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Scientists find traces of sea plankton on ISS surface

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Re: Scientists find traces of sea plankton on ISS surface

#21

Post by DanielBMarkham »

noselasd wrote: post #8
fhnjh wrote: post #4

Panspermia?

No. The ISS isn't really that far from earth and there's a lot of exchange going on between earth and the ISS, mostly from all the various spacecraft we send up.

I think they meant it the other way, from Earth outwards.

So if you find x living microbes at 200km from Earth, given thermal dispersion, shouldn't there be some y number of molecules from Earth on the Moon? (And so on)

Even if y is a really small number, it effectively means any one planet with life would most likely "pollute" the star system it finds itself in. (Would need to do the math on this, but I believe that was the commenter's point)

Re: Scientists find traces of sea plankton on ISS surface

#22

Post by mnw21cam »

mkonecny wrote: post #18
ejr wrote: post #6

It was probably blown up there by "uplifting air currents" according to : http://www.dailymail.co.uk/sciencetech/article-2728979/Never... We have to keep in mind that, even at that altitude, there are still air molecules. They're extremely sparse, but just enough that the drag they induce on the ISS and its large surface area of solar panels make periodic boosting necessary.

Would the moon ever need a "boost"? Even though it's probably not hitting any air molecules from Earth, it's still colliding with tons of space debris a day.

The moon is being continually boosted by the rotation of the earth. The moon's gravity causes tides on the earth's surface. However, the shape of the earth is slightly ahead of being directly lined up with the moon because of inertia and sloshing. That uneven earth shape exerts a slightly uneven pull on the moon which increases its angular velocity around the earth, and slows down the angular velocity of the earth's rotation.

     .--~~~--.             ^
    /      /
    '--___--'
Note, the bulge of the earth is slightly exaggerated in this diagram, and the moon is further away on this scale.

In effect, the rotation of the earth is dragging the moon around faster (which causes it to move further from the earth and go slower).

Re: Scientists find traces of sea plankton on ISS surface

#23

Post by akiselev »

narag wrote: post #11
ejr wrote: post #6

It was probably blown up there by "uplifting air currents" according to : http://www.dailymail.co.uk/sciencetech/article-2728979/Never... We have to keep in mind that, even at that altitude, there are still air molecules. They're extremely sparse, but just enough that the drag they induce on the ISS and its large surface area of solar panels make periodic boosting necessary.

So they also survived an impact with the orbitting station at 9 km/s? I don't think so.

If the bacteria floated up to LEO (which is very possible) the impact was likely in the meters/second range because it would have had to match the orbit closely enough. Because bacteria are so small (and the filaments they use to support the cell membrane is so strong) it would take an extreme impact to "splatter" them. Remember also that archaeic bacteria (as well as simple multicellular organisms) live on the bottom of oceans like the Mariana Trench where the pressure is over 1,000 atmospheres (enough to turn you into a miniature hockey puck).

Re: Scientists find traces of sea plankton on ISS surface

#24

Post by jbattle »

giarc wrote: post #16

This reminds me of a little theory in microbiology, that is that every species exists in every place. For example, if you were to build an alkaline lake in the middle of nowhere (where no alkaline lakes exists), it wouldn't take long before specific species of bacteria would colonize that lake.

That sounds suspiciously like spontaneous generation - what is the actual theory?

Re: Scientists find traces of sea plankton on ISS surface

#25

Post by dandelany »

ejr wrote: post #6

It was probably blown up there by "uplifting air currents" according to : http://www.dailymail.co.uk/sciencetech/article-2728979/Never... We have to keep in mind that, even at that altitude, there are still air molecules. They're extremely sparse, but just enough that the drag they induce on the ISS and its large surface area of solar panels make periodic boosting necessary.

That's one non-biologist's initial guess, by no means a tested theory, and certainly not backed by enough evidence yet to say "probably". Seems much more likely that it's a case of contamination - this plankton lives in the belly of shrimps and other seafood. Shrimp are one of the ISS astronauts' favorite foods. All it takes is one astronaut not washing his hands after eating and before putting on his gloves to cause contamination. If the bacteria are alive, this is definitely the basis for an interesting study re: extremophiles. But the "uplifting air currents" statement is just speculation at this point.

Re: Scientists find traces of sea plankton on ISS surface

#26

Post by jerf »

TeMPOraL wrote: post #17
DanBC wrote: post #14

Earlier quoted context omitted.

The article is unclear whether these organisms are alive or not. > Results of the scope of scientific experiments which had been conducted for a quite long time were summed up in the previous year, confirming that some organisms can live on the surface of the International Space Station (ISS) for years amid factors of a space flight, such as zero gravity, temperature conditions and hard cosmic radiation. Several surv…

So basically the Earth is a life-covered rock that spits organisms to hundreds of kilometers from its surface. This is just awesome!

