• Question: how much energy dose the world have

    Asked by to David, Johanna, Linda, Tamas, Tom on 23 Jun 2014. This question was also asked by .
    • Photo: Linda Cremonesi

      Linda Cremonesi answered on 23 Jun 2014:

      That’s a good question to give some difficulties to your scientists 😀

      So energy is a very wide concept, there are different kinds of energy: thermal energy (energy that comes from heat), kinetic energy (energy that comes from movement), gravitational energy (energy that comes from gravitational fields, just like gravity for example!) and so on …

      So on the world, we have quite a lot of energy coming from all these contributions, but energy doesn’t just stay on Earth, because Earth interacts with the universe around us, so there is a continuous exchange of energy between Earth-outer space.

      The rules of nature then tell us that energy can’t just appear or disappear, so whenever you have an interaction (or a reaction) there is some energy exchange, but the total amount of energy needs always to be constant!

      Now, the total amount of energy in the universe is balanced between the amount of matter (and antimatter) and the gravitational forces that attract star to each other. We know that this total energy is constant, but I actually don’t know how much it could be. I know that there is a theory called “zero-energy universe” that states that the total energy of the universe is exactly zero!

    • Photo: David Davila

      David Davila answered on 23 Jun 2014:

      I don’t know, like, 20?

      There is probably around 20 energy in the world.

      (sorry for the extraordinarily unhelpful answer)

    • Photo: Thomas Smith

      Thomas Smith answered on 23 Jun 2014:

      Almost all energy on Earth has come from the sun. Think about the electricity that is powering the light bulb in your classroom. It is unlikely that this electricity has been generated by the sun (solar power), it is more likely that the electricity was generated using coal or gas (fossil fuels)… but where do fossil fuels come from? well they come from trees and plants that lived on Earth millions of years ago, and these plants used energy from the sun through photosynthesis to grow.

      So as long as there is a sun, the Earth will have energy. Fortunately for you and me, the sun will continue to shine for many billions of years. The biggest problem we face now is to make better use of sunlight, so that it can generate our electricity and power our cars more directly, rather than relying on fossil fuels.

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