• Question: Why does matter exert a gravitational force? Why does a charge have an electric field?

    Asked by lewiiboii to Daniela, Hannah, Ian, Jono, Mark on 16 Jun 2013. This question was also asked by k9markred.
    • Photo: Ian Wilson

      Ian Wilson answered on 16 Jun 2013:

      Hi lewiiboii,

      Unfortunately, nobody knows why matter has gravity. There’s a lot about this force that doesn’t quite make sense to us – it’s weaker than other forces; it has no opposing force that we know of. That’s one of the things scientists working at the Large Hadron Collider are trying to find out: http://www.lhc.ac.uk/17734.aspx
      I didn’t realise until I found that link to send you that some scientists think that gravity bleeds through to other dimensions! How incredible is that? To think that what we see as our universe could be affecting another one that we can’t even imagine yet! Mind. Blown.

      As for the question about charge, I’m afraid I don’t know! Something to do with electrons? That one’s a bit beyond me :S If any of the other scientists know, I’d be just as interested as you to find out!

      Hope that (sort of) helps!


    • Photo: Daniela Plana

      Daniela Plana answered on 16 Jun 2013:

      Hi lewiiboii,

      Following up on Ian’s answer, electric fields are a bit like gravitational fields, but instead of mass, it’s electrical charges that generate them. The Earth attracts/moves everything towards it, but with charges it’s a little bit different because there are two types of charges, positive and negative ones. Two charges of the same type (two positive ones or two negative ones) will repel each other, which essentially means they don’t like each other and will force the other to move to stay as far away as possible… on the contrary, if two charges are of different types, one positive/one negative, they will attract each other, moving to be as close as possible to each other… electric fields are essentially the part around a charge in which if you try to put in another charge it will feel an effect and then move towards or away from the charge that is already there, depending on what type of charges they are…

      Let me know if that makes any sense o not!

    • Photo: Mark Hodson

      Mark Hodson answered on 17 Jun 2013:

      Hi lewiiboii,

      as you can see from Ian and Daniela’s answers those questions are really tricky, the short answer is that no one knows!


    • Photo: Jono Bone

      Jono Bone answered on 18 Jun 2013:

      Hey lewiiboii,

      Tricky questions! I had to do a bit of a search and found a lot of things that went straight over my head (I’m no physicist), but it seems someone has asked the same question on another forum and got a really good answer….

      “Matter exerts gravitational force because mass tends to bend space-time around it which influences other masses in its vicinity, It is important to stress than this bending property is a consequence of an object having mass. This influence manifests itself as gravitational force between two masses.
      Now, electromagnetic behavior is propagated by particles called photons which act as messengers between charges which, also help in exerting their presence. The interaction of photons originating from different charges gives rise to electromagnetic force.” Kranav Sharma

      Sounds like he knows what he’s talking about!

    • Photo: Hannah Brotherton

      Hannah Brotherton answered on 21 Jun 2013:

      Hi Lewiiboii and k9markred…..
      Making me think a lot this week guys lol

      So why does it have a gravitational force!?

      Stuff with matter deforms the space around it, making other stuff fall towards it – imagine a giant rubber sheet which is like space. And imagine if you put a ball on it (which is the stuff or matter). The ball with dent the middle of the sheet. So if you put a smaller ball on the sheet, it will roll down the dent to the ball.
      Why does this happen? we have no idea – but something or someone (ooo) has created this force. This force is essential for life – without gravity we would be able to live on earth, we would float around and we would probably never bump into people – so could never reproduce and continue the human race. Gravity lets things live and reproduce – causing life to occur. but this question will only be answered by knowing where the origin of gravity came from – where is the first place in the universe gravity was seen?! I expect we won’t be able to asnwer this questions for hundreds and hundreds of years.

      next question …….. why does a charge have an electric field? hmmm

      An electric charge is like gravity for small molecules – it is trying to attract other molecules. This is why we have so many different types of elements and metals in the world. Because each atom is attracting different atoms, creating a huge range of things. So why does it do this – i am not sure why , no one does, but by doing so we are able to have gold and silver, but more important carbon dioxide and oxygen, things that are important for living

      So you can see there is a same theme for both questions – Life
      These forces are here so life can happen 😀
      But how does this molecules know to make these stuff that will help us live – right now we think it is chance, and we happen to be on a planet that by chance is the perfect distance from the sun to create life, creating the chemical reactions producing oxygen. But I always wonder if there is something more to this – maybe we are not here by chance!