Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Empty Space

  1. Jun 30, 2009 #1
    According to science space time matter and energy all coexist, so when you talk about empty space, or the vacuum of empty space, I assume you talk about space without matter. How can this be?!!?!?! Would this be a different type of space beyond our normal comprehension, something beyond spacetime?
     
  2. jcsd
  3. Jul 1, 2009 #2
    There is only spacetime and energy. Matter is a form of energy.

    Empty space is a volume of spacetime that does not contain any energy and hence no matter.
     
  4. Jul 1, 2009 #3

    DrChinese

    User Avatar
    Science Advisor
    Gold Member

    Generally, in quantum field theory, a vacuum is considered the lowest energy point you can have for a volume. However, it is not zero. Try looking at the wiki on:

    Zero-point energy
     
  5. Jul 1, 2009 #4
    In everyday use, "empty space" or the "vacuum of space" are misnomers often meaning space without visible matter, such are particles or planets. But as noted above, one characteristic of "empty" space is that in it resides vacuum fluctuations which routinely produce particle and antiparticle pairs.

    Furthermore, in an otherwise "empty" volume of space, spacetime actually curves and deforms as the gravitational influences pass through. Spacetime IS something, although we don't quite know what, any more than we really know what matter or energy are.

    It is believed that matter, energy,and space time evolved together at the beginning of the universe and most likely are different forms of some single unified entity which appear so different to us today. One example of how space and time might relate is inside a black hole where mathematics shows space and time can interchange with each other, that is space becomes time and time becomes distance, suggesting a deep but as yet unknown commonality.
     
  6. Jul 1, 2009 #5
    In QM everything is made up of force waves, waves of energy, flipping bits, whatever you want to call it.

    Matter is the superposition of multiple waves. So empty space might be something like an area where the superposition of all the energy waves at that location exactly cancel themselves out. I think this is what QM is trying to state when talking about quantum fluctuations in vacuum or quantum foam.
     
    Last edited: Jul 1, 2009
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook