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One of the so called "Great Filters" is our Moon. It is providing Earth's metal core with constant moving force and refreshing the dynamo and keeping our atmosp

One of the so called "Great Filters" is our Moon. It is providing Earth's metal core with constant moving force and refreshing the dynamo and keeping our atmosphere and water not blown away by solar winds. Since the size of Earths satellite is far from ordinary, this instantly reduces chance of advanced life appearing elsewhere. And if the theory of the source of Moon is right, it formed after collision with object of a size of Earth, the filter is restricted by star systems with the planets within a certain range that had a collision with other planet in a way that left long lasting big object rotating around that planet and generating magnetic field preventing water and atmosphere from escaping. So just by applying only this "Moon filter", reduces the chances of advanced life in our own Milky Way to probably just few cases in whole galaxy. And add the probability of intelligent beings appearing on random planet that has life, it starts to seem pretty realistic that we are only ones not only in Milky Way, but also surrounding galaxies. The conclusion is we better start working on colonization techniques, because chances are that the future of life in our galaxy is in our hands.

givan 12y ago
We have bacteria that live inside volcanoes or on the bottom of the ocean in extreme conditions, life adapts, without the moon life would only look differently there is no proof that without the moon life on earth would not be possible, looking at life in the universe from a human environment point of view is flawed.
- minikites 12y ago
  But we only see complex life in a narrower range of much milder conditions. I bet there's lots of space microbes but I agree with the parent to this comment that complex, intelligent life is probably pretty rare.
  - givan 12y ago
    Milder conditions relative to our environment? this is subjective, where do you see complex life and how do you know that complex life requires "milder" conditions or that is rare if we only have ourselves as an example that happen to live in such an environment? What stops bacteria that live in harsh environments to evolve even if probably slower? harsh meaning hard/impossible for ourselves or for life as we know on earth.
    - minikites 12y ago
      So where is everyone? http://waitbutwhy.com/2014/05/fermi-paradox.html http://waitbutwhy.com/2014/05/fermi-paradox.html > That would mean there were 10 quadrillion, or 10 million billion intelligent civilizations in the observable universe. >Our sun is relatively young in the lifespan of the universe. There are far older stars with far older Earth-like planets, which should in theory mean civilizations far more advanced than our own. I think intelligent life is pretty special/rare, given the evidence.
      - givan 12y ago
        What evidence? we don't have enough data to draw conclusions on this matter, we barely sent a very limited robot on mars and some probes in the solar system, the universe is huge. We can't initiate contact because of primitive technology, we barely made it to the moon with huge costs. Why aren't advanced civilizations that can reach us contact us? we don't know, there are many theories http://en.wikipedia.org/wiki/Fermi_paradox#Explaining_the_paradox_hypothetically http://en.wikipedia.org/wiki/Fermi_paradox#Explaining_the_pa... http://en.wikipedia.org/wiki/Zoo_hypothesis http://en.wikipedia.org/wiki/Zoo_hypothesis
        minikites 12y ago
        Exactly, believing in God has about the same scientific support. I wonder how many people don't believe in God but do believe there is advanced, intelligent life that choose not to contact us and how they reconcile that set of beliefs.
        givan 12y ago
        I think it's quite the opposite, believing we are alone in the universe just because we don't have the capability to explore and detect life for me it looks the same as the belief people had a few hundred years ago that the sun orbits around the earth and we are the center of the universe.
        deleted 12y ago
        [deleted]
Udo 12y ago
Earth's magnetic field is not powered by the moon. As far as we currently know, the dynamo effect is caused by the action of molten material against a rotating solid inner core. It's true that our magnetosphere keeps the atmosphere in, but having a magnetic field is far from uncommon or unexpected for a planet of Earth's size and composition. In fact, Mars - a planet lacking powerful moons - once had a magnetic field just like ours. The problem here is the size of the planet was not sufficient to keep enough heat inside for as long as ours has. You might be conflating this with the theory that the Moon stabilizes the Earth's rotational axis and prevents it from wobbling too strongly, which would cause unpredictable summers and winters, kind of like the ones described in A Song of Ice and Fire. Yes, the Earth-Moon system probably has some uncommon features, but let's not make the mistake to postulate that a world has to be precisely like Earth in order to support intelligent life. It's not at all obvious that our ecosystem represents the only possible solution for an environment that can produce intelligence. All we know is it is one solution. > The conclusion is we better start working on colonization techniques, because chances are that the future of life in our galaxy is in our hands. I agree!
- dredmorbius 12y ago
  "Mars - a planet lacking powerful moons - once had a magnetic field just like ours." I think the salient point here is "once had". The Earths' core remains molten. Some of that is latent heat of formation, some nuclear decay, some tidal stresses. I don't know the contributions of each. Contribution from Earth-Moon tidal stresses isn't insignificant though. We _do_ know that tidal stresses can be hugely significant -- Io and Europa are thought to be heated (to differing degrees) by the stresses of orbiting Jupiter. Also one of Saturn's moons, Enceladus, which shows signs of volcanism with ice plumes. The thought occurs to me that moons of a large gas planet could also harbor formation of life, though they'd have to be rather closer to their parent star than the Solar System's giants are.
  - Udo 12y ago
    Heat from radioactive decay and primordial heat are each thought to be about half Earth's internal energy budget - tidal forces from the Moon, even though they're strong enough the change the elevation of the surface by up to half a meter, do not factor in at a significant ratio as far as I know. Of course I'm only talking about the Earth-Moon system and the claim that without the Moon we would not have any atmosphere or magnetosphere. > moons of a large gas planet could also harbor formation of life Indeed, and the fact that there are at least two ways to convey energy to an ecosystem should increase the prevalence of life in general. Moons are an excellent spot for life, in some ways maybe even better than planets. They are more numerous, they can be cozy even outside of the Goldilocks zone, to some degree they can be protected by the magnetic field of their gas giant, they are never tidally locked to the star, and they might have a better chance for volatile chemicals on the surface than your average rocky planet. Since the thread was originally about the Fermi paradox though, one has to wonder about the likelihood for bearing technological civilizations. How fruitful are ocean worlds for bringing forth tool users? Intelligence may in fact be common, but how conducive is this environment to science and engineering? We don't know. > though they'd have to be rather closer to their parent star than the Solar System's giants are If they're experiencing enough tidal stress, such as Europa is, they don't have to be close to the star at all.
dredmorbius 12y ago
NB: The collision genesis theory ("GIH" or Giant Impact Hypothesis) of the Moon's origin involves a body about the size of Mars, referred to as "Theia". http://en.wikipedia.org/wiki/Origin_of_the_Moon http://en.wikipedia.org/wiki/Origin_of_the_Moon http://www.nasa.gov/topics/solarsystem/features/moon_formation.html http://www.nasa.gov/topics/solarsystem/features/moon_formati... Otherwise, yes.

