Mars is spinning faster every year — experts don’t know why

Mars rotates a little faster each year, a new study using NASA data shows. There is also a second new discovery.

Pasadena – dates InSight space probe On the Mars They indicate that the Red Planet is spinning a little faster each year – and the Martian day is steadily shortening. The results of the search in the journal nature published. The study shows that the rotation of Mars on its axis is accelerating by about four parts of a second every year. As a result, the Martian day gets shorter by a fraction of a millisecond each year.

The research team, led by lead author Sebastien Le Maistre, has yet to discover the cause, but the research group has some suspicions. The accumulation of ice on the polar ice caps, or land masses that rise after being buried by ice, may be one of the reasons for the speeding up of Mars’ rotation.

“A shift in a planet’s mass can cause it to accelerate, just like a skater spins with his arms outstretched and then pulls his arms inward again,” says one. notice NASA’s Jet Propulsion Laboratory NASA to study.

New study: Mars rotates a little faster every year

The research team made the most accurate measurements of Mars’ rotation to date with the help of the RISE instrument on NASA’s InSight space probe. Although the spacecraft has been inactive since the end of 2022, the data it sent back to Earth by then is still valuable for research. “It’s really cool to get these recent measurements — and so specifically,” said NASA researcher Bruce Banerdt, principal investigator for the Insight mission. “I’ve been involved in the effort to get a geophysical station like InSight to Mars for a long time, and results like this make all the decades of work worthwhile.”

The RISE instrument consists of a radio transceiver and antennas. To determine the speed of Mars’ rotation, the researchers sent radio signals to InSight using NASA’s Deep Space Network. The RISE instrument reflects the signals back to Earth. There, the researchers were able to analyze how the frequency of the signal changes due to the so-called Doppler effect. The effect occurs with all signals when the distance between the sender and receiver changes over the duration of the signal.

The Doppler effect appears: Mars rotates around itself faster

On Earth, the best way to understand the Doppler effect is to listen for a siren to sound when an ambulance or police car overtakes you. As the vehicle approaches and recedes, the frequency and pitch of the signal changes. In the data from Mars, the researchers pay attention to the smallest fluctuations in the signals: “What we are looking for are fluctuations of only a few tens of centimeters over the course of a Martian year,” Meister explains to me. “It takes a very long time and a lot of data to be collected before we can even see these fluctuations.”