Thousands of meteorites fall onto the Earth each year. When a fall occurs in an accessible area, scientists and amateur space enthusiasts pursue the specimens, often submitting them to collections that serve planetary research. The Astromaterials Research and Exploration Science (ARES) division at NASA's Johnson Space Center studies meteorites and is implementing tools and technique to more easily recover meteorites.

We sat down with Dr. Marc Fries of ARES to learn more about meteorites and why they matter.

NASA: So what exactly is a meteorite fall?

MARC FRIES: For starters, a meteorite is a rock that falls to Earth from space. Often a meteorite breaks up as it travels through the atmosphere, resulting in a strewn field of fragments rather than a single rock. 'Meteorite falls' are meteorites collected after being observed by people or automated devices during their fall to Earth. We basically have enough information to know when a fall has occurred and where it landed. Meteorites that are found without prior observation are referred to as 'finds'.

Can we learn anything from these rocks after they have entered the atmosphere?

Meteorites contain a physical record of the formation and later changes to our solar system, going back approximately 4.6-billion years. Some meteorites even contain remnants of stardust created before the solar system. Meteorites can dramatically influence the course of life on Earth. Early in Earth's history they introduced at least some of the components necessary for life - simple organic compounds such as carboxylic acids and amino acids.

Additionally, large meteorite strikes can lead to major extinctions, like the one roughly 65-million-years ago that led to the end of dinosaurs. Plus, just about everyone has seen a meteor or a meteorite. These are things that you see with your own eyes and hold in your own hands. Understanding where they come from and what they are gives you a very personal connection to planetary science.

How do you know where to search for meteorites?

People see them fall. The world is interconnected like never before, and when a large meteor streaks across the sky somewhere, news of the event is often shared through social media and organizations that allow the public to make eyewitness reports, such as the American Meteor Society. Meteors are also recorded by dedicated all-sky camera systems such as NASA's All-sky Fireball Network, a network of cameras managed by the Meteoroid Environment Office at NASA's Marshall Space Flight.

Once the time and location of a prominent meteor is known, we can search through radar data sets such as weather radar imagery collected by NOAA's nationwide NEXRAD weather radar network. The ARES division has established a meteorite falls website to house tracking and landing site information as well as directions to the fall sites.

If I go out and find a meteorite, does NASA want it?

In a word, no. NASA does not maintain a collection of meteorites collected within the United States, and our interest in meteorite falls is primarily in the science of these events. NASA's meteorite collection, jointly managed by ARES and the Smithsonian Institution (with the characterization laboratory at Johnson), is devoted to specimens obtained during yearly expeditions to Antarctica by the Antarctic Search for Meteorites (ANSMET) expedition.

The reason for this is that these meteorites are most likely to be in pristine condition and allows the team to test curation techniques. The ARES meteorite falls website directs you to a listing of institutions that accept meteorite-based inquiries from the public.

Does ARES actually go out and pursue specimens after meteorite falls?

The ARES division may investigate meteorite falls of special scientific interest. For example, a recent fall in the Hamburg Township, Michigan afforded us the rare opportunity to study a meteorite which was collected in cold weather and then kept frozen afterwards. ARES collaborated with a search team from the Sloan Longway Planetarium in Flint, Michigan, which retrieved a frozen specimen roughly the size of a peach pit from Strawberry Lake. NASA does not retain these meteorites in its collections, however.

Why does ARES care about a frozen meteorite?

NASA is preparing for the return of samples from icy destinations in the solar system. These samples must be maintained at cold temperatures to preserve their original condition for research. Frozen meteorites provide an opportunity to test cold curation techniques and processes. Also, a frozen meteorite is likely less contaminated by Earth contact, which means that terrestrial alteration by humidity and our atmosphere's oxygen is lessened.

What if the meteorite falls into non-frozen water, like an ocean?

Recovery of meteorites that have fallen into bodies of water is tricky. ARES recently experimented with a recovery technique using remotely controlled submersibles deployed from the exploration vessel E/V Nautilus operated by the Ocean Exploration Trust. The collected samples are now under examination to determine if meteorite material was collected.

A similar effort is underway by the Aquarius Project run by Adler Planetarium, which is a student project to collect meteorites from Lake Michigan. A large meteorite fall occurred over the lake in 2017, with all of the meteorites from this sizable fall ending up in the water. Overall, the Earth's surface is approximately 70-percent water, so most meteorite falls end up on the ocean floor.

Can I touch a meteorite that I find?

You can, and it will not harm you. The skin oils, sweat, and microbes in your fingerprints are harmful to meteorites, however, and careful handling without contact by bare hands will preserve them. ARES' meteorite falls website has instructions for meteorite recovery and handling to minimize sample contamination.

Related Links
Astromaterials Research and Exploration Science (ARES)
Asteroid and Comet Mission News, Science and Technology

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