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How does gravity in space work?

  1. Sep 5, 2012 #1
    How does gravity in space work????

    I have an issue that woke me out of a good sleep. Newton and Einstein's theory's make complete since to me and i feel that's how everything should work(it should make sense). What absolutely makes no sense to me is "How Gravity In Space Works." The reason i'm having this problem is the fact that everything I come up with make no sense. Now add Newton and Einstein's theory's in your mind and take out all the planets, stars, and galaxies, and there would be nothing correct? SPACE IS NOTHING, BUT DUST PARTICLES FLOATING IN SPACE.
    (NOW LETS STOP RIGHT THERE)

    Gravity on earth makes sense to me, what goes up must come down, Rotation keeps us on the ground! Now in space nothing keeps us on the ground everything just floats around without gravity pulling things together and giving them direction.

    What I don't understand is how gravity pulls things together in space in the first place!(GOING BACK TO MY ORIGINAL QUESTION) BECAUSE THIS MAKE NO SENSE TO ME WHAT-SO-EVER! HOW CAN FLOATING DUST BECOME EVERYTHING. WHAT TELLS GRAVITY TO START WORKING AND HOW AND WHY ARE THERE DUST PARTICLES IN THE FIRST PLACE? PHYSICS TO ME IS MANAGED CHAOS, BUT THIS MAKES NO SENSE TO ME. GRAVITY ON EARTH MAKES COMPLETE SENSE, GRAVITY IN SPACE DOESN'T UNLESS EVERYTHING IN THE MULTI-VERSE IS ROTATING AND IF SPACE WAS EMPTY HOW DID THE DUST GET THERE TO BEGIN WITH? LIKE I SAID I WAS DREAMING AND THIS QUESTION CAME UP IN MY DREAM AND I COULDN'T MAKE SENSE OF IT AT ALL IT WOKE ME UP! BECAUSE IF I TAKE A BIG JUMP OFF THE MOON I WOULD JUST FLOAT AROUND TILL SOMETHING PULLED ME IN!

    SO I GUESS MY QUESTION IS, IF THERE IS NOTHING TO PULL FROM THE START HOW DID IT GET THERE? AND WHAT FORCE TELL GRAVITY NOT TO MIND ITS OWN BUSINESS? WHY DOESN'T SPACE REMAIN AN EMPTY VACUUM?
     
    Last edited: Sep 5, 2012
  2. jcsd
  3. Sep 5, 2012 #2
    Re: How does gravity in space work????

    Gravity acts between EVERYTHING in the universe. Even clouds of hydrogen "dust", as you put it, will slowly pull itself into a ball in the absence of any other force. These particles accumulate, growing bigger and bigger spheres of hydrogen gas, increasing the gravitational gradient and attracting more particles faster and faster until eventually, there is so much gravitational force and pressure at the center of this giant ball of hydrogen (and some other stuff) that nuclear fusion becomes possible. THAT is called a star. All stars form this way, more or less. All the hydrogen got there some time after the Big Bang when the universe cooled down enough, and lost enough energy density, to allow electrons to settle into orbits with protons, creating hydrogen atoms. Other light elements were also formed, such as Deuterium (Hydrogen + neutron) and Helium. Remember also that about 80% of the matter in the universe is Dark Matter, which gravitationally attracts itself as well as ordinary matter, so all that dark matter "dust" also helped speed along galaxy formation.
     
  4. Sep 5, 2012 #3

    Janus

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    Re: How does gravity in space work????

    Here's your problem. Rotation has nothing to do with gravity. What goes up would still come down even if the Earth were not rotating. Gravity is just due to the fact that everything with mass is attracted to everything else with mass.
     
  5. Sep 5, 2012 #4

    phinds

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    Re: How does gravity in space work????

    rondfromdale, a book that you might find interesting is "The First Three Minutes" by Weinberg
     
  6. Sep 5, 2012 #5
    Re: How does gravity in space work????

    Actually, rotation lifts us off the ground a little bit.
     
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