Study of the physical nature of stars, galaxies, and the universe. It began with the development of spectroscopy in the 19th century, which allowed astronomers to analyse the composition of stars from their light. Astrophysicists view the universe as a vast natural laboratory in which they can study matter under conditions of temperature, pressure, and density that are unattainable on Earth.
Green, red, and blue were the colours of the Eritrean People's Liberation Front (EPLF) flag which bore a yellow star at the hoist. Effective date: late 1995.