Panspermia, anyone?

[Basil]

Article from National Geographic about some folks who tested the possibility that life could survive on asteroids entering Earth's atmosphere. Interesting, to say the least.

 

http://news.nationalgeographic.com/news/2007/11/071112-space-rock.html?email=Inside16Nov07

[Nyrath]

Re: Panspermia, anyone?

 

Well, it is a convenient explanation why all the aliens in STAR HERO are more or less humanoid.

[Inu]

Re: Panspermia, anyone?

 

And for the universe, we give you... interstellar bukkake. Enjoy.

[Cancer]

Re: Panspermia, anyone?

 

Doesn't surprise me, but there's a lot more to panspermia than this. Organic matter can survive landing in a large enough delivery package; that isn't really a surprise, since there's strong suggestions in the carbonaceous chondrites that it can.

 

That's a long way from transporting life, though. There's a long period of exposure to radiation (in particular, exposure to "cosmic rays", high-energy particles against which the planetary magnetic field and atmosphere are pretty good shielding) while in any rock traversing deep space without an engine.

[Vestnik]

Re: Panspermia, anyone?

 

Doesn't surprise me, but there's a lot more to panspermia than this. Organic matter can survive landing in a large enough delivery package; that isn't really a surprise, since there's strong suggestions in the carbonaceous chondrites that it can.

 

That's a long way from transporting life, though. There's a long period of exposure to radiation (in particular, exposure to "cosmic rays", high-energy particles against which the planetary magnetic field and atmosphere are pretty good shielding) while in any rock traversing deep space without an engine.

 

I have a vague idea I picked up from somewhere that dormant fungus spores can "survive" interplanetary conditions. Don't know if it's true or not.

[Cancer]

Re: Panspermia, anyone?

 

One of the Apollo missions brought back a few parts from the Surveyor 3 lander, some 5 years after it had landed. Turns out that spores from a thumbprint on a lens they brought back were still viable. That's only five or so years, though, and inside the Sun's magnetic field, so the nasty Galactic stuff has been damped out some. The slow ride from one star system to the next will be largely outside any protection, and at least ten thousand times that length of time.

 

Interplanetary drift, between planets of the same star, that seems quite possible to me, and something worth considering in terms of astrobiology. But interstellar panspermia is another item entirely, and that's what I have real doubts about.

[McCoy]

Re: Panspermia, anyone?

 

One of the Apollo missions brought back a few parts from the Surveyor 3 lander' date=' some 5 years after it had landed.[/quote']

Apollo XII. Though they had brought bact real live ET's. Turned out to be house and garden staph.

 

Only way to tell how closely life on other planets or star systems is relate to us, go and look.

[Vestnik]

Re: Panspermia, anyone?

 

One of the Apollo missions brought back a few parts from the Surveyor 3 lander' date=' some 5 years after it had landed. Turns out that spores from a thumbprint on a lens they brought back were still viable. [/quote']

 

 

According to ever-reliable, infallible Wikipedia, this is probably false:

 

Reports of Streptococcus mitis on the moon

 

From Wikipedia, the free encyclopedia

 

•

Ten things you may not know about Wikipedia •

 

[/url]

It is widely claimed that a common bacterium from the human mouth, Streptococcus mitis, survived for two and a half years on the Moon inside the Surveyor 3 camera, to be detected when the camera was returned to Earth on board the Apollo 12 capsule. However, this claim cannot be sustained in the light of several lines of evidence:

• Streptococcus mitis lives in the mouth; there is no evidence that it can survive for long even in terrestrial environments outside the human body.
  
• Streptococcus mitis, like other oral streptococci, is a mesophile; it cannot survive outside of a narrow temperature range centered on human body temperature. It is not an extremophile nor does it produce endospores. It could not survive on the moon.
  
• Even extremophiles are unlikely to survive the extremes of temperature on the surface of the Moon (mean surface temperature day 107°C; mean surface temperature night -153°). Surveyor 3 would have gone through over thirty day-night cycles on the Moon, each one provoking freeze-thawing of bacteria. Applying multiple cycles of freeze-thawing is a commonly used technique for breaking open bacterial cells.
  
