Discoveries

February 15, 2023

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The Milky Way is no run-of-the-mill galaxy, according to a new study.

A team of astronomers recently discovered that our spiral-shaped home galaxy is actually too big for its surroundings, Science Alert reported.

The Milky Way is located in a “neighborhood” called the Local Sheet, which is a flat arrangement of galaxies that share similar velocities and are surrounded by empty space called voids.

The team explained that the Local Sheet serves as an example of a cosmological wall and separates the Local Void from the Southern Void. The relationship between the galaxies in the Local Sheet has a strong influence on their behavior, such as their similar velocities relative to the expansion of the Universe.

But the Milky Way appears to be an exception.

In their paper, researchers conducted an analysis using simulations from a project called IllustrisTNG, which models the physical Universe.

They found that, being a billion light years across and containing millions of galaxies, very few galaxies located within a cosmological wall structure are as big as the Milky Way.

The study underscores the importance of considering the local environment when studying our home galaxy, rather than assuming that it is in an average spot in the universe.

The environmental context could also help explain some previously unexplained phenomena, such as the odd arrangement of satellite galaxies around Andromeda and the peculiar lack of them around the Milky Way.

This story originally appeared in the February 15, 2023 newsletter, The Other Front.