[meteorite-list] Meteorite May Harbor Evidence of Mars Life: Study (Yamato 000593)

[Ron Baalke]

http://www.space.com/24816-mars-life-meteorite-debate.html?cmpid=514648

Meteorite May Harbor Evidence of Mars Life: Study
By Mike Wall
space.com
February 25, 2014 

Have signs of ancient Martian life been found inside a Red Planet meteorite?

A team of scientists says that microscopic tunnels and carbon-rich spherules 
that stud the interior of a Martian meteorite known as Yamato 000593 may 
have been formed by Red Planet organisms long ago, NBC News reported today 
(Feb. 25).

The new study, which was published in the February issue of the journal 
Astrobiology, does not claim that Yamato 000593 harbors conclusive evidence 
of life on Mars. But the rock may indeed contain something truly special, 
its authors say.

"We cannot exclude the possibility that the carbon-rich regions in both 
sets of features may be the product of abiotic mechanisms; however, textural 
and compositional similarities to features in terrestrial samples, which 
have been interpreted as biogenic, imply the intriguing possibility that 
the Martian features were formed by biotic activity," they write in the 
study, which you can read here.

The new study comes 18 years after researchers announced that they had 
found evidence of possible Martian lifeforms in a different meteorite 
from the Red Planet, known as Allan Hills 84001 (ALH 84001). Much of the 
scientific community was unswayed, however, saying ALH 84001's "nanofossils" 
could be abiotic in origin.

The new Astrobiology paper is already meeting with similar scrutiny and 
skepticism, as its authors undoubtedly knew it would.

"I don't think the science community will find 'textural and compositional 
similarities' compelling enough to be proof of a biological origin," Chris 
McKay, of NASA's Ames Research Center in Moffett Field, Calif., told NBC 
News.

The lead author of the 1996 ALH84001 paper - which was published in the 
prestigious journal Science - was David McKay, a scientist at NASA's Johnson 
Space Center (JSC) in Houston. (He and Chris McKay are not related.) David 
McKay, who died last year, is also a co-author on the new Astrobiology 
paper.

The research team plans to continue and expand its investigation of the 
30-lb (13.5 kilograms) Yamato 000593 meteorite, which scientists say formed 
about 1.3 billion years ago on Mars and landed in Antarctica 10,000 years 
ago after being blasted off the Red Planet by an impact event.

"We have to go to the next step of going in there and tearing these carbon 
molecules apart," Everett Gibson of JSC, who was involved in both the 
ALH84001 and Yamato 000593 studies, told NBC News.