Hey there! Sign in to join this conversationNew here? Join for free
x Turn on thread page Beta

Describe how a mass creates a gravitational field in the space around it watch

    • Thread Starter
    Offline

    10
    ReputationRep:
    Describe how a mass creates a gravitational field in the space around it
    Offline

    2
    ReputationRep:
    Bowling ball on a trampoline analogy: the bowling ball is a heavy object and the trampoline is the fabric of space.

    (despite that the reason the bowling ball sinks is because of gravity, it works pretty well)
    Offline

    1
    ReputationRep:
    I would also like to know an exam style answer for this
    Offline

    14
    ReputationRep:
    Unless you're taking General Relativity, there is no description of how this happens. In Newtonian mechanics, it's simply stated that gravitational fields are produced by the presence of a mass, and acts upon other masses; which isn't so helpful as it amounts to the answer of "why?" being "Because it's there".

    In the case of Relativity, the 'bowling ball on a trampoline' is the analogy most commonly seen. A lot of people dislike it because they feel it tries to describe gravity, with gravity; but personally I think it's a good analogy, since the sheet only shows the curvature of one plane (and probably not correctly) while gravity helps to show how the curvature in general causes the path of an object to change. Mass causes curves in space-time, and other masses travel along locally straight paths in this curved space. This is hard to think about since all your intuition and experience of space is Euclidean, whereas all this takes place in Riemannian geometry (and that's far more complicated than euclidean!). I like to think about this as how/why light cannot escape black holes, even though it's massless. Black holes create such a strong gravitational field, that the curviness of space is so great, that when light enters it travels (from an outside perspective; the light itself will think it's moving in a straight line) around these curves, and cannot escape from the black hole because none of the curves it has to travel along will lead out of it.
    Offline

    0
    ReputationRep:
    (Original post by FireGarden)
    Unless you're taking General Relativity, there is no description of how this happens. In Newtonian mechanics, it's simply stated that gravitational fields are produced by the presence of a mass, and acts upon other masses; which isn't so helpful as it amounts to the answer of "why?" being "Because it's there".

    In the case of Relativity, the 'bowling ball on a trampoline' is the analogy most commonly seen. A lot of people dislike it because they feel it tries to describe gravity, with gravity; but personally I think it's a good analogy, since the sheet only shows the curvature of one plane (and probably not correctly) while gravity helps to show how the curvature in general causes the path of an object to change. Mass causes curves in space-time, and other masses travel along locally straight paths in this curved space. This is hard to think about since all your intuition and experience of space is Euclidean, whereas all this takes place in Riemannian geometry (and that's far more complicated than euclidean!). I like to think about this as how/why light cannot escape black holes, even though it's massless. Black holes create such a strong gravitational field, that the curviness of space is so great, that when light enters it travels (from an outside perspective; the light itself will think it's moving in a straight line) around these curves, and cannot escape from the black hole because none of the curves it has to travel along will lead out of it.
    you explained that so well! very insightful
    Offline

    8
    ReputationRep:
    For A level , the field 'explanation' runs something like this.

    The mass creates a gravitational field
    The field spreads out into the space around it at the speed of light.
    When the field 'reaches' another mass, it creates an attractive force on the mass.
    Offline

    0
    ReputationRep:
    (Original post by teachercol)
    For A level , the field 'explanation' runs something like this.

    The mass creates a gravitational field
    The field spreads out into the space around it at the speed of light.
    When the field 'reaches' another mass, it creates an attractive force on the mass.
    Spent so long trying to find a good, simple explanation, thanks!
    Offline

    0
    ReputationRep:
    Take in consideration, space is warped, then time will be more or less in certain areas of space.
    And space is warping most or all of the time.
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: April 16, 2016
Poll
Do you like carrot cake?

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reply
Hide
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.