Are you ready for April 8? Astronomers across North America are: an eclipse of the Sun is coming!

Solar eclipses are spectacular to witness, interesting to predict, and facilitate some very interesting experiments, but the root cause of them is quite simple: a shadow. In the case of a solar eclipse, the Moon is blocking the Sun from our view. Thus, the shadow of the Moon sweeps over the Earth. Big deal, right? Well, if you happen to be under that shadow, as we will be on April 8, you’re bound to experience a generous helping of weird, observable effects.

The Moon’s shadow first makes landfall on the west coast of Mexico and rockets across North America toward the northeast at a rate of about 1500 miles per hour. The path of totality is only about 100 miles wide; the ~32 million people located along that path will have the full, immersive experience of a total solar eclipse. Here in southeastern PA, the Sun will be about 90% covered by the Moon. While not as dramatic as experiencing totality, there are important things to know about this kind of a deep partial eclipse.

First, it will become noticeably dark in the middle of the day! On a perfectly sunny day, if it suddenly darkened, you’d find that pretty weird, right? For us, the eclipse will begin just after 2 PM as the Moon first touches the Sun. As it slides over, shuttering out the light, only a 10% sliver will remain around 3:20 PM. Note that this is right around dismissal time for many local schools. Please prepare your children and let them know this darkness in the day is totally natural, normal (and pretty cool, too!).

Second, as it gets darker, there are things to notice in the sky and on the ground. It’s possible that crepuscular creatures will emerge (deer, especially) thinking that night has come early. There will be a few bright planets that can be seen in the sky (Jupiter to the upper left, Venus to the lower right). And don’t forget to view the eclipse itself! And having said that…

Third, this kind of eclipse should never be viewed directly without the proper eye protection. Do you have eclipse glasses left from the 2017 August eclipse? They are still good as long as you have not touched the lenses directly with your fingers and if the mylar in them is still securely attached to the frames. You might also be able to secure a free pair of eclipse glasses from your local library. Many have received supplies of these through a national project called STARNet (SEAL). There are many ways of viewing the eclipse safely using indirect methods as well. For example, if you let the Sun’s light fall on a simple kitchen colander onto the ground, look toward the ground (NOT through the colander) and you will see multiple images of the partially eclipsed Sun in projection there.

On April 8, we will bear witness to a terrific cosmic coincidence–since the Moon is 400 times closer to Earth than the Sun and also 400 times smaller, the Moon is able to completely overlap the Sun. Make sure that you and your family are a part of it!

Deborah Skapik is a NASA Partner Eclipse Ambassador, a SEAL Solar Eclipse Expert, and also a local Physics and Astronomy educator at Friends’ Central, St. Joe’s, and Delaware County Community College.

Deb recently wrote,  “Look UP, Below!  an educator’s guide to the April 8, 2024 total eclipse of the Sun.”

Check out the local library calendar below for scheduled presentations about eclipses and score yourself a free pair of eclipse glasses!