Despite the pandemic, NASA launched the Perseverance rover on Mars in July in Cape Canaveral, Florida. Its central mission will be to seek evidence of previous life on Mars.
An interesting component of the rover is a specialized drill that will collect samples of rock and soil to be stored on the surface of Mars. If all goes according to plan, the evidence will be recovered by a future mission in 2031 and, for the first time, the material from Mars will be brought back to Earth for analysis.
All Martian meteorites formed millions of years ago, when asteroids and other space rocks collided with the surface of Mars with enough force to remove pieces of its crust into orbit. Sometimes these rock fragments, which float in outer space, enter the Earth’s atmosphere, where gravity attracts them.
Meteorites land all over the Earth, but are the easiest to find in hot or cold deserts, where the lack of vegetation and other rocks helps them stand out. Martian meteorites are rare: only 261 pieces have been found on Earth, compared to 63,758 meteorites non-Martians currently cataloged, most of them from the asteroid belt.
Martian meteorites were recovered from all over the world, including Antarctica, North West Africa, Chile, the United States, India, Nigeria, Mali, Mauritania, Brazil and Oman. Currently, scientists can obtain Martian meteorites for study in two ways: either from private dealers or from the Antarctic Search for Meteorites collection.
How the rocks from Mars reach the Earth
The ANSMET program is funded by both NASA and the National Science Foundation. Antarctica is a great place to observe meteorites due to the ubiquity of ice. Even better, meteorites tend to be trapped in the moving ice flower that accumulates at the base of mountain ranges, where they often reappear on the surface.
Every year since 1976, ANSMET has sent a team of eight scientists and volunteer climbers to Antarctica in December and January to hunt meteorites.
Scientists can also buy meteorites from trusted private dealers. Martian meteorites are expensive, however, they usually run on average around $ 1,000 per gram. Most Martian meteorites are found by nomads in the Saharan desert, mainly in Morocco. Locals have been instructed to find meteorites by looking for the presence of a melting crust on a rock, which is formed when the outside of the meteor melts as it enters Earth’s atmosphere.
Initially, scientists analyzed gas pockets of meteorite minerals and compared them to the known atmosphere on Mars, which was established by NASA’s Viking rovers in 1976. When the gases matched perfectly, scientists were able to conclude that the meteorites came from Mars.
How to determine if a meteorite is from Mars
However, beginning in the 1990s, scientists began to use cheaper and easier techniques to determine the Martian origin, such as isotopic oxygen compositions, which are like atomic barcodes that are unique to each planet.
Unfortunately, many scientists do not know the exact origin of meteorites, but many are working to figure it out. Some have been able to determine the different ages of the rocks. We still don’t know for sure if the core of Mars is liquid or not, but meteorites tell us how and when volcanoes formed on the planet.
NASA’s Perseverance Rover will explore an area called Jezero Crater. It is likely that some rocks, created by volcanic activity, are present, so it will be really interesting to study the history of the crater, which formed about four billion years ago. Jezero Crater also contains two large deltas, where researchers expect to find sediments that were once transported and deposited by rivers that existed long ago.
For scientists studying Martian geology, obtaining various samples from a known field location will greatly enhance their understanding of the core of Mars, its climate history, and the potential life that may have once existed there.