18
July
2019
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04:07 PM
America/New_York

6 things we know—and don’t know—about the moon, 50 years later

Ohio State planetarium director gives a scientist’s perspective on the anniversary of Apollo 11

Humanity’s first steps on the moon 50 years ago this month gave the world a moment where the planet seemed united—a moment summed up in Neil Armstrong’s celebrated words: “That’s one small step for man; one giant leap for mankind.”

It also gave us technology—discoveries that led to sunglasses, cell phones, freeze-dried food and in-ear thermometers.

But there is still so much we don’t know about the moon. As the world celebrates the 50th anniversary of the Apollo 11 mission, Ohio State News sat down with Wayne Schlingman, director of the Arne Slettebak Planetarium at The Ohio State University, to hear more about what that first moon landing taught us and what we still have to learn about our moon. Watch the video, and read on to see more of what Schlingman had to say.

 

1.) We still aren’t totally sure how the moon formed.

Astronomers mostly think the moon formed when a giant object, roughly the size of Mars, crashed into the Earth, peeled off a layer of the Earth’s crust and sent it spinning into space, where it fell into orbit around Earth. If this theory is right, those bits of Earth’s crust eventually coalesced into one mass, continued spinning and formed the orb that is now the Earth’s moon, Schlingman said.

“We have a lot of evidence that this is true: Certain isotopes when we measure the lunar surface and the Earth’s surface are similar, so that means they’re connected,” he said. “But it doesn’t answer everything. … We don’t know what’s going on because we don’t know the whole composition of the moon.”

Learning more, Schlingman said, could require drilling into the moon’s mantle and studying the core, taking samples and testing them to see what they are made of. That requires another trip to the moon—something NASA has said it might do as soon as 2024.

 

2.) There are still a lot of moon rocks left to analyze.

And geologists and other scientists might soon get the chance to see what those rocks say about the moon and its composition.

“The first Apollo mission brought back about 50 pounds of rocks, basically a briefcase filled with rocks,” Schlingman said. “And with the other additional missions we’ve taken, we’ve been able to bring back many more rocks—and many of them have been tested in labs. But some of them, NASA sealed away.”

In 1969, Schlingman said, NASA’s scientists didn’t know what to expect from the moon’s soil and rocks: Would the rocks explode when they interacted with Earth’s atmosphere? Would the astronauts sink up to their knees in lunar dust?

NASA recently announced it would release some of those previously unstudied rocks to scientists, something Schlingman said could unlock even more secrets about the moon’s composition.

“This is exciting, because 50 years ago, we didn’t know what questions to ask about the rocks,” he said. “And now we have better technology and greater understanding: We can analyze these rocks to really get some more answers.”

 

3.) Water exists on the moon.

But we don’t know exactly how much.

“We know that there is water on the moon—we typically will find it in areas that have not been irradiated by sunlight,” Schlingman said. “So, if we think about it like here on Earth, we take mud and expose it to sunlight and the water bakes out. The same thing happens on the moon … so a lot of the places where we find water on the moon are at the poles, in places that have never seen the light of day.”

Humans have found only frozen water and in small amounts. But because we know less about the far side of the moon—the side that never faces the Earth—it is possible that more water exists there. (Learn more about the far side of the moon in a piece Schlingman wrote earlier this year for The Conversation.)

 

4.) Neil Armstrong and Buzz Aldrin almost ran out of gas.

“They’re flying this lunar module down to the surface and they notice that their landing surface is actually in a crater, and Neil said, well, we’re not going to land there, we’re going to fly somewhere else,” Schlingman said. “And this is while they have 60 seconds of fuel, total fuel that they can use to land. So, they’re flying along and they’re down to 30 seconds, and then it’s 20 seconds, and they make their landing with about 15 total seconds of fuel left to be able to land their module and still be able to get off the surface.”

When Armstrong landed, he sent a message back to NASA headquarters: “Houston, Tranquility Base here. … The Eagle has landed.”

 

5.) Humans have left a LOT behind on the moon’s surface.

Including, Schlingman said, a gold olive branch as a symbol of peace, communiques from world leaders, moon rovers, patches honoring astronauts from previous missions, and human excrement (astronauts’ waste has to go somewhere).

And the famous flag that Armstrong and Buzz Aldrin planted on the moon’s surface during that first visit on July 20, 1969?

“It’s probably been bleached white,” Schlingman said. “Think about it: It has been on the surface of the moon for 50 years, exposed to the sun’s radiation nonstop. And we know what happens when we lay stuff out here on the Earth, it just bleaches it white.”

 

6.) Equipment set up during the Apollo missions is still contributing to science.

The Apollo 11 mission, and Apollo 14 and 15—as well as two missions executed by the Soviet Union—left retroreflectors on the moon for lunar laser ranging experiments.

Scientists direct lasers at the reflectors, and measure the distance to the moon to millimeter precision.

“We still do this weekly from the Earth to measure how the moon is moving away from the Earth; it is a test of gravity,” Schlingman said.

And the Apollo 11 mission also showed how powerful science can be.

“It was the first time that we had an image of what the Earth looked like from the moon, our small little marble in space, and the first time we were able to see that there was one thing that connected us—the Earth,” Schlingman said. “The Apollo 11 mission, it really was for all mankind. Yes, we wanted to win, and yes it was for the USA, but we were unified as a planet in that we wanted to be there.”