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No Moon Needed For Extraterrestrial Life

Soulskill posted more than 3 years ago | from the sheer-luna-cy dept.

Moon 246

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."

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246 comments

No Werewolves! (1)

tom17 (659054) | more than 3 years ago | (#36298142)

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?

Re:No Werewolves! (3, Insightful)

sharkey (16670) | more than 3 years ago | (#36298162)

Possibly someplace darker and smellier.

Re:No Werewolves! (4, Funny)

Anonymous Coward | more than 3 years ago | (#36298240)

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.

Re:No Werewolves! (1)

Anonymous Coward | more than 3 years ago | (#36299388)

If New Jersey is the armpit of the nation, wouldn't the gulf coast be the taint?

Re:No Werewolves! (1)

Scarletdown (886459) | more than 3 years ago | (#36298494)

Possibly someplace darker and smellier.

I was trying to think of a way to work Uranus into this, but failed.

Re:No Werewolves! (1)

maxwell demon (590494) | more than 3 years ago | (#36298508)

They pulled it out of the atmosphere of Uranus?

Re:No Werewolves! (1)

obarthelemy (160321) | more than 3 years ago | (#36298592)

as long as we're allowed to work a way into Uranus ....

Re:No Werewolves! (0)

Anonymous Coward | more than 3 years ago | (#36298794)

Also, "10 times higher" did they just pluck that number out of thin air?

We all know that 68.19% of all published statistics are made out.

Re:No Werewolves! (1)

arisvega (1414195) | more than 3 years ago | (#36298936)

did they just pluck that number out of thin air?

No, what they pluck out of thin air is what "advanced life" is. Unless they mean "life as we know it".

Fake forumla continues to sink (-1, Flamebait)

Oligonicella (659917) | more than 3 years ago | (#36298196)

And that idiotic fake formula so many like takes another hit.

Re:Fake forumla continues to sink (1)

rubycodez (864176) | more than 3 years ago | (#36298262)

no more or less idiotic than this bias-driven modeling of speculation based on assumption which has no bearing whatsoever on reality.

Re:Fake forumla continues to sink (1)

Oligonicella (659917) | more than 3 years ago | (#36298278)

What model and what speculation?

Re:Fake forumla continues to sink (1)

rubycodez (864176) | more than 3 years ago | (#36298674)

the silly pointless simulations of the article, based on nothing but speculation and assumption and data gathering with a sample size of zero

Re:Fake forumla continues to sink (1)

Oligonicella (659917) | more than 3 years ago | (#36298956)

Oh. Seems like we agree.

Re:Fake forumla continues to sink (1)

TheTurtlesMoves (1442727) | more than 3 years ago | (#36298962)

I like astrobiology, I may even end up working on something in the field. However, i would still mod you insightful if i had the mod points.

Sample size of zero indeed. Well one could say it is one. However in statistics this is still the same thing thereabouts.

Re:Fake forumla continues to sink (1)

mandark1967 (630856) | more than 3 years ago | (#36299348)

Drats! Foiled again!

You just blabbed out the perfect formula for story submission on /.!

We'd have kept it secret but for you meddling kids!!

Re:Fake forumla continues to sink (3, Insightful)

maxume (22995) | more than 3 years ago | (#36298268)

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.

Re:Fake forumla continues to sink (-1)

Anonymous Coward | more than 3 years ago | (#36298696)

The discussions around that fake forumla are no more valuble than the discussions that take place around a hookah with some sweet smelling herbs.

Re:Fake forumla continues to sink (1)

chispito (1870390) | more than 3 years ago | (#36298282)

And that idiotic fake formula so many like takes another hit.

I assume you're talking about the probability of life emerging? I don't see how any such estimate is beneficial. For all we know we could be completely alone or the universe could be teaming with little green men.

But if you're referring to what I think you are, based on the scale of the formula, a single order of magnitude really wouldn't make much difference.

