When seen from Earth, Venus is brighter than any other planet or any star in the sky. At certain times of the year, it is the first planet or star visible in the western sky at night—and at other times, it is the last planet or star visible in the morning.
Venus is constantly covered by thick clouds of sulfuric acid, through which no visible light can penetrate. For this reason, astronomers have been unable to view the planet’s features through optical telescopes. Most of the knowledge about Venus’ surface has been gained through radar images acquired from U.S. and Soviet space probes.
