If you’re anything like us, you probably have solar eclipse fever: You've had August 21 marked on your calendar for days with dozens of sun and moon emojis; you’ve got your special viewing glasses, and you’re planning on taking your lunch break precisely at the eclipse’s peak moment (for all of you New Yorkers out there, that’s 2:44 p.m.). If you’re really committed to 2017’s total solar eclipse, you might even have travel plans to the path of totality to see the phenomenon in its truest form.
Amidst all of your preparations, you might have forgotten to look up the most basic part of the big day: what even causes a total solar eclipse in the first place? As it turns out, the reason is pretty out of this world.
Basically, a solar eclipse happens when the moon passes in front of the sun during its orbit around the earth. As the moon passes over the sun, it causes a shadow to cross over Earth, which is the moment we’re all looking forward to. Unlike lunar eclipses, solar eclipses are brief — they only last a few minutes.
The reason this solar eclipse is so special is because it’s a total solar eclipse. According to NASA, a total solar eclipse is when the sun, moon, and Earth are all directly in a straight line. When they all align, the sky becomes really dark, like nighttime dark, during the day. You can only get the full effect of the total solar eclipse in very specific areas, so that’s why the path of totality is such a big deal.
According to Jason Steffen, an astrophysicist at the University of Nevada Las Vegas, total solar eclipses are the rarest type of eclipses. What makes this total solar eclipse even rarer is the fact that it’s going to travel across the entire continental United States. It’s called the Great American Eclipse because it's the first time an eclipse like this has happened since 1918.
You’re not going to want to miss this unforgettable moment in space, so if you’ve just now caught solar eclipse fever — it’s not too late to prepare. Normal sunglasses won’t be able to protect your eyes from the sun’s concentrated rays; you can cause serious, permanent damage to your eyes if you look at the eclipse for more than a minute and a half. If you can’t get your hands on some eclipse viewing glasses, you can get crafty and make a pinhole camera to watch. Just be sure to protect your eyes.
Even if you’re not on the path of totality, you’ll still get to see some pretty epic views. NASA says smartphones are safe against the sun’s glare, so you can even snap a few photos. You’re not going to want to forget this truly stellar occasion!
For more on eclipse prep, check out our guide to Everything You Need To Gear Up For Watching The Total Solar Eclipse.