Re:Fake forumla continues to sink (1)

Oligonicella (659917) | more than 3 years ago | (#36298680)

Yes the probability formula. Factors that cannot be known.

Re:Fake forumla continues to sink (3, Insightful)

Oligonicella (659917) | more than 3 years ago | (#36298904)

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.

Re:Fake forumla continues to sink (1)

Arlet (29997) | more than 3 years ago | (#36299456)

You're forgetting the Bs factor:

http://xkcd.com/384/ [xkcd.com]

Re:Fake forumla continues to sink (1)

mandark1967 (630856) | more than 3 years ago | (#36299528)

The Mandark equation:

R* = the average rate of Clubs in our galaxy
fp = the fraction of those Clubs that have Fat Chicks
ne = the average number of Fat Chicks that can potentially be lured to your car with a twinkie (Or âoemoonpieâ if youâ(TM)re from the south)
fl = the fraction of the above that actually fit in your car without busting the suspension
fi = the fraction of the above that you can get home without your room mate/friends seeing them
fc = the probability of nailing said Fat Chick without her wandering off in search of the nearest IHOP/Dennyâ(TM)s/Waffle House in a sugar-induced trance
L = the length of time for which you can bang her without room mate/friends finding out

Any number > 0 is too scary to contemplate, tbh

Re:Fake forumla continues to sink (1)

Gilmoure (18428) | more than 3 years ago | (#36299516)

So, let's start with facts and then extrapolate.

Number of planets confirmed to have life? 1.

Number of star systems confirmed to have life? 1.

Number of galaxies confirmed to have life? 1.

Alright, I've done the hard work. I'll let the rest of y'all get on with the figuring and equationizing.

Re:Fake forumla continues to sink (0)

Anonymous Coward | more than 3 years ago | (#36298324)

And that idiotic fake formula so many like takes another hit.

What? Sounds like you need to take another hit.

Re:Fake forumla continues to sink (1)

SETIGuy (33768) | more than 3 years ago | (#36298736)

Yes, given that there was no real reason to believe that a large moon is necessary for complex life to exist. A look at the rotational axes of planets in the solar system indicates that they are more stable than would be expected with the naive moon-no-moon estimate. The only reasonable way that would happen is if other tidal torques are large enough to add stability. But given that it took nearly 4 billion years for complex life to arise here, it's probably fairly rare even if conditions would allow it to develop.

But the Drake equation is meant only to estimate the number of possible civilizations, not to be an exact calculation. There is nothing "fake" about it. When I plug in numbers I get that there is no reason there couldn't be 750,000 civilizations in our galaxy. It's also quite possible that there may only be 1 civilization per 20 million galaxies. There's a lot more certainty in some of the parameters, so I should recalculate, but that low end estimate probably won't get much larger.

Re:Fake forumla continues to sink (1)

Oligonicella (659917) | more than 3 years ago | (#36298996)

And, pray tell, what values do you plug in when you haven't a clue? Say, fl, fi, fc and L?

Re:Fake forumla continues to sink (1)

MaskedSlacker (911878) | more than 3 years ago | (#36299636)

Something between zero and one.

Re:Fake forumla continues to sink (1)

Arlet (29997) | more than 3 years ago | (#36299506)

And how many of those civilizations in our galaxy are close enough that we actually have a decent chance of picking up on their communications ?

Unless somebody is aiming a high power directional antenna right at the earth, the signal is going to drown in background noise very quickly.

Re:Fake forumla continues to sink (2)

Kjella (173770) | more than 3 years ago | (#36299218)

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.

Re:Fake forumla continues to sink (1)

Oligonicella (659917) | more than 3 years ago | (#36299432)

"Well, most of it is guesswork but it's becoming less and less guesswork."

Only for R, fp and ne; with ne being dubious, as we have only one planet's experience with what can constitute life and we've not found all the variants here.