givan 12y ago

We have bacteria that live inside volcanoes or on the bottom of the ocean in extreme conditions, life adapts, without the moon life would only look differently there is no proof that without the moon life on earth would not be possible, looking at life in the universe from a human environment point of view is flawed.

minikites 12y ago
But we only see complex life in a narrower range of much milder conditions. I bet there's lots of space microbes but I agree with the parent to this comment that complex, intelligent life is probably pretty rare.
- givan 12y ago
  Milder conditions relative to our environment? this is subjective, where do you see complex life and how do you know that complex life requires "milder" conditions or that is rare if we only have ourselves as an example that happen to live in such an environment? What stops bacteria that live in harsh environments to evolve even if probably slower? harsh meaning hard/impossible for ourselves or for life as we know on earth.
  - minikites 12y ago
    So where is everyone? http://waitbutwhy.com/2014/05/fermi-paradox.html http://waitbutwhy.com/2014/05/fermi-paradox.html > That would mean there were 10 quadrillion, or 10 million billion intelligent civilizations in the observable universe. >Our sun is relatively young in the lifespan of the universe. There are far older stars with far older Earth-like planets, which should in theory mean civilizations far more advanced than our own. I think intelligent life is pretty special/rare, given the evidence.
    - givan 12y ago
      What evidence? we don't have enough data to draw conclusions on this matter, we barely sent a very limited robot on mars and some probes in the solar system, the universe is huge. We can't initiate contact because of primitive technology, we barely made it to the moon with huge costs. Why aren't advanced civilizations that can reach us contact us? we don't know, there are many theories http://en.wikipedia.org/wiki/Fermi_paradox#Explaining_the_paradox_hypothetically http://en.wikipedia.org/wiki/Fermi_paradox#Explaining_the_pa... http://en.wikipedia.org/wiki/Zoo_hypothesis http://en.wikipedia.org/wiki/Zoo_hypothesis
      - minikites 12y ago
        Exactly, believing in God has about the same scientific support. I wonder how many people don't believe in God but do believe there is advanced, intelligent life that choose not to contact us and how they reconcile that set of beliefs.
        givan 12y ago
        I think it's quite the opposite, believing we are alone in the universe just because we don't have the capability to explore and detect life for me it looks the same as the belief people had a few hundred years ago that the sun orbits around the earth and we are the center of the universe.
      - deleted 12y ago
        [deleted]

