Does the exception prove the rule, or is the rule on shaky ground? Nobody knows.
Scientists have imaged a “transparent” galaxy that may have no dark matter, reports BBC Science.
An unusually transparent galaxy about the size of the Milky Way is prompting new questions for astrophysicists.
The object, with the catchy moniker of NGC1052-DF2, appears to contain no dark matter.
If this turns out to be true, it may be the first galaxy of its kind – made up only of ordinary matter. Currently, dark matter is thought to be essential to the fabric of the Universe as we understand it.
The study is published in Nature.
The authors of the study weren’t initially on the hunt for a dark matter-free galaxy; instead they had set out to take a closer look at large, ultra-diffuse galaxies.
These are similar in size to the spiral galaxies we’re more familiar with, but have a fraction of the number of stars.
When Prof Pieter van Dokkum, lead author of the study, first spotted NGC1052-DF2, “I stared a lot at that image and just marvelled at it… It’s like this ghostly glow in the sky.”
The galaxy has very few stars, but many of them are grouped together in unusually bright clusters. When the team studied the behaviour of these clusters, they found that the stars seemed to account for all of the galaxy’s mass.
Leaving no room for dark matter.
via Tallbloke’s Talkshop
March 28, 2018 at 01:12PM