The problem with calling this a real equation (aside from the format) is the use of the word "actually". We have to either; 1 - find and catalog intelligent life or, 2 - be around long enough and have investigated heavily enough to reasonably determine there aren't any.

Even if we found the exact values for those three tomorrow, the formula would remain useless because we can't even answer the binary question implied in fl, much less fi. We can't even judge L because we haven't stopped yet.

and given that assumption is now questioned... (1)

dAzED1 (33635) | more than 3 years ago | (#36298226)

I've seen several articles now about how much water is in the center of the moon, calling in to question this theory about the origin of the moon. I've never liked this origin theory, anyway. The large gravity well of a bigger object pulled in a smaller object. Boom, easy stuff. And how in the universe can someone talk about how unlikely it is that other planets would have moons, when our own solar system has several planets with moons? A quick google search reveals this image: http://upload.wikimedia.org/wikipedia/commons/thumb/4/4f/Moons_of_solar_system_v7.jpg/800px-Moons_of_solar_system_v7.jpg [wikimedia.org]

Re:and given that assumption is now questioned... (3, Insightful)

zav42 (584609) | more than 3 years ago | (#36298360)

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.

Re:and given that assumption is now questioned... (1)

Rogerborg (306625) | more than 3 years ago | (#36298444)

quite unique

You'd have to be nearly omniscient to know that.

Re:and given that assumption is now questioned... (1)

zav42 (584609) | more than 3 years ago | (#36298754)

Nah omniscient is an exaggeration.

OK let me rephrase: It is quite unique inside our solar system. Unless we find one other planet / moon pair with similar proportions, the only known such pair is pretty unique in my book.

Re:and given that assumption is now questioned... (0)

Anonymous Coward | more than 3 years ago | (#36298898)

it's pretty clear that GP meant uniqueness within the set of observed planets.

Re:and given that assumption is now questioned... (2)

gstoddart (321705) | more than 3 years ago | (#36298512)

And how in the universe can someone talk about how unlikely it is that other planets would have moons, when our own solar system has several planets with moons?

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.

Re:and given that assumption is now questioned... (0)

Grizzley9 (1407005) | more than 3 years ago | (#36298662)

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.

So. What. Unless we somehow rewrite the laws of physics we will never communicate or even know of them before our star burns out. While the search is a good reason to expand our tech and knowledge of our universe, when all is said and done, the Drake equation is really little more than a pastime in wishful thinking. Its just a logical formula based upon a lot of assumptions.

Re:and given that assumption is now questioned... (4, Insightful)

gstoddart (321705) | more than 3 years ago | (#36299090)

While the search is a good reason to expand our tech and knowledge of our universe, when all is said and done, the Drake equation is really little more than a pastime in wishful thinking. Its just a logical formula based upon a lot of assumptions.

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.

Re:and given that assumption is now questioned... (1)

zav42 (584609) | more than 3 years ago | (#36298918)

Isn`t it equally fascinating if we were in fact alone and not necessarily make a god or fate responsible?
If intelligent life was so common I always wonder why we didnt see any self replicating drones visiting us yet?
Think about how much time they had to and only one civilisation had to build them.

Fascinating either way...

Re:and given that assumption is now questioned... (1)

Zephyn (415698) | more than 3 years ago | (#36299298)

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.

Precisely. It seems that most news reports on exoplanet discovery either ignore or gloss over the fact that the question we're looking to answer right now is "How much of a special case is Earth?" Keep in mind that just a few generations ago we were trying to figure out where objects were at the edges of our own Solar System. Over the past 20 years science has managed to show evidence that both planetary systems and earthlike rocky planets are not the gazillion-to-one shot we thought they might be. So far it seems that the more precise our observation ability becomes and the more we find out, the higher the 'life as we know it' probability becomes. I find that very encouraging.

What about tides, seismic activity? (4, Insightful)

Anonymous Coward | more than 3 years ago | (#36298244)

Don't tides and seismic activity play big roles in how we think life evolved?

