Astronomy, WOR-ṬūS
Human beings have long been fascinated by the celestial sphere above, whose twinkling lights have inspired not only scientific theories but also many artistic endeavors. Humankind's fascination with the world beyond Earth has led to many landmark moments in history, as when space exploration took a giant step forward with the advent of technology that allowed humans to successfully travel to the Moon and to build spacecraft capable of exploring the rest of the solar system and beyond.
Astronomy Encyclopedia Articles By Title
Al Worden was a U.S. astronaut, pilot of the command module Endeavour on the Apollo 15 mission (July 26–August......
ProCon Debate: Should Humans Colonize Space? ProCon Issue in the News: The World Monuments Fund (WMF) added the......
wormhole, solution of the field equations in German-born physicist Albert Einstein’s theory of general relativity......
X-ray astronomy, Study of astronomical objects and phenomena that emit radiation at X-ray wavelengths. Because......
X-ray source, in astronomy, any of a class of cosmic objects that emit radiation at X-ray wavelength. Because the......
X-ray telescope, instrument designed to detect and resolve X-rays from sources outside Earth’s atmosphere. Because......
XMM-Newton, European Space Agency (ESA) satellite that observes celestial X-ray sources. It was launched in 1999......
Xu Yue was a Chinese astronomer and mathematician. Xu was a disciple of Liu Hong (c. 129–210), an influential government......
Yang Liwei is a Chinese astronaut and the first person sent into space by the Chinese space program. In 1983 he......
Yarikh, ancient West Semitic moon god whose marriage to the moon goddess Nikkal (Sumerian: Ningal, “Queen”) was......
Boris Borisovich Yegorov was a Soviet physician who, with cosmonauts Vladimir M. Komarov and Konstantin P. Feoktistov,......
Yerkes Observatory, astronomical observatory located at Williams Bay on Lake Geneva in southeastern Wisconsin,......
Charles Tyson Yerkes was an American financier who put together the syndicate of companies that built Chicago’s......
Yi Soyeon is a South Korean scientist and astronaut, the first South Korean citizen in space. Yi earned bachelor’s......
Yohkoh, Japanese satellite that provided continuous monitoring of the Sun from 1991 to 2001. Originally designated......
Charles Augustus Young was an American astronomer who made the first observations of the flash spectrum of the......
John W. Young was a U.S. astronaut who participated in the Gemini, Apollo, and space shuttle programs. He was the......
Franz Xaver von Zach was a German Hungarian astronomer noted for being the nexus of astronomical information in......
zenith, point on the celestial sphere directly above an observer on the Earth. The point 180° opposite the zenith,......
Zhai Zhigang is a Chinese astronaut who performed China’s first spacewalk. Zhai was the child of an illiterate......
Zhang Heng was a Chinese mathematician, astronomer, and geographer. His seismoscope for registering earthquakes......
Zhao Youqin was a Chinese astronomer, mathematician, and Daoist who calculated the value of π, constructed astronomical......
zodiac, a belt around the sky extending 9° on either side of the ecliptic, the Sun’s apparent annual path, which......
zodiacal light, band of light in the night sky, thought to be sunlight reflected from cometary dust concentrated......
Zond, any of a series of eight unmanned Soviet lunar and interplanetary probes. Zond 1 (launched April 2, 1964)......
Zu Chongzhi was a Chinese astronomer, mathematician, and engineer who created the Daming calendar and found several......
Zu Geng was a Chinese government official, mathematician, astronomer, and son of Zu Chongzhi (429–500). Beginning......
Niccolò Zucchi was an Italian astronomer who, in approximately 1616, designed one of the earliest reflecting telescopes,......
Fritz Zwicky was a Swiss astronomer and physicist who made valuable contributions to the theory and understanding......
Anders Jonas Ångström was a Swedish physicist, a founder of spectroscopy for whom the angstrom, a unit of length......
Ernst Öpik was an Estonian astronomer who was best known for his studies of meteors and meteorites and whose life......
Ōsumi, first Earth satellite orbited by Japan. It was launched on Feb. 11, 1970, from Kagoshima Space Center on......
Milan Štefánik was a Slovak astronomer and general who, with Tomáš Masaryk and Edvard Beneš, helped found the new......
Bahāʾ ad-dīn Muḥammad ibn Ḥusayn al-ʿĀmilī was a theologian, mathematician, jurist, and astronomer who was a major......
Naṣīr al-Dīn al-Ṭūsī was an outstanding Persian philosopher, scientist, and mathematician. Educated first in Ṭūs,......