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Does energy have gravity?

  1. Jan 10, 2014 #1
    I'm thinking about an explanation of what dark matter is. Would it make sense to say that energy has gravity?

    For example when a galaxy was formed after the Big Bang a big amount of energy was converted into matter but an even greater amount of energy could have never been converted into mass so it ends up surrounding the galaxy.

    So if all that energy has gravity wouldn't that stick to the description of dark matter? (surrounds galaxies, it's invisible and has a gravitational effect on the galaxy).

    You could think of energy as potential or virtual matter, where certain amount of energy floating in the space represents a certain amount of mass (that is already proven to be made of energy).

    It's like a dismantled atom but in certain conditions an spectator could feel its effect as a real atom.
  2. jcsd
  3. Jan 10, 2014 #2


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    You can't just say that something is energy without describing in what FORM is this energy!

    A lot of the so-called "pure" energy is in the form of photons/electromagnetic radiation. If this is what you are claiming, then we can already rule this out easily. Such energy can and should have been detected. Yet, we know that one of the properties of dark matter that we have learned so far is that it emits no such radiation!

    I would suggest that before you try to offer a suggestion, you need to look at all the properties of dark matter that we already know of as of this moment. Or else, you will come up with something that can already be contradicted by what we have, or have not observed.

  4. Jan 12, 2014 #3


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    To bounce off of ZapperZ's post, I'd just like to make sure you understand that there is no such thing as "pure energy" like you've seen in movies, books, cartoons, etc. The energy must be in some sort of "form". AKA there must be some object or process that has energy, such as a bullet having kinetic energy or an electromagnetic wave carrying energy from one place to another.
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