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Evidence of bacteria on Mars

 
 
Reply Sat 28 Nov, 2009 09:23 pm

http://www.timesonline.co.uk/tol/news/science/space/article6934078.ece

Nasa scientists have produced the most compelling evidence yet that bacterial life exists on Mars.

It showed that microscopic worm-like structures found in a Martian meteorite that hit the Earth 13,000 years ago are almost certainly fossilised bacteria. The so-called bio-morphs are embedded beneath the surface layers of the rock, suggesting that they were already present when the meteorite arrived, rather than being the result of subsequent contamination by Earthly bacteria.

“This is very strong evidence of life on Mars,” said David Mackay, a senior scientist at the Nasa Johnson Space Centre , who was part of the team of scientists that originally investigated the meteorite when it was discovered in 1984.

In a 1996 study of the sample, Dr Mackay and others argued that the microfossils were evidence of life, but sceptics dismissed the claims, saying that similar-shaped structures might not be biological. The new analyses, the product of high resolution electron microscopy, make a strong case for the Allan Hills 84001 Meteorite having carried Martian life to Earth. The microscopes were focused on tiny magnetite crystals present in the surface layers of the meteorite, which have the form of simple bacteria. Some argued that these could be the result of a carbonate breaking down in the heat of the impact.


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.

Dennis Bazylinski, an astrobiologist from the University of Nevada who peer-reviewed the findings, said: “Until now I was on the fence but this paper has really thrown out the non-biological explanation.” However, he added that the study was not a “smoking gun” for life on Mars. “One meteorite is never going to answer such a complex question,” he said.

According to scientists, the meteorite was broken off the surface of Mars by the impact of an asteroid, and reached Earth after floating through space for about 16 million years. It landed in Allan Hills in Antarctica. Scientists were able to trace the meteorite back to Mars, as its chemical composition matched the relative proportions of various gases measured in observations of the atmosphere of Mars made by the Viking spacecraft in the 1970s.

The meteorite also preserves evidence of liquid water on Mars, suggesting that the planet may have had more suitable conditions for life to develop in the past. The investigation was published in the November issue of Geochimica et Cosmochimica Acta, the journal of the Geochemical and Meteoritic Society. Nasa is expected to announce the findings formally on Monday.

The team has also been studying two other Martian meteorites " Nakhla, which landed in Egypt in 1911, and Yamato 593, which was found by a Japanese expedition to Antarctica. In research due to be published shortly, the scientists claim that both of these fossils also show evidence of microbial life.

Bill Clinton, then the US President, said of the research in 1997: “It speaks of the possibility of life. If this discovery is confirmed, it will surely be one of the most stunning insights into our Universe that science has ever uncovered. Its implications are as far-reaching and awe-inspiring as can be imagined.”

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Type: Discussion • Score: 10 • Views: 4,897 • Replies: 21
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tsarstepan
 
  1  
Reply Sat 28 Nov, 2009 09:39 pm
http://spaceflightnow.com/news/n0911/24marslife/marslife.jpg
Biological structures that only an asexual mother could love! Razz
0 Replies
 
Merry Andrew
 
  1  
Reply Sun 29 Nov, 2009 12:41 am
okay, but are they intelligent?

ne' mind
dlowan
 
  1  
Reply Sun 29 Nov, 2009 04:21 am
@Merry Andrew,
Merry Andrew wrote:

okay, but are they intelligent?

ne' mind


Are we?
0 Replies
 
NickFun
 
  2  
Reply Sun 29 Nov, 2009 02:15 pm
@edgarblythe,
Keep in mind, there are many other compelling reasons to believe in life on Mars. The presence of methane being the strongest http://news.bbc.co.uk/2/hi/science/nature/7829315.stm
Tai Chi
 
  2  
Reply Sun 29 Nov, 2009 02:21 pm
@NickFun,
http://gerii.files.wordpress.com/2009/01/cowsonmars1.png?w=450&h=338
Setanta
 
  2  
Reply Sun 29 Nov, 2009 03:12 pm
@Merry Andrew,
Merry Andrew wrote:
okay, but are they intelligent?

ne' mind


For quite a long time after i had begun using the screen name i now have, when people would address me as Set, i often thought of Seti--the search for extraterrestrial intelligence. It always seemed to me that it would be more profitable to find intelligent life on this planet, before we go looking for it elsewhere in the cosmos.
0 Replies
 
tsarstepan
 
  1  
Reply Sun 29 Nov, 2009 03:19 pm
@Tai Chi,
Astmoonauts!
0 Replies
 
Lightwizard
 
  1  
Reply Sun 29 Nov, 2009 04:16 pm
The Shrub spent eight years looking for bacteria on the desk in the Oval Office to give him more intelligent advice than Karl Rove and DICK Cheney.
0 Replies
 
JTT
 
  1  
Reply Sun 29 Nov, 2009 07:49 pm
Quote:
It showed that microscopic worm-like structures found in a Martian meteorite that hit the Earth 13,000 years ago are almost certainly fossilised bacteria.


