The Calm Before the Storm?


NGC 799 & NGC 800This pair of galaxies, NGC 799 (below) and NGC 800 (above), is located in the constellation of Cetus (The Whale) about 300 million light-years away. Our face-on point of view lets us see these objects are both spiral galaxies with characteristic long arms winding towards a bright bulge at the center.

It may appear that these spiral galaxies are coexisting in an everlasting peace, but that is unlikely. What we see is probably the calm before the storm. Typically, when two galaxies are close enough, they interact over hundreds of millions of years through mutual gravitational attraction. In some cases, only minor interactions occur, causing shape distortions, but sometimes galaxies collide, merging to form a single, new and larger galaxy.

We’ll have to check back in a few hundred million years.

Image Credit: ESO

3 thoughts on “The Calm Before the Storm?

  1. Since the universe is expanding, it seems to me that galaxies should always be getting further apart, rather than closer together. Are they actually being attracted to each other by gravity?

    • While the Universe as a whole is expanding, some bits of it have been attracted to each other by gravity. If that were not the case, neither you nor I would exist.

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