atmosphere The envelope of gases surrounding Earth or another planet.
corona The envelope of the sun (and other stars). The sun’s corona is normally visible only during a total solar eclipse, when it is seen as an irregularly shaped, pearly glow surrounding the darkened disk of the moon.
distort (n. distortion) To change the shape or image of something in a way that makes it hard to recognize, or to change the perception or characterization of something (as to mislead).
mass A number that shows how much an object resists speeding up and slowing down — basically a measure of how much matter that object is made from.
star The basic building block from which galaxies are made. Stars develop when gravity compacts clouds of gas. When they become dense enough to sustain nuclear-fusion reactions, stars will emit light and sometimes other forms of electromagnetic radiation. The sun is our closest star.
sun The star at the center of Earth’s solar system. It’s an average size star about 26,000 light-years from the center of the Milky Way galaxy. Also a term for any sunlike star.
yellow dwarf A medium-sized star. Our sun is an example of a yellow dwarf.
