X-ray radiation;High-energy radiation with an extremely short wavelength.
Yellow dwarf;Sun-like star that is in the same stage of development as the Sun.
Zenith;Point in the celestial sphere located directly above the observer.
Zodiac;Imaginary belt across the celestial sphere extending to both sides of the ecliptic. It contains the twelve signs (constellations) of the zodiac.
Zodiac belt;Area extending to both sides of the ecliptic in which the Sun, the Moon and the planets pass through the sectors of the twelve signs of the zodiac.
