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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

#71

Post by joshvm »

CodeTheInternet wrote: post #11

Couldn't this simply be from an astronaut sneezing on a glove prior to a spacewalk, then grabbing a handrail? We already know about water bears that can survive in space, so why not bacteria.

Pretty much - even opening the air lock will do it.

> The former cosmonaut, who spent nearly a year in orbit back in the 1980s, said that outer surface of ISS is “heavily contaminated” by the waste products from engines of the arriving spacecraft, atmospheric discharges from the station during spacewalks by the crew and other factors.

https://www.rt.com/news/181472-iss-marine-plankton-space/

There is also evidence that bacteria get carried up on air currents and the ISS orbits low enough that it can intercept this stuff. (note that while this is widely reported, there doesn't seem to be anything actually published, and the air current theory is, well, a theory).

There are several papers on interior contamination though, e.g http://www.sciencedirect.com/science/article/pii/S0923250805...

Re: Bacteria on the outside of the International Space Station

#72

Post by antonvs »

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.

> How is your list any more remarkable than life starting on Earth in the first place?

Because the list includes that probability and adds a number of other extremely unlikely events that have to take place.

Re: Bacteria on the outside of the International Space Station

#73

Post by Razengan »

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?

You infinitely underestimate the size of the universe.

Re: Bacteria on the outside of the International Space Station

#74

Post by ufmace »

astrodust wrote: post #68
ufmace wrote: post #66

Earlier quoted context omitted.

Orbit is doubtful - what natural process could accelerate a bacteria to those speeds after getting it out of the atmosphere? Maybe some bacteria somehow floated up high enough to be hit by the ISS, but I would think they would be obliterated by the impact, despite being microscopic.

Given kinetic energy is a function of mass, and bacteria way basically nothing it doesn't seem impossible for them to enter orbit, only improbable.

I may be rusty on my physics, but I think momentum/impulse is what you need here. You can throw all the energy you want at a bacteria or spec of dust or something, and you might vaporize it, but you aren't going to accelerate it to 20k mph relative to the surroundings, much less launch it out of the top of the atmosphere at those speeds. Even a bacteria is quite massive compared to particles that can hit those speeds by random collisions.

Re: Bacteria on the outside of the International Space Station

#75

Post by ufmace »

JoeAltmaier wrote: post #67
ufmace wrote: post #66

Earlier quoted context omitted.

Orbit is doubtful - what natural process could accelerate a bacteria to those speeds after getting it out of the atmosphere? Maybe some bacteria somehow floated up high enough to be hit by the ISS, but I would think they would be obliterated by the impact, despite being microscopic.

The usual argument relies on meteor impact throwing detritus into the upper atmosphere. We have rocks from Mars that got here by that means.

Meteor impacts throwing debris into space can happen for sure, but we're talking about stuff that ends up on the outside of the ISS. The bacteria would have to be on something large enough to shelter it from the heat and wind of the original impact and high-speed passage through the atmosphere. It would have to end up in a stable orbit in the ballpark of where the ISS is. Surviving bacteria would then have to make their way out of this object and float around in space. And then their orbit drifts until they hit the ISS, mostly likely at very high speed unless they happen to be in almost exactly the same orbit. Feels pretty unlikely.

Re: Bacteria on the outside of the International Space Station

#76

Post by agumonkey »

euyyn wrote: post #69
agumonkey wrote: post #10

Earlier quoted context omitted.

What's there around ? solar rays for sure. Enough gazeous particules ? but that's it isn't it ?

Yeah, thin atmosphere, very low humidity, temperature that varies drastically every 45min... what's not to like!

but mostly my question was "what feed them"

Re: Bacteria on the outside of the International Space Station

#77

Post by PeterisP »

greggarious wrote: post #63
PeterisP wrote: post #51

Earlier quoted context omitted.

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 advance…

Did they get a head start though? All these atoms bouncing around started with the big bang after all :) One theory I'm fond of is that we are not alone, but life is so rare that the distances between intelligent civilizations are too vast for us to ever observe them (or vice versa).

Many, many other planets had conditions suitable (as far as we understand what's suitable) for creating life when our planet didn't exist yet; out of all feasible planets we're younger than average, so others would have had a head start.

Re: Bacteria on the outside of the International Space Station

#78

Post by JoeAltmaier »

AnimalMuppet wrote: post #65
JoeAltmaier wrote: post #60

Earlier quoted context omitted.

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.

No, the inevitability of it being present in a nearby planet went way up if the probability of it moving from one planet to another planet is decently high - and not otherwise.

Probability is over time. With enough time (billions of years?), the total probability approaches 1.0.

Re: Bacteria on the outside of the International Space Station

#79

Post by AnimalMuppet »

JoeAltmaier wrote: post #78
AnimalMuppet wrote: post #65

Earlier quoted context omitted.

No, the inevitability of it being present in a nearby planet went way up if the probability of it moving from one planet to another planet is decently high - and not otherwise.

Probability is over time. With enough time (billions of years?), the total probability approaches 1.0.

No, it doesn't. If the probability per year is 10^-15, then the probability over 10 billion years (10^10) is still 10^-5. (I mean, yes, over a quadrillion years the probability approaches 1.0, but I don't think that helps your position.)

You keep trying to say "but big numbers of planets, and big amounts of time" to make this idea reasonable. But it doesn't work. You have to deal with how low the probability actually is of it happening from one planet in one year. If that's low enough, you can't salvage it just by saying "billions of years and billions of planets".

Re: Bacteria on the outside of the International Space Station

#80

Post by JoeAltmaier »

AnimalMuppet wrote: post #79
JoeAltmaier wrote: post #78

Earlier quoted context omitted.

Probability is over time. With enough time (billions of years?), the total probability approaches 1.0.

No, it doesn't. If the probability per year is 10^-15, then the probability over 10 billion years (10^10) is still 10^-5. (I mean, yes, over a quadrillion years the probability approaches 1.0, but I don't think that helps your position.) You keep trying to say "but big numbers of planets, and big amounts of time" to make this idea reasonable. But it doesn't work. You have to deal with how low the probability actually…

...and you can't refute it by making up tiny numbers. Statistics is hard and you can be fooled by big/small numbers. Until some reasonable estimate of the actually probability of an asteroid making it from one system to another (oh look! There's one in our system now!) you can't make conclusions.
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