How Special is this Solar Eclipse?

Image Credit: NPS.gov

Global media attention, mass migrations across state lines to secure the perfect viewing spots, and martian solar eclipses- here is what you need to know about this year’s eclipse:

The 2017 solar eclipse is the first total eclipse that can be viewed from the continental US since February 26, 1979. The path of “total eclipse”will range from the Pacific to the Atlantic, providing many with the chance to see a total eclipse or at least a partial one, but how does a solar eclipse even happen?
An eclipse occurs when a new moon blocks the sun causing the moon’s shadow to be cast on Earth. A solar eclipse doesn’t happen at every new moon however due to the moon’s five-degree axial tilt, so the sun is only aligned when at its node.

The moon is much smaller than the sun, so how does it can block the sun so perfectly?

The sun is about 400 times larger than the moon, but the sun is also 400 times farther away from Earth. That is why the sun and moon appear the same size.

Image Credit: Timeanddate.com

What is the path of totality, and why are so many people traveling?

The path of totality is the trajectory of the moon’s shadow across the Earth. The small shadow cast here is called the umbra, and is where you can view a total solar eclipse. This year the total solar eclipse will last about two and half minutes maximum. Once a solar eclipse goes total, you do not need eclipse glasses, and you will be able to view the sun’s corona. From everywhere else in the US the larger moon shadow will be cast, called the penumbra, which allows you to view the partial eclipse with glasses, or a projection device.

How often do solar eclipses occur? Is this a rare event?

Solar eclipses are actually quite common. Total and annular solar eclipses occur about every 1-2 years. An annular eclipse is where the moon still blocks the sun, but the angle is not quite right, so the sun is not completely obscured. The only thing that is rare about this eclipse is the fact that it sweeps across the US from west to east, covering many states on its way.

 

Can I use sunglasses to look at the eclipse?

No. sunglasses are not nearly dark enough to protect your eyes from the sun. In order to properly view the eclipse get authentic eclipse glasses. You can also make a Sun Funnel.

Phobos, one of Mars’ moons blocking the sun. This photo was taken by the Curiosity Rover. Image Credit: NASA

Do other planets, such as Mars experience a solar eclipse?

For a planet to experience a solar eclipse, the planet must have a moon. That means Mercury and Venus cannot have eclipses. Mars has two moons, Phobos and Deimos, but the problem is that they are not large enough to fully obscure the sun. Although Mars is farther away from the sun than Earth, neither of its moons are big enough to create a total eclipse. The view from the moons themselves is more interesting however, with mars eclipsing the sun very frequently, sometimes every day.

Whether you view the eclipse in totality or not, I hope you enjoy the event, and can now answer some of your friend’s and neighbor’s questions. And if you’re bummed out that you can’t travel to see this eclipse in totality, don’t worry, there’ll be another total solar eclipse in 2024 that stretches from Texas to Maine.

Author: Leo Borasio