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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."
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?
And that idiotic fake formula so many like takes another hit.
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
Don't tides and seismic activity play big roles in how we think life evolved?
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.
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.
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.
Calling that event dramatic would be like calling cannibalism inconvenient.
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
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?
"First they came for the slanderers and i said nothing."
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.
'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.
âoeTolerance applies only to persons, but never to truth. Intolerance applies only to truth, but never to persons.
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.
There is a fine line between being a cultivated citizen and being someone else's crop. - A. J. Patrick Liszkie
In other words "We really have no idea what the chances are that life could evolve elsewhere. Nor what that life could be."
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.
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
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.
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.
Anons need not reply. Questions end with a question mark.
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.
politicians are like babies' nappies: they should both be changed regularly and for the same reasons
Who ever said that a moon was REQUIRED for life to exist?
fecking morons
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.
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.
Here's to hot beer, cold women, and Glaswegian kisses for all.
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"...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.
"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.
That is just keep making it worse.
I would love a job where I could just sit on my ass and speculate all day.
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.
And will these same 'scientists' tell you that blacks are less intelligent than whites? Of course not. Because there is no 'science' nowadays, just political dogma.
(Cue some idiot calling me "racist" but being laughably unable to provide a SHRED of evidence to back up their (insane) position, that blacks are as intelligent as whites...)
"through a dramatic collision with a Mars-sized body that knocked a huge chunk of Earth loose"
So where is the hole on the earth that the moon supposedly created, hmm?
We're making an assumption that because it worked this way here, it can work this way elsewhere and the likelihood of life arriving under other conditions is unknown at best, and probably rather difficult. We have no basis for this assumption. It's in fact, equally likely that life arriving on earth was an extremely rare occurrence and that in most other situations it could have arrived much much earlier. For all we know even the planets in our own solar system could be swimming with life and we just haven't seen it yet. The only planet we've even scratched the surface of is Mars and we've literally only scratched the surface of an exceedingly small area.
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. ...
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
For any denominator in Drake's equation where we don't have the technology to measure it, shouldn't the null hypothesis be that Earth (and by extension us) is dull and ordinary?
Other assumptions just sound like the echos of geocentrism.
My God, it's Full of Source!
OUTSIDE_IP=$(dig +short my.ip @outsideip.net)
No Moon, no tides, no critters.
Sorry, you critter lovers.
a twice-daily tide from a binary system like ours could have a significant influence on vertebrate development. I bet there's a lot of inverts out there awaiting discovery, but it's a lot harder to evolve critters the rest of us would find interesting.
Is it a rule, that there's an exception to every rule?
I have a few questions and perhaps one of the more enlightened slashdotters can help me out.
If the Earth was really hit with a Mars sized object that eventually became our moon, does that put the earth "behind" other earth like planets in the amount of time it would have taken the earth to restabilize and have the right conditions for life? In other words, if the Earth was never hit by the Mars sized object and conditions for life were still present, would the Earth have developed life millions if not billions of years sooner? So there is a chance could be millions of years behind other extraterrestrial civilizations.
My other question: If we assume the earth was hit by a Mars sized object, giving our oceans tides and our mantel stability, and if we also assume that the these factors speed up the evolutionary process, is it possible that we could be much more advanced than other alien civilizations?(assuming we all started at the same time). They could still be working on crawling out of the water.
Scary thought either way.
"To Err is Human To Forgive is Divine neither of which is Marine Corp Policy"-My SNCOIC
Tidal action certainly contributed to the evolution of aquatic creatures to land-based creatures, and without a large moon, tidal action is not as great. I didn't see this mentioned in the article. Am I overestimating lunar influence on tides?
Proverbs 21:19
First let me state that, to paraphrase an SMBC comic don't listen to people talking about something they are not an expert in.
Second, rarely do the "you can't have life/intelligent life because..." people have both a biology degree and an astrophysics degree. You need both to make those kind of comments.
Thirdly, we now just about jack-sh!t about the majority of the mass of the universe. Most mass is "dark matter", and of the stuff that isn't dark matter, most of it is in the objects we call black holes at the center of galaxies. So we have no freaking idea at all about whether the majority of the universe is capable of supporting life/friendly to it.
