EPISODE · Apr 13, 2018 · 29 MIN
Episode 02: Dark Matter Is Out There, Even When It's Not
from syzygy · host Chris Stewart
If you like what you've heard on Syzygy, let us know:Find us on Twitter: @syzygypod twitter.com/SyzygyPodor just visit us at home: syzygy.fmEmily at the University of York: www.york.ac.uk/physics/people/brunsden/Chris online: kipstewart.comTell your friends, leave us a review on iTunes or your podcast directory of choice, or just drop us a note to say hi!Some of the things we talk about in this episode:Dark Matter in the news: https://arstechnica.com/science/2018/03/galaxy-seems-to-lack-dark-matter-stumping-astronomers/Nature Paper: https://www.nature.com/articles/nature25767PDF of the paper: http://www.astro.yale.edu/dokkum/papers/mass.pdfGalaxy Rotation Curve: https://en.wikipedia.org/wiki/Galaxy_rotation_curveMACHOs, WIMPS & other weirdness: https://theconversation.com/from-machos-to-wimps-meet-the-top-five-candidates-for-dark-matter-51516Dark matter and galaxy clusters: https://www.nasa.gov/feature/jpl/galaxy-clusters-reveal-new-dark-matter-insightsGalaxies in collision: https://phys.org/news/2016-10-galaxies-collide.htmlThe Bullet Cluster: https://apod.nasa.gov/apod/ap060824.htmlhttps://en.wikipedia.org/wiki/Bullet_Cluster
What this episode covers
A cosmic riddle for you: When does not finding something where you expect to it to be tell you that it exists? In the 1960s and 70s, astronomers measured the speed of stars and gas clouds orbiting at the edge of our galaxy, and discovered something strange: their rotational velocities were too fast. Way too fast. So fast, there’s no way the gravity from the visible mass in the galaxy could possibly keep them in orbit. There was clearly some mass out there across the galaxy that astronomers couldn’t see. Like, more than three quarters of it. Awkward! Astronomers call this invisible stuff Dark Matter, and fro decades the evidence has mounted for its existence across the universe. But in March 2018 astronomers found a galaxy with no Dark Matter at all … which, in a wonderful leap of logic, gives them even more confidence that this mysterious material exists.
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Episode 02: Dark Matter Is Out There, Even When It's Not
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