By what process does a chunk of rock, of any size, escape the gravitational pull of Mars? Do chunks of other planets often escape to roam the solar system?
tsarstepan
 
  1  
Reply Sun 29 Nov, 2009 08:01 pm
@JTT,
JTT wrote:

Quote:
It showed that microscopic worm-like structures found in a Martian meteorite that hit the Earth 13,000 years ago are almost certainly fossilised bacteria.


By what process does a chunk of rock, of any size, escape the gravitational pull of Mars? Do chunks of other planets often escape to roam the solar system?


Let me find the link and the source. But speculation states that they expected a massive asteroid collided into Mars. The cataclysmic impact was strong enough to throw debris into space and eventually landing on Earth.
tsarstepan
 
  1  
Reply Sun 29 Nov, 2009 08:09 pm
@tsarstepan,
Quote:
1. The original igneous rock solidified within Mars about 4.5 billion years ago, about 100 million years after the formation of the planet. (Based on isotope ages of the igneous component of the meteorite)
2. Between 3.6 and 4 billion years ago the rock was fractured, presumably by meteorite impacts. Water then permeated the cracks, depositing carbonate minerals and allowing primitive bacteria to live in the fractures.
3. About 3.6 billion years ago, the bacteria and their by-products became fossilized in the fractures. (Based on isotope ages of the minerals in the fractures)
4. 16 million years ago, a large meteorite struck Mars, dislodging a large chunk of this rock and ejecting it into space. (Based on the cosmic ray exposure age of the meteorite)
5. 13,000 years ago, the meteorite landed in Antarctica.
6. The meteorite, ALH84001, was discovered in 1984 in the Allan Hills region of Antarctica.

http://nssdc.gsfc.nasa.gov/planetary/marslife.html
Quote:
The meteorite was catapulted away from Mars fifteen million years ago when a huge comet or asteroid impacted the surface.

http://www.marsnews.com/focus/life/
JTT
 
  1  
Reply Sun 29 Nov, 2009 10:48 pm
@tsarstepan,
Thank you, Tsarstepan. So that would pretty much have to mean that chunks of the other planets are whizzing around. Have any of them hit Earth/been discovered?
0 Replies
 
rosborne979
 
  1  
Reply Mon 30 Nov, 2009 06:26 am
@NickFun,
NickFun wrote:
Keep in mind, there are many other compelling reasons to believe in life on Mars. The presence of methane being the strongest http://news.bbc.co.uk/2/hi/science/nature/7829315.stm

Assuming there is life on Mars, it would be really nice to know if it's based on DNA or not.

If there's life on Mars and on Earth, then it's probably on the Jovian and Saturnian moons as well.
NickFun
 
  1  
Reply Mon 30 Nov, 2009 08:23 pm
@rosborne979,
True Ros. Methane is actually abundant on those moons. Most strikingly, the tiny Saturnian moon Eneceladus which also has abundant liquid water!
rosborne979
 
  1  
Reply Mon 30 Nov, 2009 08:41 pm
@NickFun,
NickFun wrote:
True Ros. Methane is actually abundant on those moons. Most strikingly, the tiny Saturnian moon Eneceladus which also has abundant liquid water!

1. We need to know if there really is/was life on Mars. This piece of information is just too fantastic to trust to ambiguous evidence and deductions based on probabilities. Just because we can't explain where methane comes from on Mars doesn't mean we can deduce that it must be from life (as much as I would like it to be).

2. If there is/was life on Mars, then we really need to know if it evolved independently or if one seeded the other. And we can't know this without a lot more detail about the composition of that life.

So in both cases, we need more detailed evidence. And I think that means we've got to get some much better robots onto the surface of Mars. Hopefully before I die.
edgarblythe
 
  1  
Reply Mon 30 Nov, 2009 08:44 pm
"
Hopefully before I die.
"

Aye. There's the rub.
rosborne979
 
  1  
Reply Mon 30 Nov, 2009 09:26 pm
@edgarblythe,
edgarblythe wrote:

"
Hopefully before I die.
"

Aye. There's the rub.

At least the LHC will be powered up and smashing away pretty soon. If I can avoid getting whacked by a random act of lethality I should be able to see the results of that.

You know what... if they do prove life on Mars, and it turns out to be DNA based and Mars seeded Earth, I'm gonna be disappointed. It's not interesting enough. All that will tell us is that DNA evolved once and then got knocked around the solar system by asteroid impacts. That's not bad, but it's not nearly as interesting and a brand new replicative formula forming on two different worlds, both evolving into microbial life. Now that would be really cool Smile
0 Replies
 
Lightwizard
 
  1  
Reply Mon 30 Nov, 2009 09:56 pm
@rosborne979,
Well, one thing we know -- there's unlikely any cattle on Mars.
tsarstepan
 
  1  
Reply Mon 30 Nov, 2009 10:54 pm
@Lightwizard,
Why are you such a Doubtin' Thomas?!
http://i46.tinypic.com/2utg1e0.jpg
0 Replies
 
 

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