Fourth, to paraphrase a visually dramatic, but (aside from this quote), fairly innane movie "Life will find a way". The entire thing about life is that it adjusts ITSELF to the universe, not the other way around. We are a life form that likes 1 g, 1 atmosphere of pressure, etc. not because those conditions are helpful for life but instead because THAT is where we evolved. Yes, 100g and 100 atmosphere would be harder to create life in, evlove in, but at the same time, we cant survive in 4g, 10 atmospheres, but life can easily evolve to do so.
The best argument there is against intelligent life being wide spread is the lack of signs/contact. But that says nothing about unintelligent life, and assumes that life would use radio waves. It is as likely that other intelligent life forms are dark matter based - and never discovered radio - as it is for there to be no other intelligent life in the galaxy. Or simply that radio waves have disadvantages we don't know about. A quantum physics related random shifts in signal over long distances could obscure intelligent content, rendering radio waves indistinguishable from background radiation.
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Intelligent life may evolve differently, for example the dominant lifeform might be 3 legged with 2 heads and its brain in its belly.
Vulcan has no moon.
Search as I may... I can not find a detailed paper on this study.
The study as only been presented at various conferences and short abstracts made available.
My understanding is that large impacts late in formation are probably common (it probably happen to venus but hit the other way and slowed its rotatation right down).
Had the Earth moon collision occur differently, the earth and Theia merged but the same angular momentum resulted. Then the earth would still be spining fast enough (less than 12 hrs) to have a stable non chaotic spin axis. Whats more the spin and compersition of the earths core would have still have resulted in a strong magnetic field shielding us from loss of water to space.
That said
How common are Earth-Moon planetary systems?
see http://arxiv.org/abs/1105.4616
... is that a moon is required.
Back in 1985 I've done some "artificial evolution" simulations on a computer. What I learned is that if living conditions are good, then no evolution happens. It's when conditions are tough when evolution kicks in. But if conditions are "marginal" all the time, life will simply die out. What is needed are cycles. Good times are succeeded by bad times and vice versa.
And the good thing about earth is that we have lots and lots of cycles. Ripples on the oceans have a period of about 10Hz. Waves 1Hz to 0.1Hz. then there are cycles with higher and lower waves. Then there are the tides at every 12 hours. Then day-and-night at 24 hours. Then the moon at 28 days. Then seasons at once a year. Then the solar cycle at 11 years, and very likely the earth is also involved in larger cycles causing ice ages and things like that.
Life on earth with the dinosaurs and such was "stable". Nothing much changed. Only when a catastrophe hit, did things get moving again.
The evolutionary reason for this is that when a certain trait (gene) is 5% better for the individuals that carry it, the carriers will not overtake the whole population. Some percentage of the population will evolve to have the gene, but not all. This is essential for evolution: If this didn't happen, life would die out quickly. Some genes that carry an advantage have disadvantages as well. So a gene that helps individuals when it's rainy might prove fatal in a drought. So it is essential that the pool of genes remains large. Then when "bad times" arrive, some of the bad genes might prove fatal for the individuals carrying them. Population shrinks. Some lines will die out.
Once the good times are back, all remaining genes will multiply and a differently diverse population is ready for the next catastrophe.
In conclusion. No a moon is not necessary. However on earth it is responsible for two of our cycles that have pushed evolution forward. If a planet is to support life, it will have to have many cycles at many orders-of-magnitude, and if it doesn't have a moon it will most likely not have enough.
Life and no moon? Possible in theory, but very unlikely.
What I don't get is why we're excluding gas giants that we're finding in the habitable zones. If Jupiter were where Earth is in our system, Callisto would be a great candidate. Ditto Saturn/Titan and Neptune/Triton. In fact, a gas giant in the goldilocks zones should offer more chances at a habitable body; the moon simply has to be far away enough not to be toasted by the planet's magnetosphere.
I'm sure the scientists are aware of this, but why has this eluded the journalists informing the general public?