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No Moon Needed For Extraterrestrial Life
sciencehabit writes "Given the generally accepted idea of how Earth got its big moon — through a dramatic collision with a Mars-sized body that knocked a huge chunk of Earth loose — astronomers estimate that only 1% of all Earth-like planets in the universe might actually have such a hefty companion. That would mean planets harboring complex life might be relatively rare. But researchers have now carried out large numbers of detailed numerical simulations of 'moon-less Earths,' which show that the consequences are less dire than is generally assumed. According to the simulations, these planets would have ample time for advanced land life to evolve. As a result, the number of Earth-like extrasolar planets suitable for harboring advanced life could be 10 times higher than has been assumed until now."
Possibly someplace darker and smellier.
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"Outlook not so good." That magic 8-ball knows everything! I'll ask about Exchange Server next.
YAY! We can be safe from Werewolves on these 'that's no moon' planets.
Also, "10 times higher" did they just pluck that number out of thin air?
Possibly someplace darker and smellier.
New Jersey.
Don't tides and seismic activity play big roles in how we think life evolved?
It's only idiotic if you demand that it be accurate, if you use it as a framing of the discussion, it is a nice place to start.
Nerd rage is the funniest rage.
Why was there ever an assumption that a moon is required for complex life? Stabilization of the axis and climate regions? Or did we just assume it because it worked here?
Developers: We can use your help.
I think you misunderstood. The uniqueness is not in the fact that it has a moon but in its extraordinary size (in relation to the planet size). That IS quite unique and it may be essential to life development. Or it may not... IMO its a strange approach to try to solve this question with a simulation. The outcome seems to depend on lots of factors whose influence on the development of intelligent life are just not known yet. Without knowing how intelligent life develops a simulation seems like just guesswork.
Here's what a rational, realistic analysis of tech progression would expect. GIVEN that life on earth can self replicate itself and use a huge range of molecules for fuel, it seems obvious that more sophisticated life is possible than already exists. Our star exhausts enormous amounts of free energy into space every second. Thus, one would expect that some day, perhaps next century or thousands of years from now, we will develop more sophisticated life that can use ALL of the matter in our solar system (rather than just a narrow range in the biosphere) and will use solar energy to rapidly convert all matter into parts of this life. This expectation is known as the singularity, and generally is assumed to require both artificial intelligence and molecular manufacturing (nanotechnology) to take place. There are plausible reasons to think that this event might happen in this century.
Well, if this is GOING to happen, and one would expect other intelligent life to do the same, and to eventually reach the same point. Then why don't we see the evidence of this out in space? Most of the stars should be missing, radiating mostly in the infrared. There should be a cacophony of data transmission between stars, although we might not be able to detect this. There should be other evidence of lively interstellar civilizations.
Theories :
1. The singularity is not physically possible. That means, of course, that our theories of physics are massively wrong as well, and that all our assumptions about intelligent life are as well.
2. Every single intelligent civilization self destructs. This also seems ludicrous...even if it happens some times, there should at least be remnants.
3. We are the first within our region of space. It took life on this planet ~3 billion years to get to this point, and many billions of years for this planet to form with the elements it has. The universe is only ~13 billion years old. Possible...
4. Technology can do even more than we assume. Maybe you don't actually need to surround stars with solar collectors to get energy...And our neighbors obey the prime directive...
And so forth. The number of possible theories is infinite, the number of probable theories large.
Because, the default position has been that life is exceedingly difficult to make happen, and that you needed a truck-load of favorable conditions to even hope it could happen. I think the notion was that we were a rare and unique solar system.
I seem to recall in the late 80s/early 90s when the notion of finding an exoplanet was pretty far fetched. I think the more we see and learn, it seems the more we start to realize that planets are anything but uncommon, and planets which could potentially house life are ... maybe not common, but not quite so dramatically rare as we once thought.
The more time passes, the more it's hard not to look at Drake's equation and figure that he might have been onto something ... if there's bazillions of planets, and a good chunk of those have moons, and a couple of those are in a habitable section ... well, maybe it's possible that there is far more life in the universe than we've previously thought.
Hell, there could be life in this galaxy, and it would be still so far away as to make it something we could never find or get to. If there was just one or two civilizations in any galaxy, the universe would still have loads of them.
I think those guys from SETI seem less like crackpots every year ... we may never find them or interact with them ... but I'm increasingly finding it hard not to believe they're out there.
Lost at C:>. Found at C.
On all of your points.
According to TFA we did assume based on some calculations from 1993 that "Without the moon, gravitational perturbations from other planets...would greatly disturb Earthâ(TM)s axial tilt".
And as with all other assumptions we ever made on extraterrestrial life - if it worked here...
There IS though, another point in the "moon equation" that is only hinted at in the article. Possibly cause it is assumed to be taken for granted (more of the "if it worked here...").
That would leave ample time for advanced land life to evolve under relatively stable climatic conditionsâ"although what would happen to such life during an axial shift remains unclear.
If you want your sea-dwelling life to migrate to land, stable yet powerful tides that regularly wash the aforementioned sea-dwelling life ashore surely are a plus.
For plants and for animals that would feed on them.
Mit der Dummheit kämpfen Götter selbst vergebens
The Drake equation:
R* = the average rate of star formation per year in our galaxy
fp = the fraction of those stars that have planets
ne = the average number of planets that can potentially support life per star that has planets
fl = the fraction of the above that actually go on to develop life at some point
fi = the fraction of the above that actually go on to develop intelligent life
fc = the fraction of civilizations that develop a technology that releases detectable signs of their existence into space
L = the length of time for which such civilizations release detectable signals into space.[3]
So, with fl,fi,fc and L (4 of 7) being completely unknowable, the result N is something more than parlor talk? No.