Udo 12y ago

Earth's magnetic field is not powered by the moon. As far as we currently know, the dynamo effect is caused by the action of molten material against a rotating solid inner core. It's true that our magnetosphere keeps the atmosphere in, but having a magnetic field is far from uncommon or unexpected for a planet of Earth's size and composition. In fact, Mars - a planet lacking powerful moons - once had a magnetic field just like ours. The problem here is the size of the planet was not sufficient to keep enough heat inside for as long as ours has. You might be conflating this with the theory that the Moon stabilizes the Earth's rotational axis and prevents it from wobbling too strongly, which would cause unpredictable summers and winters, kind of like the ones described in A Song of Ice and Fire. Yes, the Earth-Moon system probably has some uncommon features, but let's not make the mistake to postulate that a world has to be precisely like Earth in order to support intelligent life. It's not at all obvious that our ecosystem represents the only possible solution for an environment that can produce intelligence. All we know is it is one solution. > The conclusion is we better start working on colonization techniques, because chances are that the future of life in our galaxy is in our hands. I agree!

dredmorbius 12y ago
"Mars - a planet lacking powerful moons - once had a magnetic field just like ours." I think the salient point here is "once had". The Earths' core remains molten. Some of that is latent heat of formation, some nuclear decay, some tidal stresses. I don't know the contributions of each. Contribution from Earth-Moon tidal stresses isn't insignificant though. We _do_ know that tidal stresses can be hugely significant -- Io and Europa are thought to be heated (to differing degrees) by the stresses of orbiting Jupiter. Also one of Saturn's moons, Enceladus, which shows signs of volcanism with ice plumes. The thought occurs to me that moons of a large gas planet could also harbor formation of life, though they'd have to be rather closer to their parent star than the Solar System's giants are.
- Udo 12y ago
  Heat from radioactive decay and primordial heat are each thought to be about half Earth's internal energy budget - tidal forces from the Moon, even though they're strong enough the change the elevation of the surface by up to half a meter, do not factor in at a significant ratio as far as I know. Of course I'm only talking about the Earth-Moon system and the claim that without the Moon we would not have any atmosphere or magnetosphere. > moons of a large gas planet could also harbor formation of life Indeed, and the fact that there are at least two ways to convey energy to an ecosystem should increase the prevalence of life in general. Moons are an excellent spot for life, in some ways maybe even better than planets. They are more numerous, they can be cozy even outside of the Goldilocks zone, to some degree they can be protected by the magnetic field of their gas giant, they are never tidally locked to the star, and they might have a better chance for volatile chemicals on the surface than your average rocky planet. Since the thread was originally about the Fermi paradox though, one has to wonder about the likelihood for bearing technological civilizations. How fruitful are ocean worlds for bringing forth tool users? Intelligence may in fact be common, but how conducive is this environment to science and engineering? We don't know. > though they'd have to be rather closer to their parent star than the Solar System's giants are If they're experiencing enough tidal stress, such as Europa is, they don't have to be close to the star at all.

dredmorbius 12y ago

NB: The collision genesis theory ("GIH" or Giant Impact Hypothesis) of the Moon's origin involves a body about the size of Mars, referred to as "Theia". http://en.wikipedia.org/wiki/Origin_of_the_Moon http://en.wikipedia.org/wiki/Origin_of_the_Moon http://www.nasa.gov/topics/solarsystem/features/moon_formation.html http://www.nasa.gov/topics/solarsystem/features/moon_formati... Otherwise, yes.