Now that summer is finally upon us, I realized that we at the BSR let the most recent solar eclipse slip through the cracks.  Given how awesome and rare an event like this is, I’d like to apologize.  To make it up to you, I thought I’d explain a bit about these rare celestial occurrences, and give you a heads up to a particularly cool one coming up soon. As everybody knows, an eclipse occurs when the moon passes in front of the sun, but there are actually all kinds of different eclipses that happen, depending on where the moon, sun, and earth are positioned relative to one another. The moon and sun look to be about the same size because the sun is about 400 times larger than the moon, while the moon is about 400 times closer than the sun.  From earth, it may seem like things don’t change too much up there in space, but the distance between all of these objects actually changes on a fairly regular basis.  For example, check out the table below:

Note that the largest moon is always bigger than the largest sun – that’s why we get a total solar eclipse, complete with the famous corona that astronomy buffs everywhere live for.  However, this won’t always be true – it turns out that the moon is actually moving further away from earth at about four centimeters per year.  This means that in the past, the moon was always larger than the sun, whereas at some point in the future, a total solar eclipse may never happen again.