Sure, even micro-organisms would be a major discovery, but ultimately imho of limited interest and impact.
According to Nick Lane in The Vital Question:
We already know two things with certainty:
- a very small amount of material transits between Earth and Mars.
- all material on Earth contains microbes.
It would seem we also know that there are microbes on Mars, though at insignificant levels and likely not flourishing.
The dV to then end up on either planet doesn't matter because aerobraking and lithobraking do all the work for you.
significantly larger, because it has to get through our atmosphere once on the way in, and then the ejecta has to do it again on the way out, keeping in mind that drag is proportional to velocity squared, and that whatever ejecta is making this trip has to find a way not to get cooked into sterility by impact energy or friction with the air....
Too many extra factors are in play, each of which adds an exponent to the unlikelihood. But that's just my uneducated opinion, I'm certainly open to discussion.
It would be particularly exciting to discover life that is similar to Earth but with an opposite chirality, or a genetic code that encodes amino acids using different base pairs.
(I'd be thrilled to be wrong about this, of course, just as I would be fascinated with any xenobiological discovery at all. But I do think the 'endless forms most beautiful' are also strongly constrained by simple physics, and thus the solutions found by an evolutionary random walk will resemble what we already know.)
EDIT: It also makes me wonder how different an ecosystem could be. Imagine one that did not require macroorganisms eating other macroorganisms, like ones that feed on heat or wind.
EDIT 2: Maybe mating requires 3 genders, etc. There seems to be a lot of room for variation.
Invertebrates are much more relaxed about number of eyes etc.
We can go from "humans are the optimal form!", to "well, some kind of mammal", "c'mon, it's got to be a vertebrate", then get into the Cambrian experiment, go back further to different DNA (RNA anyone), then to different metabolic pathways, then to different organic biochemistry, then to non-carbon... and why should life have a chemical basis, anyway? So chemocentric.
How can we tell when he go from too anthropocentric to too anti-anthropocentric? We have guesswork only. We're like a child rebelling against its parents.
It seems to me, that elephants, dolphins, parrots, octipuses, and even spiders could have undergone the rapid brain-size increase that happened to some apes. (We don't even know why it happened to us.) They might still do so, in a few million years.
Note that some earth creatures - deep sea and underground - have almost lost eyes. Like [blind mole rats](https://wikipedia.org/wiki/Spalax). They have appropriately alien-like nose-antennae.
If there's light, they'll have eyes. Probably.
My pet theory is that microscopic life is relatively common but complex life, let alone intelligent life, is exceedingly rare.
Edit: I'm guessing downvoters are low-openness types. But this is a speculative discussion, _that's the point_. In particular this is a question of the level of universality of what we on Earth consider universally-human principles, but we see consciousness outside of humanity as well. So where does it stop?
If there exist other life forms with consciousness, the question of whether they share consciousness in the form of shared archetype is not a question with no takeaways. It's important stuff to consider! The implication could be that a life form found on Earth is in some way multi-planetary, for example, and part of a wider consciousness-granting bio-system.
: A "shared consciousness" must communicate in some way; no signals (in the form of either electromagnetic, gravitic, strong or weak nuclear force) have been detected that could accomplish this.
On the speculative end perhaps you'd have phenomena like shared intuitions or visions; however that's still a gradient; in some fields like Jungian psychology these are seen as products of a long and convoluted physical sensing processes, not as magic, for example.
I also agree with Tomas who opined that for a long time it was presented that water was 'rare' and somehow special. And while we can agree that the triple point is pretty narrow set of conditions that have to exist, we now know it flowed on Mars at one time, is probably currently flowing on Europa, and that ice is literally everywhere.
Time to rewrite our Science Fiction tropes.
We could crack lots of cryo propellant, and far more easily than the old plans. The moon could become a huge propellant, fuel, structural materials and life-support depot with a very easy gravity well to get out of--way easier than Earth. That makes it very important for future Mars missions as well. It's easier to stop off at the moon for a bit than to go straight to Mars from Earth.
Regolith has all kinds of neat stuff in it, such as aluminum and that legendary helium-3 which may or may not be a miracle fuel if fusion ever breaks even (and we figure out how to do it with aneutronic fuels, which is way harder). The aluminum can be made into solid rockets, which are good enough to get off the moon but damn near useless for anything else because of their pathetic specific impulse. But it would be a great way to get this water off the moon without having to waste much on shipping.
If we set up nuclear furnaces we could crack some of the minerals to get oxygen, but it would be so energy-intensive compared to melting ice, and hydrogen is super rare on worlds with easy gravity wells. Hydrogen likes to sublimate off into space and there's practically none anywhere this late in the game. That would be a big bottleneck on ISRU. But all this water ice hidden away near the surface really changes things.
