1,000,000 to 1
I'll get my spacesuit.
Japanese space agency JAXA has been given the all clear from eggheads to attempt a landing on Mars' largest moon, drill into it, and bring a sample back to Earth without an Andromeda Strain incident. The mission, dubbed MMX and scheduled for 2024, will involve a robot arm attached to a spacecraft boring a hole into Phobos. It …
Earth microbes have almost certainly made it to the moon and probably mars numerous times via impact ejecta in the last few billion years already (probably trillions of microbes were ejected into space when the dinosaur killer hit 65m years ago alone). If it had any viability on these other bodies it would already be thriving there. As far as we can tell it isn't, at least not in any obvious way, so why on earth carry out these absurd sterilisation precautions?
You could easily survive there with a suitable space suit. However, if you were on Earth (already wearing that space suit), and something hit you hard enough to propel you to the Moon, how do you rate your chances?
There's a not-so-subtle distinction between being able to survive in an environment, it being possible to transport you to that environment, being able to survive that transport, and the combination of all three...
There are no trees on the moon/Mars. And as hard as it is to accept our assumptions were wrong about life on Mars. We were wrong.
If there was, we would see it. While of cause, even deserts and ice caps here have some form of life that may be difficult to see, 99.9% of it will discolour or change the environment so much, that after a little peek you cannot miss it.
If Mars had life, then we would see it. However, contamination is contamination, at least for the space agencies and their equipment, even if Mars could shrug off a common cold with no problem! ;)
Complicated life "only" started about 1 billion years ago (depending what you count as complicated, but plants date from around then), while single celled organisms have been around about 4 billion years. There's a big gap before things kicked off. If Mars is less hospitable then there's a chance there is life there that hasn't developed beyond single cells.
An exercise for the reader:
You are able to throw a rock hard enough to reach the Moon. Exactly how hot does it get from atmospheric heating?
There's a reason that most meteorites that are found on Earth are of the metallic type; chondritic (rocky) meteorites are typically small and well fractured by the time they arrive, and those don't have to be travelling at escape velocity to get here. Note that these form in space, so can be reasonably large when they start out. You're going to need a pretty big impact to have a chance of dislodging anything bigger than a pebble into orbit, and those sorts of impact tend to sterilise the area they are about to hit before they even arrive due to the radiant heating from atmospheric impact. The last of these arrived some 65 million years ago, and caused a bit of a kerfuffle at the time...
Now, there's an argument that thngs could arrive here inside rocks that have been knocked off other planets, notably ones without a substantial atmosphere, if the inside of that rock doesn't get too hot, and whatever is inside it can survive the force of impact, and is also resistant to the irradiation it will have received whilst in space, possibly for millions of years.
"There's a reason that most meteorites that are found on Earth are of the metallic type"
I'm absolutely for sure not a meteorite expert. But my understanding is that the reason most reported meteorites are metallic is possibly selection bias. Metallic meteorites are relatively recognizable, magnetic, and pretty durable whereas stony meteorites tend to look more like just another rock, laugh at magnets, and some decompose fairly readily in wet environments. I've read that in Antarctica where all the rocks on the icecap are assumed to have arrived by air, the percentage of metallic objects is quite low.
As to whether living critters can by blasted into space from Earth. I dunno. Too many variables. For one thing, there's that whacking great initial acceleration required. Because of drag during exit, initial velocities well in excess of escape velocity of 11.2 km/s would be needed. OTOH, algal cysts ("acritarchs") are really durable. And they've been around for billions of years and presumably many Earth-bolide encounters. For large impactors, there may be some possibility of single celled organisms riding along inside rocks. My understanding is that variety of living creatures were found living deep in the Kola super-deep borehole despite the great heat and pressure. Maybe some of the creatures living deep in the Earth can tolerate cold and millenia in transit as well.
Even stony meteorites contain enough iron to deflect a small, powerful magnet suspended on a thread. (Saw this on Youtube, therefore must be true.)
Otherwise, agree with everything about selection bias.
I'm still puzzled that the exo-planet community make such a big thing about finding so many gas giants orbiting really close to stars. They use a number of techniques to find exo-planets, but the transit method is really good at finding large planets in close orbits.
