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Astronomy #3
Term | Definition |
---|---|
constellation | imaginary patterns formed from groups of stars |
parallax | the apparent change in the position of an object when seen from different places |
light-year | the distance light travels in one year; 9.5 million million kilometers (9.5 trillion km) |
Hertzsprung-Russell diagram | graph showing the relationship between a star's temperature and its brightness |
solar nebula | large cloud of gas and dust such as the one that formed our solar system |
spiral galaxy | galaxy with a bulge in the center and arms that spiral outward like a pinwheel |
elliptical galaxy | galaxy shaped like a round or flattened ball, generally containing only old stars |
binary star | star systems that have two, or double, stars |
quasar | extremely bright, distant galaxy with a giant black hole at its center |
refracting telescope | uses convex lenses to gather and focus light |
reflecting telescope | uses a curved mirror to collect and focus light |
radio telescope | device used to detect radio waves from objects in space |
optical telescope | uses lenses and mirrors to collect and focus visible light |
nebula | large cloud of gas and dust spread out in an immense volume |
protostar | contracting cloud of dust and gas with enough mass to form a star |
white dwarf | blue-white hot core of a star after the outer layers have expanded and drifted into space |
supernova | the brilliant explosion occurring of a dying supergiant star |
neutron star | the remains of a dense, high-mass star after a supernova |
pulsar | rapidly spinning neutron star that produces radio waves |
black hole | an object with gravity so strong that nothing, including light, can escape |