Far out cosmology: our galaxy is huge (Introduction)

by David Turell , Sunday, November 08, 2020, 19:44 (1264 days ago) @ David Turell

New study finds it is much bigger than known before:

https://www.sciencenews.org/article/astronomers-have-found-edge-milky-way-size

"Our galaxy is a whole lot bigger than it looks. New work finds that the Milky Way stretches nearly 2 million light-years across, more than 15 times wider than its luminous spiral disk. The number could lead to a better estimate of how massive the galaxy is and how many other galaxies orbit it.

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"Now, Alis Deason, an astrophysicist at Durham University in England, and her colleagues have used nearby galaxies to locate the Milky Way’s edge. The precise diameter is 1.9 million light-years, give or take 0.4 million light-years, the team reports February 21 in a paper posted at arXiv.org.

"To put that size into perspective, imagine a map in which the distance between the sun and the Earth is just one inch. If the Milky Way’s heart were at the center of the Earth, the galaxy’s edge would be four times farther away than the moon actually is.

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"Although dark matter makes up most of the Milky Way’s mass, the simulations reveal that stars should also exist at these far-out distances. “Both have a well-defined edge,” Deason says. “The edge of the stars is very sharp, almost like the stars just stop at a particular radius.”

"In the future, astronomers can refine the location of the Milky Way’s edge by discovering additional small galaxies nearby. Astronomers could also search for individual stars out at the boundary, says Mike Boylan-Kolchin, an astrophysicist at the University of Texas at Austin who was not involved with the study. The farthest such stars will be very dim, but future observations should be able to find them.

:The measurement should also help astronomers tease out other galactic properties. For instance, the larger the Milky Way, the more massive it is — and the more galaxies there should be revolving around it, says Rosemary Wyse, an astronomer at Johns Hopkins University who was not part of the new work. So far, there are about 60 known Milky Way satellites, but astronomers suspect that many more await discovery."

Comment: We are a giant and that may well relate to why we have life. We know the Earth exists well out from the nasty dangerous center. My view is God plans well.