• There is evidence to suggest that the camera was contaminated after return to Earth [1]. Leonard D. Jaffe, who was Surveyor program scientist and custodian of the Surveyor 3 parts brought back from the Moon, wrote to the Planetary Society stating that somebody on his staff, who had witnessed the biological test which gave positive results, reported that a "breach of sterile procedure" took place at just the right time to produce a false positive result. One of the implements being used to scrape samples off the Surveyor parts was laid down on a non-sterile laboratory bench, and then was used to collect surface samples for culturing. It was that sample set which showed the presence of Streptococcus mitis. To quote Jaffe, 'It is, therefore, quite possible that the microorganisms were transferred to the camera after its return to Earth, and that they had never been to the Moon."
  
• The Surveyor 3 camera was returned from the Moon in a nylon duffel bag, and was not in the type of sealed airtight metal container used to return lunar samples in the early Apollo missions. It is therefore possible that it was contaminated by the astronauts in the Apollo 12 capsule itself.
  
• The test for recovery of bacteria could only be performed once, and the parts were subsequently taken out of quarantine and fully re-exposed to terrestrial conditions (the Surveyor 3 camera is now on display in the Smithsonian Air and Space Museum in Washington, D.C.), so there is no way now that anyone can now replicate or investigate the claims.

On the above evidence, the most parsimonious explanation for the reported recovery of Streptococcus mitis from the Surveyor 3 camera is contamination after its recovery from the Moon. Survival of this bacterium on the surface of the Moon would be very unlikely. This claim has never been documented in any peer-reviewedscientific publication and remains a telling example of the phenomenon of urban myth.

NASA is funding an archival study in 2007 that will try to locate the film of the camera-body microbial sampling to confirm the report of a breach in sterile technique.

 

http://en.wikipedia.org/wiki/Reports_of_Streptococcus_mitis_on_the_moon

[Cancer]

Re: Panspermia, anyone?

 

Hm, OK. I last looked into this episode in the mid-1990s.

[Vestnik]

Re: Panspermia, anyone?

 

It's one of those things that SHOULD be true.

[Maur]

Re: Panspermia, anyone?

 

But some bugs can survive for extremely long times encased in ice:

 

Bugs repair own DNA to survive eons in ice

http://www.cbc.ca/news/story/2007/08/28/tech-bugs.html

 

Recycling of pathogenic microbes through survival in ice

http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WN2-4CDJCTM-8&_user=56861&_coverDate=12%2F31%2F2004&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000059542&_version=1&_urlVersion=0&_userid=56861&md5=404cee81143404f40cc2e4e3f4d96e5b

http://linkinghub.elsevier.com/retrieve/pii/S0306987704002543

 

Recovery and Identification of Viable Bacteria Immured in Glacial Ice

http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WGF-45FC183-69&_user=56861&_coverDate=04%2F30%2F2000&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000059542&_version=1&_urlVersion=0&_userid=56861&md5=f8c4fa4509a68f08f45119a0e799f52b

[Vestnik]

Re: Panspermia, anyone?

 

Whatever happened to that "Martian microbe fossils found in meteorite" story about 10 years ago?

[Cancer]

Re: Panspermia, anyone?

 

Whatever happened to that "Martian microbe fossils found in meteorite" story about 10 years ago?

 

That was the meteorite ALH84001.

 

Most people in the racket now think they are nonbiological. The rock itself is very interesting for all sorts of reasons (it's pretty conclusive in indicating that there was liquid water for at least a moderately extended time on Mars) but the scale of the structures are too small for them to be even nanobacteria.

[Nyrath]

Re: Panspermia, anyone?

 

The thing about panspermia is that it doesn't answer the question, it just delays it.

 

Instead of explaining how life arose on Earth, you have to explain how life arose on the alien planet that provided the panspermia bits that seeded life on Earth.

[Vestnik]

Re: Panspermia, anyone?

 

The thing about panspermia is that it doesn't answer the question, it just delays it.

 

Instead of explaining how life arose on Earth, you have to explain how life arose on the alien planet that provided the panspermia bits that seeded life on Earth.

 

Ya know, if some version of the Steady State theory is true, this isn't a problem, since life could have always existed.

[Kristopher]

Re: Panspermia, anyone?

