Three galaxies on a collision course: a rare event

Three galaxies on a collision course: a rare event

You regularly see images on Saintias of two colliding galaxies. However, it could be a little more extreme.

This week’s satellite image shows three galaxies on a collision course. Astronomers call this triple SDSSCGB 10189. The galaxies are less than 50,000 light-years apart. By comparison, the Andromeda galaxy – the nearest galaxy to the Milky Way – is 2.5 million light-years from Earth.

The image below clearly shows that the galaxies are strongly pulling on each other, and therefore they are distorted. For example, the spiral galaxy on the right has one elongated spiral arm.

Three galaxies colliding in the constellation Oxenherd.

In the future, the three galaxies will merge to form one big galaxy. Astronomers use this image to learn more about the formation of giant galaxies in our universe, and in particular about the so-called BCGs (The brightest galaxy cluster). These are the heaviest galaxies at the core of galaxy clusters (or groups of multiple galaxies).

Curious about what shape the future galaxy will take? In the 1970s, computer simulations predicted that when galaxies merged, this would result Elliptical galaxies. It is now clear that merging galaxies often become spiral galaxies. Unfortunately, we will not be able to see the final result of the merger of SDSSCGB 10189, as this will take several hundred million years.

Over the past few decades, space telescopes and satellites have taken beautiful pictures of nebulae, galaxies, star nurseries, and planets. Every weekend, we retrieve one or more great space photos from the archives. Enjoy all the pictures? Show them on this page.

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