Solar Eclipses Are More Common Than You Think

The total solar eclipse was an event. The reactions from across the path of totality affirmed its sheer “awesomeness.” The total solar eclipse also did something else. It brought out all of the hyperbole related to the fate of humanity, unsubstantiated links to climate change and more. Here in the U.S., extra emphasis was likely due to the path of totality covering such accessible populated areas. I get it. There is, however, a teachable moment from this week’s “science in the spotlight” because eclipses actually happen more frequently than you may realize.

We actually have about two to five per year, according to a NASA website. The rare aspect is frequency of occurrence for a given location. According to University of Missouri astronomer Haojing Yan, an associate professor in the Department of Physics and Astronomy, “For a specific location ... a total solar eclipse will only happen once every 360-410 years.” The next one visible in parts of the U.S. will be in 2044. A year later, a total solar eclipse will cross most of the lower 48 states.

But how do scientists know when they will happen? It is simple orbital mechanics. According to NASA’s website, “Astronomers first have to work out the geometry and mechanics of how Earth and the Moon orbit the Sun under the influences of the gravitational fields of these three bodies.” You throw in Newton's laws of motion, and information about the motion of celestial bodies can be calculated. The website goes on to say, “Scientists then feed the current positions and speeds of Earth and the Moon into these complex equations, and then program a computer to "integrate" these equations forward or backward in time to calculate the relative positions of the Moon and Sun as seen from the vantage point of Earth.” They are typically accurate to within less than a minute in time. My March Madness predictions were terrible, but science allows us to predict eclipses over tens to hundreds of years.

By the way, if you have eclipse fever, the table below shows the opportunities over the next few years. However, you will likely have to hop on a plane or a ship if you live in the U.S. If you want to track future solar eclipses, this NASA website is helpful.