What is dark matter and dark energy in simple words?

Dark Matter Core Defies Explanation. This image shows the distribution of dark matter, galaxies, and hot gas in the core of the merging galaxy cluster Abell 520. The result could present a challenge to basic theories of dark matter. Another explanation for how space acquires energy comes from the quantum theory of matter. read more

Dark matter is a hypothetical type of matter distinct from baryonic matter (ordinary matter such as protons and neutrons), neutrinos and dark energy. The existence of dark matter would explain a number of otherwise puzzling astronomical observations. read more

Dark matter emits no light, and cannot be directly observed, but scientists think that it and dark energy make up most of the mass of the universe. read more

Unlike for dark matter, scientists have no plausible explanation for dark energy. According to one idea, dark energy is a fifth and previously unknown type of fundamental force called quintessence, which fills the universe like a fluid. read more