Is there life on Mars? - November 27, 2009
Well, British tabloid The Sun says there is.
It reports breathlessly:
Martian bugs arrived on Earth 13,000 years ago, scientists have discovered. The microscopic aliens arrived on a meteorite which smashed into the wastes of the Antarctic.
And where The Sun leads, The Telegraph and The Daily Mail follow.
This all seems to stem for a piece on Spaceflight Now from Tuesday which describes research on the martian meteorite ALH 84001, found in 1984 at Allen Hills in Anatrctica.
Back in 1996, Science published a paper which revealed that ALH 84001 contained organic compounds, along with carbonate globules or discs that contained tiny crystals of the iron mineral magnetite. This chemical cocktail looked rather similar to the residues of bacterial life here on Earth, and the paper suggested that they “could thus be fossil remains of a past martian biota.”
Queue Cue David Bowie.
A lot of scientists were sceptical, to say the least, although Bill Clinton was impressed
But the team behind the 1996 paper have been plugging away ever since to answer their critics, and they appear to have converted some at least. Dennis Bazylinski, of the University of Nevada at Las Vegas, told Spaceflight Now:
"I work on magnetic bacteria, and one indication there was life on ancient Mars are these particular magnetite crystals in the meteorite that look like they came out of magnetic bacteria. At first [when the data was reported in 1996], I thought there might have been an error. I have no doubt about that now. I know there is no error."
The main bone of contention about ALH84001 has always been that you can’t really be sure that the carbonate / magnetite didn’t have a non-biogenic origin. Maybe it was a result of the heat and shock involved in ripping the rock away from Mars 15 million years ago, as John Bradley, of Georgia Technical School of Materials and Technology, told the BBC back in 2000, the last time this story broke out in a major way.
Now, NASA’s Kathie Thomas-Keprta and colleagues involved in the original Science paper have a new report out in Geochimica and Cosmochimica Acta that supposedly boosts the case that ALH84001 does contain the remnants of martian life.
They looked again at whether the carbonate formed in relatively hot or cold conditions, and concluded the latter. They looked again at the magnetite, and reckon that most of the crystals came from somewhere else – not from some thermal process going on in the carbonate.
So the magnetite came from somewhere else? “This origin does not exclude the possibility that a fraction is consistent with formation by biogenic processes, as proposed in previous studies,” the team conclude in their paper.
Hmmmm. For me, going all the way from "does not exclude the possibility that ..." to "Martian bugs arrived on Earth 13,000 years ago" still seems like a bit of a stretch.
Comments
Thanks for this analysis. I wish people would stop crying wolf about life on Mars – if and when it really does happen (and I hope it's 'when'!), everyone will think it's just another overreaching press release.
p.s. I know this is pedantic but it's 'Cue David Bowie.'
Posted by: Karen James | November 27, 2009 06:29 PM
Humanity is so desperate to find alien life that it grasps at every straw. I cannot comment on the validity of this claim as I am not a scientist but I can fully understand the media seizing on the most tenuous of evidence. When life is finally found then it will be headlines but I will still have to come here for the undoctored facts. ;)
Posted by: pceaneagle | November 28, 2009 04:36 AM
IF NASA CONFIRMS (MONDAY) THAT ONCE THERE WAS LIFE ON MARS, I AM CONFIDENT THAT IT IS REALLY SO.
LIFE ON MARS?
WHY NOT...I BELIEVE THAT IT IS TIME TO SAY CLEARLY:
"-YES,IN THE PAST THERE WAS LIFE ON MARS!!!"
AND NOW?
-FOR ME,POSSIBLY EVEN NOW...(BUT I AM NOT SURE OF THAT).
Posted by: DR.KATHRINE MARTINEZ-MARTIGNONI | November 28, 2009 01:15 PM
there is hematite on both planets, earth and mars. evidence of oxygenated water; and hence of oxygenated atmosphere, secondary to photosynthesis.
Posted by: zanardm | December 8, 2009 07:40 AM