# News from Mathnasium of Wauwatosa

### The Math Behind the Solar Eclipse

Aug 20, 2017

The excitement of the Solar Eclipse is upon us!

On Monday, August 21, 2017, the City of Wauwatosa is expected to experience the Maximum Eclipse at 1:17pm.

A solar eclipse occurs when the moon passes between the sun and the Earth and blocks all or part of the sun, casting a shadow on Earth.

Here's the basic math behind the solar eclipse we get to experience...

- The sun is almost exactly 400 times larger in diameter than the moon. The sun is about 1,391,000 kilometers in diameter, while the moon is roughly 3,475 kilometers in diameter. (Remember, diameter of a sphere is a straight line from one point on the sphere to another that passes through the center.) Multiply the moon's diameter by 400 and you get almost the exact diameter of the sun.

- The center of the sun is about 152,000,000 kilometers away from the center of the Earth. The center of the moon is about 380,000 kilometers from the center of the Earth. Guess what number you get when you divide the distance from the Earth to the sun by the distance from the Earth to the moon?! That's right, 400.

Here's a great visual of what's happening with the solar eclipse. For all you 7th graders getting into proportions this year, pay attention as this will sound familiar in a few months.

The distance from the Earth to the moon divided by the diameter of the moon is proportional to the distance from the Earth to the sun divided by the diameter of the sun. Both sides of this equation approximately equal 400 and that's why we are experiencing this solar eclipse as the moon and sun align.

(To be fair, I simplified the solar eclipse process and there is a lot more that goes into, so just check out the NASA link below for all the info you need. You might find yourself lost in all the math and a bit confused, but that's OK. Math is supposed to be confusing at times!)

If you happen to like this post and the links that inspired it, please share with your family and friends!

**Happy Solar Eclipse Day everyone!**

A few links worth checking out...

https://eclipse2017.nasa.gov/math-challenges

https://www.timeanddate.com/eclipse/in/@5278167

http://www.quickanddirtytips.com/education/math/the-math-of-a-solar-eclipse (the inspiration for this post)