Look: Ghostly, mysterious galaxies help unlock the secrets of dark matter

xponentialdesign via Giphy

NASA, ESA, and P. van Dokkum (Yale University)

But another type of galaxy, called an ultradiffuse galaxy (UDG) is the antithesis of the populated cluster we call home.

While the Milky Way is packed with stars and gas, UDGs are dim and sparse.

In 2016, researchers discovered a UDG called Dragonfly 44 that was 99 percent dark matter.

Teymoor Saifollahi and NASA/HST via Wikimedia Commons

Now, we're getting closer to unlocking the secrets of these ghostly galaxies — starting with how they formed.

Writing on September 6 in the journal Nature Astronomy, an international team of researchers used simulated UDGs to shed light on how they come to exist.

The faint aura of light in the right-hand image is a UDG, imaged by the Hubble Space Telescope in 2019. On the left is a UDG analyzed in the recent simulation. ESA/Hubble


It was thought previously that UDGs had to exist in clusters in order to lose their gas and stop making stars.

But, strangely enough, some have been found isolated in the universe.

NASA, ESA, and P. van Dokkum (Yale University)

It’s kind of like how Halley’s Comet flies through our solar system every 75 years, but spends most of its time isolated in space.


“This means a lot of dwarf galaxies lurking in the dark may have remained undetected to our telescopes.”

Laura Sales, study author and professor of physics and astronomy at University of California Riverside

NASA, ESA, and P. van Dokkum (Yale University)

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