PSU math prof: Here’s how to predict eclipses

The solar eclipse will happen August 21, 2017

Steven Bleiler, professor of mathematics and statistics at Portland State University, holds a model of the Earth, moon and sun, August 16, 2017 (KOIN)
Steven Bleiler, professor of mathematics and statistics at Portland State University, holds a model of the Earth, moon and sun, August 16, 2017 (KOIN)

PORTLAND, Ore. (KOIN) — To Steven Bleiler, predicting eclipses is easy.

“It’s just the sort of mathematics you use in grade school and an understanding of what we in music would call harmony,” he said. “When is it that various tones, frequencies line up with each other.”

Bleiler, a professor of mathematics and statistics at Portland State University, explained how eclipses can be predicted by anyone using basic tools found around the house.

“Eye on the Eclipse” – a KOIN 6 News special at 8 p.m. Saturday

“You can start in your backyard with a conveniently placed pole, like a tether ball pole or a light pole across the street and a good timepiece. And if you have the same place to sit every night and pick a specific celestial object — like the sun or the moon, a bright star or one of the planets — and you just time when it goes by that pole.

“The other thing, if you have some way to measure angles, like a protractor or just 2 pieces of wood with a single nail stuck between it so that you can measure the angle between the horizon and the object you’re looking at when it goes past your pole, that’s all you need to do enough measurements for you to be able to see an eclipse coming.”

He added a 4th-grade science class could predict lunar eclipses. “That’s pretty straightforward.”

Steven Bleiler, professor of mathematics and statistics at Portland State University, holds a model of the Earth, moon and sun, August 16, 2017 (KOIN)
Steven Bleiler, professor of mathematics and statistics at Portland State University, holds a model of the Earth, moon and sun, August 16, 2017 (KOIN)

Predicting eclipses has been done for centuries, he said.

Complete Coverage: Oregon Solar Eclipse

“2000 years before the Christian era began, the civilizations in China and Babylonia and the Mediterranean were noticing lunar eclipses, the moon becomes copper-colored. These are hard to miss because you can see them over half the Earth. Because they understood the motions, they could count out the cycles and could predict when the next eclipse was coming,” Bleiler said.

Steven Bleiler, professor of mathematics and statistics at Portland State University, holds a model of the Earth, moon and sun, August 16, 2017 (KOIN)
Steven Bleiler, professor of mathematics and statistics at Portland State University, holds a model of the Earth, moon and sun, August 16, 2017 (KOIN)

“The priesthood, who could do the arithmetic, they tended to keep this secret. They didn’t want the sort of general population to know that this was just a regular occuring phenomena. So they could use this to time rituals.

He pointed to a famous passage in the Mark Twain book ‘A Connecticut Yankee in King Arthur’s Court,’ when the time traveler astounded the people by appearing to blot out the sun with his powers.

Bleiler said there’s no magic to it — merely observation, basic tools and some math.

Watch the entire KOIN 6 News interview with Professor Bleiler here.