Re:What about tides, seismic activity? (2)

jbeaupre (752124) | more than 3 years ago | (#36298836)

The sun also causes tides.

Re:What about tides, seismic activity? (2)

newcastlejon (1483695) | more than 3 years ago | (#36299278)

The sun also causes tides.

I would expect so, but my hasty back-of-the-envelope (read: Wolfram Alpha [wolframalpha.com] ) says that the Moon's influence is about 75 thousand times larger.

IANAA, so please point out how I'm wrong but bear in mind that just saying "you're wrong" isn't at all helpful.

Re:What about tides, seismic activity? (4, Informative)

Arlet (29997) | more than 3 years ago | (#36299422)

Actually, the Moon's influence on the tides is only 2.21 times larger than the Sun's:

http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/961029b.html [nasa.gov]

Re:What about tides, seismic activity? (1)

newcastlejon (1483695) | more than 3 years ago | (#36299598)

Very informative, thank-you. I must have a good look at that later to see why I was so very far off.

Re:What about tides, seismic activity? (0)

Anonymous Coward | more than 3 years ago | (#36299622)

I think you need to square distance in that equation (G*M1*M2/r^2). That gives a factor of 199 instead of 75,000. Wolfram Alpha [wolframalpha.com]

We are alone in the universe. (-1)

Anonymous Coward | more than 3 years ago | (#36298260)

There is definitely no life outside of planet Earth. The unique combinations of factors that have occurred here to allow life are exceedingly improbably to occur anywhere else - the fact that the solar system has not been visited by robotic exploration / colonization craft proves that we are alone, for the short period of time we exist before we extinguish ourselves.

Re:We are alone in the universe. (1)

maxwell demon (590494) | more than 3 years ago | (#36298906)

There is definitely no life outside of planet Earth.

Ah, so you know every planet in the universe?

The unique combinations of factors that have occurred here to allow life are exceedingly improbably to occur anywhere else

Yes, but the universe is a large place. It's like the fact that you are extremely unlikely to win the lottery, yet almost every week someone wins. And yes, a planet getting life is much less probable than winning the lottery, but then, there are many more planets in the universe than lottery players for a given lottery.

the fact that the solar system has not been visited by robotic exploration / colonization craft proves that we are alone, for the short period of time we exist before we extinguish ourselves.

No. It only proofs that there's no intelligent species which had the chance to reach us. It doesn't preclude non-intelligent life on other planets (maybe it's a highly unlikely event that intelligence evolves on planets with life), nor does it preclude intelligent life anywhere where it couldn't have reached us (I think even Andromeda is far enough that an intelligent species would have had no chance to visit us or send robots; anyway, an intelligent species 10 billion light years from here definitely wouldn't have come here.

And even for intelligent life in our galaxy, it's not a disproof of intelligent life; it just makes it more unlikely. Imagine there are exactly two intelligent species evolving in our galaxy. Then there's a 50% chance that they are behind us. And since we ourselves didn't ever get to a planet of another star, it's no surprise that they didn't come here anyway. Even three intelligent species would not make it too improbable that we are the first.

Moreover, it's not a given that any intelligent species will do space exploration beyond their solar system. Indeed, it might be that most just don't survive long enough.

Re:We are alone in the universe. (0)

Anonymous Coward | more than 3 years ago | (#36298966)

You really don't understand the law of large numbers, do you? Yes, the chances are vanishingly small, but the number of solar systems is exceedingly large. Multiple the two together and you will still get a very, very large number.

Please explain (4, Interesting)

truthsearch (249536) | more than 3 years ago | (#36298274)

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?

Re:Please explain (1)

chispito (1870390) | more than 3 years ago | (#36298314)

Or did we just assume it because it worked here?

And what other frame of reference is available, exactly?

