DARK MATTER AND DARK ENERGY By Armaan Gupta, Independent Researcher and Undergraduate at BITS Pilani Immediately after the Big Bang, universe expanded or ballooned rapidly in a split- second era called inflation. The universe continued its expansion for a couple of a billion years or so, creating the early universe- galaxies, clouds and many more things. But then the gravitational force (weakest of the four fundamental forces, namely gravitational, electromagnetic, strong nuclear, and weak nuclear) somehow managed to decrease the rate of rapidly expanding universe and began to slow it down. But as the universe got larger and normal matter got more diluted, something mysterious started happening and it again started the expansion of universe and till present, universe is expanding. Scientists called this mysterious force “dark energy”. Eleven billion years ago, dark energy made up less than 10 percent of the total content of the universe; today it makes up almost three-quarters. DARK MATTER AND DARK ENERGY DARK MATTER Everything we see in our universe, ultimately is made from different combination of same fundamental particles. There are generally two types of particles: matter particles, also known as fermions. Fermions include all quarks and leptons, as well as any composite particle made of an odd number of these. They follow Pauli Exclusion Principle. They takes up space. And Force particles, also known as Bosons. They follow Bose–Einstein statistics. They can pile on top of each other. Ordinary matter is made up of fermions, held together by bosons. There are twelve types of known fermions. Some of them are electron, muon, tau, up quark, down quark etc. Every type of force is associated with some bosons: For electromagnetism, there is photon, for gravitational force, there is gravitons, for higgs force, and there is higgs bosons, for weak interactions- W & Z bosons, for strong interactions- 8 gluons. Together these bosons and fermions comprise standard model of particle