Science 9 astronomy

Terms in this set (33)

Galaxy
large group of stars, dust, and gas held together by gravity; can be elliptical, spiral, or irregular
Star
(astronomy) a celestial body of hot gases that radiates energy derived from thermonuclear reactions in the interior
Celestial Body
a natural object in space, such as the sun, moon, a planet, or a star.
Astronomers
scientists who study the stars and other objects in the sky
Electromagnetic Radiation
energy that is caried or radiated space in the form of waves
Spectrum
wavelengths of visible light that are separated when a beam of light passes through a prism; range of wavelengths of electromagnetic radiation
Spectroscope
an instrument that separates light into a spectrum
Cosmological red shift
wavelengths of radiated light that are constantly being stretched (lengthened) as the light crosses the expanding universe
red shift
a shift toward longer wavelengths of the spectral lines emitted by a celestial object that is caused by the object moving away from the earth.
Nebula
an immense cloud of gas (mainly hydrogen) and dust in interstellar space
Spiral galaxy
A galaxy with a bulge in the middle and arms that spiral outward in a pinwheel pattern.
Elliptical galaxy
a galaxy shaped like a round or flattened ball, generally containing only old stars
irregular galaxy
a galaxy that does not have a regular shape
star clusters
a cluster of stars that have a common origin and are held together by gravity.
interstellar matter
the gas and dust located between the stars in a galaxy
low mass stars
Start out as dim, cool red dwarfs. Last 100 billion years. hot and small white dwarfs.
Intermediate mass stars
consume hydrogen more quickly, 10B year lifetime
At end of life, core contracts causing temps to increase and star expands into a red giant
eventually outer layers of gas released into space and the star becomes a white dwarf
High mass stars
The star will supernova and the core is left behind as a black hole, where gravity is strong enough to attract light such that is can not escape the gravitational well
supernova
the brilliant explosion of a dying supergiant star
Nuclear fusion
a nuclear reaction in which nuclei combine to form more massive nuclei with the simultaneous release of energy
black hole
final stage in the evolution of a very massive star, where the core's mass collapses to a point that its gravity is so strong that not even light can escape
Doppler effect
change in the apparent frequency of a wave as observer and source move toward or away from each other
solar prominence
large eruptions of luminous hydrogen gas that rise thousands of kilometers above the chromosphere
sunspots
areas on the Sun's surface that are cooler and less bright than surrounding areas, are caused by the Sun's magnetic field, and occur in cycles
photosphere
the part of the sun that is the thin layer. In this turbulent area hot gas rises to the surfface in a cycle.
Chromosphere
a gaseous layer of the sun's atmosphere (extending from the photosphere to the corona) that is visible during a total eclipse of the sun
corona
the outermost region of the sun's atmosphere can reach 3000000 degrees celcius.
Solar flare
a sudden eruption of intense high-energy radiation from the sun's surface
solar wind
a stream of electrically charged particles produced by the sun's corona
astronomical unit
a unit of length used for distances within the solar system
Mercury
Closest planet to the sun. Hottest planet. one third size of Earth
Venus
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Earth
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