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B Potential Organism Sustaining Planets

  1. Mar 19, 2016 #1
    Hi there. So it seems there are multiple reasons for why our galaxy will come to an end. A potential cause is that a black hole will engulf our sun. Let's say that in another galaxy a star is born. There is a chance that a nearby planet will have the potential for sustaining organisms. How exciting if this is the case.

    It seems that for this to happen the planet should be very similar to earth. It should have an atmosphere with gases carbon and oxygen and hydrogen. And probably most of the other gases on our periodic table. this probably means that the life forms that would develop would probably be similar to Earth's? Would any planet that would sustain organisms probably be very similar to earth? Is there a very unique set of conditions required to sustain organisms basically? is there a very unique cycle of evolution of organisms?
  2. jcsd
  3. Mar 19, 2016 #2
    Sorry. I am just a beginner when it comes to astronomy. Not very knowledgable on this subject. In highschool I attend a summer seminar on astronomy. These are some of the subjects discussed. So these questions just come up out of curiosity. There is no purpose in discussing astronomy with me. I am just curious. Hope you are having a good day.
  4. Mar 19, 2016 #3


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    Nonsense. There is every reason to discuss astronomy with you. :wink:

    It is very difficult to make predictions about extraterrestrial life since we haven never discovered any. It may be the case that extraterrestrial life is very similar to life here on Earth, but it could also be the case that extraterrestrial life is very, very different than anything we've ever seen or dreamed of.

    That being said, the fact that we know that life here on Earth is based heavily on specific chemical reactions and interactions between carbon, oxygen, hydrogen, and other elements, all within water, encourages us to look for those substances when looking for life.

    As for the path that evolution takes, it is extremely unlikely that extraterrestrial life would develop the same specific species as Earth, but there could be broad similarities. We just don't know.

    For more information I recommend the wikipedia page on extraterrestrial life and the links within: https://en.wikipedia.org/wiki/Extraterrestrial_life
  5. May 2, 2016 #4

    Hi there. This is so thoughtful. It satiates the curiosity leading me to post this. Lots of love to Drakith. Hope he is having a great night.
  6. May 3, 2016 #5
    Observations suggest that our galaxy will 'end' with a merging of it and the Andromeda galaxy in around 4 billion years.
    The result will be one much bigger galaxy, but some stars and other material could be ejected during the process.
    Both galaxies have central black holes that ultimately will probably merge, but in general collisions of stars and other objects are not very likely - there is a lot of space in between stars.
    It won't much affect the solar system because by this time the Sun will be in it's final stages anyway, a bloated red giant soon to fade away as a white dwarf.
    There won't be life on Earth any more, then Sun will fill half the sky and all the oceans will have evaporated, it's even possible that the Sun will bloat enough to absorb the Earth completely.
    Earth based life maybe could relocate before that happens though.

    On your more general question about life arising independently of Earth based life, that is one of the very big open questions in science.
    All that can be said is that so far there have been no signs of life anywhere else, yet the basic chemical building blocks for life are abundant - water, hydrocarbons, even amino acids (which make proteins) have been detected in space.
    Personally I would bet that life in some form is not unique to Earth, we just didn't find any yet.
    Last edited: May 3, 2016
  7. May 3, 2016 #6
    There is no reason to suspect that life can't exist in other more exotic ways. Life requires building blocks to create and maintain itself, energy to manipulate those blocks, and a medium to do those reactions. That's it.

    Building blocks are easy: It's got to be either carbon or silicon. Life is complex and requires long chains of information, the only way to do that is with a long, complex molecule and carbon and silicon are the only atoms that can bond to 4 other atoms and exist in great quantity. On earth, all life uses carbon. Carbon exists is large quantities on every planet in the solar system and throughout deep space.

    Energy is a little trickier, it can either come from the star, or from within the planet. On earth, most energy used by life comes from the sun, which gets stored in molecules like sugar. Sugar is not the only effective way to store energy: acetylene would work just fine too. Jupiter imparts a lot of energy into it's moons via gravitational tides, that's why they are so interesting.

    Medium just needs to be some liquid that chemical reactions can take place without affecting the reactions themselves. Water is very very good at this because it's not completely neutral, it will tear apart molecules given enough time. Liquid methane could easily perform the same job, as could liquid nitrogen, however that makes it harder because at the energy levels required to have liquid nitrogen, you probably won't have enough energy left over to preform organic chemistry.

    We like earth-like life because we're 100% certain that it can exist: we are it. The rest is just theoretically possible, but without any evidence. That's why Mars, Europa, Encelidus are so interesting. However, you'll also hear discussion of Saturn's moon Titan. The chemical soup of theoretical life is there, but if it is, it's chemical makeup is completely alien.
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