The Elementary Particle-Astrophysics Connection
Look up. What you see are stars and galaxies, of course made up of stars. The stars shine because of the thermonuclear reactions in their cores which produce light (Photons) and other particles. Look at your computer - it's made up of aluminum, plastics with carbon, steel made of iron, glass made from silicon. In short, your computer - and your body - is made up of atoms which are relatively complex and heavy compared to more than 99% of the universe which is hydrogen and helium. Where did the iron and aluminum and silicon come from? How did those heavy atoms make it to earth in order to be mined and formed into your computer, or perhaps more miraculously, into you?
Well, from those self-same stars that you see when you look up. Some of them are inherently unstable in the last moments of their lives, after all of their nuclear material has been depleted. Some of them, rather than going quietly, go out with a bang - a superbang - driven in part by elementary particles which drive part of the explosive momentum of the later products of that unfortunate star's late-stage nuclear burning. The heavier atoms of the universe are all products of this explosive distribution system, which in turn gets its force from the interactions of elementary particles such as photons and neutrinos.
Look back in time. How do you do that? Well, through the amazing fact that the Universe is expanding in all directions, the objects which are furthest away from us, are also the oldest. We "see" to the edges of time by collecting, not just light in telescopes, but infrared, gamma, x-ray radiation. We also "see" with neutrinos to the various horizons which present us with a weird picture now of what was going on at the earliest fractions of a second of the beginning of All Time. How does this work? Well, with the details explained by Einstein in his General Theory of Relativity - the story of how geometry itself is curved and shaped by mass (there's mass again) and energy. While we've not found it yet, we have hints that just like electromagnetism is carried by Photons, gravity must also be carried by an elementary particle, dubbed Graviton.
Now...the sky looks to be highly populated by stars. What you see with your eye are our neighboring stars of our Milky Way galaxy. With the Hubble telescope breathtaking images of thousands of Galaxy fields themselves have been revealed: the Universe is a high-population operation. When detailed studies are done of the motions of galaxies as well as the characteristics of some Supernovae (they really are quite frequent), we find surprisingly that something's missing: Like most of Everything is missing! What we can see, feel, measure, detect must be less than 5% of the total mass-energy in the Universe...whatever else is there has yet to manifest itself in any form that we can measure. Unless the last 100 years of theoretical physics is totally mistaken, the form of this missing stuff must itself be of an elementary particle origin. We're looking for it in every elementary particle experiment underway or planned.