Thursday, March 29, 2018


Hey Space Placers!

This new discovery of a galaxy that contains little or NO Dark Matter is so huge it puts my blog about yesterday's "Return to The Moon" conference in Washington, D.C. on hold.

Astronomers just announced yesterday that using an array of commercial 400mm telephoto lenses called Dragonfly they have found a galaxy called NGC 1052-DF2 that is the size of the Milky Way Galaxy (MWG), contains less than 0.5% of the stars in the MWG, and has little or no Dark Matter which is found in every other galaxy to date.

This galaxy is so sparse that when the Hubble Space Telescope (HST) photographed it distant background galaxies could be seen through it!

Hubble Views ‘Ghostly’ Galaxy Lacking Dark Matter
This large, fuzzy-looking galaxy is so diffuse that astronomers call it a “see-through” galaxy because they can clearly see distant galaxies behind it.
The ghostly object, catalogued as NGC 1052-DF2, doesn’t have a noticeable central region, or even spiral arms and a disk, typical features of a spiral galaxy. But it doesn’t look like an elliptical galaxy, either. Even its globular clusters are oddballs: they are twice as large as typical stellar groupings seen in other galaxies.
All of these oddities pale in comparison to the weirdest aspect of this galaxy: NGC 1052-DF2 is missing most, if not all, of its dark matter. An invisible substance that makes up the bulk of our universe, dark matter is the underlying scaffolding upon which galaxies are built. It’s the glue that holds the visible matter in galaxies — stars and gas — together.
The galaxy contains at most 1/400th the amount of dark matter that astronomers had expected. But how it formed is a complete mystery.
The galactic oddball is as large as our Milky Way, but it had escaped attention because it contains only 1/200th the number of stars as our galaxy. Given the object’s large size and faint appearance, astronomers classify NGC 1052-DF2 as an ultra-diffuse galaxy.
Based on the colors of its globular clusters, NGC 1052-DF2 is about 10 billion years old. It resides about 65 million light-years away.
The image was taken Nov. 16, 2017, by Hubble’s Advanced Camera for Surveys.
NASAESA, and P. van Dokkum (Yale University)
The Dragonfly team has other candidate galaxies to explore which is important because other galaxies lacking Dark Matter need to be discovered to provide more examples/data for study. Dragonfly is uniquely equipped for making such discoveries because it can really detect faint objects better than large telescopes.

This discovery will force astronomers to rethink how galaxies form as NGC 1052-DF2  shows that DM isn't present in all galaxies as they once thought. It also shows that DM is real and not some type of gravitational interaction that allows galaxies to form mimicking DM. If that was true then NGC 1052-DF2 would have to be like very other galaxy.

As I have always said, "Stay tuned as the Universe always surprises us."

Sky Guy in VA

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