Venus: atmosphere ensures different lengths of day


The extremely dense atmosphere of Venus is responsible for the fact that the lengths of a day on the planet differ from one another by up to 20 minutes. This is probably one of the most exciting findings from the most precise measurements to date of various characteristics of the second planet in the solar system, which a research team has now presented. The results suggest that the extremely dense atmosphere of Venus exchanges kinetic energy with the surface on its way around the planet and thus speeds up or slows down the rotation of the planet. This also happens on Earth, but here there are only differences in the range of milliseconds.

The analysis is now in the trade magazine Nature Astronomy presented. For their work, the team used around Jean-Luc Margot from the University of California, Los Angeles, two large radio telescopes. With the 70-meter Goldstone antenna in California, they sent signals to Venus a total of 21 times between 2006 and 2020, which reflected them. They then received the echo with both the Goldstone telescope and the Green Bank observatory. From the time differences between the reception of the echoes, they were able to determine, among other things, how fast the planet is rotating. In addition, they could have determined the inclination of Venus ten times more accurately than before.

According to the measurements, a day on Venus lasts an average of 243.0226 earth days. The results also explain why different values ​​have so far been determined in measurements. From the precise measurements of the rotation of Venus, the team was even able to calculate that the core of the second planet has a diameter of around 3500 kilometers. It is comparable to that of the earth. However, they cannot yet say whether the core is liquid or solid.

Research shows once again how little we still know about Earth’s other neighboring planets. Venus has long been in the shadow of Mars, which is currently being studied by several probes and even rovers. The researchers now want to extend their method for measuring Venus to other celestial bodies in the solar system and first target the Jupiter moons Ganymede and Europe. Both of them assume oceans below the surface and they hope that the radar measurements could confirm and measure them.


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