How Much Dark Matter Does the Milky Way Contain?

-- Siu-Fung | October 21, 2020

Question:

Dear Jeff, I have a question in regards to the galaxy rotation curve. Hypothetically speaking, what factor increase in gravity would be necessary for the rotation curve to match observations?

I hope this wasn’t too open-ended. Thanks!

-- Siu-Fung

Answer:

You can read about how the Milky Way galaxy’s rotation curve is measured and how this rotation curve indicates that there is a significant amount of dark matter in our galaxy at the Strobel’s Astronomy Notes page. It turns out that about 90% of the mass of the galaxy appears to be in the form of dark matter, which means that only 1/10 of the total mass of the galaxy is accounted for by things we can measure, like stars, dust, gas, planets, etc.

-- Jeff Mangum

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