Scientists Find the 'Missing' Dark Matter from the Early Universe

[Judi Lynn]

By Mara Johnson-Groh, Live Science Contributor | January 7, 2019 07:28am ET

Dark matter, it seems, has been clinging to galaxies for a very long time. Most galaxies that existed 10 billion years ago had about as much dark matter as galaxies do today, contradicting earlier studies that suggested less dark matter lurked around galaxies in the early universe.

"Dark matter was similarly abundant in star-forming galaxies in the distant past as it is in the present day," said Alfred Tiley, an astronomer at Durham University in England and lead author on the new study. The research was recently submitted to the journal Monthly Notices of the Royal Astronomical Society and published Nov. 16 in the preprint journal arXiv. "It wasn't a complete surprise, but in reality, we didn't know whether the observational reality would align with expectations from theory." [The 11 Biggest Unanswered Questions About Dark Matter]

Dark matter makes up approximately 85 percent of the total mass in our known universe, but the mysterious substance does not interact with light, leaving scientists in the dark about the its precise nature. So, instead of viewing it, astronomers must rely on dark matter's gravitational pull on the normal matter, called baryonic matter, that makes up the stars, nebulas and planets we see in the night sky, as well as all the trees, rocks and people on Earth.

Dark matter tends to clump into halos around galaxies; astronomers discovered this by measuring how fast galaxies rotate. According to Newton's law of gravity, stars on the outskirts of a galaxy should rotate much more slowly than those at the center. But in the 1960s, astronomers found speedy suburban stars on the fringe of the Milky Way that hinted at extra matter hiding out beyond those stars' galactic orbits.

More:
https://www.space.com/42892-dark-matter-around-galaxies-constant.html

[fascisthunter]

1. Dark Matter is the Oil Our Water Floats with...

... I wonder what would happen if the two mixed: a black hole?

[Beakybird]

2. The soul of the GOP is made of the same dark substance

[Tribalceltic]

3. My Dark Matter Radar

Shows lots of hits in the White House and Senate!