Fifty years ago, NASA made history by sending humans to the surface of the Moon for the first time. Astronauts traveled back and forth to the Moon for three years gathering more than just data — they brought back pieces of the Moon.

A Moon rock brought to Earth by the Apollo 14 mission in 1971. Credit: NASA

Some of the lunar samples were studied right away, but some were preserved in the hopes that future technology would be able to pry even more information from their grasp. Now, teams of scientists across the United States are beginning to open these lunar time capsules in hopes of learning more about lunar chemistry and the history of the Sun, including how it impacted life on Earth.

NASA is investing millions of dollars to continue maximizing on Apollo era science, with nine teams selected to study the preserved Moon rocks. There are only three samples left and six of the nine teams will study just one of them. This particular sample was collected during the final Apollo mission in 1972. It is a core sample that will reveal layering beneath the Moon’s surface.

Scientist-astronaut Harrison H. Schmitt collecting lunar samples during the first Apollo 17 extravehicular activity (EVA) at the Taurus-Littrow landing site. Credit: Eugene A. Cernan, Apollo 17 Commander

The whole Moon could be considered a time capsule, containing preserved information about the history and evolution of our solar system. Without wind or water, the surface of the Moon is largely unaffected by erosion. By studying its layers, we can look back in time to see our cosmic neighborhood in different stages of development.

New Discoveries About the Young Sun

The teams will continue studying the samples in the coming months, taking care to adhere to stringent protocols to ensure they make the best possible use of the samples while avoiding the possibility of contamination. Results have already started coming in, revealing new information about the Sun’s tempestuous first billion years.

Solar activity has the potential to harm life today, but it was even more vicious in the Sun's younger years. Credit: NASA/SDO/AIA

“We didn’t know what the Sun looked like in its first billion years, and it’s super important because it likely changed how Venus’ atmosphere evolved and how quickly it lost water,” said Prabal Saxena, lead author of the study and an astrophysicist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “It also probably changed how quickly Mars lost its atmosphere, and it changed the atmospheric chemistry of Earth.”  

We already knew that the Sun used to spin much more quickly than it does now, but a study using lunar soil revealed that it only spun about half as fast as similar stars. That has major implications for life on Earth because a speedier-spinning Sun would have experienced violent outbursts like enormous solar flares more frequently. The young Sun was still chaotic, but not as vicious as it could have been. We might owe our lives to the Sun’s relatively mellow pace.

An artist's concept of the early Earth, showing a surface pummeled by large impacts that caused deep-seated magma to seep onto the surface. Credit: Simone Marchi

What About the Thousand-Year-Old Samples?

Moon samples have actually been here on Earth for thousands of years before we visited the Moon in person. They exist in the form of meteorites — bits of the lunar surface that were blasted off in dramatic impact events. There are a couple of reasons we still needed to go collect additional lunar samples, however. There’s no way to tell where exactly on the Moon’s surface the meteorites came from, plus the samples are affected by the violent impacts that carry them to Earth (and the fiery entry into Earth’s atmosphere).

A meteorite that traveled all the way to Antarctica from the moon. Credit: NASA

Still, scientists manage to glean interesting information from lunar meteorites, which tell us about interesting things like radioactivity on the Moon. They’re also useful in filling the gaps, because they come from random parts of the Moon. The Apollo missions, however, specifically targeted “interesting” areas — regions that are not typical of the Moon.

Findings from the Samples Opened 50 Years Ago

Astronauts brought samples back from the Moon 50 years ago because of the benefits of studying them here on Earth. While it’s true that astronauts and even rovers can conduct sample studies away from Earth, scientists have the benefit of using more equipment and conducting far more analyses here than would be possible elsewhere (it’s extremely expensive to launch things into space, so mission planners are forced to pick and choose what equipment gets sent up during each mission).

The Moon to Earth trip is much easier than the reverse because of the Moon’s lower gravity — it doesn’t take as much power to launch a spacecraft home from our neighbor as it does to take us there in the first place. The Apollo 15 mission in 1971 brought back nearly 80 pounds of Moon rocks, and since this mission included a vehicle the samples were from diverse areas on the lunar surface. One of the rocks collected was determined to be over four billion years old and helped scientists understand more about what the solar system was like in its youngest stages.

These scientists are studying preserved Apollo Moon samples at NASA's Johnson Space Center in Houston, Texas. Credit: NASA/James Blair

For the Apollo 17 mission of 1972, astronauts collected even older lunar samples and studied the possibility of relatively recent volcanic activity. Scientists studying these samples found evidence that the Moon used to have its own magnetic field, like Earth. This mission gathered samples from 22 different places on the lunar surface, which NASA scientists are eager to dive into once again.

New Moon Sample Studies & Implications for Future Exploration

We’ve already learned more about the young Sun from the lunar time capsules, but additional findings are expected to roll in soon. One thing scientists will examine as they open the samples is which preservation techniques are best — vacuum sealed, frozen or stored in helium — so they can compare and make improvements. More excitingly, scientists will make “Moon tea” by mixing some of the samples in a fluid medium for study. The goal is to find out whether samples that were in shadow were affected differently by the Sun and cosmic rays than samples in full sunlight.

What does all of this mean for future exploration of the Moon? NASA is sending astronauts back to the Moon in 2024 to add more pieces to the lunar puzzle. The mission, called Artemis will focus on an area of the Moon astronauts have never visited before — the south pole. Material in the bottom of some of the craters in this area are permanently in shadow, which provides natural preservation from sunlight and cosmic rays. Results from these future samples, which will contain water ice, could have implications for the study of life in the universe. Perhaps some of those samples will be preserved for future generations to study, too.