For a planet that has a lot to do with us – and just happens to be our nearest neighbor – there is actually a terrible lot that we did not know about Venus. And it’s not for lack of effort. The position and speed of Venus has put an end to an incredibly long process, so to make it easier to analyze, scientists took inspiration from the dance floor.
In a study published in Nature Astronomy on Thursday, a team descended from UCLA used radar to lower Venus’s length of a day, the size of its origin, and its exact tilt angle. “We use Venus as a giant disco ball,” said UCLA professor Jean-Luc Margot.
Between 2006 and 2020, the UCLA-led team aimed radio waves at Venus from the Goldstone Antenna in the Mojave Desert, California, acting like a flashlight. Like reflectors on a disco ball, waves rise in the landscape of Venus, allowing the team to track reflections and calculate details about the spin and tilt of the planet.
Experimentation is needed to work with precise timing to get accurate results. Both Venus and Earth had to be positioned correctly to get an accurate reflection.
The results show Venus tips from 2.6392 degrees on one side, gradually changing orientation over the course of 29,000 years. By comparison, the Earth tilts at 23 degrees and it takes only 26,000 years to change its orientation.
On top of this, the results indicate that an average day on Venus lasts for about 243.0226 Earth days – about two-thirds of the Earth year – with a rotation rate that varies 20 minutes more or less on any given day.
Using all these measurements, the team first calculated the size of Venus’s core: about 3,500 kilometers in diameter (about 2174.799 miles).
However, there is still much to learn about Venus – we do not know if the core is solid or liquid, for example, so the team will continue to investigate the disco ball to find out more.