The Soviet probe Venera 4 reaches Venus and becomes the first spacecraft to measure the atmosphere of another planet.
Venus is the second planet from the Sun. Similar in size and mass to Earth, Venus has no liquid water, and its atmosphere is far thicker and denser than that of any other rocky body in the Solar System. The atmosphere is composed mostly of carbon dioxide and has a thick cloud layer of sulfuric acid that spans the whole planet.
At the mean surface level, the atmosphere reaches a temperature of 737 K, making it the hottest planet in the solar system and also a pressure 92 times greater than Earth's at sea level, turning the lowest layer of the atmosphere into a supercritical fluid. From Earth, Venus is visible as a star-like point of light, appearing brighter than any other natural point of light in the sky, as either the brightest "morning star" or "evening star".
It was also given the poetic name Ēarendel in Old English, meaning "ray of light" along with the two previous epithets.
Watch: What Makes Venus The Deadliest Planet In Our Solar System? | Zenith | Progress
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Sources and further reading: Wikipedia — Venus, Soviet Union, Venera 4 (CC BY-SA). Images: Wikimedia Commons.