Can't find it any more, but over ten years ago there was a report of the discover of halite crystals in a presumably "Martian" meteorite recovered in Antarctica. Salt is known from various other meteorites already: http://www.psrd.hawaii.edu/Nov99/PurpleSalt.html. The commonest souce are chondritic meteorites, and it has been observed that common methods of preparing meteorite samples for examination use water - oops. But that brings up really intriguing things like, chondrites exposed at the surface might have any salt they carry dissolved by rain, and if there were organics within that salt, they would then be released into the environment. Consider that the Murchison meteorite had so much organic material in it that it literally stank.
"You could easily survive there with a suitable space suit. However, if you were on Earth (already wearing that space suit), and something hit you hard enough to propel you to the Moon, how do you rate your chances?"
For myself (or for that matter, any other life form big enough to be visible) not very highly - but as they say, F=ma, so if you have as little mass as a virus does then the force needed to produce the necessary acceleration is not that great.
A flea can jump to many times it's own height and land safely afterwards - why can't elephants do the same?
For a lone bacterium, I think the issue will be more about acceleration and speed/air resistance than force.
Getting instantaneously accelerated to escape velocity* means over 1000 Gs, and then you have to survive going through the atmosphere at said escape velocity.
*You'll need to be going much faster than that initially to account for drag.
Plenty of junk left around. Earth is already well contaminated anyway, so we don't worry so much about it (less than we should probably). All the bits that end up on mars have gone through VERY extensive decontamination and sterilisation procedures, including things like the heat shields and parachutes that get jettisoned during the descent to the surface.
I recall one of the Burroughs' Mars books I read as a schoolboy set much of the adventure on one of the Martian moons, I forget which. They were already known to be very small, so to get his story going, Burroughs invented a law of nature that caused everything approaching the moon to shrink appropriately.
Let's see what happens to the Japanese probe...
"as long as the probability of taking a single, unsterilized particle, measuring no less than 10 nanometers in diameter, contains a single microbe is less than 0.000001 per cent"
Who's setting those odds, though? Since we can say very little about the possibility of Martian microbes from whatever landers / rovers there, how are these odds estimated if not by basically making them up out of a bunch of assumptions?
Reminds me of Feynman's assertion in the shuttle investigation that every layer of management at NASA had an order-of-magnitude lower estimate of failure possibility than the layer below. When the data is so sparse, probability calculations are hardly better than guesswork.
Crichton was well aware of climate change and gained the emnity of climate change fanatics by writing "State of Fear" which used exaggerated claims of sea level rise as a plot device. The fact that the book was actually about constructing phony crises (e.g. Saddam Hussein's nonexistent weapons of mass destruction) completely escaped them. I don't recommend the book unless you need to occupy a few hours and the only alternative is something by Dan Brown or James Patterson. It's readable. But ... Thin plot. Too much polemic. Crichton wrote some good books, but even if you agree with the premise, State of Fear wasn't really one of them.
Crichton's concerns about politization of science are probably better (and certainly more concisely) stated in his 2003 Cal Tech lecture "Aliens Cause Global Warming" https://stephenschneider.stanford.edu/Publications/PDF_Papers/Crichton2003.pdf
I second the recommendation to read "Aliens Cause Global Warming". It's quite good.
Michael Crichton was an excellent writer. He had some good books and bad, as all writers do. However "State Of Fear" was not that bad. It wasn't his best, but, certainly not as bad as you suggest. I found the book more interesting because of its impact. In the back he lists URLs leading to the documents he used for his research. United Nations sites, government sites, etc. There were many. Right after the book was published, those documents disappeared. Not just moved, removed from the net. He writes about this at the end of the paperback version of the book which came out about a year later. Pick it up or get it from the library and read it for yourself.
And about Hussein's' "nonexistent weapons of mass destruction"... You put too much faith in the story as reported. Have friends in the right places and you'll find that they did indeed exist and were secreted out of the country to not embarrass the allies who had previously provided him the tech.
" Any life, however, would have to survive the impact of the collision, the aerodynamic heating of travelling to Phobos, and the heavy solar and cosmic radiation Phobos receives from outer space."
So if they do find any life in the samples brought back to Earth, it's going to be bloody hard to kill.
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