This story is part of, our series exploring the red planet.
Let's deal with this name issue right away. "Tooting Crater" on Mars is a large and fairly young impact site. Mars craters expert Peter Mouginis-Mark identified the landmark and named it Tooting after his birthplace in the London suburb. It's OK to giggle about it, especially when thinking about the crater ejecting material out into space that ended up reaching Earth.
According to Curtin, 166 Martian rocks are known to have landed on our planet over the past 20 million years, but it's been tough to trace their precise origin points on Mars. It takes a lot of energy to blast a bit of Mars out into space, so the researchers looked at craters that might be responsible.
The team created a database of 90 million impact craters on Mars and used a machine learning algorithm to narrow down potential meteorite launch sites. Tooting was a match for a certain group of the Martian meteorites (categorized as "shergottites") found on Earth.
"By observing the secondary crater fields -- or the small craters formed by the ejecta that was thrown out of the larger crater formed recently on the planet -- we found that the Tooting Crater is the most likely source of these meteorites ejected from Mars 1.1 million years ago," Lagain said in a statement on Wednesday.
Knowing where the meteorites came from can help fill in missing information about Mars and its geologic processes. Tooting Crater is in a region known for its volcanic history and it was formed in an area shaped by lava flows.
"This finding implies that volcanic eruptions occurred in this region 300 million years ago, which is very recent at a geological time scale. It also provides new insights on the structure of the planet, beneath this volcanic province," said co-lead author Gretchen Benedix, a cosmic mineralogist and astro-geologist at Curtin.
Having pieces of Mars in hand on Earth can tell scientists a lot about the red planet. That's why NASA is working to bring back rock samples through the efforts of theand a future Mars sample-return mission. In the meantime, the Martian meteorites we already are telling a fascinating story all their own.