World Science Scholars

2.7 Gravitational Field Energy

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    • Have you ever previously heard that the energy of a gravitational field can be negative? Does it surprise you? Are you convinced by the derivation given in the lecture?

    • I have heard this before and still find it surprising, but am willing to accept it if it allows consistency with theories and calculations. But I dont find the demonstration totally convincing. Allan says there is no gravitational field inside the sphere because the force from around the sphere cancels out. But isnt this only true at the centre? Away from the centre isnt there a net force because such a point is closer to one side of the sphere? So if there is a field there before the collapse, as the field contracts it isnt the case that a field appears where there was no field before.Also what happens if the sphere collapses without generating power. The same region of supposedly no gravitational field will after collapse have the same field with out doing any work. All very interesting!

    • Very interesting, I have heard this before and enjoy the concept.

    • Yes, persuasive demonstration from principle of conservation of energy in closed system.

    • Totally spurprised by this and I’m still trying to wrap my head around it. Obviously, newbie here.

    • I had never before heard of the Gravitational field having negative energy and I was so surprised to see how Prof. Guith through a simple thought experiment established it. And yes I do believe in the derivation as so far we have not encountered any exception to the conservation of energy and this also successfully shows that indeed energy would be conserved during inflation if we agree on the fact that gravitational filed have negative enegry.

    • Hello Ladies and Gentlemen,

      I have no exposure to negative gravity fields. It does not surprise me, growing up near a nuke power plant allows open minds to science.

      I am convinced by the lecture to keep listening to highly decorated Prof. Guth until i have the Aha!.

      Most things in existence have a yin and yang, so to hear the gravity field as yeilding, negative, wet, and yin is ok.

      It will have its` mirror.

    • some of this is like hearing just believe, and then given a number or formula that seems to only satisfy the fitting of the theory being postulated, then if it doesn’t fit observations adding another constant or formula. Or maybe I just don’t get it yet. but I’m still learning, so maybe there’s hope for me in the future.

    • This is new to me

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