This scanning electron microscope image of a polished thin section of a meteorite from Mars shows tunnels and curved microtunnels. The clay mineral iddingsite is present in this meteorite, named Yamato 000593, which was found in Antarctica in 2000 and identified as originating from Mars. The scale bar at lower left is 2 microns. (Photo : NASA/ Jet Propulsion Laboratory in Pasadena, Calif.)

Latest analysis of a Martian meteorite has revived the idea that the Red Planet might have supported life a long, long time ago.

The meteorite in question is the Yamato 000593 (Y000593), a 30-pound rock that fell on Antarctica some 50,000 years ago. The alien rock was found by Yamato Glacier in Antarctica by the Japanese Antarctic Research Expedition in 2000.

Researchers have now found tiny, carbon-containing spheres and burrows in the Martian meteorite. The tunnels look quite similar to those seen in terrestrial rocks that have been carved by microbes.

The Martian rock was formed 1.3 billion years ago in a lava flow and was hurled from the Red Planet after an impact event, which occured some 12 million years ago.

The study was conducted by researchers at NASA's Johnson Space Center in Houston and the Jet Propulsion Laboratory in Pasadena, Calif.

Martian meteoritic materials have different composition of oxygen atoms within the silicate minerals and trapped gases, which distinguishes them from rocks on earth and moon, according to a news release from JPL.

For the study, they analyzed Yamato 000593 (Y000593) and found that it had micro-tunnels. These structures are similar to those found in terrestrial basaltic glasses exposed to bacteria, suggesting that the rock might have supported biotic life.

Researchers also found nanometer- to-micrometer-sized spherules present between the layers within the rock, according to a news release. These spherical structures were earlier seen in the Martian meteorite Nakhla that landed in 1911 in Egypt. These holes have more carbon than the surrounding iddingsite layers.

"The nature and distribution of Martian carbon is one of the major goals of the Mars Exploration Program. Since we have found indigenous carbon in several Mars meteorites, we cannot overstate the importance of having Martian samples available to study in earth-based laboratories. Furthermore, the small sizes of the carbonaceous features within the Yamato 000593 meteorite present major challenges to any analyses attempted by remote techniques on Mars," Everett Gibson at NASA's Johnson Space Center in Houston said in a news release.

The team hasn't denied the possibility that the burrows might be a result of contamination or non-microbial activity on earth.

"This is no smoking gun," said JPL's Lauren White, lead author of the study. "We can never eliminate the possibility of contamination in any meteorite. But these features are nonetheless interesting and show that further studies of these meteorites should continue."

This isn't the first time that researchers have suggested that the Red Planet might have supported life. Previously, David McKay, Everett Gibson and Kathie Thomas-Keprta published an article in Science saying that they had found evidence of biological life in the Allan Hills 84001(ALH84001) meteorite.

NASA's Curiosity rover, too, showed that the rocks on the Red Planet had chemicals needed to begin life.

The study is published in the journal Astrobiology.