100 Days Until Totality Blog Series: 79 Days Left – How Long Will the Earth Have Total Solar Eclipses?

Credit: NASA

In a previous blog post we talked about the formation of the Moon and discussed how it was originally 15 times closer and has slowly moved away to its current position. Considering that the Moon is still moving away from us to this day we can surmise that total solar eclipses will not occur on Earth forever.

The longest solar eclipses occur when the Moon is close to the Earth and the Earth is far from the Sun. During these solar eclipses the Moon appears 4.6 % larger than the Sun in our sky. So when the Moon has moved far enough away to appear over 4.6% smaller there will be no more total solar eclipses. For this to happen the Moon has to be 4.6% farther away, which means it would need to go about 10,500 miles further from the Earth. With the Moon’s current rate of recession it is seen that the Moon will be too far to produce a total solar eclipse in about 500 million years. The Earth will then only being able to produce annular eclipses and partial eclipses. As you can see in the picture to the right, our celestial neighbor, Mars also is unable to have total solar eclipses.

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