Astronomy 28.1-28.4

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Electromagnetic Radiation

Back 1

Energy radiated in the form of a wave, resulting from the motion of electrical charges and the magnetic fields they produce.

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Electromagnetic Spectrum

Back 2

A continuum depicting the range of electromagnetic radiation, with the longest wave length at one end and the shortest at the other.

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Emission Spectrum

Back 3

A spectrum consisting of individual lines at characteristic wavelengths produced when light passes through an incandescent gas; a bright line spectrum.

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Continuous Spectrum

Back 4

A spectrum that contains all colors of wavelengths.

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Absorption Spectrum

Back 5

A continuous spectrum crossed by dark lines produced when light passes through a non-incandescent gas.

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Constellation

Back 6

A group of stars that appear to form a pattern in the sky.

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Apparent Magnitude

Back 7

The measure of how bright a star appears to be to an observer on earth.

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Astronomical Unit

Back 8

The average distance between Earth and the Sun, about 150 million kilometers.

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Light Year

Back 9

The distance that light travels in 1 year, about 9.5 trillion kilometers.

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Parsec

Back 10

A unit of measurement used to describe distances between celestial objects, equal to 3,258 light-years.

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Luminosity

Back 11

The brightness of a star.

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Absolute Magnitude

Back 12

The measure of how bright a star would be if it were located 10 parsecs from Earth.

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Cepheid Variable

Back 13

A variable star that brightens and dims regularly, or pulses and whose distance can be determined from its period of pulsation.

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Main Sequence

Back 14

A star that is at the point in its life cycle in which it is actively fusing hydrogen nuclei into helium nuclei; also, the band of the Hertzsprung-Russel diagram depicting stars.

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Giant Star

Back 15

A large star with great luminosity and a diameter 10 to 100 times greater than that of the Sun.

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Supergiants

Back 16

The most luminous massive stars, with diameters greater than 100 times the diameter of the Sun.

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White Dwarfs

Back 17

The remnant of a giant star that has lost its outer atmosphere; the glowing stellar core.

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Nebula

Back 18

A large cloud of gas and dust in space.

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Planetary Nebula

Back 19

A halo of gases that is formed by expelled layers of a star's atmosphere.

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Supernova

Back 20

The brilliant burst of light that follows the collapse of the iron core of a massive star.

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Neutron Star

Back 21

The super dense remains of a massive star that collapsed with enough force to push all of its electrons into the nuclei they orbit, resulting in a mass of neutrons.

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Pulsar

Back 22

A distant neutron star that emits rapid pulses of light and radio waves instead of steady radiation.

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Black Hole

Back 23

The final life stage of an extremely massive star, with a gravitational field so intense that not even light can escape.

Front 24

Galaxies

Back 24

A group of millions, or billions, of stars held together by gravity.

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Quasar

Back 25

A very distant, extremely luminous celestial object that scientists consider to be a type of active galactic nuclei.

Front 26

Big Bang Model

Back 26

The theory holding that the universe originated from the instant expansion of an extremely small agglomeration of matter of extremely high density and temperature.