Men first set foot on the moon in 1969. Like tourists seeking souvenirs for the folks at home, they brought back some chunks of lunar land. What have we learned from the rocks they collected? Where are the moon rocks today? How can you get a look at them? Can you hold one in your hand? These and other questions are answered by one of the scientists who first studied the moon rocks in 1969.
Martin Prinz, now Curator of Meteorites at the American Museum of Natural History in New York, was working at the Institute of Meteoritics at the University of New Mexico in 1969 when he became one of the first investigators of the moon rocks. Along with other groups of petrologists (geologists who study the origin, composition, and alteration of rocks), Dr. Prinz studied samples from all of the Apollo missions.
How Many Missions Went to the Moon?
Six different Apollo missions gathered moon samples, beginning with Apollo 11, which landed on the moon July 20, 1969, and ending with Apollo 17 in 1974. All but Apollo 13 successfully landed on the moon and were able to collect and bring back lunar samples.
The Russians have made three unmanned missions to the moon in which they brought back samples. The two countries have shared samples for study.
How Many Moon Rocks are There?
It's hard to count the number of individual rocks. In all, 840 pounds of rocks were brought back from the moon. The samples ranged from "soil" actually loose dirt, to large rocks. Some were made into "thin sections" which are slices of rock only 30 microns thick that can be viewed through a microscope.
Where Are the Moon Rocks Kept and Can I Get to Touch One?
Most of the moon rocks are in Houston, Texas at the Johnson Space Center's Building 31, called the Lunar Facility. It was designed as a safe, secure, clean building. About 20 percent of the moon rocks are kept nearby in another building as a sort of safe deposit box, in case disaster were to strike Building 31.
A few of the moon rocks are on exhibit at various museums around the country. At the American Museum of Natural History in New York, you can see three rock samples. The Smithsonian in Washington, DC has a few samples you can actually touch, but from years of big and little hands touching them, they've gotten pretty dirty!
Are Moon Rocks Like Earth Rocks?
The moon has many, many different rock types. Most of the rocks are breccias, which are hard, solid rocks that have broken up and formed back together in different combinations. Since the moon is constantly changing from the impact of meteors, breccias are continually being formed. Breccias aren't unique to the moon. Volcanic areas on earth have a lot of breccias, as well. Many of the moon rocks are a very dense hard rock called basalt that is also a very common rock on earth. Most of Hawaii is basalt.
The biggest surprise about the moon rocks was that over 80 percent of the moon seems to be light colored feldspar, which is also the most common rock on earth. This supports a theory that at one time the entire surface of the moon was molten, just one huge magma ocean 300-400 miles deep! As it cooled, the lighter minerals, like feldspar, floated to the top. The heavier ones, like the darker colored basalt, stayed below the surface.
Did We Go to the Moon Just to Get the Moon Rocks?
Even though the moon rocks have taught us and are continuing to teach us so much about the moon and the earth, the Apollo missions weren't originally planned as scientific studies. After the Soviet Union launched Sputnik in 1957, the US launched the space program. It was a time of international rivalry between the USSR and the US, and once we started sending men into space, America was determined to put a man on the moon before the USSR and before the 60s ended. We managed to do both.
As the race to the moon wore on, scientists pushed to add a scientific mission to the Apollo program. The astronauts didn't know much about geology, so they had training in New Mexico, Hawaii, and California, places geologists thought would be most like the moon. Out of 12 people to walk on the surface of the moon, the only actual geologist to go was Harrison "Jack" Schmidt, who was on the very last Apollo mission.
Did the Rocks Come from Different Parts of the Moon?
Yes. Each mission built on what was learned in the flights before it. When Apollo 11 landed in the Sea of Tranquility there were still a lot of unknowns about the surface of the moon. That area was chosen because it appeared to be a safe, flat place to land, but at the time no one had any idea how deep the dust would be on the moon or whether the module would sink when it landed. For Apollo 12, scientists studied photos and telescope images to find a site that appeared safe, but was more geologically complex.
What Did the Moon Rocks Tell us about the Man in the Moon?
What we call the Man in the Moon is actually a pattern of basalt that fills up the large craters, or impact basins, that were formed when meteors hit the moon. When a meteor hits the moon, solid rock below the surface of the basin melts and the dark rock seeps up to the surface, like in a volcano. These basins are called seas (Mares, in Latin) since when man first began wondering about the moon, he thought those large areas were filled with water. Everyone wanted to know whether there really was water on the moon, but the moon rocks showed us that not only is there no water on the moon now, but there never was a single drop!
Were People Afraid of the Moon Rocks at First?
At first people were worried that the rocks might contain microbes and germs that could contaminate the earth, but when no life whatsoever was found in the rocks, the concern switched to keeping the rocks from being contaminated by us.
How Did the Moon Rocks Teach us about the Earth?
"Rocks are history books," says Dr. Prinz. "There is recorded information in there. You just have to learn how to get it out." There is so much to learn from these rocks that scientists have been continually studying them for decades.
Before the Apollo missions to the moon there were quite a few theories about how the moon formed. After studying the moon rocks and finding what ways they are similar to and what ways they are different from earth's rocks, a new theory stands out.
This theory says that since the moon and the earth are very closely related, the moon must in some way have formed from the earth. Around four and a half billion years ago when the earth was forming, a huge planetary chunk of material about the size of Mars hit the earth. This caused an enormous explosion. Part of the material which blew off formed the moon.
When Are we Going Back to the Moon?
Japan has plans for an unmanned mission, but the US is currently looking further afield. The study of the moon rocks has created the field of planetary science and now Mars is the next big thing, even though it takes at least two years to reach Mars, and at the time of the Apollo flights, it took only three days to reach the moon.
The knowledge we have gained from those geologic 'history books' we call moon rocks has put us on the road to far off lands, and one day will no doubt send us to "a galaxy far, far away."