But there was once liquid water and on earth we have found worm like creatures which survive in ice so the idea that mars couldn't have at least bacterial life (or something like it) isn't that far fetched.

I wish we knew more about how life got started on Earth (at the molecular level). That could give us more clues to the likelihood of life elsewhere.
Mars did have liquid water at one point. Enough to form river beds and canyons. The surface temperature on mars never reaches above the freezing point of water though, so if liquid water existed on mars, what kept it from freezing? My guess is volcanic eruptions and their lava flows kept the temperatures warm enough for liquid water. But, since the atmospheric pressure is too low for water to remain in liquid form, it either turned to ice or vapor. The high altitude water vapors probably left the planet, so if Mars had oceans of water at one point, its all bled off into space now.

So, there are a few interesting questions to ask about mars and life:
If we do find evidence of life on mars, can we prove that it originated on mars? What's to say that a massive asteroid impact on earth didn't send life contaminated rocks to mars?
Could we find DNA or its building blocks on mars? (assuming of course, that all life in the universe has DNA)

In my completely unauthoritative opinion, the chance of there being any sort of life anywhere on mars is probably 1%. Sending a probe to search for that figurative needle in a haystack is probably going to give a 0.0001% of finding that evidence of life. However, I don't think we can completely rule out the possibility of there being life on Mars (problem of induction and all that).

It is possible there is life, but it is pretty clear that walking the surface and grinding random stones for water is not the right approach to finding it.

QFT, beautifully put.

Maybe I'm lacking the "romantic feeling" for it, but it's a bit beyond me why one would want to burn considerable resources (both money and "real" resources, e.g. rocket fuel) on studying a planet that is already known to be naturally uninhabitable for us when we are 7/8 on the road to making our own planet uninhabitable. The billions spent on such a project would be much better put in protecting the world we live in. When you buy a new car, it's well regulated how much CO2-per-100km is allowable and whatnot, and you're told to save energy, you can't buy real lightbulbs in the EU any more, and everywhere you're told about "green" and "eco" and all that bullshit (much of what's "eco" is just as bad or sometimes worse anyway, getting to think of this poster I saw last week about using the gulf stream to produce energy) -- a single unnecessary Atlas V launch probably produces as much CO2 as a million people are able to economize in a year.
Plus, the Curiosity project swallowed something around 1.2 billion dollars, if Wikipedia is right. I wish they had put that money into either saving some trees or into averting the financial crisis if you don't care about environment (those people who lost their houses probably wish that, too).

So maybe there is life on Mars, maybe there isn't. Apart from curiosity (no pun intended), what is it good for knowing about it? Is this knowledge so impotant that it justifies such a massive endeavour? If there is intelligent life, they most obviously don't want to talk with us, or they would have by now (and they must live deep underground, or be very good at hiding). If there exist micro-organisms, which is the more likely variant, why would we care and burn extra fuel to find out when we already have enough problems on our own planet?

That said, I hope there really is no life on Mars, because if there is then undoubtly some "genious" will decide that it is a very clever idea to launch another rocket and bring some "life samples" home, so they can be studied better. Surely that'll be a perfectly safe thing to do, rockets never crash, and lab accidents don't happen.
Invasive species have long, sad history on biodiversity, but of course man never learns. That's probably because so far "biodiversity" never meant "man". An unknown micro-organism from another planet might not be able to live here -- but it might as well. Do we really want to find out?

Correct me if I'm wrong, but rocket engines use liquid oxygen and liquid hydrogen for generating thrust. The byproduct is water vapor, not CO2.

CO2 emissions and pollution is a global problem. The main source of pollution is from coal fired power plants. Who burns the most coal? China. Do they care? No. They're running at 100mph into a brick wall of ecological destruction because it's fueling their economic growth. What the chinese don't realize is that economic prosperity is closely tied to ecological health. When they overrun thier ecological carrying capacity, they're going to crash very hard and the amount of human suffering is going to be pretty catastrophic (in terms of health consequences and the burden it puts on their state run health care system). Its like... I'm paying you $1 per cigarette you smoke, and you start smoking thousands of cigarettes and think you're rich. Then you get lung cancer and have to use all of that money to pay for treatment.

