Question: what is the universe made of ?

Heather Walton answered on 11 Jul 2020:

This is a fascinating question!
Matter, all the stuff that we can see or detect in other ways, is all made up of atoms, of the 118 types shown in the periodic table, and the subatomic particles they are made of. Then the universe also contains light, X-rays, gamma rays etc which are energy. This makes up all of the universe which we can study.
However, from the laws of physics scientists have calculated that all the matter and energy we can measure isn’t enough to make up the universe! For example, galaxies spin more quickly than they ‘should’ according to our measurements of them. Therefore scientists have predicted that the universe is made of not only matter and energy, but also ‘dark matter’ and ‘dark energy’, which have the same effects but which we cannot see or detect in any other way. I believe the calculations say these actually make up about 70% of the universe (for exact numbers you’d have to ask an astrophysicist I think!) so figuring out what they are is a really massive question for science.