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Thread: Aliens

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    Aliens

    Humans eat matter (meat & vegetables, etc.) to convert to energy and sustain life.
    Is it possible that Aliens consume energy directly so sustain life?

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    Quote Originally Posted by bodiebill View Post
    Humans eat matter (meat & vegetables, etc.) to convert to energy and sustain life.
    Is it possible that Aliens consume energy directly so sustain life?
    Many species on Earth already do this - plants and some other photosynthetic species. Of course, they need matter too, but they can convert it into chemicals to store energy. Photosynthetic aliens would likely be sedentary like Earth plants and for the same reason - low energy density - unless they are something really exotic that can live on a Mercury-like world. Lots of energy there!

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    There's certain bacteria that can get energy from electrical sources. Shewanella and Geobacter, both anaerobic species that thrive in anoxic environments. But they do require sulfur and/or metals to do so.
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

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    Unless the aliens can convert the energy into matter, or don't suffer any material degregation then they will require matter in some form.

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    Right. Any system will have some losses.
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

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    Don't you think that there are some "aliens" who are excatly like humans? With the same needs: air, water, food, etc. As we have already found out - there are exoplanets which can possibly support life as we know it. Why then we can't suggest that somewhere there is Earth 2?

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    Quote Originally Posted by CharlotteBridge View Post
    Don't you think that there are some "aliens" who are excatly like humans? With the same needs: air, water, food, etc. As we have already found out - there are exoplanets which can possibly support life as we know it. Why then we can't suggest that somewhere there is Earth 2?
    Given the immense varieties of form and function that even our own one planet has produced, why would aliens be like us? Evolution has a random component to it. I can imagine that alien intelligence might exist, but not that they'd be close to humans with our very specific path of development.

    However, the Universe is huge, there might be room for similarities, if not exact copies of our life. But by the same token, it's a very big Universe; the odds of similar beings close enough to ever meet us... not too likely.
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

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    Quote Originally Posted by CharlotteBridge View Post
    Don't you think that there are some "aliens" who are excatly like humans? With the same needs: air, water, food, etc. As we have already found out - there are exoplanets which can possibly support life as we know it. Why then we can't suggest that somewhere there is Earth 2?
    Earth 2 must be a possibility with humans 2 too, but meeting them? Very unlikely to.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

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    Quote Originally Posted by CharlotteBridge View Post
    Don't you think that there are some "aliens" who are excatly like humans? With the same needs: air, water, food, etc. As we have already found out - there are exoplanets which can possibly support life as we know it. Why then we can't suggest that somewhere there is Earth 2?
    There is a possibility that the entirety of the universe is infinite. If that is the case then there could be infinite Earth duplicates, but they would likely be so far away it would be literally impossible to reach them. I would be very surprised if there were an Earth 2 anywhere near us. Also, I don’t want to assume how likely it is that life exists elsewhere.

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    Max Tegmark calculated that the closest world with an exact copy of you is about 1010000000000000000000000000000 metres away. Note that the edge of the observable universe is only 1026 metres away, so this hypothetical clone world is far outside the part of the universe we have access to.

    -------
    Concerning aliens which consume 'energy'; if you mean electromagnetic radiation, then that's what plants consume. There may well be intelligent plants out there, although the path of evolution leading to such a thing would be interesting.

    But if you mean electricity, then there may be aliens up there which are some kind of robot, or some kind of computer, or a mixture between the two; indeed, some people have speculated that robots are the next stage of evolution. But even artificial robot aliens would also need resources made of matter in order to repair themselves, because their bodies will be subject to wear and tear, just like everyone else's.

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    Quote Originally Posted by CharlotteBridge View Post
    Don't you think that there are some "aliens" who are excatly like humans? With the same needs: air, water, food, etc. As we have already found out - there are exoplanets which can possibly support life as we know it. Why then we can't suggest that somewhere there is Earth 2?
    While there are some scientists who think it highly likely that intelligent aliens may look like humans and there are some pundits who seem to think they'll need similar metabolism, I suspect that aliens "excatly [sic] like humans" are extremely unlikely. I have not seen a really cogent argument that the human bauplan is either a theoretical optimum or physically inevitable.