Re:Please explain (0)

Anonymous Coward | more than 3 years ago | (#36298342)

Ah, so clearly life must not exist on planets with multiple moons then, because we have no frame of reference for it.

And all swans are white.

Re:Please explain (2)

gstoddart (321705) | more than 3 years ago | (#36298332)

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?

As I recall, the moon itself protects the planet from some amount of meteors and asteroids. Might reduce the chances of life getting wiped out too early.

And, I think that the tides provided by a moon would keep things moving around instead of stagnating.

Those are my best guesses from memory.

Basically... Yeah. (2)

denzacar (181829) | more than 3 years ago | (#36298586)

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.

Re:Basically... Yeah. (1)

arisvega (1414195) | more than 3 years ago | (#36299168)

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.

I think you got it backwards; life started in the sea, so there would be nobody to feed upon the first creatures that were washed and/or moved ashore.

Plants went ashore to avoid being grazed upon, then followed the grazers to graze without competition and without being preyed upon, and the predators were last to follow to prey upon forementioned grazers without competition in those new hunting grounds.

Plus, the buffer zone exists anyway because oceans are turbulent- my guess is tides would not be that crucial.

Re:Please explain (1)

zav42 (584609) | more than 3 years ago | (#36298648)

Some factors can be tested and calculated in a simulation. Example: We have a very large planet far out in our solar system that catches objects that could otherwise collide with earth, therefore changing the timespan between extinction level events upwards far enough for intelligent life / civilizations to develop. Check. How likely do solar systems have things of the size of Jupiter that far out?

But for the majority of factors it is pointless to argue from the cause towards the effect unless you understand how exactly intelligent life develops. We know how much time it roughly took and we know that only one species has made that leap yet.

On many other contributing factors you can only argue backwards from observing our existing world: Earth has an exceptionally large moon (relative to earths size) and it therefore makes sense to look at this factor as a possible contribution to our existence.

Making a simulation of a process that we dont understand is not science IMO.

Re:Please explain (2)

WrongMonkey (1027334) | more than 3 years ago | (#36298666)

Tidal forces are a big part of it. Both with the sea and with the liquid mantle. Before life at thermal vents was discovered, tidal pools were the chief candidates for the environment where life first evolved. They are a convenient interface between the sea, land and atmosphere. With no moon, there would be no tidal pools. Tidal interaction with the mantle is complex, but it may be the reason we have a strong magnetic field, unlike Mars or Venus.

Re:Please explain (1)

SETIGuy (33768) | more than 3 years ago | (#36298786)

Yes, axis stabilization. But I don't know who ever believed it was a requirement. Planets in our solar system without large moons appear to have fairly stable axes.

Re:Please explain (1)

Anonymous Coward | more than 3 years ago | (#36299378)

The moon is a favorite inspiration for poets and the lyrics to popular songs: "Moon River", "Blue Moon", "Old devil moon", "It's only a paper moon", etc.

Songwriters on moonless planets would have to make do with something else, possibly crippling the emotional lives of intelligent beings which could result in premature extinction.

Okaaayyyy, that's interesting... (1)

NoNonAlphaCharsHere (2201864) | more than 3 years ago | (#36298288)

They're saying that the moon stabilizes the axial tilt wobble, so the climate doesn't change drastically (over loooong periods of time), so therefore life would have time to evolve, which is an interesting notion. However, I thought it was generally accepted that the moon's tidal effect on the oceans (literally "the tides") was one of the big contributors to the emergence of life. Seems they're hand-waving that part.

Re:Okaaayyyy, that's interesting... (1)

maxwell demon (590494) | more than 3 years ago | (#36299018)

Well, AFAIK there are several competing theories about the origin of life. One being that life started at the black smokers in the deep sea; that one would certainly not need any tides.

Dramatic? (1)

Anonymous Coward | more than 3 years ago | (#36298328)

...through a dramatic collision with a Mars-sized body that knocked a huge chunk of Earth loose

Calling that event dramatic would be like calling cannibalism inconvenient.

