I managed to catch the tail end of the NASA press conference this morning. This had created quite a flutter on the internet with some speculating that NASA was going to announce the discovery of evidence for extraterrestrial life.
Well, it proved to be a bit more realistic than that – but nevertheless quite exciting. The press conference discussed research indicating the possibility that arsenic can substitute for phosphorus in a bacteria. Neil deGrasse Tyson explained this in a brief tweet:
“Like Carbon & Silicon in Periodic Table, Phosphorus & Arsenic sit above &b elow one another, making them kindred souls of chemistry.”
Researchers present their findings in the paper “A Bacterium That Can Grow by Using Arsenic Instead of Phosphorus.” It has the usual laundry list of authors (12) we have come to expect for significant work. The lead author is Felisa Wolfe-Simon. And here is the abstract:
Life is mostly composed of the elements carbon, hydrogen, nitrogen, oxygen, sulfur, and phosphorus. Although these six elements make up nucleic acids, proteins, and lipids and thus the bulk of living matter, it is theoretically possible that some other elements in the periodic table could serve the same functions. Here, we describe a bacterium, strain GFAJ-1 of the Halomonadaceae, isolated from Mono Lake, California, which substitutes arsenic for phosphorus to sustain its growth. Our data show evidence for arsenate in macromolecules that normally contain phosphate, most notably nucleic acids and proteins. Exchange of one of the major bioelements may have profound evolutionary and geochemical significance.
And here is a short video on the work:
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NASA’s Alien Life News: The Real Story from Sci…, posted with vodpod
The scientists at the press conference disagreed on the actual role of the arsenic and how stable such life forms could be. Clearly more work will be done on this and Wolfe-Simon is publishing further results in February.
This is way out of my area of expertise so I won’t comment further on the research. But I was interested to here the scientists and reporters discuss the feelings that often come with significant discoveries. Ryan Anderson from The Martian Chronicles expressed my thoughts exactly with his comment:
I thought it was great to hear Wolfe-Simon say during the question session that there wasn’t a “eureka moment” where they knew what they had found, it was more like “Hey, this isn’t right.” It reminds me of this Isaac Asimov quote:
The most exciting phrase to hear in science, the one that heralds new discoveries, is not ‘Eureka!’ (I’ve found it!), but ‘That’s funny…’ -Isaac Asimov.
NASA Scientists Find Microbes With Arsenic DNA
NASA-Funded Research Discovers Life Built With Toxic Chemical
Of Arsenic and Aliens
Living off Toxic Waste—Bacteria Swap Out Phosphorus for Arsenic
- Nasa reveals bacteria that can live on arsenic instead of phosphorus (guardian.co.uk)
- Bacteria use arsenic to build DNA (cbc.ca)
- NASA Finds New Arsenic-Based Life Form in California (wired.com)
- NASA Announcement: New Life Form (manolith.com)
- Poison-Based Bacteria Redefines Life As We Know It [Video] (kotaku.com)
- “NASA scientist discovers arsenic-based alien life form – on Earth” and related posts (personalmoneystore.com)
- Arsenic-eating bacteria find recipe for life (cbc.ca)