Astronomers have discovered the largest ‘ghost galaxy’ in known existence, made up of 99.99% black matter.
The discovery makes the galaxy, which has been named Dragonfly44, officially the darkest known galaxy in the entire universe.
Dragonfly44 was first spotted by astronomers in Hawaii back in 2014, but it is only more recent observations that have confirmed its huge size and shed light on how it maintains stability.
Scientists were baffled by how the dark galaxy could have a similar mass to the Milky Way but contain only 1% of the stars.
If this were the case they argued that it would surely have ripped itself apart using nothing but its own gravitational force.
It seems the answer lies in dark matter.
Astronomers predict that the ghost galaxy, which is so dimly lit it evaded detection for decades, would have to be made up of 99.9% dark energy to sustain its size.
If the only thing holding it together was it’s own gravitational force, it would have collapsed in on itself a long time ago.
Yale University astronomer Marla Geha said: “I’m hoping these objects are rather rare and/or only form in special environments such as a dense galaxy cluster. Otherwise we may need to rewrite galaxy formation.”
According to NASA there is only 27% dark matter in the observable universe and no one quite understands what it is or how it works – we only know it exists because we know it affects expansion of the universe.
Lead researcher Pieter van Dokkum said: “They are found in a dense, violent region of space filled with dark matter and galaxies whizzing around, so we think they must be cloaked in their own invisible dark matter ‘shields’ that are protecting them from this intergalactic assault.”
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