Across North America, people will get to witness a rare celestial event today: a solar eclipse, which occurs when the moon passes between the Earth and sun.
While certain parts of the United States will experience a total eclipse, Cleveland will only see a partial one, with 80 percent of the sun covered by the moon at maximum eclipse.
It may be tempting to peer up to the sky to watch it, but don’t—at least not without special eclipse glasses to protect your eyes.
The Department of Astronomy will provide protective eyewear at two viewing events it’s hosting today (Aug. 21) at Kelvin Smith Oval and on the roof of A.W. Smith Building, where the department will provide access to the telescope. In both locations, astronomy faculty, staff and students will be there to answer questions. Learn more about the viewing parties.
Can’t make it to the parties—and don’t have protective eyewear to watch on your own? NASA will live-stream the eclipse at nasa.gov/eclipselive.
So what should everyone should know about solar eclipses in advance of today’s event?
We asked Stacy McGaugh, professor and chair of the department, to share his expertise:
1. A historical perspective
People have been aware of this phenomenon for a very long time. Some of the earliest written records are astronomical tables. The ancient Sumerians started writing these things down as soon as they invented writing.
One of the things the Babylonians and others obsessed about was eclipse seasons. It was a big deal for an agrarian early culture if the sun was taken away—they relied on that in their everyday life and for agriculture. If you don’t understand what’s going on, it’s a very startling event. That made such a huge impression on the human mind historically that we, as a species, had already worked out that there was a rhythm to it.
2. A modern perspective
We understand these things—we understand the motion of the moon and the Earth around the sun extraordinarily well. We understand that, once in awhile, they line up closely enough that the shadow of the moon falls on the Earth. There’s nothing especially extraordinary about that, any more than a seagull flying across the sun and casting its shadow on you while you’re on the beach.
But it’s a rare enough event and something that people don’t get to witness in their lifetimes very often. It is a dramatic thing.
3. The timeline of today’s partial eclipse
It starts at 1:06 p.m. local time and reaches its maximum extent at 2:30, when the disk of the moon will block about 80 percent of the disk of the sun. It will end at 3:51 p.m. Learn more.
4. Safety
I would reiterate that one should not stare directly at the sun for any length of time. With suitable glasses, you can observe this event quite easily with your eyes. Just as you can see the moon on a normal night and resolve features on it with your naked eye, so, too, the disk of the sun and the moon are big enough that you will basically see the glowing orb of the sun with a big bite taken out of it. And you don’t need any magnification to help with that—you just need the very dark glasses to protect your eyes. Ordinary sunglasses do not suffice, so don’t try it. That’s why we’ll be handing out eclipse glasses.
5. The next full eclipse after today’s
The next big full eclipse of the sun is in 2024—April 8. That time, totality will go right through here—unlike now, where we only get a partial eclipse and you have to travel a ways south to see a full eclipse. If you’re patient, in seven years, you can see the full thing here. That is a big deal in the sense that we’ll get about an 80 percent maximum eclipse [today], and that is noticeable if you’re really paying attention, but it’s also like a cloudy day. Whereas, totality, you notice for sure. It gets completely dark and you can see the other stars come out in the sky.