Suppose that Mars was like the earth, early in its history, and that life evolved about up to the age of dinosaurs. Then, the planet cooled off, and lost its atmosphere. Now, many astronomers think that there may be vast pockets of underground ice , and possibly liquid water as well. When the first manned expeditions reach Mars, they will probably drill into the crust, and take samples back for analysis. My question: is there any chance that any microbila life on Mars could be deadly to humans? Howwould we defend ourselves from such bacteria…and, could a plague spread to the earth?:eek:
I imagine any specimins will be in a sealed container, and any specimins on the outside of the craft would be destroyed during re-entry.
IANABiologist but shouldn’t the bacteria have more to fear from our immune systems? Mars has been in equilibrium a long time so whatever may be there is tied very closely to that environment. Earth, has had massive climate changes; millions of years of bacteria/viruses vs. animals vs. plants etc. In short haven’t we developed a sophisticated defense that simply attacks anything not recognized as friendly?
The poor bacteria are going to have to figure out how to work a cell system they’ve never encountered while being attacked.
Keep in mind that Earth and Mars trade rocks all the time. Rocks get blasted off the surface of each planet due to impacts. They then wander around in space for about a million years ago, and a lucky few hit a planet again.
There is a class of meteorites called the SNCs that we know to be from Mars because they contain tiny bubbles of air that exactly match the composition of the martian atmosphere as measured by the Viking landers.
The rocks can be chucked into space without being significantly heated. Bacteria can go into a spore form that requires no water or sustinance, and is highly resistant to extremes of temperature–even radiation. They can then spring back to virulence when they encounter the right conditions.
So if there are bacteria on Mars, we have most likely already recieved a visit from our single-celled neighbors.
And contrarywise. We go to a tremendous amount of trouble to sterilize our landers to avoid contaminating Mars, and then rocks lousy with terrestrial bacteria fall out of the sky anyway.
That won’t stop us from observing rigorous containment protocols to prevent any martian life from escaping from samples returned to Earth–and to prevent those precious martian samples from being contaminated by terrestrial bacteria. If we are lucky enough to get martian life in a lab we want to keep it nice and safe and happy so’s we can study it. Also, historically, it has turned out to be bit embarassing to “discover” life from Mars which is later revealed to be plain old earthling bacteria. (It’s happened, with meteorites.)
My vague intuition is that bacteria are pretty specialized critters, well adapted to the conditions they find on their home planets, and unlikely to survive if transplanted to a wildly different environment. Thus, martian bacteria would fare poorly in the teeming microbe-eat-microbe ecosphere of Earth, while terrestrial bacteria would shrivel up and die in the harsh conditions of Mars. However, that is a WAG, and you’d certainly find many astrobiologists who would disagree with me.
If you’re interested in the topic, try searching on “Planetary Protection”, which is the catch-all NASA buzzphrase encompassing efforts to avoid contaminating other planets with terrestrial bacteria on spacecraft, as well as keeping extraterrestrial bugs from escaping on Earth.
Not likely, even with the warm wet mars epoch tossed in. A lot of years have passed since then, and any bacteria that survived through the intervening cold/dry eons would long since have adapted to those extreme climactic conditions. Since the human body is warm and wet, the martian organisms would have to evolve again before they’d make good human pathogens.