I'm all for parlor talk and will ponder extraterrestrial life with anyone. My personal opinion is there is other intelligent life, it's just really friggin' far away.
Make a percentage estimate? Pfffft! It's bullshit.
I don't know that I'd call it wishful thinking ... it's a framework to discuss the likelihood that another planet exists out there with an intelligent civilization.
Whether or not we're alone in the universe has been one of the "great questions" of man for centuries now ... I don't think knowing the answer to that, or working towards one it just wishful thinking.
Drake's equation is more of a starting point to have a discussion, it mostly just tries to frame the complexity of what's being discussed. It's like Moore's law -- it's value isn't so much in that it authoritatively explains anything. It certainly has very few assumptions inherently built into it -- it's an expression of what the chances are based on how much we think the values of the individual terms change. It is definitely more of a thought experiment than it is an equation, which was the whole point.
Quite frankly, I'd rather know that there's life out there, even if we can't ever reach it or communicate with it. If for nothing else, to have something to throw up in the face of the creationists who believe that god created the entire universe just for us -- not that I'd expect them to believe anything based on science.
I think now that we've started discovering hundreds of exoplanets, Drake's equation starts to get a few more terms filled in -- and the number of stars with planets has become a much greater number than previously thought. I seem to recall 15 or so years ago, the assumption was that stars with planets would be exceedingly rare and that we were a fluke. Change that one assumption alone, and you need to think about it differently.
Lost at C:>. Found at C.
Well, most of it is guesswork but it's becoming less and less guesswork. Take for example the number of planets. 20 years ago we didn't have a single confirmed extrasolar planet, now we're gathering statistics on them. True, we don't know what "habitable" is but we're approaching it from both angles:
1) We're trying to determine just how "earth-like" a planet is - this is a never ending story of orbit, mass, composition, satellites and whatnot getting closer and closer
2) We're trying to determine just how flexible life is looking at our extremophiles, how different can a planet be from earth and still be habitable.
Maybe there's life that's weirder than we can imagine, but these are just boundaries and if they cross, if we find planets that are so earth-like the life we *do* know could exist on them that would be a huge step. We are working on abiogenesis, with enough time we may discover exactly what conditions are necessary for life to begin, that is how tight the needle eye is. I doubt we could ever properly simulate life as such, but if we could show that primitive life would move towards more modern single-celled life I think the essence of evolution into more advanced life would follow.
By far the hardest to ever say if intelligent life like humans would ever evolve - I mean most species on earth do well and thrive without being that intelligent and have done for millions of years. Humanity almost went extinct 1.2 million years ago, we're rather crappy animals without tools, not being particularly strong or fast, no hide, no fur, no claws or teeth to scare anyone and our newborn defenseless. It takes a lot of energy to run our big brains, our evolutionary success was far from certain - it just seems so in retrospect as the tools have so far greater potential than even the toughest animal.
Live today, because you never know what tomorrow brings
Long term, tidal lock to the star will happen. A moon slows that down.
Yeah, I can see that is the reason. I can see all the aminoacids and whatnot swimming in the early oceans, happily combining into more and more complicated molecules, searching for the one that can self-replicate, suddenly looking towards the sky and saying: "Oh shit, no moon here, in like billions of years this planet will become tidal locked to the star, and it will be a very unpleasant place to be. Forget it, guys, lets pack up and go home!"
AccountKiller
Yep. Citing xkcd indeed introduces massive amounts of bullshit into the discussion. Basement dwelling dorks like Munroe don't seem to get that the Drake equation is not for actually calculating something, but a summation of identified parameters needed for the emergence of life. You gotta define the framework before you can work on the actual details. But hey, fapping off to your own perceived wit is so much easier, and that seems to be all Munroe does lately. He used to be good - 3 years ago or something. These days, he just got his head so far up is ass that he can lick is own tonsils from down below.
Ubi solitudinem faciunt, pacem appellant.
By what definition of 'life' is a planet 'alive'?? None that I've heard.
No, they're restricting their search to actual science.
They're not precluding a life form which exists in ways that we can't fathom or imagine. They're saying that we will restrict our search to things we can fathom and imagine since we have no idea of what to look for otherwise.
There would be no meaningful scientific basis to look for lifeforms based on chemistries we can't even begin to guess at. It's not like we know what we'd be looking for.
It seems every time this topic comes up, some clever guy comes along and says "we should be looking for life forms nothing like us" ... what, exactly, would we be looking for? You could point at anything and say "well, something we can't imagine might live there" ... you'd be right, but there would be nothing you could do with that. It's a completely vacuous statement to say that there could be something out there we can't imagine and that we should be looking for it.
The whole point is to look based on things we do know ... otherwise, it's not science any more ... it's random speculation based on, well, nothing actually. We can rule out places that couldn't support something like us ... we can't rule out anything based on something so unlike us that we can't think of what it is.
Tell you what, help me find my keys. They look like no keys you've ever seen, and I'm not going to give you any information on where to look for them or how to know if you've found them. In fact, I won't even tell you if you succeed. That's more or less what you're proposing -- looking for something that you have no way of looking for and no way of identifying if you're even close.
Lost at C:>. Found at C.