TOTAL ECLIPSE OF THE HEART


Eclipse

The total solar eclipse has come and gone. It was either awe-inspiring, spectacular, life-changing - a reminder of our insignificance in the universe - or rather banal. After all, eclipses are really just a function of our place in space.

On our planet, eclipses occur when the Earth, moon, and sun are aligned. Seems simple enough. Except the moon's orbit around Earth is tilted by about 5 degrees. When the moon's orbit lines up just right though and the moon passes between the Earth and sun, it casts a shadow on Earth - that's a solar eclipse. When the moon is aligned on the other side of Earth, our planet blocks sunlight from hitting the moon and we cast a shadow on the moon - that's a lunar eclipse.

During a total solar eclipse, like the one that just happened, the moon perfectly blocks the light of the sun. But zetus lapetus, how can this be? The moon is wayyyyy tinier than the sun... Even though the moon is about 400 times smaller than the sun, it's also 400 times closer to Earth. So coincidentally, to us humans, the moon and sun can appear to be the same size.

There are other kinds of solar eclipses too. During a partial eclipse, the moon only partially blocks the light of the sun. Hence the name. And since the moon's orbit is elliptical (not circular), sometimes the moon appears bigger to us and sometimes it appears smaller. So when the moon is too far away to completely block the sun, we see a ring of sunlight around the moon - that's called an annular eclipse.

Weird sidebar: The moon is moving further away from Earth at a rate of about 1.5 inches per year. And at some point, the moon will no longer appear to be the same size as the sun from Earth. So the very last total solar eclipse will happen in less than a billion years. After that, the creatures on Earth (mostly jellyfish?) will only see partial and annular eclipses.

During the recent solar eclipse on August 21, I only witnessed a partial eclipse because I was not in the path of totality. But I watched it with a bunch of other geeky Earth scientists. Which was super entertaining. One scientist set up an optical projection using a telescope and projected a magnified image of the eclipse onto a piece of paper. Other scientists made pinhole projectors using Cinnamon Toast Crunch, Honey Nut Cheerios, and other assorted General Mills cereal boxes. But most of us just had eclipse glasses. Needless to say, the eclipse was out of this world!!