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B "Newton's space is the gravitational field"?

  1. Feb 10, 2017 #1
    I just read Carlo Rovelli new book "Reality is Not What It Seems: The Journey to Quantum Gravity" in one sitting and quoting the relevant passage:

    "The world is not made up of space + particles + electromagnetic field + gravitational field. The world is made up of particles + fields, and nothing else; there is no need to add space as an extra ingredient. Newton's space is the gravitational field. Or vice versa, which amounts to saying the same thing: the gravitational field is space"

    Is the phrase "Newton's space is the gravitational field" correct if one will repeat it in articles?
  2. jcsd
  3. Feb 10, 2017 #2


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    Staff: Mentor

    I've always read that Newtonian Gravitation existed within spacetime, much like how objects and other fields exist within spacetime. This is unlike in General Relativity where gravitation is not separate from spacetime.
  4. Feb 10, 2017 #3
    I think Rovelli was talking about space existing in the classical way. As I understood it he was saying that at the smallest scale distance needs to be treated as a quantum measurement in a similar way to energy, with a 'smallest possible' distance existing. He describes space as like a quantum foam where distance is effectively defined by the number of 'bubbles' between two points. The geometry is constantly changing at any point so actual 'distances' are calculated in a statistical manner. A higher density (as measured in classical space) of matter or energy would lead to an increased density of 'bubbles' effectively increasing the distance measured between two points. This then becomes the cause of the 'bending' of space in General Relativity and is what leads to gravity.

    To say that Newtons space is the gravitational field would be missing a key point. The change in measured distance within Newtons space is what leads to gravity, not the space itself.

    It is worth noting that Rovelli stresses that this is an emerging science and many of the conclusions are still highly speculative. That said, it was a good read and the broad sweep of ideas fits very well with my world view.
  5. Feb 10, 2017 #4


    Staff: Mentor

    It sounds like a pop sci book. Please recognize that pop sci books are meant for entertainment rather than education.
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