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Total Solar Eclipse Durations

-- Shaun | November 18, 2024

Visual of different stages of an eclipse

Question:

Currently a total solar eclipse isn’t quite perfect since the moon’s apparent size is slightly smaller than the sun. And that’s changing as the moon moves further away from earth.

Has there ever been a time when the solar eclipse was “perfect”, with the moon being the exact size as the sun? If so, when?

-- Shaun

Answer:

In fact, all total solar eclipses are due to the projected disk of the Moon completely covering the projected disk of the Sun. As the relative separations of the Earth, Moon and Sun vary, though, the amount of time that the Moon’s disk completely covers the Sun’s disk can vary from just a few seconds to about 7.5 minutes. From the NASA Eclipse FAQ page, for the period between 4000 BCE to 8000 CE, the longest total solar eclipse will occur on July 16, 2186 and will last 7 minutes and 29 seconds. The shortest total solar eclipse happened on Feb. 3, 919 CE, and lasted just 9 seconds.

-- Jeff Mangum

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