Question: because the sun gives gravitational pull why do we not travel toward the sun

Asked by pooger12 to Simon, Blaire, Elizabeth, Jenny, Shona on 17 Mar 2013. This question was also asked by kwald27.

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  1. Photo: Simon AllenSimon Allen
    answered on 17 Mar 2013:

    We do.
    Check out Keplers Laws in wikipedia. We are trapped in Orbit around the sun. If the sun suddenly dissappeared we would carry on in a straight line out into the void somewhere. BUT as the planet tries to go in a straight line (mass x velocity) it is pulled towards the sun. so it doesn’t go in a straight line it describes an orbit around the attractor (the sun) Good diagrams on wikipedia beat my description hands down.

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  2. Photo: Shona MarksShona Marks
    answered on 19 Mar 2013:

    Hi pooger12,

    Simon has the right answer. There are two forces acting on the earth. One is the gravitational pull from the sun and the other is called inertia. have you heard of inertia? Inertia is the physics that says a object will continue to travel in the direction that it is going, rather then change its direction.

    So the earth is a very big object travelling very fast, and inertia would make it travel in a straight line. Straight out of the solar system into space.

    But the gravitational pull, trying to crash us into the sun is equal to the inertia trying to fling us into space….. so we are held by these two forces in a circle around the sun… which I think is very lucky for us!!!

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  3. Photo: Blaire DobieckiBlaire Dobiecki
    answered on 20 Mar 2013:

    Yep, Simon and Shona have explained this really well. Inertia is a ‘law of motion’ that everything in the universe experiences, not just the planets. It is the reason that when someone slams on the breaks in the car, you still fly forward after the car has stopped. Your body was moving in the same direction and same speed as the car, until hopefully your seat belt stops you.

    So, our planet will never hit the sun, but eventually the sun will grow into a red giant and engulf the Earth. This won’t happen for another 5 billion years though, so no need to worry 🙂

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