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

Energy in relation to space and time

  1. Jan 3, 2008 #1
    I'm curious if space and time need to exist for energy to exist? I've tried looking everywhere to see if someone has commented on this idea, but I can't seem to get a straight answer. Any help would be appreciated...

  2. jcsd
  3. Jan 3, 2008 #2


    Staff: Mentor

    Energy is the capacity to do work and work is force times distance. I don't see how you could have forces without space and time nor how you could have distances without space. Frankly, I don't know of any physics concept that makes sense without space and time.
    Last edited: Jan 3, 2008
  4. Jan 3, 2008 #3
    Here's what I was thinking and excuse my lack of physics knowledge.

    A Neutrino is a just energy in motion, which is a particle but it is just moving at the speed of light and it has no mass. In this scenario, if something has no mass, does it need to exist in a space? Considering my relativity to the neutrino that is traveling at the speed of light, wouldn't traveling at the speed of light be the equivalent to time standing still? Thus something like energy (if I define it as a Neutrino) doesn't need space or time to exist? Or am I missing something?

  5. Jan 4, 2008 #4
    Maybe energy is the wrong word that I am using. I am trying to understand if something needs to exist in space and time. From what I gathered, the only thing that can go at the speed of light, is light. Apparently there was some new findings that Neutrinos actually have mass, as small as it may be.

    To answer whether light needs to have space or time, I found this site:
    http://people.cornell.edu/pages/jag8/lightfield.html [Broken]

    John Gowan basically explains that "light's position in 4-dimensional spacetime cannot be specified", as "light has no x (length) or t (time) dimensions".

    So it seems that I have to look at photons a little more. To help me a bit, are photons energy?

    Last edited by a moderator: May 3, 2017
  6. Jan 4, 2008 #5


    User Avatar

    Staff: Mentor

    Neutrinos do have small masses and therefore must travel at speeds less than light speed. Look up "neutrino oscillations," which have been a major experimental subject during the last several years.
  7. Jan 4, 2008 #6
    Oops, bad timing jtbell, he said that just a few minutes before you did.

    To my knowledge, there is no way of modeling physics without space and time. The closest thing to this I suppose would be loop quantum gravity, which is attempting to achieve background independence. That's not exactly the same as removing time and space from the framework, though.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook