Katie Mack @AstroKatie (a.k.a. Dr Katherine J Mack) astrophysicist/cosmologist, occasional freelance science writer, connoisseur of cosmic catastrophes Aug. 07, 2019 1 min read

“Dark matter” is kind of a misnomer because it suggests something that is black (i.e., absorbing all colors of light). But as far as we can tell light just passes right through it. It’s invisible, not dark.

The REALLY COOL thing about that is that if #DarkMatter really is invisible it’s also untouchable. Invisible means “doesn’t interact with electromagnetism” & when you touch something, it’s electromagnetic repulsion between you & it that makes it feel solid  https://slate.com/technology/2014/02/what-is-dark-matter-searching-with-gravity-lensing-wimps-and-antiparticles.html 

Also important to keep in mind in any discussion of #DarkMatter:  https://www.xkcd.com/1758/ 

“What if #DarkMatter is not real but gravity just works differently?” People have been trying to make this work for decades. It doesn’t. Dark matter fits the data; models without it don’t.

I mean, feel free to keep trying to come up with new models! But maybe don’t put out a press release every time you fit a galaxy rotation curve, while ignoring the fact that your model fails when confronted with absolutely every observation done on cosmological scales.

You can follow @AstroKatie.


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