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barred spiral galaxy
a spiral galaxy with a central bar consisting of stars and gas
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baryonic
made up of baryons (elementary particles such as protons and electrons)
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baryonic matter
"normal" matter composed of elementary particles called baryons
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baryons
elementary particles such as protons and neutrons composed of three quarks
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baseline
the line between two observational points or two telescopes of an interferometer
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billion
1,000,000,000 (in American usage)
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binary star
a system of two stars that orbit a common center of gravity; also known as a double star
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binoculars
a small, usually hand-held instrument with two tubes that is used to magnify the view of astronomical objects; the two numbers used to describe the binoculars refer to its magnification and its aperture in millimeters, respectively
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black hole
a region of space where gravity is so powerful that not even light can escape; black holes can form either from the death of high-mass stars or in the cores of galaxies
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black holes
regions of space where gravity is so powerful not even light can escape; black holes can form either from the death of high-mass stars or in the cores of galaxies
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blazar
a high-energy, variable type of quasar which astronmers believe has a jet of material aimed in our direction that causes it to appear more energetic than other quasars
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blink comparator
An instrument that allows astronomers to view two images of the same region of sky simultaneously. Objects that have changed their brightness or position appear to stand out of the plane of the picture.
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blueshift
a decrease in the wavelength of light coming from an object due to its motion toward Earth
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bolide
a brilliant meteor or fireball that explodes in mid-air
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bolides
brilliant meteors or fireballs that explode in mid-air
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brown dwarf
a gaseous object that forms like a star but lacks the necessary mass to sustain nuclear fusion in its core; a body intermediate in mass between a star and planet
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buckyball
a naturally occurring form of carbon known as C-60, its molecular structure resembles the geodesic domes once designed by Buckminster Fuller
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bulge
the generally spherical, central region of a spiral galaxy
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