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B Birth of the earth

  1. Jan 2, 2016 #1
    Actually I would like to start with the big bang theory which tells us the age of our universe and cosmos. Literally cosmos doesn't mean only the space around us but also the life present around us. So what big bang tells us is that the universe was a small atom which exploded and started to expand and contrast becoming the very known universe today. When the atom blasted the small particles got projected to the outer space which later formed stars and galaxies. But the most important question is what was there before the big bang? Was there another universe already? This is a puzzling question. As Stephen Hawking said our universe is still expanding and contrasting. By the way there are many other theories other than the big bang like the string theory or the dark matter theory which was told by the MIT that the universe is made up of dark matter it did not undergo big bang. But it is still under talks. Like this our galaxy and our solar system was formed. So our earth and its neighbouring planets was formed by the constant collision of the asteroids and then it formed a huge ball of stone which was hot and full of volcanoes and stuff.
    So why does our earth rotate? The answer is that when the asteroids came together they were rotating in high speed which due to law of inertia it still rotates now. After millions of years of cooling and condensing our earth was formed.
  2. jcsd
  3. Jan 2, 2016 #2


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    Most of your post is based on serious misconceptions about various aspects of cosmology. I'll address some:

    No, it absolutely does NOT tell us that the universe was "a small atom". The size of the universe at the beginning of the big bang (AFTER the singularity) is unknown. It might have been infinite, but any any case was not the size of an atom. What likely was the size of an atom was not the universe, but that portion of universe which we call the Observable Universe.

    This is probably the most common misconception in cosmology, due to popular science shows ALWAYS presenting it in that completely incorrect fashion. The big bang was not an explosion and did not take place at a point in space. It was an expansion of the universe (of unknown extent) from a hot dense plasma, to what we have today.

    Good question. Find the answer and I guarantee you a Nobel Prize.

    yes, it is expanding, but I have no idea what you mean by "contrasting"

    This is totally garbled and makes no sense. String Theory and dark matter have nothing to do with the big bang

    No, they were NOT "rotating in high speed". In fact, it is possible that the rocky chunks that came together were in fact not rotating at all. They simply came together at an angle and the total angular momentum caused an increase in rotational speed of the resulting body, exactly like what happens when a skater spins with arms outstretched and then spins faster when the arms are brought in tightly to the body.
  4. Jan 2, 2016 #3
    Okay, let's just take this one piece by piece.

    The time between when the big bang happened and when the Earth formed is almost twice as long as the time between now and when the Earth formed. While they both ultimately appeal to that "why are we here?" itch, they are completely separate considerations.

    It's also not where we get the age of the universe from.

    Sure, if we take "cosmos" in its literal meaning, meaning "the natural world taken as an orderly system", then yes, but there's no need to point this part out. Biology is a part of the universe, but you don't need to appeal to cosmology when mentioning biology:


    It wasn't an "atom" and it didn't "explode".

    The outer space wasn't there yet. The big bang happened everywhere in the universe at once.

    That's like asking about what's north of the North Pole. It's not really a meaningful question because as far as we can tell time and space didn't exist before then, so no hypothesis about what happened "before" the big bang can be scientifically testable, and I don't see that changing for a long time, if ever.

    Not contracting yet, and a lot of scientists have said this.

    Theories about the nature of dark matter and string theory do not conflict with the fact that the big bang occurred. The amount of dark matter in the universe compared to the amount of energy in the universe does reveal some important things about the future evolution of the universe and about what exactly happened during the big bang, but not whether or not it happened, or what happened before it.

    Of course it's still being talked about, because scientists talk about those things. That's their job.

    Again, completely separate considerations. The formation of the Milky Way galaxy was a separate process from the formation of the Solar System, which was a separate process from the big bang, which had nothing to do with the formation of the Earth and the origin of life on Earth.

    It was more like it accreted out of dust and small pieces of rock, along with the occasional asteroid. But yes, this is more or less a qualitative picture of what happened.

    Technical term :P

    What a day for "let me Google that for you" to be down, because this is the perfect place for it. Really, you should have Googled this, there are resources explaining this in great detail that are accessible to all skill levels. Try this one: https://www.khanacademy.org/science...history-life-earth-tutorial/v/earth-formation

    When you strike something at an angle relative to the line between the striking particle and the center of mass of the target, the target object will rotate. It's not that the Earth inherited the angular momentum of the particles it formed out of, but because it formed out of an accretion disk where all of the particles that were pulled together were moving at angles relative to the center of mass of the accretion disk.
  5. Jan 2, 2016 #4


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  6. Jan 2, 2016 #5


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    Welcome to the PF, @Yashas CS -- please check your personal messages. :smile:
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