The Immensity of Our Galaxy

In the nineties, we started discovering planets around other stars. We've now discovered enough that we can do good estimates of how many planets there are in total in our galaxy. There must be planets around a billion stars in our galaxy, maybe a hundred billion planets. It'sare very hard to detect, and it takes some very specialized equipment so the telescope observes the star a more than the planet itself. So imagine looking at our solar system edge on, and the planets around the star. And ah, you can see the star just get a little bit fainter when the planet is in front of it,. Then the star gets bright again when the planet goes around the other side.