe.

A universe that makes us wonder: is it unique, or merely one among many others?
Are we the only ones asking this question?