NASA is believed to have found strong evidence that there was once life on Mars. Scientists working on a meteorite discovered in 1984 told the Spaceflight Now website that mineral microstructures in the rock were the remains of magnetic bacteria.
Back in 1996, NASA reported that it had found what looked like tiny fossils in the Allen Hills (ALH) 84001 meteorite, which crashed in Antarctica around 13,000 years ago. But critics argued that the shapes were formed by non-biological processes or that the rock was contaminated.
The team has been using high resolution electron microscopy to focus on magnetite crystals found in the rock. These crystals are found in certain bacteria on Earth, where they have very unusual shapes - shapes which parallel those found in the meteorite, says NASA.
In addition, certain chemical signatures in the rock indicate a bilogical rather than geological origin, and a possible interaction with water, TG Daily reports.
The new analyses show that this is very unlikely to have resulted in the kinds of structures seen in the rock. Close examination suggested that about 25 per cent of the crystal structures were chemically consistent with being formed from bacteria.
"We feel vindicated. We’ve shown the alternate explanation is absolutely incorrect, leading us back to our original position that these structures are formed by bacteria on Mars," Dr Mackay said, according to Times Online.
Emily Baldwin, deputy editor of the UK's Astronomy Now magazine, told Sky News Online: "If the features in the meteorite do turn out to have an extra-terrestrial biological origin then that's pretty exciting stuff in terms of understanding how life is distributed across the solar system."
The findings are expected to be officially released by Nasa in the next few days, Sky informs.