If you really want to complain about wastes of resources, just look at all of the trillions of dollars spent on the wars in Afghanistan and Iraq, and possibly the lost opportunity costs. The costs of an international space program are a drop in the bucket by comparison. I could fix all of that if I was the world dictator...

Burning hydrogen does not emit CO2, but making it does. So does just about all kinds manufacturing. But in global perspective, space exploration is a fart in a pig farm.


Ultimately, humanity has to choose between expanding into space or become extinct. The earth will not habitable in 3-4 billion years from now if we dont advance technologically (which space exploration is an example of). Sure, everyone living now will be dead by then, but most of us will not live long enough to be affected by global warming either.


By the way, chinese government is not stupid. Their main concern is energy crisis though, not global warming. Which is why they invest more than the US in renewable energy (at least they did a year back or so).

Maybe I'm lacking the "romantic feeling" for it, but it's a bit beyond me why one would want to burn considerable resources (both money and "real" resources, e.g. rocket fuel)[/quote]

At this point in time, most of the money spent on space goes towards labour costs, not the resource costs of the rocket and fuel. The Shuttle was expensive because it took a huge "standing army" of people just to maintain its launch facilities and process the orbiters. Most expendables are much better on that account, but nevertheless the money is going towards employing people to build and process the rocket and payload - many of whom are highly-educated, high-technology workers. The money paying those guys isn't exactly being "burned" - it's going back into the economy, not being dumped in a hole or used to pay for CEO bonuses.

The billions spent on such a project would be much better put in protecting the world we live in.[/quote]

How? What would you spend it on? What difference would $1.2 billion make in the long run? And (more importantly, in my opinion) why pull it from space exploration/exploitation, when you could pull it from military funding? I'll bet all those tanks and jet fighters driving/flying around produce more carbon dioxide in a day than the whole Atlas V launch infrastructure would in a year at its maximum flight rate. How much could you spend on "protecting the world" if you aren't fighting useless wars in little countries in the middle east?

Surely that'll be a perfectly safe thing to do, rockets never crash, and lab accidents don't happen... An unknown micro-organism from another planet might not be able to live here -- but it might as well. Do we really want to find out? [/quote]


There are ways of making sure accidental releases are very unlikely. Look into how radioisotope thermal generators, which in case you aren't aware contain very radioactive Plutonium-238, used on deep-space spacecraft are protected - the one that came back to Earth with Apollo 13 when it wasn't supposed to (it was supposed to stay on the moon and power experiments) is currently sitting unharmed in the Tonga trench at the bottom of the Pacific Ocean after surviving the breakup of the LEM and subsequent fall through the atmosphere and oceanic impact. I seem to remember hearing about plans to retrieve it, but they were scrapped because it was thought that they weren't worth the effort. The biggest threat of contamination from such devices comes from scrappers illegally dismantling them (as has happened in Russia a few times) - given how much scrutiny a sample return mission would be under, I don't think this likely.

As for a "lab accident", if a sample return mission happened, there would be very strong measures to prevent interaction between our biosphere and the sample - because we wouldn't want Earth's microbes to contaminate the sample and ruin it! In fact, this is already a pre-launch processing issue for lander spacecraft, which if I recall correctly are routinely sterilized before launch specifically to prevent Terran microbes from hitching a ride on the lander and contaminating soil samples after landing. Any sample return mission would take even stronger precautions. Furthermore, I highly doubt that if the sample was exposed it would result in the microbes within taking over Earth's biosphere, or doing anything other than dying out due to being out competed by microbes already adapted to our environment.

Burning hydrogen does not emit CO2, but making it does. So does just about all kinds manufacturing. But in global perspective, space exploration is a fart in a pig farm.

This. In fact, hydrocarbon-burning rocket engines ultimately add LESS carbon dioxide to the atmosphere than hydrogen burning rocket engines do because of how the hydrogen is currently obtained (mainly from hydrocarbon refining, funnily enough).

As far as I know, Mars' atmosphere got cold and low-pressure because its magnetosphere is too weak to prevent solar wind from slowly blowing Mars' atmosphere away.

What I'm more interested in knowing is that, if there is life on Mars, what are the implications for us? Could such an organism be useful to us in some way? How could we exploit it? What are the ethical concerns regarding the exploitation of a new alien species compared to a new species discovered on earth?

