ASTRONOMY CHEAT SHEET

========================== ASTRONOMY: (By SimoTheFinlandized - 2021) ========================== Astronomy (from the Greek astron (ἄστρον) meaning "star" and nomos (nόμος) meaning "law") is the scientific study of celestial bodies such as stars (massive burning balls of hydrogen and helium-based plasma that give off tremendous amounts of light, heat, and enormous gravity to form star systems), planets (smaller balls of rock, ice, or gas that develop around and orbit stars in configurations called "star systems"), comets (tiny figments of ice and dust that semi-regularly orbit stars and their planets), and galaxies (very large collections of hundreds-of-billions to trillions of star systems and nebulae {vast stellar birthing grounds} bound together by super-massive black holes). The objects studied include stars, galaxies, planets, moons, asteroids, comets and nebulae, among much else in space. Phenomena outside the Earth's atmosphere are also studied. That includes supernovae explosions (utterly-massive bursts of energy and matter given off by a huge dying star), gamma ray bursts (bursts of gamma-ray radiation given off by astronomical objects), and cosmic microwave background radiation (microwave radiation given off from the Big Bang Event that birthed the Universe that lingers around in space today). Astronomy concerns the development, physics, chemistry, meteorology and movement of celestial bodies, as well as the structure and development of the Universe. Astronomy is one of the oldest sciences. Ancient people used the positions of the stars to navigate, and to find when was the best time to plant crops. Astronomy is very similar to astrophysics. A related subject, cosmology, is concerned with studying the Universe as a whole, and the way the universe changed over time. Astronomy is not the same as astrology, the belief that motion of the stars and the planets may affect human lives. Since the 20th century there have been two main types of astronomy, observational and theoretical astronomy. Observational astronomy uses telescopes and cameras to observe or look at stars, galaxies and other astronomical objects. Theoretical astronomy uses maths and computer models to explain the observations and predict what might happen. Working together, theories predict what should happen and observations show whether the predictions work. The main work of astronomy is to explain puzzling features of the universe. For thousands of years the most important issue was the motions of planets; now many other topics are studied. ==========================