Free Republic
Browse · Search
News/Activism
Topics · Post Article

Skip to comments.

Search for ancient Martian life continues (25% of Magnetite in Meteorite produced by bacteria)
NASA News Release ^ | August 4, 2002

Posted on 08/03/2002 7:48:03 PM PDT by John H K

In the latest study of a 4.5 billion-year-old Martian meteorite, researchers have presented new evidence confirming that 25 percent of the magnetic material in the meteorite was produced by ancient bacteria on Mars. These latest results were published in the journal Applied and Environmental Microbiology.

The researchers used six physical properties they refer to as the Magnetite Assay for Biogenicity (MAB) to compare all the magnetic material found in the ancient meteorite -- using the MAB as a biosignature. A biosignature is a physical and/or chemical marker of life that does not occur through random processes or human intervention.

"No non-biologic magnetite population, whether produced by nature or in the laboratory, has ever met the MAB criteria," said Kathie Thomas-Keprta, an astrobiologist at NASA's Johnson Space Center (JSC) in Houston and the lead researcher on the study. "This means that one-quarter of the magnetite crystals embedded in the carbonates in Martian meteorite ALH84001 require the intervention of biology to explain their presence."

Magnetotactic bacteria, which occur in aquatic habitats on Earth, arrange magnetite crystals in chains within their cells to make compasses, which help the bacteria locate sources of food and energy. Magnetite (Fe3O4) is produced inorganically on Earth, but the magnetite crystals produced by magnetotactic bacteria are very different -- they are chemically pure and defect-free, with distinct sizes and shapes.

Four of the MAB biosignature properties relate to the external physical structure of the magnetite crystals, while another refers to their internal structure and another to their chemical composition.

In their earlier studies, the researchers found that approximately one-quarter of the nanometer-sized magnetite crystals in ALH84001 had remarkable physical and chemical similarities to magnetite particles produced by a bacteria strain on Earth called MV-1. This is the first time, however, that any researcher has used the full MAB range of biosignature properties to compare the proposed bacteria- produced crystals in Mars meteorite ALH84001with the bacteria-produced crystals from Earth and with the other magnetites in the meteorite.

The comparison between the proposed bacteria-produced crystals in the meteorite and crystals known to be produced by Earth-bacteria MV-1 is striking and provides strong evidence that these crystals were made by bacteria on Mars.

The fact that Mars Global Surveyor data suggest that early Mars had a magnetic field is consistent with a reason why Mars would have magnetotactic bacteria. "Our best working hypothesis is that early Mars supported the evolution of bacteria that share several traits with magnetotactic bacteria on Earth, most notably the MV-1 group," said Simon Clemett, a coauthor of the paper at Johnson.

Mars has long been understood to provide the sources of light and chemical energy sufficient to support life, but in 2001 the Mars Global Surveyor spacecraft observed magnetized stripes in the crust of Mars, which showed that a strong magnetic field existed in the planet's early history, about the same time as the carbonate containing the unique magnetites in ALH84001 was formed.

In June, researchers using the Mars Odyssey spacecraft announced that they had found water ice under the surface of Mars. These attributes, coupled with a carbon dioxide-rich atmosphere, would have provided the necessary environment for the evolution of microbes similar to the fossils found in ALH84001.

"We believe this latest study proves that the magnetites in ALH84001 can be best explained as the products of multiple biogenic and inorganic processes that operated on early Mars," Thomas-Keprta said.

An international team of nine researchers collaborated on the three-year study. The team, led by Thomas-Keprta of Lockheed Martin at Johnson Space Center, was funded by the NASA Astrobiology Institute. Co-authors of the study are Clemett and Susan Wentworth of Lockheed Martin at JSC; Dennis Bazylinski of Iowa State University (funded by the National Science Foundation); Joseph Kirschvink of the California Institute of Technology in Pasadena; David McKay and Everett Gibson of JSC; Hojatollah Vali of McGill University in Canada; and Christopher Romanek of the Savannah River Ecology Laborator


TOPICS: Miscellaneous
KEYWORDS: bacteria; life; mars; meteorite
Navigation: use the links below to view more comments.
first 1-2021-4041-49 next last
Kind of a weird generic unexciting headline, stuff in parenthesis mine (and actually describes the article.)
1 posted on 08/03/2002 7:48:03 PM PDT by John H K
[ Post Reply | Private Reply | View Replies]

To: John H K
"A biosignature is a physical and/or chemical marker of life that does not occur through random processes or human intervention."

Man, some scientist/reporter is about to be out of a job. It is not permitted for people to publicize statements that imply that Life (or a signature of life) needs something besides unintelligent random processes in order to form...

2 posted on 08/03/2002 7:51:47 PM PDT by Southack
[ Post Reply | Private Reply | To 1 | View Replies]

To: John H K
I have strong doubts. Seems like they just won't let go.

My own guess is that there was never life on Mars; however I am prepared to be surprised by evidence to the contrary--which is not provided in this article.

