An image of Venus compiled in 1974 using data from the Mariner 10 spacecraft NASA / JPL-Caltech
Since Venus is right next to Earth, you can assume that we know everything about our neighbor in the solar system. In fact, however, we don’t know much about this planet as factors such as the thick layer of sulfuric acid clouds hide most of its surface. And there are some seemingly basic questions about the planet that we don’t have the answers to – including the exact duration of a Venusian day.
Now, after 15 years of careful observation, researchers at the University of California at Los Angeles finally have an answer to this mystery. Using radar to ricochet signals off the planet’s surface, they were able to learn not only the length of its days, but also the size of its core and the axis about which it is tilted.
“Venus is our sister planet, and yet these fundamental properties have remained unknown,” said Jean-Luc Margot, UCLA professor of Earth, planetary and space sciences who led the research, in a statement.
A day on our sister planet lasts 243.0226 earth days, which corresponds to about two thirds of an earth year. Venus spins extremely slowly, which is why its days are so long, and it also spins in the opposite direction to Earth and most other planets. In addition, the speed of rotation changes over time, with the length of a day changing by up to 20 minutes. This has made it difficult to come up with an exact number for the length of his days.
“That probably explains why previous estimates were inconsistent,” said Margot.
The researchers believe that Venus’ strange, thick atmosphere may be responsible for this variation. Its atmosphere spins much faster than the planet, which could affect the rotation through momentum.
The team also discovered that Venus is tilted 2.6392 degrees and that its core is about 2,200 miles in diameter, making it a similar size to Earth’s core. Researchers made these discoveries by firing radio waves at the planets and observing when the waves bounced back and the echo could be captured by telescopes on Earth.
“We’re using Venus as a giant disco ball,” said Margot. “We illuminate it with an extremely powerful flashlight – about 100,000 times brighter than a typical flashlight. And if we follow the reflections of the disco ball, we can infer properties of the spin [state]. ”