How will the crazies respond? Will new cults start? Will this mean the end of organised religion on earth? Or will it just mean a fresh batch of religious wars?

Life on mars, yes or no and why so?

The probability is non-zero, therefore yes, there is almost certainly life on Mars somewhere/time. However, there might not be life on Mars in your apparent reality.

I had another weird thought the other day. Of the millions of years of evolution and millions of species of life on earth, why are human beings the first to become space faring civilizations?

Turn it around - given the observation that humans are the first space-faring civilisation on earth, how many alternate histories (starting from big-bang to now) could have led to this event in spacetime, and how probable is the sum of those histories?
I have a feeling that the answer to this reversed question would show that such an event is a pretty mediocre observation, almost guaranteed to be occur in the grand scheme of things, and thus isn't that interesting or surprising.

What are the ethical concerns regarding the exploitation of a new alien species compared to a new species discovered on earth?

Conservationists tying themselves to Martian rocks to prevent terraforming? I have a feeling that initial Martian colonists will be too busy being depressed at their fate -- being stranded on a cold, dead rock, monitoring the life-support equipment -- to protest at the microbes dying to make their life a bit more earth-like.

Will this mean the end of organised religion on earth? Or will it just mean a fresh batch of religious wars?[/quote]We've already reached a point where science can explain everything we ever needed God for (except if you believe in dualism, where a human is both made of matter and 'soul' -- in which case, 'soul' is usually defined as to be that which can't be observed, and thus is ignored by science) and yet, religion persists. So I don't think it's going away any time soon, due to new scientific discoveries.
We've gone from "earth is flat", to "earth is round and central", to "earth is right next to the central sun", to "there is no centre, earth is not special", to "wait a minute, there is no objective shared reality, and any mathematical model, including heliocentrism or geocentrism are all just as real as each other", which means that when someone says "the earth is the central rotation point of the universe", then science can no longer say that they're wrong, only that they're making the mathematics inelegant. So in a way, modern science has reached the point where it's easy to co-exist with and tolerate "the crazies".

What I'm more interested in knowing is that, if there is life on Mars, what are the implications for us? Could such an organism be useful to us in some way? How could we exploit it? What are the ethical concerns regarding the exploitation of a new alien species compared to a new species discovered on earth?

How will the crazies respond? Will new cults start? Will this mean the end of organised religion on earth? Or will it just mean a fresh batch of religious wars?

I doubt it would be the "end" of organized religion altogether. I can't claim to know what will happen if evidence of life is found on other planets but I'm sure more cults will come up. The fact is, we don't necessarily know where the original microorganisms came from on Earth (the ones we all descended from). The first cells could've appeared organically on our own planet, or they could've come from Mars or some other planet somewhere. And vice versa as well -- we could find microorganisms on another planet or other mass in space (such as a large asteroid) and find that the cells most likely originated from Earth. We're all in one big cosmic pool of rocks and stars all revolving around each other, it's pretty easy to believe that pieces of Earth may have hit other planets after some of our more terrifying asteroid collisions.

And that's exactly why I think we will find life out there eventually. I don't know if we'll find it on Mars. I think we have a better chance of finding life (be it microorganisms or possibly more developed species) on some of the moons in our solar system, the big ones I'm thinking of right now are Jupiter's moon Europa and Saturn's Titan. It seems that Europa has a good possibility of oceans of water residing underneath its giant icy exterior, and Titan has certain conditions that could potentially be ideal for non-carbon, non-water based life forms.

Mars is just an easier target for us to hit, at least in the grand scheme of things. And I'm all for it -- I'm fascinated with this stuff and I would much rather us advancing our space technology than developing even more anti-life military technologies . Maybe chasing extraterrestrial life isn't something we should spend all of our money on, sure, but we should absolutely be looking forward into space for the future. We can try and protect our planet now, but I'd like to see us do more research being done on possibly inhabiting other planets/moons.

Imagine going to the Moon or Mars for a vacation.. that'd be incredible.

I hope there is life on Mars. I believe there should be microbes and such. Martians... not so much. If we did find a plant frozen in ice on Mars, what then? What would we do with that knowledge? I would like to see moon bases and space stations and interstellar travel. However, with the way things are now, NASA will not be running such things but corporations/private businesses will. I will stop now before I make too offtopic. However, religions are staying. Sorry, guys.