Now if we'd only get serious and go nuclear and get people back in space. Check out the always incredible Atomic Rockets by Winchell Chung for great spacecraft diagrams, mission profiles, pdfs of charts and graphs and nomograms and more. It's a treasure trove for space nerds who wish NASA went the way we thought it was going to go in the fifties and sixties.
You say that offhandedly, as if they decided not to move forward with a Moon base due to bureaucracy or because some upper management people decided to go in a different direction.
A permanent moon base in the 70s and 80s was largely impossible as far as the technology is concerned. Hell, we're approaching 2020 and we still have several major hurdles before we could put a permanent base on a body or planet that is not earth. Everything from radiation to supplies are still problems that need solved. Expecting them to solve them in the late 70s or early 80s is almost laughable.
I know HN and reddit likes to think it was congress who is responsible for the shift in NASAs goals (after all, they control the purse strings so they get to dictate/approve budgets & goals), but they did so precisely because NASA told them it was impossible to establish a permanent moon base at that point in time. On top of the insane cost, what more was there to be gained that justified the immense cost? If they wanted to go to the moon and study rocks, that's what the Apollo program was for. There was only so much we could learn with the technology we had at the time. People forget, the rest of the solar system awaited exploration too, but only so much money to go around.
"But we can use the moon as a base to launch further missions out into the solar system and beyond!" It's a nice pipe dream, but getting the materials there and/or manufacturing facilities to create everything needed is cost prohibitive. Also, the logistics of doing something like that today is insane, let alone 30 years ago.
When I was in college, I got a chance to intern with Jerry Pournelle who was on the White House science advisory council and we talked about moon bases at one point. Jerry asserted (and I believe him) that NASA had a program "ready to go" to put a permanent installation on the moon. The budget challenges however were large.
I also got to meet Gerard O'Neill through Jerry who was pushing for colonizing space and had lead NASA to develop plans for how a Moon base would support the development of space habitats.
This let me understand that while the technical challenges were hard, they were engineering and budget challenges, no new science or equipment or materials had to be developed. The same materials that survived for years in orbit would survive on the Moon, the same resupply requirements that there were for a space station there would be for the Moon etc.
President Regan was open to the idea but the only way to fund big space initiatives was to make it sound like a war. That has historically been the only motivation that gets Congress to appropriate the funds. And in the late 70s, early 80's it was going to take a lot of funds.
Really smart people tried to make the argument that the economic benefits of adding 'space' to a country's economic operating zone would be immense, and create growth that could be taxed to fund the rest of the expansion fell on skeptical ears. Even O'Neil's pitch that space based solar power satellites would give the US a built in economic advantage; 'Cheap' energy would lower the development cost of all goods. Wasn't enough to get people to commit to the groundwork for this. When I last talked with Jerry about this, he suggested that a cost effective single stage to orbit capability, built to support Regan's SDI initiative, would enable space colonization as well (that was in 1990 or 1991).
Here we are, nearly 30 years after 1990, and SpaceX is on the cusp of making access to space an order of magnitude cheaper than it was in the 90's. This presentation  from 2007 could have been the SpaceX pitch deck!
Now I need to go dig around and see if I can find NASA's plans they did in the 80's.
P.S. There's also Europa Clipper, but the funding is less certain: https://en.wikipedia.org/wiki/Europa_Clipper
The second-most prevalent element, helium, doesn't form molecules (to any meaningful extent, if at all).
Methane (CH4) likely comes next.
On airless worlds with less gravity than ours, water near the surface tends to sublimate and float off into the great old void. It's extremely rare to find it in places that are relatively easy to access. Even Earth isn't a great source, because all that atmospheric drag and gravity makes water a pain to loft up and out.
This new store of ice on the moon is right on our doorstep. Europa is not on our doorstep. Having it on the moon changes all the plans for future manned missions outside Earth's orbit. With hydrogen and oxygen readily available on the moon--and without nuclear reactors and massive chemical processing plants--it suddenly becomes a complete no-brainer to go over there and start making stores of cryogenic fuel for our more ambitious plans.
That is if we ever undertake another ambitious plan. New Horizons was amazing, it really was. But it's nothing like a manned flight.
People say robotic exploration is just as good, but the intangible things really matter. They really do. Think of just how much the moonshot in the 60s drove people into STEM and got everyone excited about the future. Look at science fiction then vs. now. It went from utopian and focused outward to heavily dystopian, obsessively focused inward. It's so sad.
It's impossible to calculate the value of the inspiration of the moonshot, let alone the advances in technology (solid-state computers anyone?). Just imagine how much of a boost it would give our society to go to Mars. This discovery makes it a lot more closer.