Chapter 8 Glossary Terms

• Radiation consisting of electromagnetic waves that travel at the speed of light
• i.e.- Visible light, radio waves, and X rays)

• A telescope that uses a lens to collect the light from an object
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• A telescope that uses a mirror to collect light from an object
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• An artificial (human made) object or vehicle that orbits Earth, the Moon, or other celestial bodies; also a celestial body that orbits another of fa larger size
• i.e.- the Moon is Earth's natural satellite

Observatories that orbit other celestial objects

• The theory that described how stars and planets form from contracting, spinning disks of gas and dust. This is shown below.
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A celestial object body made of hot gases, mainly hydrogen and some helium

A vast cloud of gas and dust, which may be the birthplace of stars and planets

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
• Shown on the right hand side below

• An area of strong magnestic fields on the photosphere
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A stream of fastmoving charged particles ejected by the Sun into the solar system

• A solar flare is when complex groups of sun spots eject solar wind. 
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• The Sun is needed for all life on Earth. Energy from the Sun drives most processes on Earth that support daily activities
• i.e.- Sun is necessary in finding sufficient food, and providing shelter. The Sun is also responsible of the natural heating and lighting of the Earth

A star's total energy output per second; its power in joules per second (j/s)

The magnitude of a star that we would observe if the stars were placed 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 of 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 the upper left (bright, hot stars) to the bottom right (dim, cool stars)
• About 90% of stars including hte Sun are in the main sequence

A small, dim, hot star

A massive explosion on which the entire outer portion of a star is blown off

A star so dense that only neutrons can exiat in the core

Low-mass stars consume their hydrogen slowly over a time frame that may be up to 100 billion years. As they age they loose mass, become white dwarfs. 

They consume hydrogen faster than low-mass stars. When their hydrogen is used up the core collapse. The layers begin to expand and the temperature rises. It now appears red and is called a red giant. 

These consume fuel faster than the other 2 and die quickly and violently. The stars expand into supergiants and heavy elements form by fusion. The outer part of the star creates a supernova, which can be billions of times brighter than the original star. A supernova ejects elements into the universe becoming new planets, stars, etc. 

• A tiny patch of space that has no volume, but has mass and gravity
• Extremely strong gravitational pull means nothing can escape, not even light