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Bacteria on the outside of the International Space Station

independent.co.uk

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Re: Bacteria on the outside of the International Space Station

#51

Post by PeterisP »

greggarious wrote: post #26
antonvs wrote: post #22

Earlier quoted context omitted.

If the alien organism originally evolved independently of life on Earth, then analyzing its genetic material - its equivalent of DNA - would tell us a lot. We haven't yet found any organisms on Earth that have evolved independently, so an organism found in space that has a different genetic structure from Earth life would be a good bet for being alien in origin. An alternative, albeit unlikely, possibility is that Ea…

>An alternative, albeit unlikely, possibility is that Earth life was originally seeded from somewhere else - panspermia, https://en.wikipedia.org/wiki/Panspermia . I've seen this hypothesis before. I've also seen the oft repeated assumption that other intelligent life might be out there, more advanced than ours. Crazy though: what if we are the most advanced life in th universe?

If the probabilities are such that it's feasible that we're the first/most advanced life in the universe, then (given our planets comparably young age) it's exceedingly likely that we're the only life in the observable universe.

It would be plausible for us to be alone, and it would be plausible for us to be one of the less advanced lifeforms among many, but it would be quite surprising if we'd to be the most advanced civilization among many; since many/most of them would have gotten a significant head start.

Re: Bacteria on the outside of the International Space Station

#52

Post by PeterisP »

wil421 wrote: post #48
antonvs wrote: post #31

Earlier quoted context omitted.

Is is possible? Yes. Is it likely compared to the alternative? No. Comets are theorized to have brought us water from within the solar system, so the comparison doesn't really apply unless life evolved in our solar system but somewhere other than Earth. Here's some of what has to happen for life to cross naturally between planets in different solar systems: 0. Life evolves somewhere else 1. Somehow, some of that life…

How is your list any more remarkable than life starting on Earth in the first place? What’s the probability of adding water and heat to a planet then waiting a few billion years for life? I hope we can send some probes to Saturns moons and find out. Even Mars could have a trace of life in the dirt.

Assuming that the above list has a 10% chance of happening, that would be 10 times more remarkable than life starting on Earth in the first place; since you'd have the probability of adding water and heat to a (non-Earth) planet and waiting a few billion years for life and that whole list as well.

Re: Bacteria on the outside of the International Space Station

#53

Post by Sir_Cmpwn »

Spare_account wrote: post #46
Sir_Cmpwn wrote: post #28

Earlier quoted context omitted.

Actually, they ship it down to Earth during the resupply missions.

I'm getting conflicting information from NASA on this. According to the first link (PDF, sorry), waste is disposed of in re-entry craft. But according to the second link, it's ejected to burn up in the atmosphere. https://www.nasa.gov/sites/default/files/files/issrdc_2013-0... https://www.nasa.gov/mission_pages/station/research/news/inf...

In any case, we know that they use special waste storage containers, and don't expose feces to space directly (presumably until these systems fail during re-entry - far away from the ISS). Take your pick of the several videos on YouTube that describe the ISS's toilet to see the waste containers in question.

Re: Bacteria on the outside of the International Space Station

#54

Post by ams6110 »

BeefySwain wrote: post #50
QAPereo wrote: post #44

Earlier quoted context omitted.

Remember that human feces ended up in orbit, although not from recent sources.

That sounds interesting. Do you have more info on that? A source perhaps?

Early manned space capsules dumped human waste (at least urine) overboard.

https://history.nasa.gov/SP-368/s6ch2.htm

No idea what the Soviets did.

Re: Bacteria on the outside of the International Space Station

#55

Post by JoeAltmaier »

antonvs wrote: post #45
JoeAltmaier wrote: post #33

Earlier quoted context omitted.

Bad conclusion. There are billions of 'other planets' and only one Earth. You'd have to add up the marginal probabilities of all the other scenarios, to compare with just the Earth scenario.

> You'd have to add up the marginal probabilities of all the other scenarios, to compare with just the Earth scenario. There aren't even close to billions of other planets that could have been candidates for sending a life-bearing asteroid to Earth. Some of the restrictions are: 1. A planet capable of having developed life. 2. A planet close enough for an asteroid from it (I have trouble typing that because it's such…

Add in : asteroids in close orbits around suns developing life elsewhere (or here). Precursor chemicals to life surviving the asteroid trip even if whole organisms do not (accelerating life development on Earth by millions/a billion years).

