Astronomers know that the Universe is full of dark matter, but we still don’t fully understand it…

New results from the Hubble Space Telescope have now answered a mystery about a galaxy that seems to be free of dark matter!

The Mysterious Dark Matter

Dark matter is a mysterious and peculiar material that got its name because it doesn’t give off any light - it’s totally invisible. Yet, we know that dark matter exists because we can see the effect that it has on the things around it. Like seeing paw prints in the snow made by an invisible dog. And we know that it mostly hangs out around galaxies - we believe it’s what helps keep them held together!

Where Did it Go?

But what if a galaxy has no dark matter? Well, that’s just what the NASA/ESA Hubble Space Telescope found! Using Hubble, scientists found two galaxies that seem to be missing dark matter: NGC1052-DF2 and NGC1052-DF4.

Now, new Hubble Space Telescope data has provided an answer to this conundrum by taking a deeper look at the galaxy NGC1052-DF4. They found evidence for a process known to astronomers as tidal disruption. This means that the gravity forces of the neighbouring massive galaxy NGC 1035 are tearing NGC 1052-DF4 apart! During this process, the dark matter is removed. 

Now, the neighbouring galaxy is slowly tearing the galaxy itself apart! This means the galaxy’s clusters of stars are being pulled away from the smaller galaxy into the larger galaxy.

Astronomers were delighted and relieved to find evidence of tidal disruption in galaxy NGC 1052-DF4. Why? Without it, scientists would have to fully reconsider our current understanding of the laws of gravity!

Image credit: ESA/Hubble, NASA, Digitized Sky Survey 2. Acknowledgement: Davide de Martin.