 

Panspermia is a cheap dodge, regarding the question of how life began. However it began, it is far more likely to have done so here, and not far across the galaxy. As Nyrath points out, not only does do you have to figure out how life began, you also have to figure out how it got here, as well, and the odds of there being life on Earth or any other single planet get exponentially worse with each step you add with panspermia.

 

Panspermia is the Rube Goldberg version of the origin of life.

 

The steady state model? Even if the universe is somehow, against all observed evidence, not expanding from a single point of origin in space and time, life had to begin at some point in time, somewhere. "It was always here" is... not a viable answer.

[Vestnik]

Re: Panspermia, anyone?

 

 

The steady state model? Even if the universe is somehow, against all observed evidence, not expanding from a single point of origin in space and time, life had to begin at some point in time, somewhere.

 

Why? If the universe has always (that is, for an infinite amount of time) existed in more or less the same form it has now, then talking about the beginning of stuff is kind of moot.

 

(I am not endorsing this hypothesis. In fact, I think it's empirically highly unlikely.)

[Maur]

Re: Panspermia, anyone?

 

Scientists have recreated on a small scale the atmosphere of early Earth and found that the conditions on it cause the formation of nucleotides and amino acids without the need to resort to things like "Intelligent Design".

 

http://www.tufts.edu/as/wright_center/cosmic_evolution/docs/text/text_chem_5.html

[Curufea]

Re: Panspermia, anyone?

 

the need to resort to things like "Intelligent Design"

 

Well, that is the "magic answer" (ie "how does this work?" "it must be magic, Q.E.D" ) which is the diametrically opposed philosophical viewpoint to science - which is all about seeking answers and explaining things. So it isn't much of a stretch to imagine them not resorting to "Intelligent Design".

[Vestnik]

Re: Panspermia, anyone?

 

Well' date=' that is the "magic answer" (ie "how does this work?" "it must be magic, Q.E.D" ) which is the diametrically opposed philosophical viewpoint to science - which is all about seeking answers and explaining things. So it isn't much of a stretch to imagine them not resorting to "Intelligent Design".[/quote']

 

Anyway, the idea that if something didn't come about by chance it must have been "designed" by something is a notion that really only goes back to the Middle Ages and the scholastic arguments for the existence of God. Before that the usual notion was that order (essences) was (were) immanent in the world and naturally exist in it without the intervention of an outside intelligence, but not by chance either.

 

This is not to endorse Aristotelian or Platonic metaphysics, but just to point out that even if the ID people are right that there are natural phenomena that could not have arisen due to chance (or are highly unlikely to have done so), that does not logically imply the existence of a designer.

[Kristopher]

Re: Panspermia, anyone?

 

Why? If the universe has always (that is, for an infinite amount of time) existed in more or less the same form it has now, then talking about the beginning of stuff is kind of moot.

 

(I am not endorsing this hypothesis. In fact, I think it's empirically highly unlikely.)

 

For the sake of argument, treat that the universe has always existed as a given for a moment. In what way does this imply or require that life has always existed?

[Cancer]

Re: Panspermia, anyone?

 

For the sake of argument' date=' treat that the universe has always existed as a given for a moment. In what way does this imply or require that life has always existed?[/quote']

 

It doesn't require it, but it provides the opportunity to put the origin of life into the same logical singular point as the origin of the Universe. That is, it removes the issue tautologically.

[Vestnik]

Re: Panspermia, anyone?

 

What Cancer said.

[Clonus]

Re: Panspermia, anyone?

 

Gaming-wise there is an appeal to panspermia. It justifies having a galaxy full of life and even having the life being more or less interedible. It works better though if you have a means of moving the life at FTL speeds by some hypothetical precursor species though.

[McCoy]

Re: Panspermia, anyone?

 

Panspermia is a cheap dodge' date=' regarding the question of how life began. However it began, it is far more likely to have done so here, and not far across the galaxy. [/quote']

Could I see the math on how you arrived at that conclusion?

 

Life appeared on Earth almost as soon as conditions were right for it to do so. Had to be a fairly simple process, yet despite our knowledge of conditions on Earth at that time we have been unable to replicate the experiment. Given my current state of ignorance about the origin of life it seems at least as likely to have been brought here from Elsewhere as to have originiated here so quickly.

 

Of course, if Mars, Europa and Titan do turn out to be lifeless, that will pretty much put the nail in the coffin of Panspermia.