Why was this ever an issue? (1)

n5vb (587569) | more than 3 years ago | (#36298346)

Why would a moon the size of ours be a requirement? That never made sense to me.

Kind of helps to have an active geodynamo and the resulting magnetosphere though ..

Re:Why was this ever an issue? (0)

Anonymous Coward | more than 3 years ago | (#36298416)

Long term, tidal lock to the star will happen. A moon slows that down.

Re:Why was this ever an issue? (2)

lahvak (69490) | more than 3 years ago | (#36299642)

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!"

Collision? (1)

phantomfive (622387) | more than 3 years ago | (#36298350)

I'm not an astrophysicist, so I'm a bit behind here, but how could the earth have collided with a Mars-sized object? Wouldn't it have caused the orbit to be much more eccentric than it is now?

Re:Collision? (1)

The Great Pretender (975978) | more than 3 years ago | (#36298724)

This theory bothers me as well, but more for the simpler perspective of how the hell did the chuck of rock knocked off earth become so round in space? Shouldn't it be more like a big jaggiedy piece? It's not like it would weather down to a nice nice round object up there.

Re:Collision? (0)

Anonymous Coward | more than 3 years ago | (#36298938)

This theory bothers me as well, but more for the simpler perspective of how the hell did the chuck of rock knocked off earth become so round in space? Shouldn't it be more like a big jaggiedy piece? It's not like it would weather down to a nice nice round object up there.

It wouldn't be a chunk that got rounded down, it would be a whole bunch of dust and debris that coalesced together over time.

Re:Collision? (1)

julesh (229690) | more than 3 years ago | (#36298942)

This theory bothers me as well, but more for the simpler perspective of how the hell did the chuck of rock knocked off earth become so round in space? Shouldn't it be more like a big jaggiedy piece?

No. Gravity of any sufficiently large object causes it to become spherical over time.

Re:Collision? (1)

Arlet (29997) | more than 3 years ago | (#36299542)

Especially if it's soft and gooey.

Re:Collision? (0)

Anonymous Coward | more than 3 years ago | (#36299556)

It wasn't one piece that was knocked up into orbit around Earth, it was trillions of tiny chunks - think of the debris that goes flying when a mortar shell goes off or when you throw something large and heavy really fast into a pile of gravel. Gravity eventually pulled that stuff together and it formed a round shape, just like everything we see in the sky larger than a mid-sized asteroid.

Re:Collision? (0)

Anonymous Coward | more than 3 years ago | (#36299310)

There's an excellent write up on it here: http://en.wikipedia.org/wiki/Giant_impact_hypothesis

This is a SIGNIFICANT problem (2, Interesting)

ShooterNeo (555040) | more than 3 years ago | (#36298400)

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.

Re:This is a SIGNIFICANT problem (1)

Arlet (29997) | more than 3 years ago | (#36298594)

2. Every single intelligent civilization self destructs. This also seems ludicrous...even if it happens some times, there should at least be remnants.

We've had already two dozen civilizations on earth that self-destructed, so this seems like a likely scenario. The remnants are likely too hard to detect. Our current civilization is pretty much undetectable beyond the orbit of Pluto, and is probably already past its peak.

Re:This is a SIGNIFICANT problem (0)

Anonymous Coward | more than 3 years ago | (#36298842)

Well I still like the other theory about how we are on a dirt ball of spit from another universe that was spit out and are sitting a hole on a different planet that is now only been there for 2 sec there time but billions of year our time. SO looking for life outside our spit is useless because we will never reach the end of the spit bubble and if we by some chance of luck did we would find nothing because all is too big to us to see or imagine. Just face the facts somethings are better left unknown. Mucus 101 reporting. hahahahha

Re:This is a SIGNIFICANT problem (1)

NoNonAlphaCharsHere (2201864) | more than 3 years ago | (#36298844)

I just had a timecube moment.

