• last year
First and perhaps most perplexingly, researchers remain unsure about what exactly dark matter is. Originally, some scientists conjectured that the missing mass in the universe was made up of small faint stars and black holes, though detailed observations have not turned up nearly enough such objects to account for dark matter's influence.

Astrophysicist Paul Sutter explains what #darkmatter is and how physicists can determine the invisible substance exists.
Transcript
00:00 What is dark matter dark matter?
00:02 Should be called
00:05 Invisible matter it's matter that doesn't interact with light or with any other charge particles
00:13 Matter that has nothing to do with light. That's the point
00:16 I'm Paul Sutter in this is Paul explains the show where I
00:21 you know
00:24 Explain how do we know that dark matter exists? Well, we don't see it in Earth or the solar system
00:32 You have to look at big scales before dark matter really starts to reveal itself
00:39 And we saw it first in the 1930s with the motions of galaxies inside of galaxy clusters
00:46 They the galaxies were just moving way too fast. The galaxy cluster should have ripped itself apart billions of years ago
00:53 But there was still
00:55 Existing so something had to be gluing all those galaxies even our own galaxy
01:01 The Milky Way just shouldn't be here then in the 1970s
01:05 We discovered that stars are again
01:09 moving way too fast
01:12 there has to be an extra source of
01:16 Gravity to hold the stars in in this source of gravity can't come from something we see like stars or nebula
01:23 Or anything else that glows
01:26 Otherwise, we would have seen it. We would have accounted for it. There is something inside of galaxies
01:32 There is something inside of galaxy clusters that has mass that has gravity
01:36 But isn't emitting any light
01:39 since the 1970s we've gone even further to
01:44 Solidify our understanding of dark matter that we know it exists from the earliest moments of the universe
01:51 We have the cosmic microwave background. This is leftover light from when the universe was just
01:57 380,000 years old and by studying tiny little variations in that light
02:02 We can get a picture a map of what the universe was like back then and guess what?
02:07 There was a lot of matter back then that didn't interact with light
02:11 So we have all these different pieces of evidence that all fit together and all point to dark matter
02:18 very likely
02:20 Dark matter or invisible matter is streaming through the room you're in right now
02:26 But it doesn't interact with light doesn't interact with charged particles. It doesn't interact with normal matter
02:31 So you just don't see it. You just don't care about it's invisible to you
02:35 But at the very largest scales it affects how things move what we do know for sure
02:41 Is that the dark matter does?
02:44 exist
02:47 [Applause]

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