Slashdot Mirror
Earth Bacteria May Hitch A Ride To The Stars
An anonymous reader writes "Space.com has an article on how old rocket stages are carrying bacteria from Earth to interstellar space. For example, four upper rocket stages were used to boost deep space probes Voyager 1, Voyager 2, Pioneer 10 and New Horizons. The spacecraft were sterilized, but the rocket stages were not, and they now carry the bacteria of the engineers who handled them. If the rocket stages hit a habitable planet, and the bacteria survive the journey, they would be able to reproduce and colonize the planet ... not that there's a high liklihood of that. 'In 40,000 years, this wayward 185-pound (84 kilogram) lump of metal will pass by the star AC+79 3888 at a distance of 1.64 light-years. ... Given the sheer expanse of time that lies ahead of the four discarded rockets, at least one is likely to eventually encounter a planet. But even if that planet's environment is conducive to life, the long dormant bacteria will not just gently plop into some exotic ocean. No soft landing can be expected.'"
> Being exposed to the near-vacuum of space for an extended period of time, aren't the bacteria likely to be "pulled apart" at the molecular level?
r s/970603.html
No.
http://imagine.gsfc.nasa.gov/docs/ask_astro/answe
Vacuums are basically harmless. There isn't much difference in the forces involved between being in a vacuum and being at twice ordinary Earth pressure. In fact, humans can survive being unprotected in space for short periods of time, with no permanant damage:
You will of course die if you don't get some oxygen fast. Don't even try holding your breath to get an extra few minutes - the pressure will damage them. Just let the air escape and hope for rescue.
I'll probably be modded down for this...
As all great discoveries start with "gee that's weird.." we can thank the Space Shuttle Columbia for proving to us that bacteria can survive an atmosphere entry and planet impact. http://www.cmu.edu/magazine/03fall/wormsurvive.htm l
"The price good men pay for indifference to public affairs is to be ruled by evil men." ~Plato (427-347 BC)
urine is sterile. I should hope everyone washes their hands after taking a dump.
thank God the internet isn't a human right.
For an easier reading about human exposure in space, check out Damn Interesting's article. It's the same facts as the NASA link but written with the idea that you don't need everything phrased in the form of a question and answer.
urine is sterile, unless you have some kind of abnormal infection up there in which case it's not (obviously)
"What are the causes of UTI?
Normally, urine is sterile. It is usually free of bacteria, viruses, and fungi but does contain fluids, salts, and waste products. An infection occurs when tiny organisms, usually bacteria from the digestive tract, cling to the opening of the urethra and begin to multiply. The urethra is the tube that carries urine from the bladder to outside the body. Most infections arise from one type of bacteria, Escherichia coli (E. coli), which normally lives in the colon."
thank God the internet isn't a human right.
http://en.wikipedia.org/wiki/Panspermia
It is likely that Mars become more hospitable to life earlier than early by solidifying sooner. Dozens of Martian meterites have been discovered on earth. Perhaps there have been thousands or millions Martian meteorites over the eons. Bacteria have been found living five miles deep in earth where they may have been cut off from the surface from tens of millions of years or longer. They either live extremely slowly or metabolize other nutrients inside rocks. Rocks are excellent insulators from the heat and pressure of bombardment. Some meteors hitting earth are cool inside, even though their out layers have evaporated away from the heat.
Some these all together and you can make a case for bacteria first evolving on Mars and then infecting earth through meteroic hitchhiking, this happening billions of years ago. then they evolved on Earth while Mars became hostile to life.
Orbit capture is an extremely improbable event. In a pure two-body situation it can't happen at all: the approaching body will either hit the primary body or zing by it in a hyperbola. Something has to decelerate it during a critical period as it's arriving, and that means there has to be a third body in the right place at the right time. A wandering rocket would have to experience thousands of encounters to have a realistic probability of being captured in one.
rj
I guess you missed the article about NASA putting living bacteria in one of the Mars Rovers. We've already polluted one of our neighboring planets, why are we concerned about rocket stages drifting in space?l e544976.ece
http://www.timesonline.co.uk/tol/news/world/artic
Just to add to this: The habit of washing your hands after going to the bathroom has nothing to do with needing to clean off residue from going to the bathroom. The primary reason it was originally encouraged was because people weren't washing up on a daily basis, at all. As a public hygine issue it was decided to encourage people to wash their hands regualary, and bathrooms normally have running water, so that was a good time to do it. (People do use them every day, and the resources for washing were avalible.)
This is not to say you don't need to wash your hands after wiping your ass. But most people would do that anyway: They'll smell that they need to wash that off. The original public hygene campain that created 'wash your hands when you leave the bathroom' was unrelated to that, and was during the Renaissance, when medicine was re-discovered in Europe.
'Sensible' is a curse word.
After thousands of years of radiation, there's no way the bacteria could have any DNA intact. Alive, bacteria can repair damage or simply reproduce those who survive radiation. These bacteria on space objects are dormant, so the damage just builds up.
Aside from all the aforementioned problems, we have a small design flaw in our form of organic life: DNA is inherently unstable. Thymine dimerization is energetically favored, and is catalyzed by UV and other forms of radiation. But even apart from radiation, these dimers will form given the passage of time and non-absolute-zero temperatures. Our DNA-based life requires constant molecular upkeep to repair these problems. Any putative bacterial hitch-hikers would have had to sporulate to be able to continue existing without any metabolism, so no upkeep will be possible. Even if they become detached from the booster and are able to avoid a fiery re-entry onto a hospitable planet, they still have to hit it within a few centuries or their information will be irretrievably corrupted.
The problem is conservation of energy. The star creates a gravity well. It takes a certain amount of energy to climb to a certain distance from the star, a certain height up the gravity well. Thus the gravity well translates directly to an energy well. Since the object was far away from the star and moving it has at least that much energy. Since energy is conserved, if it falls down the energy well, that energy will be converted into kinetic energy, as it swings around the star it will thus have extra kinetic energy, more than is required to stay at that point in the energy well, thus it will fly outwards until it has used this kinetic energy up again. Since the object started with some though it will end up back at the distance it started with (nearly) the same velocity (probably not the same position). As a result if it starts "Very far away" and with some kinetic energy, then it has too much to be captured by a single body. The only way to be captured is to transfer that energy to another body, a concept feasible in a 3 body system, but not with only 2.
I say nearly the same velocity because technically some energy is lost, of course, just think thermodynamics, but that amount will be small enough that it's not really relevent here. In fact, that small amount also means that such a thing as "stable" orbit doesn't actually exist, since bodies in orbit always decelerate and fall towards the body it orbits around. This is an affect though on a very very large timescale - note that the earch hasn't hit the sun yet, so it's not really very interesting here.
Interestingly, bacteria kinda anticipate that; the sporulation process contains some protections for DNA. Spores have some fairly sophisticated DNA repair machinery that begins operating very early in the germination process, and they use a lower water content and SASPs (small, acid-soluble proteins) to lock their DNA into a more A-like configuration during the sporulation process. A reasonably large population of bacterial spores can probably remain viable in outer space for a surprisingly long period of time. If you're interested in the subject, I recommend the paper "Resistance of Bacillus Endospore to Extreme Terrestrial and Extraterrestrial Environments" in Microbiology and Molecular Biology Reviews. This paper refers to meteor impacts rather than transfer via rocket components, though.