Why does Saturn have rings and Jupiter doesn’t?  A computer model might have figured it out

Why does Saturn have rings and Jupiter doesn’t? A computer model might have figured it out

Jupiter, the fifth planet in our solar system and by far the most massive, is a mine of scientific discoveries. Last year, two studies found that the planet’s iconic Great Red Spot is 40 times deeper than the Mariana Trench, the deepest place on planet Earth. In April, authors of an article in the journal Nature Communications examined a double ridge in northwest Greenland with the same gravity-scaled geometry as on Europa, one of Jupiter’s moons, and concluded that Europa was more likely than expected to have life.

Now scholars think they’ve cracked another major Jupiter mystery — namely, why it lacks the spectacular rings sported by its celestial neighbor Saturn. Because it’s a very massive gas giant with similar composition, the evolution of the two planets is thought to be similar – meaning the reason why one has a prominent ring system and the other doesn’t has always been a mystery.

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With results now online and soon to be published in the journal Planetary Science, researchers at the University of California-Riverside have used modeling to determine that Jupiter’s huge moons nip possible ring formation in the bud.

Using a computer simulation that included the orbits of all four of Jupiter’s moons, astrophysicist Stephen Kane and graduate student Zhexing Li realized that the gravitational forces of these moons alter the orbit of any ice that might have come from a comet, ultimately preventing its accumulation in one would become a possibility to form rings as happened at Saturn. Instead, the moons would either fling the ice away from the planet’s orbit or drag the ice onto a collision course with itself.

Not only does this explain why Jupiter currently has only the tiniest of rings; it suggests that it probably never had large rings.


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There is more at stake here than just understanding why the aesthetics of Jupiter differ from the aesthetics of Saturn. As Kane explained in a statement, a planet’s rings hold many clues to that planet’s history. They can help scientists understand what objects might have collided with a planet in the past, or perhaps what type of event created them.

“For us astronomers, they are the spatters of blood on the walls of a crime scene. When we look at the rings of giant planets, it’s evidence that something catastrophic happened to put that material there,” Kane explained.

The scientists say they don’t plan to end their astronomical studies on Jupiter; Your next stop is Uranus, which also has tenuous rings. Researchers speculate that Uranus, which appears to have flipped on its side, may not have rings due to a collision with another celestial body.

Technically, Jupiter has a ring system, it’s just incredibly small and faint. In fact, Jupiter’s rings are so small that scientists didn’t discover them until 1979, when the Voyager spacecraft passed by the gas giant. There are three faint rings, all composed of dust particles emitted from the nearby moons – a flattened main ring 20 miles thick and 4,000 miles wide, a donut-shaped inner ring more than 12,000 miles thick, and so on—dubbed the “razor-thin” ring, which is actually three much smaller rings made up of microscopic debris from the nearby moons.

NASA itself has expressed amazement at the subtle rings that accompany our solar system’s most conspicuous giants — particularly the size of the particles that make them up.

“These grains are so tiny that a thousand of them combined are only a millimeter long,” writes NASA. “This makes them as small as the particles in cigarette smoke.”

In contrast, Saturn’s rings are famous for their beauty, and some of the particles in these rings are “as big as mountains.” When the Cassini spacecraft finally got a close-up look at Saturn’s rings, it found “spokes” longer than Earth’s diameter and possibly made of ice — as well as water jets from Saturn’s moon Enceladus, which would provide much of Saturn’s material in the E -Ring of the planet.

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