Today’s Factismal: The Venera 4 probe was launched 47 years ago; it became the first probe enter another planet’s atmosphere.
Though the Moon and Mars grab all of the headlines, it is Venus that is Earth’s closest twin. Venus is just slightly smaller than Earth and has a surface that is very similar to Earth. But in 1967, about all that was known of Venus (or Venera in Russian) was that it was covered with clouds. If we wanted to know what was under them, we needed to send a probe.
Though Venus had been visited before by several probes, including the Venera 1 and Venera 2 probes from the USSR and the Mariner 2 and Mariner 5 probes from the USA, but none have them had actually done more than take a few readings as they sped past the planet. The Venera 3 probe had managed to crash-land on the planet but returned very little in terms of data. So the Russians and scientists everywhere had a lot riding on Venera 4. Fortunately, we got what we wanted.
Venera 4 managed to enter Venus’ atmosphere at a speed slow enough to keep it from disintegrating into useless bit of flaming metal. Instead, it came apart into carefully planned sections, including a large (1 yard across) capsule that was designed to float in the oceans that everyone knew covered Venus’ surface. When the probe landed, it showed that there were no oceans. Instead, Venus had an atmosphere composed of carbon dioxide and had sulfuric acid rain and a surface pressure nintey-two times greater than that of Earth and a temperature of 450°F. (To imagine what it would be like on Venus, pour acid over yourself while you are sitting in an oven at the bottom of the ocean. Fun times.) The results were so spectacular that many scientists wanted to disbelieve them. But they couldn’t, especially when later probes showed the same thing.
Of course, scientists are still interested in learning more about Venus. If you’d like to take part, then why not join the Venus Winds project as they try to discover why the atmosphere of Venus rotates faster than the planet itself?