Space buffs, scientists, nature-lovers, and beyond are counting down the days to August 21st—and for good reason. Beginning at 9am in the northwestern United States and continuing on until about 3pm in the southeast, a solar eclipse will sweep the nation, exciting and amazing 10 states and, potentially, 47 million Americans.
So what’s so cool about a solar eclipse? Well, for starters, they are incredibly rare (don’t believe me? Watch this.) A total eclipse of the Sun can only happen when a New Moon moves precisely between the Sun and the Earth, blocking the Sun’s rays entirely and casting a shadow, or “umbra,” on parts of the planet.
The conditions must be perfect; the Moon must be near the point of its orbit that is closest to Earth, and the Sun and New Moon must be near one of two “lunar nodes” (the two points where the Moon’s path around the Earth meets the Earth’s path around the sun).
Because the Sun is approximately 400 times larger than the Moon, a solar eclipse is not always possible. But, when the Moon is at the point of orbit that is closest to Earth, it is about 400 times closer to us than the Sun. This creates the ideal situation for a solar eclipse to occur, making the Sun and Moon appear to be the same size from our perspective here on Earth. Science, am I right?
Confused yet? Check out NASA’s helpful video on YouTube.
While solar eclipses do happen about every 18 months, total solar eclipses are far rarer. And even more rare than that is the probability that a total solar eclipse will happen over land rather than sea. Because 71 percent of the Earth’s surface is covered in water, the odds of a total solar eclipse happening where land-dwelling humans can see it is only about 30 percent. And don’t even get me started on the likelihood of clouds impairing visibility.
And that’s just the science. In addition to being super rare, solar eclipses are downright breathtaking. The shadow the Moon will cast will create twilight in the middle of the day. Viewers of past total eclipses have reported being able to actually watch the shadow cast from the Moon come towards them and then move away as the Earth rotates on its axis. According to Space.com, skywatchers have also reported seeing “jets and ribbons of light, twisting and curling out into the sky.”
Unfortunately, not everyone in the US will be able to see the eclipse in totality. Because of the Sun and Moon’s natural path this year, residents and visitors of Oregon, Idaho, Wyoming, Nebraska, Missouri, Illinois, Kentucky, Tennessee, Georgia, and South Carolina will be the lucky spectators of the eclipse (You can see NASA’s interactive map here.)
Never fear, though! Those in outlying states will still see a partial eclipse this year, and, according to NASA, the 2024 solar eclipse will stretch from Mexico and Texas up through the Midwest and northeastern U.S.
In the meantime, if you live in New York, the Natural History Museum’s planetarium is hosting a live broadcast of this year’s solar eclipse, free with museum admission! Or, if you live elsewhere, you can watch NASA’s live stream.
Do you live in the path of the eclipse and all of those (super cool) facts still aren’t enough to convince you to watch the eclipse on the 21st? Get this: according to TIME, a total solar eclipse only occurs on a given spot on the planet once every 375 years. Avoid the ultimate #FOMO, take a long lunch, and experience the magic of a total solar eclipse.
If you’re itching to read more about space, check out our post Books for Space Buffs. Want more Moon? Check out our 2018 Moon Calendar Card.
