• Question: What Is the Universe Made Of?

    Asked by beth5000 to Claire, Matt, Sam on 27 Jun 2013.
    • Photo: Sam Geen

      Sam Geen answered on 27 Jun 2013:

      Most of the energy in the universe is unknown! We call it “dark energy” because we don’t knowp what it is. Most of the particles in the universe we don’t know either! We call this “dark matter” because it is invisible but makes gravity. And most of the atoms in the universe are hydrogen, with some helium and a small amount of other elements (1 to 2% in the Sun).

    • Photo: Claire Lee

      Claire Lee answered on 27 Jun 2013:

      The most awesome thing about the universe is that we have no idea about most of it!

      So everything we can see – everything that makes up you, me, that cat, the earth, stars, sun, moon, galaxies, etc – all of that is made up of a set of 17 basic particles. In fact, of those 17, 3 of those particles make up all the atoms in the universe. 4 particles carry forces, there is (so far) 1 Higgs particle which helps to give mass to the others, and the rest of them seem to be there to keep physicists on their toes.

      So, at first glance, the universe is made of particles. But as Sam says, it’s not that simple. If you add up all of that everything, we get to a grand total of…

      4% of the universe!

      In other words, 96% of the universe is “missing” (we call it dark, since it’s not really missing, it’s sort of right here before our…erm, telescopes. We just can’t see it and we have no idea what it is).

      Of that 96%, it’s not even the same stuff. Some of it is a type of matter. We know it is matter because it has gravity – though that’s about the only thing we know. Well, we also know that it is definitely not like any of the 17 particles that make up the 4%. We think it may be a whole new particle that we just haven’t discovered yet – in fact, some people are actually looking for this at the LHC!

      But most of that 96% is not even matter. It doesn’t have gravity. In fact, it almost works in the exact opposite way to gravity – it seems to be pushing the universe apart faster and faster and faster.

      So maybe the best answer to your question of “What is the universe made of?” is… “A lot of future PhD’s” 🙂

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