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Dark Energy

  1. Jun 11, 2010 #1
    Can dark energy be the fifth force?
    We know 4 fundamental forces (3 if you don't take gravity), electromagnetism, gravity, strong and weak nuclear force. So can Dark Energy be the fifth force. All we know about dark energy is that it accelerates the expanding universe and it works on larger scales. Not in solar systems, galaxies or galaxy clusters but further away.
    I don't know the math in it but take the other forces for example:
    -Strong Force dominates on small scales
    -Electromagnetic force is stronger at a bit bigger range then the Strong Force
    -Gravity is stronger then Electromagnetism on larger scales
    -Dark Energy could be stronger on even larger scales then Gravity
    Is this possible?
  2. jcsd
  3. Jun 11, 2010 #2


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    Science Advisor

    No. Dark energy causes the universe to expand (at an accelerating rate) as a result of its odd gravitational properties. One way to think of it is that dark energy is gravitationally repulsive, in contrast to 'ordinary' matter/energy, which is gravitationally attractive.

    So, dark energy is a form of matter/energy -- ie it belongs on the RHS of Einstein's Equations. It creates a gravitational force (LHS of Einstein's Equations) that causes the universe to accelerate.
  4. Jun 14, 2010 #3
    How is dark energy distiquishable from time? If events from a billion years ago are a billion lightyears away, hasn't the passage of time expanded create space?
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