We may not know what dark matter really is, but a galaxy lacking this shadowy, invisible substance is quite odd.
Recent Hubble data show that a galaxy as vast as the Milky Way has no spiral arms, no bright center, and less than 1 % of our galaxy’s stars. What’s wrong with it?
Astronomers might know why and a closer look unveils something peculiar.
Here is what you need to know.
Where is the Dark Matter?
The galaxy in question has been dubbed NGC 1052-DF2, or DF2. As per astronomers’ findings, this is an ultra-diffuse galaxy that you almost can see through it.
Previous data show other ultra-diffuse galaxies, but not a single one resembles DF2. Why is that?
A team of astronomers first discovered DF2 back in 2018, and they knew something odd is happening.Â
They used various telescopes, including the Hubble Space Telescope, but couldn’t find what really makes DF2 so unique.Â
However, in 2020, they took another look via the Hubble Telescope and found something intriguing.
The new data helped astronomers showed DF2 was about 72 million light-years away from Earth. Such a distance confirms the previous research that there is much less dark matter in DF2 than expected.
“[…] It would be nice if there were a simple explanation, like a wrong distance. But I think it’s more fun and more interesting if it actually is a weird galaxy,” explained Pieter van Dokkum, the lead author of the new study and an astronomer at Yale University in Connecticut.
DF2 is Not Alone
The list of galaxies with little dark matter is now increasing. In addition to DF2, we also have DF4.Â
Astronomers are still unsure how this phenomenon happened, but these galaxies are fascinating to look at!
More research will be soon available as astronomers will figure out more things about such dark-matter-deficient galaxies.