TYLER, Texas — The Great American Solar Eclipse is fast approaching. But what causes a solar eclipse? It's quite simple but also very impressive.
An solar eclipse occurs when the moon passes between the sun and the Earth. The moon's shadow is cast on the Earth. But a solar eclipse only happens at the new moon phase. The moon has to be between Earth and the sun for a solar eclipse to occur.
The moon and the sun have to be aligned on the same side of the Earth and that only happens during the new lunar moon phase or when the moon is in the daytime sky.
New moons happen once a month, but solar eclipses don't happen every month. Why? Because the moon's orbit is tilted, which changes the moon's shadow.
So, sometimes the shadow is too high, sometimes it's too low. There are only two times a year the shadow can be just right. These are called eclipse seasons.
But even then the Earth, sun and moon have to perfectly aligned for a total solar eclipse to occur. The sun is 400 times bigger than the moon, but it's also 400 times farther away. So when everything lines up, we get a total solar eclipse like the Great American Eclipse on Monday, April 8.
