Class Notes: 4f – Venus
- The second closest planet to the Sun
- Because of the planet’s cloud cover, little can be seen on the planet
- Its almost circular orbital period around the Sun lasts is 224.7 Earth days
- A Venusian day lasts a whopping 118 Earth days
- And the Sun rises in the west and sets in the east since Venus rotates in the opposite direction to Earth!
- It’s the brightest planet in the Solar System, earning it the nickname of ‘the Morning Star’
- Venusian geography is comprised of a huge plain and some highlands and lowlands.
- The highlands cover approximately 27% of the planet, the lowlands 8%, and the plains the rest. There are two main highland areas known as Ishtar Terra and Aphrodite Terra as well as a third, smaller highland area called Beta Regio where Rhea Mons, Theia Mons, and a shield volcano are found.
- The highest points on Venus, on the eastern side of the Ishtar Terra, are the Maxwell Mountains that were named after the Scottish physicist James Clerk Maxwell.
- The atmosphere consists almost entirely (96%) of carbon dioxide, a greenhouse gas responsible for the incredibly hot, greater than 400ºC conditions on Venus, surpassing the melting point of lead.
- The rest of the atmosphere is comprised of 3% nitrogen, 0.003% water vapour, and small quantities of other gases.
- The atmosphere rises to about 400km above the surface of the planet. The clouds situated around 30 km above the surface are rich in sulfuric acid; during precipitation the acid rain evaporates before hitting the ground.
- The 19th Century astronomer – Franz Von Paula Gruithuisen, believed that inhabitants on the planet were responsible for lighting objects in celebration of the accession of a new emperor
- Until the early 1960s, Venus was believed to possibly be oceanic even though the temperature was enough to make it a vast desert. Finally, in 1962, the Mariner 2 spacecraft passed by Venus and sent back data putting an end to this hopeful theory.
- In 1970, the Soviet Union landed the first spacecraft on the planet’s surface. Venera 7 sent back information for 23 minutes before losing contact with ground control (most likely due to the temperature).
- in 1975, Venera 9 landed and sent back the first image of the rocky Venusian surface (thereby confirming the high temperatures) and returned atmospheric data.