--Boris

3 posted on 08/03/2002 7:52:19 PM PDT by boris
[ Post Reply | Private Reply | To 1 | View Replies]

To: RadioAstronomer; Scully; PatrickHenry; VadeRetro; general_re; RightWingNilla
Magnetotactic ping
4 posted on 08/03/2002 7:57:49 PM PDT by longshadow
[ Post Reply | Private Reply | To 1 | View Replies]

To: boris
Am I remembering incorrectly when I think I learned that Mars doesn't actually have a magnetic field like Earth's? Why would the bacteria that use a 'compass' mechanism aligned magnetite if there were no field to exploit?
5 posted on 08/03/2002 8:01:53 PM PDT by MHGinTN
[ Post Reply | Private Reply | To 3 | View Replies]

To: John H K
"Search for ancient Martian life continues"

Excuse for not accepting that we are the one and only children of God, and the height of his creative hand continues.

6 posted on 08/03/2002 8:06:10 PM PDT by VaBthang4
[ Post Reply | Private Reply | To 1 | View Replies]

To: John H K
In the latest study of a 4.5 billion-year-old Martian meteorite

I don't seem to recall reading the news of the launch of a probe to Mars and its return to Earth with this "meteorite". < /so >
7 posted on 08/03/2002 8:08:20 PM PDT by pyx
[ Post Reply | Private Reply | To 1 | View Replies]

To: John H K
Magnetotactic bacteria

Assuming there are such magnetotactic bacteria on Mars, or were a few ages ago.

8 posted on 08/03/2002 8:09:05 PM PDT by RightWhale
[ Post Reply | Private Reply | To 1 | View Replies]

To: AndrewC; Doctor Stochastic
This may be of interest after recent conversations.
9 posted on 08/03/2002 8:10:29 PM PDT by Nebullis
[ Post Reply | Private Reply | To 1 | View Replies]

To: MHGinTN
Why would the bacteria that use a 'compass' mechanism aligned magnetite if there were no field to exploit?

Checked my Boy Scouts compass. It has a North, an East, a West, and a South, but no Food. Still wondering how bacteria use magnetite to find food whether there is a magnetic field or not.

10 posted on 08/03/2002 8:11:58 PM PDT by RightWhale
[ Post Reply | Private Reply | To 5 | View Replies]

To: John H K
The baseball player that threw that rock to earth must have had quite a pitching arm.
11 posted on 08/03/2002 8:12:00 PM PDT by aimhigh
[ Post Reply | Private Reply | To 1 | View Replies]

To: John H K
This has got to be one of the most stupid things that people have ever fallen for. Scientists find a rock in Antartica and say, "Gee, this here rock fell from Mars four and a half billion years ago", as if they had some kind of time machine that showed that rock being hurtled inot space and landing on earth AND PEOPLE BELEIVE THEM! If this is evidence of life on other planets, then call me a skeptic because I think it is crap.
12 posted on 08/03/2002 8:13:29 PM PDT by Blood of Tyrants
[ Post Reply | Private Reply | To 1 | View Replies]

To: MHGinTN; RightWhale
The food is Fe.
13 posted on 08/03/2002 8:17:17 PM PDT by Senator Pardek
[ Post Reply | Private Reply | To 5 | View Replies]

To: Senator Pardek
Okay, but what of the 'field' on Mars?
14 posted on 08/03/2002 8:20:34 PM PDT by MHGinTN
[ Post Reply | Private Reply | To 13 | View Replies]

To: MHGinTN
No need for a field, I suppose. Magnetite directs the bacteria to the free Fe in the soil.
15 posted on 08/03/2002 8:24:44 PM PDT by Senator Pardek
[ Post Reply | Private Reply | To 14 | View Replies]

To: Senator Pardek
If their food is iron, they would be called ferrophores. Is that all they eat?

"Would you like ketchup with that?"

16 posted on 08/03/2002 8:25:48 PM PDT by RightWhale
[ Post Reply | Private Reply | To 13 | View Replies]

To: RightWhale
I suppose the older bacteria scoff at the idea of taking Geritol.
17 posted on 08/03/2002 8:28:49 PM PDT by Senator Pardek
[ Post Reply | Private Reply | To 16 | View Replies]

To: Senator Pardek
... from the article: Magnetotactic bacteria, which occur in aquatic habitats on Earth, arrange magnetite crystals in chains within their cells to make compasses, which help the bacteria locate sources of food and energy... I'm lost now, so I'm climbing back up on the porch.
18 posted on 08/03/2002 9:11:02 PM PDT by MHGinTN
[ Post Reply | Private Reply | To 15 | View Replies]

To: MHGinTN
I believe that means local/personal compasses - the way a magnetized bar attracts iron filings, regardless of the earth's magnetic field.
19 posted on 08/03/2002 9:14:40 PM PDT by Senator Pardek
[ Post Reply | Private Reply | To 18 | View Replies]

To: Blood of Tyrants
It's not hard to tell if a meteorite came from Mars. I could do it myself for a few kilobucks. (Assuming anyone would let me have the rock itself.)
20 posted on 08/03/2002 9:16:34 PM PDT by Doctor Stochastic
[ Post Reply | Private Reply | To 12 | View Replies]


Navigation: use the links below to view more comments.
first 1-2021-4041-49 next last

Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.

Free Republic
Browse · Search
News/Activism
Topics · Post Article

FreeRepublic, LLC, PO BOX 9771, FRESNO, CA 93794
FreeRepublic.com is powered by software copyright 2000-2008 John Robinson