    Aliens that need air, food, and water similarly to humans? Many organisms are heterotrophs, which means they need to get their organic carbon from other organisms (humans are heterotrophs; so are all animals and fungi and some plants). Most plants and many unicellular organisms are autotrophs, which means they get the carbon they need from inorganic sources, like carbon dioxide.

    That aliens need air, food, and water doesn't imply that they can use the same food. I can also conceive of aliens that don't use water (there are quite a few simple polar solvents, such as ammonia, hydrogen cyanide, and formamide that could serve the role of water; non-polar solvents may also be possible, but there is some research which indicates that cell membranes may not be able to be formed in a non-polar solvent)
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    Quote Originally Posted by CharlotteBridge View Post
    Don't you think that there are some "aliens" who are excatly like humans? With the same needs: air, water, food, etc. As we have already found out - there are exoplanets which can possibly support life as we know it. Why then we can't suggest that somewhere there is Earth 2?
    While there are some scientists who think it highly likely that intelligent aliens may look like humans and there are some pundits who seem to think they'll need similar metabolism, I suspect that aliens "excatly [sic] like humans" are extremely unlikely. I have not seen a really cogent argument that the human bauplan is either a theoretical optimum or physically inevitable.

    Aliens that need air, food, and water similarly to humans? Many organisms are heterotrophs, which means they need to get their organic carbon from other organisms (humans are heterotrophs; so are all animals and fungi and some plants). Most plants and many unicellular organisms are autotrophs, which means they get the carbon they need from inorganic sources, like carbon dioxide.

    That aliens need air, food, and water doesn't imply that they can use the same food. I can also conceive of aliens that don't use water (there are quite a few simple polar solvents, such as ammonia, hydrogen cyanide, and formamide that could serve the role of water; non-polar solvents may also be possible, but there is some research which indicates that cell membranes may not be able to be formed in a non-polar solvent)
    Information about American English usage here. Floating point issues? Please read this before posting.

    How do things fly? This explains it all.

    Actually they can't: "Heavier-than-air flying machines are impossible." - Lord Kelvin, president, Royal Society, 1895.



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    I dreamed I saw an alien world,
    Brought closer as the spacetime curled,
    And as the alien clouds drew near,
    I heard a whisper in my ear.
    “Ho hum, to tum” the voices swirled,
    Just then the twisted scene unfurled,
    In life I know there is no hope,
    To do the same with telescope.
    But if I eat the same blue cheese,
    I just might go there again with ease.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

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    Quote Originally Posted by CharlotteBridge View Post
    Don't you think that there are some "aliens" who are excatly like humans? With the same needs: air, water, food, etc. As we have already found out - there are exoplanets which can possibly support life as we know it. Why then we can't suggest that somewhere there is Earth 2?
    This is pretty popular with the sci-fi writers especially with the idea of multiple universes.

    What do you mean by exactly like? I would interpret that as meaning identical. This, as others have mentioned, would be highly unlikely. as Noclevername says, you only have to look at the diversity of life forms here on Earth whom share a common environment. Even in the vastness of the observable universe for "humans" to have developed on exo planets would be an extremely long shot.

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    Okay, let's start with what kind of aliens we are taking for this question, because an alien can be just a person from the other end of space, a planet, etc. This means that he eats as we do, in general, if you do not take into account spices and taste preferences. Well, if you take the aliens, as they are shown to us in films, big heads, long arms, etc. then I think that their food can be so different that it is impossible to count or even imagine it, but I think there is about one way, refuel yourself and get energy.

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    Are we defining "food" as the energy source or simply as a catalyst for energy gathering? Because life forms exist that use materials simply to help them absorb energy or to grow. If we're using the former definition then no, they don't "eat", although they still need to intake matter to live.
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

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