Key-Terms Quiz Answers

• A bowl-shaped depression formed by the impact of an asteroid or meteoroid. Also the depression around the opening of a volcano. (Crater)
• A bright celestial object that gives off x-rays as a major portion of its radiation. (X-ray Star)
• A celestial body orbiting a star or stellar remnant that is massive enough to be rounded by its own gravity, is not massive enough to cause thermonuclear fusion, and has cleared its neighboring region of planetesimals. (Planet)
• An imaginary line in the sky traced by the Sun as it moves in its yearly path through the sky. (Ecliptic)
• An instrument that uses lenses and sometimes mirrors to collect large amounts of light from distant objects and enable direct observation and photography; can also include any instrument designed to observe distant objects by their emissions of invisible radiation such as x-rays or radio waves. (Telescope)
• The amount of light emitted by a star. (Luminosity)
• The angular distance of an object in the sky from the celestial equator. (Declination)
• The technique of observing the spectra of visible light from an object to determine its composition, temperature, density, and speed. (Spectroscopy)
• Electromagnetic radiation that are visible to the human eye. (Visible Light)
• The two points at which the Sun crosses the celestial equator in its yearly path in the sky; occur on or near March 21 and September 22. (Equinox)