Something astonishing is about to happen this summer, and there's an incredible reason why you won't see it again for a long, long time.
The incredible event is almost upon us, the Great American Solar Eclipse, and it will be a very long time until we see it again for a very surprising reason. The total solar eclipse will have have a line of totality stretching from coast to coast of the United States on Aug. 21, an incredibly rare event, even if total solar eclipses somewhere on Earth are not.
In reality, the moon blocks the sun’s light fairly regularly. But yet total solar eclipses are quite rare for a number of fascinating reasons. For one thing, the moon follows an elliptical orbit, meaning the it changes its distance from the Earth and therefore its apparent size, so at some points in its orbit it is not large enough to totally cover the sun.
Also, the moon’s orbit is locked into our equator, so that most of the times when the moon eclipses the sun, we can’t see it from Earth, as the shadow goes either above the Earth.
But even if the distance and incline match up, which happens between two and five times per year, only a third of the Earth has land, so most eclipses are only visible at sea. And, of course, if there’s cloud cover, you won’t get to see it either, although it will get eerily dark.
As the planet’s rotation continues to slow down and the days get longer, total solar eclipses will get more and more rare.
So treasure this upcoming event, as it’s unlike any you’re likely to see again for a very, very long time.