1900s Gallery

1919 solar eclipse

1919 solar eclipse. Image 2 of 3. This set of images, taken by the British astronomer Arthur Eddington (1882-1944), confirmed Einstein's theory of general relativity. The stars near the Sun appear slightly shifted because their light is curved by its gravitational field. This shift is only noticeable during a solar eclipse as at other times the Sun's brightness obscures the stars. This is a total solar eclipse, when the moon fits over the Sun so only its corona (atmosphere) is visible. Image taken form Principe Island, Gulf of Guinea, on 29 May 1919. For a sequence of the eclipse see R506/416-R506/418

© ROYAL ASTRONOMICAL SOCIETY/SCIENCE PHOTO LIBRARY

Alexei Leonov, first space walk, 1965

First space walk. Soviet cosmonaut Alexei Leonov (born 1934), outside the Voskhod 2 spacecraft in a spacesuit on 18 March 1965, while orbiting the Earth (in the background). This was the world's first extravehicular activity (EVA), or space walk. Voskhod 2 had launched earlier that day, and Leonov exited the spacecraft at 08:30 UTC. He remained outside for 10 minutes, before trying to re-enter. Because his suit had ballooned while outside, he had to let some of his air out before he could successfully re-enter. Cameras mounted on the airlock were meant to record the space walk, but most had to be abandoned due to the problems with Leonov's spacesuit. The CCCP on Leonov's helmet refers to the USSR

© RIA NOVOSTI/SCIENCE PHOTO LIBRARY

Carl Sagan, US astronomer

Carl Edward Sagan (1934-1996), US astronomer and astrochemist. Sagan was a consultant and adviser to NASA, and worked on the Apollo mission, as well as the Mariner, Viking, Voyager, and Galileo space probes and planetary exploration programs. He proposed theories to explain the high temperature of Venus, the seasonal changes on Mars, and the reddish haze of Titan. He was a prominent sceptic and populariser of science, writing many books on the subject. He also campaigned for nuclear disarmament, and spoke at the conference of the International Physicians for the Prevention of Nuclear War in Moscow in the summer of 1987. Photographed in 1987, in Moscow, Russia

© RIA NOVOSTI/SCIENCE PHOTO LIBRARY