00:01
This question is asking us about evidence of dark matter based on the rotation curves that are observed in the milky way galaxy.
00:09
So the rotation curve describes the rotational speed of the galaxy at different distances from the center of the galaxy.
00:17
So i have a little graph drawn out here.
00:19
So in red, i'm going to put what is predicted from kepler.
00:23
So from kepler's prediction, the rotation curve increases until we hit the point of maximum mass and then it should start to decrease.
00:30
And fall off slowly here like this, as we get farther and farther from the center of the galaxy.
00:35
But because of the presence of dark matter, there's a deviation from this.
00:39
So it does follow the original trend here, but then at the point here where it's supposed to start dropping back down, i'll draw in green, we have the actual.
00:49
So it looks more like this.
00:51
So we'll label this a for actual.
00:54
We'll label the red e for expected for the rotational curves...