Early Wednesday morning, Americans west of the Mississippi River can watch the moon turn blood red, when it plunges through Earth’s shadow in a lunar eclipse.
But if you could somehow hitch a ride to the moon, you would witness a magical celestial show seen only by astronauts: a spectacular total solar eclipse more than an hour long.
A solar eclipse of such duration is more than 20 times longer than the amazing total solar eclipses witnessed by millions of Americans in August. It lasted two minutes and 41 seconds at the most. (The longest a solar eclipse can ever last on Earth is seven minutes and 29 seconds.)
A solar eclipse seen from the moon would not only last much longer than the Earth version, but it would also take on a unique appearance as Earth blocks the sun. (During a solar eclipse seen from Earth, the moon blocks the sun.)
Watching a solar eclipse from the moon, the disk of the Earth would appear over three times larger than the sun. (During an earthen solar eclipse, the moon and sun are roughly the same size. That’s why they produce such an exquisite site during their heavenly flirtations up above.)
On the moon, as the solar eclipse progressed, the bright side of the moon would gradually darken as the earth interrupts the flow of sunlight. Shadows would become sharper, and the color of the light would change. The ordinarily bland sunlight would transition to a bronze tinge that would wash over everything.
Then, as Earth wedges into more and more of the sun, the light streaming down to the moon would shrink into a bead — the same “Bailey’s Bead” phenomenon that we saw during the Great American Eclipse. But that’s when things become markedly different.
Next, a red ring would form around Earth, which would otherwise appear as an inky-black sphere across the dark vastness of space. It would be much brighter on one side of the outlined earth. This “ring of fire” would develop as the last rays of sunlight streamed through the earth’s atmosphere tangentially to the surface, filtering out all but the red wavelengths. It’s the same reason sunsets look red from the ground.
This razor-thin crimson ring would be an “incredible sight,” said Karen Runyon, a science teacher in Massachusetts. Runyon is passionate about everything science and shares this love of learning in the classroom. Of all that the field encompasses, space science is her favorite.
“When I stare in wonder at the simplicity of a lunar eclipse,” she said, “I often think about the view from the moon. Imagine seeing every sunrise and sunset on Earth all at once against a starry backdrop, the moon bathed in a dusky glow. It would be simply astonishing!”
The elusive solar corona, too, would emerge. But because Earth would cover more of the space surrounding the sun, lunar residents wouldn’t be able to see the chromosphere — the fiery region of high-energy flares ejecting from the sun’s surface. Likewise, “coronal loops” of plasma that snake around magnetic field lines close to the solar surface would be out of view, the inner corona obscured as well.
But Earth wouldn’t hide everything. Depending on the shape of the corona, long silky prominences would shimmer well beyond the void cut out by Earth. These icy-white tendrils would stretch out for millions of miles, like hair radiating from Earth. While some of the coronal structure fades into the twilight sky during solar eclipses on Earth, it would blaze against a pitch-black background in space.
Moreover, the dark side of Earth facing the moon wouldn’t be completely dark. From the moon, you would be able to see the nighttime lights of distant cities a quarter million miles away. Likewise, the corona’s color would change — whitest toward the edges, then blue, and finally a peachy orange toward the center. And this wouldn’t be a fleeting event as on Earth; it would last more than an hour!
In addition to this, Earth would seem to “glow” red from light scattered through and around the atmosphere. This is known as “earthshine.” It’s the reason we can sometimes see the dark side of the moon from Earth, even though the moon produces no natural light of its own.
What does a lunar eclipse look like from the moon? It’s a solar eclipse… and then some! pic.twitter.com/SnnAhIU5TY
— Matthew Cappucci (@MatthewCappucci) January 29, 2018
Allyson Bieryla is an astrophysicist at Harvard University; she witnessed her first solar eclipse in the summer, and in her words, it was “mind-blowing.”
“It was such a breathtaking sight that I now want to become an eclipse chaser,” she said. “I can only imagine that seeing a solar eclipse from the moon must be an incredibly humbling experience.”
Many who witnessed the solar eclipse from Earth in August reported feeling significantly more grounded after. It’s a transformative and deeply spiritual experience for many as they stare up and marvel at the grandeur of the universe.
“Cosmic events such as an eclipse are so surreal that they force us to stop and remember that we are all part of something much bigger,” Bieryla said. “Standing on the moon this Wednesday watching as our distant home passes in front of the sun is not something that I imagine would leave a person underwhelmed.”