Chapter 8 Glossary Terms

Radiation consisting of electromagenetic waves that travel at the speed of light (such as visible light, radio waves, Xrays).

A telescope that uses a lens to collect the light from an object.

A telescope that uses a mirror to collect the light from an object.

An artificial object or vehicle that orbits Earth, the moon or other celestial bodies; also a celestial body that orbits another body of larger size ie. the Moon is Earth's natural satellite.

Observatories that orbit other celestial objects.

The theory that describes how stars and planets form from contracting, spinning disks of gas and dust.

A celestial body made of hot gases, mainly hydrogen and some helium.

An interstellar cloud of gases such as hydrogen, helium and other ionized gases.

A hot condensed object at the center of a nebula.

The process of energy production in which hydrogen nuclei combine to form helium nuclei.

The surface layer of the Sun.

An area of strong magnetic fields on the photosphere.

A stream of fast moving charged particles ejected by the sun into the solar system.

A large brightening on the surface of the sun which is known to release energy.

The sun is our supply of daylight which is required for photosynthesis and to keep our planet warm.

A star's total energy output per second; its power in joules per second.

The magnitude of a star that we would observe if the star were 32.6 light years from Earth.

An optical instrument that produces a spectrum from a narrow beam of light, and usually projects the spectrum onto a photographic plate or a digital detector.

Certain specific wavelengths within a spectrum characterized by lines spectral lines identify specific chemical elements.

A graph that compares the properties of stars.

A narrow band of stars on the H-R diagram that runs diagonally from left (bright, hot stars) to the lower right (dim, cool stars); about 90 percent of stars, including the Sun, are in the main sequence.

A small, dim, hot star.

A massive explosion in which the entire outer portion of the star is blown off.

A star so dense that only neutrons can exist in its core.

The remnant of a supernova explosion with a gravitational field so strong that nothing can escape its pull.