Life on earth

Discussion in 'Biology & Genetics' started by timojin, Sep 29, 2017.

  1. timojin Valued Senior Member

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  3. James R Just this guy, you know? Staff Member

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    Earth is about 4.5 billion years old.
     
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  5. timojin Valued Senior Member

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    Well since we are in the mood, is our milky way older the our earth or younger ?
     
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  7. Janus58 Valued Senior Member

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    Older. The Milky way is ~ 3 times older than the Earth. This makes sense as our Sun is a 2nd generation star in that, in part, it contains elements forged in at least one star that lived and exploded along before the Sun formed.
     
  8. spidergoat Valued Senior Member

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    Maybe before there was the Earth, there was a diffuse cloud of water, minerals, and gas where life could have arisen.
     
  9. Yazata Valued Senior Member

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    https://en.wikipedia.org/wiki/Earliest_known_life_forms

    Demonstrating that apparent signs of biological activity really are signs of biological activity isn't a for-sure thing. So the evidence for a very early appearance of life on Earth just a few hundred million years after the Earth first formed from planetesimals might be a little iffy.
     
  10. Counter Registered Senior Member

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    The current measurement of time is inadequate. Days is the Earth's rotation, years is the Earth travelling around Solaris. This is changes in space, not time...
     
  11. Janus58 Valued Senior Member

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    The scientific definitions of the day and year are no longer tied to the Earth's motion. Instead, they are defined as set multiples of the SI second, which itself is defined as the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom. A day is 86400 of these seconds, and the year is 365.25 of these days (this is known as the Julian year, which distinguishes it from the Tropical year on which we built our calendar around).
    It may seem ironic that the "year" used in astronomy is now divorced from the astronomical phenomenon which it was its origin, but a unit was needed that could be considered fixed in length and not variable.
     
  12. DaveC426913 Valued Senior Member

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    Our sun's name is simply Sol, a proper name, distinct from sol.
    It is also called Sun, also a proper name, distinct from sun, just like Moon is a proper name, distinct from moon.

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  13. timojin Valued Senior Member

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    So you are saying the clumping or gathering was before fragmentation ? I would suspect the formation of entity as galaxy would be after the initial force of fragmentation would subside or diminished and that gravitation would bring loose fragments together into entity .
     
  14. DaveC426913 Valued Senior Member

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    What is this 'fragmentation' you speak of?
     
  15. timojin Valued Senior Member

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    Don't you believe in the Big Bag ? If there is no big bang than everything would be in on lump, Or if you believe the universe is as it was , your choice, than all our present theory is hogwash
     
  16. Janus58 Valued Senior Member

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    Unevenness in the early universe led to collections of gases that coalesced together into what would become the galaxies. When they became dense enough, the first stars formed. The larger of these stars burned up their fuel and then exploded into Supernovae which forged the higher elements. These elements were scattered and mixed in with hydrogen that had yet to condense into stars. The stellar systems and stars that formed from this mixture are the second generation stars like our own. Individual star formation has continued since the early stars formed and continues to this day. The galaxy is filled with stars of various ages; some are quite young while others are quite old. The larger the star, the shorter its lifespan. Large stars burn out fast but small ones, like red dwarfs can live to be old enough to have lasted from the time of the early galaxy.
     
  17. James R Just this guy, you know? Staff Member

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    I believe in the Big Bag!

    (Sorry, couldn't resist. Please continue.)
     
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  18. DaveC426913 Valued Senior Member

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    So, by fragmentation, you mean Big Bang. That's not word that's ever been used in association with the Big Bang.

    As for galaxy formation, it didn't occur until a billion years later.
    https://en.wikipedia.org/wiki/Chronology_of_the_universe
     
  19. timojin Valued Senior Member

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    I can't resist either, please explain to me. To be a Big Bang in the beginning what happen, was there any material , solid liquid or gas ? Even if you tell me Plasma , so how long it had to be , before something had to happen , and than what initiate the plasma ? My ears are open.
     
  20. timojin Valued Senior Member

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    Tell me what you know , I have wiki in my computer
     
  21. Gawdzilla Sama Registered Member

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    Just curious, are you looking for ways to disprove the Big Bang?
     
  22. DaveC426913 Valued Senior Member

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    I think you have not read it. You should, so at least the questions you ask are informed.

    For example, you might consider leveraging it to use common terminology, so we don't have to ask you what you mean by words you insert.
     
  23. James R Just this guy, you know? Staff Member

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    timojin:

    There was a very hot, dense soup of quarks and gluons and photons and other fundamental particles. Call it a plasma if you like.

    It didn't take very long at all - a tiny tiny fraction of a second - before the universe started to expand. Initially it seems there was a period of very rapid expansion - almost like anti-gravity pushing things apart. This is called the inflationary period. The universe increased in size exponentially for a short while. This was long before atoms formed or the universe became transparent to light.
     

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