How long is a day on Saturn? With Saturn's rings as seismographs, the mystery is finally solved.

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How long is a day on Saturn? With Saturn's rings as seismographs, the mystery is finally solved.

2019-01-22 17:30:54 305 ℃
After decades of uncertainty,

, scientists finally calculated the length of a day on Saturn. Saturn's unique magnetic field and landmark-free surface have long hindered scientists'ability to determine its rotation rate.

But thanks to Cassini's data, they have now solved the mystery. The vibrations captured by particles in Saturn's rings for the first time provide a window for understanding Saturn's internal motion, revealing that a day on this cold planet lasts only 10 hours, 33 minutes and 38 seconds.

According to a new study published in the Journal of Astrophysics, particles in Saturn's rings respond to Saturn's internal vibration just as seismographs do to earthquakes. This produces measurable fluctuation patterns. Christopher Mankovich, a graduate student at UC Santa Cruz, said that particles in Saturn's rings had no effect on the gravitational field, but felt these oscillations.

"At a specific location on the ring, these oscillations capture particles in the ring at the appropriate time in orbit, gradually accumulating energy, which is observed as observable waves."

Previous scientists believed that Saturn's day was estimated to be about 10 hours, 39 minutes and 23 seconds, based on radio signals captured by the Voyager spacecraft in the 1980s.

Others, based on Cassini's data, thought it might be any time between 10 hours, 36 minutes and 10 hours, 48 minutes. However, Saturn's magnetic field is not a reliable source of information for the calculation of Saturn's day, because it is almost identical to the planet's rotation axis.

Linda Spilker, a scientist at Cassini, said: "Researchers peered into Saturn's interior using the waves in Saturn's rings and then detected the basic features of the planet we've been looking for for for for a long time." This is a very reliable result. The answer lies in Saturn's ring. The discovery of

is only the latest discovery of Cassini after its mission ended in September 2017. On many Saturn orbits, it has observed Saturn's rings in more detail than ever before.

said Jnathan Fortney, professor of astronomy and Astrophysics at UC Santa and member of Cassini's research team, "Twenty years later, in the final years of Cassini's mission, scientists analyzed mission data and found features in Saturn's rings at Mark's predicted location."

"Current research aims to make full use of these observations." What did Cassini find in its 20-year space mission?

In 1997, Cassini was launched from Cape Canaveral, Florida. After seven years of flight, it circled Saturn for 13 years.

In 2000, it spent six months studying Jupiter until it reached Saturn in 2004. During this period, it discovered six satellites around Saturn, three-dimensional structures on Saturn's rings, and a huge storm sweeping Saturn for nearly a year. On December 13, 2004, it flew over Saturn's satellites Titan and Titan for the first time.

On December 24, ESA launched the Huygens probe built by ESA on Saturn's Saturn Saturn Saturn Titan to study its atmospheric and surface composition. Where

, it found strange hydrocarbon lakes composed of ethane and methane.

In 2008, Cassini completed its main mission of exploring Saturn's system and began its extended mission (Cassini Equinox Mission).

In 2010, it began its second mission (Cassini Solstice), which lasted until its crash in Saturn's atmosphere in 2017.

In December 2011, Cassini acquired the highest resolution image of Saturn's moon Enceladus.

In December next year, it tracked the transit of Venus to test the feasibility of observing extrasolar planets.

In March 2013, Cassini flew over Titan for the last time, measuring its internal structure and gravity. In July of the same year, Cassini observed a black Saturn, examined its rings carefully and took a picture of the Earth.

In April 2017, it completed its last mission over Titan and began its last large orbit flight on September 15. Andrew Coates, head of the planetary science team at the Mullard Space Science Laboratory at University College London, said: "This mission has changed our perception of where life might exist outside the Earth."

"In addition to Mars, exoplanet satellites like Titan, Europa and even Titan are now major competitors for extraterrestrial life," he added.

"We have completely rewritten the textbook on Saturn."