Phase of Beauty

By Phil Plait

SLATE

Posted Sunday, Jan. 20, 2013, at 8:00 AM ET

Like Earth, like Moon: Two worlds seen from space.
Image credit: NASA

Astronauts, unsurprisingly, get a unique view of Earth. Their perspective removes them from the day-to-day strife those of us surface-dwellers experience, and over time they get a whole-world viewpoint. So many of them feel that way that they formed a group called Fragile Oasis, where they try to bring some of that perspective down to Earth.

I follow Fragile Oasis on Twitter, where they commonly post lovely pictures taken from space. Still, I was stunned when I saw this amazing, beautiful, serene photo of our Moon at the top of this post. Here's a closer look:

The old Moon, rising over the Earth's morninglit edge. Image credit: NASA

Sigh. This photo was taken by an astronaut on the International Space Station on Sep. 4, 2010. The Moon was just a few days before new, and if I’ve pictured the geometry correctly in my head, the Moon had just risen over the Earth’s edge a few moments earlier. A minute or so later the Sun would’ve risen farther along the curve of the Earth; the thin crescent of our planet shows the space station was about to head into the daylit side of the Earth, the half facing our nearest star.

This picture possesses a simple beauty, the majesty of the Earth with our Moon so far in the distance. As a scientist I can’t help but notice how gray the Moon looks compared to the intense blue of our atmosphere. Note how dim and dark the Moon is as well; on average it reflects about a third as much sunlight as the Earth does, making it appear dusky compared to our bright, shiny planet.

As a space enthusiast I see the Moon for what it is: our nearest cosmic neighbor, but still so terribly remote in human terms it takes more than three days to get there. And I think of how no human has set foot on it since Gene Cernan stepped back on the Apollo 17 lunar module ladder more than 40 years ago.

As a human, a scientist, and a space enthusiast I can’t help but wonder: When will we disturb that gray dust once again?

As an optimist—which I will, sometimes, admit to being—I think it will be soon.

The same view, but taken a day later, on Sep. 5, 2010. Can you see the Moon is a slightly thinner crescent?
Image credit: NASA