Panspermia is a theory for a reason. As an explanation for life on Earth itself it has a challenge ahead of it, but due to the small amounts of life that Earth is known to be flinging about it's a known fact that Earth life has landed on the other planets. (Or at least their corpses, but it seems reasonably likely that some of it would survive the trip in some form of stasis or spore, given how resilient we know microscopic life can be.)

If life is ever found on Mars, the next question to be asked after identification is, "is it related to Earth life?" Which we'd check by checking certain of the parameters of life on Earth that do not seem to be "forced" by physics, but are universal on Earth (how DNA codes for proteins, for instance). If they all matched up, it would strongly suggest one single common origin... though that origin could conceivably be on Mars.

Interestingly, this also means that if the Solar System is still otherwise sterile despite the arrival of Earth life, that has interesting implications of its own.

Re: Scientists find traces of sea plankton on ISS surface

#27

Post by Nogwater »

Involute wrote: post #20

Apollo 12 retrieved a Surveyor 3 camera that had been on the Moon for over two years and contained Streptococcus mitis bacteria that survived in a dormant state and were recultured back on Earth. Pete Conrad, Apollo 12 commander, said, "I always thought the most significant thing that we ever found on the whole...Moon was that little bacteria who came back and lived and nobody ever said [anything] about it."

Of course, there's a They Might Be Giants song about this incident. https://www.youtube.com/watch?v=xulaYpsnkcg

Re: Scientists find traces of sea plankton on ISS surface

#28

Post by giarc »

jbattle wrote: post #24
giarc wrote: post #16

This reminds me of a little theory in microbiology, that is that every species exists in every place. For example, if you were to build an alkaline lake in the middle of nowhere (where no alkaline lakes exists), it wouldn't take long before specific species of bacteria would colonize that lake.

That sounds suspiciously like spontaneous generation - what is the actual theory?

Not sure I ever read about it in a textbook... more of a micro professional talked about it so I can't provide a source.

Re: Scientists find traces of sea plankton on ISS surface

#29

Post by daveslash »

Involute wrote: post #20

Apollo 12 retrieved a Surveyor 3 camera that had been on the Moon for over two years and contained Streptococcus mitis bacteria that survived in a dormant state and were recultured back on Earth. Pete Conrad, Apollo 12 commander, said, "I always thought the most significant thing that we ever found on the whole...Moon was that little bacteria who came back and lived and nobody ever said [anything] about it."

As much as I WANT to believe, and I did for a long while, that Strep was on the moon for years, it's possible that this was a false positive. That being said, I think this is still an important event and is a good starting point for experimentation.

"One of the implements being used to scrape samples off the Surveyor parts could have been laid down on a non-sterile laboratory bench, and then was used to collect surface samples for culturing. It is, therefore, quite possible that the microorganisms were transferred to the camera after its return to Earth. Furthermore, 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 and the environment in the Apollo 12 capsule itself. The bacterial test is now non-repeatable because the parts were subsequently taken out of quarantine and fully re-exposed to terrestrial conditions."

source: http://lsda.jsc.nasa.gov/scripts/experiment/exper.aspx?exp_i...

Re: Scientists find traces of sea plankton on ISS surface

#30

Post by dandelany »

DanielBMarkham wrote: post #21
noselasd wrote: post #8

Earlier quoted context omitted.

No. The ISS isn't really that far from earth and there's a lot of exchange going on between earth and the ISS, mostly from all the various spacecraft we send up.

I think they meant it the other way, from Earth outwards. So if you find x living microbes at 200km from Earth, given thermal dispersion, shouldn't there be some y number of molecules from Earth on the Moon? (And so on) Even if y is a really small number, it effectively means any one planet with life would most likely "pollute" the star system it finds itself in. (Would need to do the math on this, but I believe that…

> So if you find x living microbes at 200km from Earth, given thermal dispersion, shouldn't there be some y number of molecules from Earth on the Moon?

I doubt it - even if the "uplifting air currents" hypothesis were proven true, there's a massive difference between low earth orbit and the moon. Around 8 km/s of delta-V to be exact.[1] This means that, to make it to the moon, the molecule not only has to reach LEO, it has to be moving at 8 km/s (a pretty insane speed) by the time it gets there. I can't imagine any earthly air current moving that fast, in fact it's likely impossible because the speed of sound is only 0.35 km/s.

[1] https://en.wikipedia.org/wiki/Delta-v_budget#Earth-Moon_spac...

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