People on the East Coast this morning could see the beginning of a hybrid eclipse sweeping across the Atlantic and Africa, climaxing half a world away.
A hybrid eclipse is one that starts out as one kind of eclipse but morphs into another. In this one, as the moon slides across the sun its distance means it isn’t quite big enough to completely block out the sun. There’s still a “ring of fire” shining around the moon even when it should be completely blocking the sun. They call that an annular eclipse.
As the moon’s shadow slides across the Earth, the globe’s curve brings the shadow a little closer. Later in the eclipse, it becomes big enough to give us a total eclipse, completely blocking the sun.
An eclipse where the distances involved are so delicately balanced that the Earth’s shape can change it from an annular to a total eclipse is rare. It isn’t a once-in-a-lifetime thing, it’s once in two lifetimes. We won’t see another one like this for 160 years.