The Great North American Eclipse is coming up on Monday. The Moon will briefly cover the Sun. That will turn day to night along a narrow path across Mexico, the United States, and Canada.

The timing of the eclipse is known down to the second, and has been for decades. And today, astronomers can predict eclipses far into the future. But making such predictions isn’t easy. It requires a detailed knowledge of the Moon’s orbit around Earth, Earth’s orbit around the Sun, and even the shapes of Earth and the Moon.

People tried to predict eclipses for a long time. Just when they first succeeded is unclear.

There’s little doubt that people have been predicting lunar eclipses for centuries. But lunar eclipses are easier to predict. Earth’s shadow is dozens of times bigger than the Moon’s, so you don’t need to be quite as precise to get it right.

There are stories that the Chinese were predicting solar eclipses more than 4,000 years ago, but no confirmation. An eclipse in 585 BC that stopped a war supposedly was predicted by a Greek scientist, but many modern-day scientists doubt that.

The first confirmed prediction was made by Edmond Halley, using the new laws of gravity devised by Isaac Newton. He forecast that an eclipse would cross England on May 3rd, 1715. And he was right. So the eclipse is known as Halley’s Eclipse — honoring the prediction of an astronomical spectacle.

More about eclipses tomorrow.

Script by Damond Benningfield