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radiarion consisting of electromagnestic waves that travel at the speed of light (such as visible light, radio waves, and X rays)

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 (human-made) object or vehicle that orbits Earth, the Moon, or other celestial bodies; also, a celestial body that orbits another of larger size (for example, the Moon is Earth's natural satellite)

the set of moral principles and values that guide a person's activities and help him or her decide what is wrong

a spacecraft designed to go into orbit, especially one not intended to land

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

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

hot condensed object at the center of the 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 brief eruption of intense high-energy radiation from the sun's surface
• associated with sunspots and causing electromagnetic disturbances on the earth, as with radio frequency communications and power line transmissions.

• finding sufficient food
• providing ourselves with adequate shelter
• powers wind and currents
• drives all weather from soft summer winds to gigantic hurricanes
• provides energy required for photosynthesis

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 star was placed 32.6 light years away from Earth

an optical instrument that produces a spectrum from a narrow beam of light, and usually projects the spectrum onto the 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 continuous and distinctive band of stars that appears on plots of stellar color versus brightness

a small, dim, hot star

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

a star so dense that only neutrons can exist in the core

a region of space having a gravitational field so intense that no matter or radiation can escape.