• Question: what is gravity where does it come from, what is it made by

    Asked by domo14 to Enda, Jean, Kate, Kev, Tim on 15 Nov 2012.
    • Photo: Jean Bourke

      Jean Bourke answered on 15 Nov 2012:

      I honestly do not know. I will ask some physicists and get back to you!

      I found a physicist! See the comment below.

    • Photo: Tim Downing

      Tim Downing answered on 17 Nov 2012:

      Hi Domo14,

      Yeah as Jean says the Space zone scientists will be able to help you more.

      Gravity is the force of attraction between two objects due to their size. So an elephant exerts a greater force on a mouse than a mouse does on an elephant. This applies to planets, which is why our small planet revolves around the Sun and not the other way around.

      We interpret the force of gravity this as our weight, which is really the force of Earth pulling us down to keep our feet on the ground. If we did not have gravity, everything would fly away! So understanding how it operates is important.

      For people in the biological sciences rather than physics, gravity has a smaller effect because we study smaller things. So when we study cells the effects of the protein structures and relationships have a bigger effect than gravity. An exampel of this is static electricity: when you rub a baloon, it will try to attach to your clothes due to these molecular forces. Likewise, water droplets will collect on the inside or outside of a glass (this is called cappilliarity). So this is why physicists study gravity a lot more than biologists do!

      Tim

    • Photo: Enda O'Connell

      Enda O'Connell answered on 17 Nov 2012:

      Hi Domo14

      Gravity is a force, and one of four ways particles interact with each other. The others are called Electromagnetism, the Weak force and the Strong force. The scientists in the Space zone might correct me on this but as far as I know, Gravity is the weakest of the four forces but acts throughout the universe and depends on size and distance. Particles are what matter is made of and matter is what you are made of so this means that everything in the universe is pulling on you, and you on everything in the universe. You only feel the effect of the Earth’s gravity because it is so big compared to you and so close to you (you are probably on it right now!). The other three forces are actually stronger but only act over short distances.

      You might be interested in a branch of science called Astrobiology, which is a very broad area of research. Some of the things an astrobiologist might study are: the presence of other planets in the so called “Goldilocks zone” around a star (not too hot, not too cold, but just right to support life); the suitability of conditions on these planets for human life (e.g. temperature, atmosphere, presence of water); and the ability of life, human and otherwise, to adapt to life in space and on other planets.

      One area of study is “Gravitational biology”, looking at the effect of gravity on life on Earth and elsewhere. On Earth, gravity has always been constant, and has an effect on the size of cells and the growth and movement of plants and animals (e.g. plants grow upwards and have to resist the pull of gravity).

      To look at the effect of different strengths of gravity (the pull of gravity is different in space and other sized planets), scientist do experiments in hypogravity (lower than the Earth’s gravity, e.g. in space) and hypergravity (higher than the Earth’s gravity, e.g. during take-off off a space shuttle and even aeroplanes). Biology experiments have been carried out during space missions for decades and now they even have permanent labs on the International Space Station, where the effects of gravity and other stresses of life in space are studied.

      Do you think you’d like to study biology in space? I know I would…

      If you want to read more about Astrobiology check out NASA’s website https://astrobiology.nasa.gov/

Comments

  • Photo: Colin

    Colin commented on :

    I can’t tell you what gravity is, but I can tell you what it does.

    Gravity is one of the basic ‘things’ in the Universe. We do not fully understand it it, but we know fairly well what it does.

    Gravity is generated by matter. Every object generates a gravitational field, heavier the object, the stronger the field. An object’s gravitational field gets weaker the further you move away from the object but it is still there no matter how far you go.

    Here on Earth we experience Earth’s gravity as the force which makes things fall or keeps satellites in orbit. In more extreme environments, like close to black holes, gravity has stranger still effects on space and time…but that’s a whole other can of worms.