Don't we fail the Copernicus test? (0)

Xaedalus (1192463) | more than 3 years ago | (#36298978)

Isn't it interesting that the Earth is situated on the inner edge of the arm of our galaxy? Close enough to stay within the Galaxy's gravity well and prevent being thrown out into the void, but not so close that we're going to get sucked into the core. We're nowhere near any black holes, or extreme gravitational tides that would tear our solar system apart. We're well over 600 light years away from any giant or supergiant stars so we're outside the range of supernovae. We're not near the galactic core either, so we're not getting burned to a crisp by extra-solar radiation.

Then we've got Jupiter conveniently positioned in the mid-to-outer reaches of our solar system to sweep away comets and asteroids, not to mention Saturn, Uranus, and Neptune. Our sun is a medium orange star and probably one of the most stable configurations out there as far as stars go. We're at a convenient range away from the sun, plus we're on a planet that has an active core and thus can generate a magnetic field to protect us from the solar wind. And then, there's the Moon - a abnormally-sized piece of extraordinarily round rock that happens to be in a stable orbit around our planet.

Given all the possibilities and probabilities out there, I feel there's a legitimate case for saying we fail the Copernicus test, and that there's more than just coincidence to our existence here.

Re:Don't we fail the Copernicus test? (1)

Oligonicella (659917) | more than 3 years ago | (#36299132)

Meh. I don't. The universe is big. Small odds *will* happen. All conditions you mention will occur in other systems, even within our galaxy. By the way, the moon is being lost, just slowly.

Re:Don't we fail the Copernicus test? (0)

Anonymous Coward | more than 3 years ago | (#36299502)

Well, given that we expect to lose our moon in roughly 50 billion years and the Sun is slated to go boom in approximately 10 billion years, I don't think we have to worry overly much about that partiular issue.

Re:Don't we fail the Copernicus test? (1)

Squidlips (1206004) | more than 3 years ago | (#36299384)

Check out a book called Rare Earth by Ward et. al.; the authors make a convincing case for the scarcity of other advanced life forms outside the solar system, but they say that single-cell life could be common. There is the other camp on this issue, the Saganites such as David Darling who argue, not quite as convincingly, for ubiquitous life. It is an interesting issue, but I am not even convinced, as Ward is, that single-celled life is common.

Re:Don't we fail the Copernicus test? (1)

ElectricTurtle (1171201) | more than 3 years ago | (#36299482)

Anthropic principle. This place is coincidentally conducive to life, therefore there is life here to wonder why it's so coincidentally conducive to life that it couldn't be coincidence. Further, it wouldn't matter if we were further out from the galactic core. So long as the sun is the same, the solar system has very little if any meaningful interaction with objects outside of the system.

(Also, you are wrong about there being no giant stars for hundreds of ly. Pollux is a giant, and only 33 ly distant. Arcturus is as well, at ~36 ly. Beta Triangulus Australis and the Capella binary at 40 and 42 ly respectively. etc.)

Non-science. (1)

fish_in_the_c (577259) | more than 3 years ago | (#36298446)

'There would be more then enough time' presumes you know what conditions are necessary for that time to start counting, Just because life started on earth at a specific time, does not mean every planet would have that event happen , if it ever, at the same point in planetary time line as it did on earth. there is no way to know if 'enough' would be normal when you can't explain IF little lone WHEN there is a start.

Re:Non-science. (0)

Anonymous Coward | more than 3 years ago | (#36298726)

I could have told you the same without even reading the details. Virtually every time you hear people saying our planet is unique, or even close to it, it'll be wrongheaded morons trying to convince themselves that they're still the center of the universe.

Ridiculous Speculation (1)

LS (57954) | more than 3 years ago | (#36298514)

We have no fucking clue what it takes to support life as we know it, and we won't until we fully understand life and the process of abiogenesis. We do know a lot about where life cannot survive though, e.g. no oxygen, no water, etc. These equations are pretty much arbitrary.

