This well known meteorite contains a wealth of clues. Image Credit: NASA
For the first time ever, organic compounds containing nitrogen have been found inside a meteorite from Mars.
Discovered in Antarctica's Allan Hills more than 35 years ago, the meteorite - which is known as ALH84001 - dates back 4 billion years to a time when Mars was very different to how it is today.
You've probably heard of this particular meteorite before - back in the 1990s a team of scientists controversially claimed to have identified microscopic fossilized bacteria contained within it.
The discovery became headline news worldwide and while it has since been downplayed as inconclusive, the research played a key role in advancing the field of astrobiology.
Now, more than 20 years later, scientists analyzing the meteorite have discovered evidence of fixed nitrogen - a strong indication that Mars may have once been home to the ingredients of life.
"Early in the solar system's history, Mars was likely showered with significant amounts of organic matter, for example from carbon-rich meteorites, comets and dust particles," said Atsuko Kobayashi from the Tokyo Institute of Technology.
"Some of them may have dissolved in the brine and been trapped inside the carbonates."
While it remains unclear how these organic compounds may have arisen, their presence represents some of the strongest evidence yet of the past habitability of the Red Planet.
"Whatever the origin, the presence of the organic and reduced nitrogen on early/middle Noachian Mars indicates the importance of Martian nitrogen cycle," the study authors wrote.