We started with, it took an Earth to develop life, but if it came from elsewhere we'd have to expand our ideas to include all other possible sources of life, not just Earthlike. Because our premise changed.

Re: Bacteria on the outside of the International Space Station

#56

Post by bdamm »

PeterisP wrote: post #52
wil421 wrote: post #48

Earlier quoted context omitted.

How is your list any more remarkable than life starting on Earth in the first place? What’s the probability of adding water and heat to a planet then waiting a few billion years for life? I hope we can send some probes to Saturns moons and find out. Even Mars could have a trace of life in the dirt.

Assuming that the above list has a 10% chance of happening, that would be 10 times more remarkable than life starting on Earth in the first place; since you'd have the probability of adding water and heat to a (non-Earth) planet and waiting a few billion years for life and that whole list as well.

We don't know precisely what the ideal concoction is for life to get started, nor can we measure how close to ideal our planet is relative to others. So maybe Earth is not the most efficient planet at developing life, and in that case, the probability equation could tip back to panspermia.

Re: Bacteria on the outside of the International Space Station

#57

Post by JoeAltmaier »

AnimalMuppet wrote: post #43
JoeAltmaier wrote: post #33

Earlier quoted context omitted.

Bad conclusion. There are billions of 'other planets' and only one Earth. You'd have to add up the marginal probabilities of all the other scenarios, to compare with just the Earth scenario.

But of those billions of other planets, as they get further and further away, the probability of an asteroid from them finding Earth goes down. So does the probability of life on the asteroid surviving the trip. I think that the number of planets within a distance R is O(R^2), but the probability of an asteroid from such a planet reaching us is O(1/R^2). But if the probability of life on the asteroid surviving the tr…

The panspermia idea is, that it started somewhere and somewhen, and has been planet hopping ever since. We only need one nearby life-bearing planet to seed earth; it got seeded from further away and so on.

Similar to how ancient Romans wore silk but didn't have trade with China. It only took each trader to trade with their neighbor, and silk could travel thousands of miles.

Re: Bacteria on the outside of the International Space Station

#58

Post by JoeDaDude »

There are a handful of scientists attempting to collect life forms from very high altitudes using balloons. In one instance [1] they discovered UV resistant bacteria. Could it be remotely possible that high altitude species have managed to live on the ISS?

[1] https://www.sciencedaily.com/releases/2009/03/090318094642.h...

Re: Bacteria on the outside of the International Space Station

#59

Post by AnimalMuppet »

JoeAltmaier wrote: post #57
AnimalMuppet wrote: post #43

Earlier quoted context omitted.

But of those billions of other planets, as they get further and further away, the probability of an asteroid from them finding Earth goes down. So does the probability of life on the asteroid surviving the trip. I think that the number of planets within a distance R is O(R^2), but the probability of an asteroid from such a planet reaching us is O(1/R^2). But if the probability of life on the asteroid surviving the tr…

The panspermia idea is, that it started somewhere and somewhen, and has been planet hopping ever since. We only need one nearby life-bearing planet to seed earth; it got seeded from further away and so on. Similar to how ancient Romans wore silk but didn't have trade with China. It only took each trader to trade with their neighbor, and silk could travel thousands of miles.

OK, but at that point, the "billions of planets out there" argument doesn't work. You're left with the probability of it transferring from a nearby planet.

Re: Bacteria on the outside of the International Space Station

#60

Post by JoeAltmaier »

AnimalMuppet wrote: post #59
JoeAltmaier wrote: post #57

Earlier quoted context omitted.

The panspermia idea is, that it started somewhere and somewhen, and has been planet hopping ever since. We only need one nearby life-bearing planet to seed earth; it got seeded from further away and so on. Similar to how ancient Romans wore silk but didn't have trade with China. It only took each trader to trade with their neighbor, and silk could travel thousands of miles.

OK, but at that point, the "billions of planets out there" argument doesn't work. You're left with the probability of it transferring from a nearby planet.

Right, and the inevitability of it being present in a nearby planet went way up. Because once it started somewhere (and there are billions of 'somewheres') it would spread like a virus and infect every possible receptive environment.

The statistics is hard. No simple counting of planets is enough. All the vectors have to be accounted for.

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