In other words (1)

kenbo11 (1097593) | more than 3 years ago | (#36298522)

In other words "We really have no idea what the chances are that life could evolve elsewhere. Nor what that life could be."

Magnetosphere? (1)

Pro923 (1447307) | more than 3 years ago | (#36298558)

It seems to me like one of the factors that is essential for complex life to evolve is the presence of a magnetic field, in order to protect life (and a thin atmosphere) from the harmful effects of the sun. While we're at it with the search for extraterrestrial life - shouldn't the presence of a magnetic field be one of the "must have"s? I've always been under the impression that the large moon is what keeps the Earth's core churning and thus the magnetic field - but maybe that's less fact and more something that I came to believe on my own.

Don't get too excited (1)

WrongMonkey (1027334) | more than 3 years ago | (#36298616)

This is just a computer simulation regarding the stabilization of the axial tilt. It doesn't take into account other contributions the moon would have on the development of life. Tidal forces, both with the ocean and the liquid mantle, are believed to have had a major contribution to the formation of life.

deceptive title (1)

Gravis Zero (934156) | more than 3 years ago | (#36298710)

the title should be No Moon Needed For Extraterrestrial Life In Computer Simulation

they fail to account for a lot of factors in which the moon plays a vital role.

Validation (1)

petes_PoV (912422) | more than 3 years ago | (#36298806)

That's all very nice. When the scientist have found a representative number of worlds - what shall we say; 10? an even dozen? moonless, life-containing worlds, then they'll have a theory worth considering. Until then, they've got nothing.

Silly question but (0)

Anonymous Coward | more than 3 years ago | (#36298834)

Who ever said that a moon was REQUIRED for life to exist?

fecking morons

The moon does more... (1)

SteveW928 (2030878) | more than 3 years ago | (#36298890)

than just stabilize the tilt. While I'll have to wait till some real astrophysicists to analyze the implications of this, I know that much off the top of my head.

As Blackadder might put it: (1)

QilessQi (2044624) | more than 3 years ago | (#36299044)

"So what you're saying, Percy, is that some number you've never calculated might be ten times larger than some other number you've never calculated."

don't get the math (0)

Anonymous Coward | more than 3 years ago | (#36299124)

"...astronomers estimate that only 1% of all Earth-like planets in the universe might actually have such a hefty companion"
"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"

If Earth-like planet with moons represents 1% of of all Earth-like planets. Now that we can take all Earth-like planet, so changes are 100 times higher, not 10.

they're framing the question wrong (0)

Anonymous Coward | more than 3 years ago | (#36299156)

"Given the generally accepted idea of how Earth got its big moon"... the exact manner in which we got our moon doesn't really have much bearing on whether or not a moon is needed for the development of life, although it may "impact" the continued existence of any life already present. Every planet further out than Earth has more moons than us (totaling 139 so far, http://www.spacetoday.org/SolSys/Moons/MoonsSolSys.html ) , and I can say with reasonable certainty that the moons of the gas planets were not created by collisions between those planets and unnamed impactors.

Fermi Paradox (1)

medv4380 (1604309) | more than 3 years ago | (#36299418)

That is just keep making it worse.

Tremendous contributions (1)

fractalspace (1241106) | more than 3 years ago | (#36299536)

I would love a job where I could just sit on my ass and speculate all day.

Enough Assumptions. (1)

dadelbunts (1727498) | more than 3 years ago | (#36299574)

Why do we keep assuming that life, even complex life had to be created in a habitat like our own. Hell even the variation of organisms here on earth show that life can exist and thrive in hostile places. Hostile to us at least. We need to stop thinking that just because WE are here then all other life will follow the same path. We are the product of our environment not the other way around. All these little "perfections" in the balance of life on earth are due to us evolving for billions of years and adapting to them. What might be right for you, might not be right for some.
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