Solar eclipses get all the attention, but if you are able to catch a glimpse of a lunar eclipse, you can see evidence that the Earth is, indeed, round. Here's how it works: Earth passes between the moon and sun, so that the sun projects Earth’s shadow onto the Moon in the night sky. You've probably seen a partial lunar eclipse without even noticing it; if the moon looks orange, that's a sign of a lunar eclipse. If you've ever seen a total lunar eclipse, you probably noticed that the shadow did not look like this.A round shadow crossed over a round object. This does not sound like a thing that would happen if we were on a plane with all of the celestial bodies simply hovering overhead—or, perhaps more assinine, if the sun were orbiting Earth and not vice versa. The last total lunar eclipse took place on January 31, 2018, but it was not visible in most of the United States. Fear not, as you only have to wait a few months for one that will be visible in the Americas on July 27, 2018.
