I was driving to a meeting on the Cape last winter when I happened to listen to Dr. Derrick Pitts, chief astronomer at the Franklin Institute,
talking about the upcoming solar eclipse on NPR’s “Skytalk,” a weekly discussion of what’s new and interesting in astronomy.
He was so interesting, I checked him out on the Franklin Institute website: “It’s coming: August 21st, 1:04 pm. The slowly progressing cycles of earth and moon orbit around the sun and bring us closer to a special triple alignment every minute. This special alignment, called a solar eclipse, is visible from someplace on earth about every 18 months — that’s two total eclipses every three years.
“Often described as the most spectacular astronomical event to be seen from earth, I recommend that no human should leave the planet without seeing a solar eclipse. Mabel Loomis Todd, an avid eclipse chaser in the 19th century, said this after witnessing the May 28, 1900, total solar eclipse at Tripoli, North Africa:
“‘I doubt if the effect of witnessing a total eclipse ever quite passes away … a startling nearness to the gigantic forces of nature and their inconceivable operation seems to have been established. Personalities, towns, and cities, and hates and jealousies, and even mundane hopes grow very small and far away.’”
Well, “no human should leave the planet without seeing a solar eclipse” — we’re not about to pass this up. But let’s start with a little about what exactly a solar eclipse is.
It’s just light and shadows
A solar eclipse has to do with the alignment of three objects, the earth, the moon, and the sun. When the moon lines up directly between the sun and the earth, it blocks sunlight from reaching a narrow strip of earth for a few hours. If the moon doesn’t exactly line up in front of the sun, only part of the sun is eclipsed, and the event is a called a partial solar eclipse. When the sun is completely blocked by the moon, this event is called a total solar eclipse. And at this moment in the history of the earth, although the sun is 400 times larger than the moon, the sun is also about 400 times further away.
It’s actually quite simple. Dr. Pitts suggests you try this experiment: “Stand outside in bright sunlight. Allow your shadow to fall on a nearby person, plant, or pet. Your body, blocking light from the sun, creates a shadow, causing a solar eclipse for whatever is in your shadow. Likewise, the moon, in blocking light from the sun, creates a shadow, causing a solar eclipse for whatever is in its shadow. Get it? That’s all an eclipse is! But that’s not to say eclipses aren’t complicated and even fascinating as individual events — in fact, for scientists who study eclipses, they are incredibly complicated, and each solar eclipse has its own signature.”
This is big
As soon as I got back to the library, I shared all this with my fellow librarians, and we decided to do lots of programming at the West Tisbury library around this event. On August 2, we hosted Bridgewater State University professor of physics Martina Arndt, who gave a presentation about eclipses — how they happen, how they contribute to scientific discovery, and why her research team collects data during eclipses. On August 14 we hosted Jane Paquet from the Martha’s Vineyard Public Charter School, and she showed kids how to make their own pinhole viewer for eclipse viewing. Then on the day of the eclipse, Ms. Paquet will be at the library, where the eclipse will be shown streaming live by NASA. Unfortunately, Nelia Decker, the children’s librarian at the West Tisbury library, and I will be unable to be at this event.
We’re going to Nebraska, baby!
The path of totality — the path where there will be a total eclipse — crosses the entire continental U.S. It’s called the Great American Eclipse. I was chatting on the phone with an old friend of mine recently who has a farm in Manhattan, Kansas, very close to the path of totality, and I thought maybe, just maybe, I should check this out in person. I mentioned this to my fellow librarian, Nelia Decker, and she said, “Are you kidding? I’m all in!”
“We are planning to be in the center of the path of totality,” said Nelia, “which is an hour and a half away from Manhattan, by driving a rental car to Homestead National Monument, along with thousands (maybe millions) of other people. It is one of 22 National Parks that are in the path of totality.
They will be offering an entire weekend of events, talks, and activities to celebrate this event. Apparently, even though the eclipse itself is an amazing event, experiencing it with humanity is a large part of the experience. And you don’t often get a chance to witness such a natural spectacle in the presence of so many other people who will be so moved by what they are viewing.”
For all those here on the Island, here are the vital statistics:
Eclipse on the Vineyard
Begins: Monday, August 21, 2017, at 1:29 pm
Maximum eclipse: Monday, August 21, 2017, at 2:48 pm
Ends: Monday, August 21, 2017, at 4:01 pm
Global type: Total Solar Eclipse
Martha’s Vineyard Island: Partial Solar Eclipse
Duration: 2 hours, 32 minutes
Magnitude (The magnitude of a solar eclipse is the fraction of the sun’s diameter covered by the moon.) 0.72