PLANET: A celestial body that revolves around a star. Derived from Greek work “PLANETES” which means wanderer.
STAR: A natural luminous body burning gas which is held together by gravity.
- Planet earth and life on it.
- Philosophically; the whole of the physical universe, “world” of an individual.
- Comes from old English; “weorold”; wer-man, eld-age; which means “age of man”.
- Distinguishes entire planet or population from any particular country or region.
UNIVERSE: Derived from old French word “unvers” which is in turn derived from Latin “Universum”. Defined as all existing matter and space considered as a whole.
COSMOS: Implies viewing the universe as a complex and orderly system (or) entity. ( the opposite of chaos). First used by Pythagoras for the (implying) order of the universe.
COSMOLOGY: Understanding of reasons for nature’s existence and significance. Study of Cosmos.
COMET: A chunk of ice and rock originating from the outer solar system, often accompanied by a coma and tail.
ASTEROID: A rock in orbit; the larger chunk of rocks.
METEOROID: A space rock that is bigger than a dust grain but smaller than an asteroid.
METEOR: The streak of light when a space rock enters the atmosphere and starts burning up (falling star).
METEORITE: If a meteor doesn’t entirely burn up. A piece of space rock that lands on earth are called as a meteorite.
GALAXY: A system of millions or billions of stars and planets together along with gas and dust held together by gravitational attraction.
NEBULA: Interstellar cloud of dust, hydrogen, helium and other ionized gases.
MULTIVERSE: Hypothetical group of multiple universes.
PARALLEL UNIVERSE: Different universes within multiverse.
BLACK HOLE: A concentration of mass so dense that nothing, not even light can escape its gravitational pull once swallowed.
NEUTRON STAR: A celestial object of very small radius (~30km) but which is extremely dense composed of closely packed neutrons.
QUSARS (Quasi Stellar Radio Source): Extremely luminous active galactic nucleus.
BLAZAR: A feeding supermassive black hole producing high energy jets which are viewed face-on from earth.
DARK MATTER: Invisible matter.
DARK ENERGY: Force that repels gravity.
ANTI MATTER: Opposite of normal matter.
STRING THEORY: earlier referred as a 1-d entity having dynamic properties similar to those of flexible elastic string.
SUPER STRING THEORY: Supper symmetry + string theory.
SUPERSYMMETRY: Each particle from one group (fermions, bosons) would have an associate particle.
GALAXY NAMING is based upon two categories.
- Messier( named after Charles Messier)
- New general category (NGC).