By Ken Croswell, Knowable Magazine on May 31, 2019

The Mighty Milky Way
A view of the Milky Way, as seen by ESA’s Gaia spacecraft. New research suggests our galaxy is far bigger and brighter than most others in the universe.

In this big universe, it’s easy to feel small and insignificant, as if there’s nothing special about our planet, our star, our celestial neighborhood. After all, the sun is just one of hundreds of billions of stars in the Milky Way galaxy. What do we have to brag about?

Yet astronomers in the know have long realized that our galaxy is exceptional. By size alone, it’s “in the top percentile of all the galaxies that exist,” says Joss Bland-Hawthorn, an astronomer at the University of Sydney who helped compile the galaxy’s vital statistics for a 2016 article in the Annual Review of Astronomy and Astrophysics. He puts the Milky Way’s mass at a hefty 1.0 trillion to 1.6 trillion times that of the sun, outweighing the vast majority of its peers by a factor of 10 to more than a million and greatly outshining them as well.

This brilliance isn’t obvious, however. Look through a telescope and most of the galaxies you see are comparable in size, brightness and mass to ours. Well-known galaxies such as Andromeda and the Whirlpool are cases in point.

But that’s only because these prominent galaxies radiate about as much light as our own, which makes them easy to see, even across vast distances. That creates the impression that the Milky Way is average, when it’s actually a colossus. Judging galaxies by the rare giants is like evaluating people by the famous names you see on the front pages of newspapers. For people and galaxies alike, you’ll probably get a much more representative sample by checking out your nearest neighbors.

New Galaxies Nearby

To see how the Milky Way fits into the broad spectrum of galaxies, astronomers must survey all the types of galaxies that exist, from bright to dim. That’s most easily accomplished by looking...

read more: https://www.scientificamerican.com/article/the-mighty-milky-way/?redirect=1