Jupiter, the fifth planet in our solar system and by far the most massive, is a treasure trove of scientific discoveries. Last year, a pair of 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 a paper in the journal Nature Communications studied a double ridge in Northwest Greenland with the same gravity-scaled geometry as those found on Europa, one of Jupiter’s moons, and concluded that the likelihood of life on Europa is greater than expected.
Now scientists believe they have cracked another major Jupiter mystery – namely why it lacks the spectacular rings displayed by its celestial neighbor, Saturn. As a very massive gas giant with a similar composition, the evolution of the two planets is thought to be similar – meaning that why one has a prominent ring system and the other doesn’t has always been something of a puzzle.
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With results currently online and soon to be published in the journal Planetary Science, researchers from the University of California–Riverside used modeling to determine that Jupiter’s huge moons nip the formation of possible rings in the bud.
Using a computer simulation of the orbits of each of Jupiter’s four moons, astrophysicist Stephen Kane and graduate student Zhexing Li realized that the gravity of these moons would change the path of any ice that might come from a comet and ultimately prevent it from accumulating in one. a way to form rings, as happened with Saturn. Instead, the moons would either throw the ice away from the planet’s orbit or pull the ice on a collision course with itself.
This not only explains why Jupiter currently has only the smallest rings; it suggests that it probably never had large rings.
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There is more at stake here than simply understanding why Jupiter’s aesthetic differs from Saturn’s. As Kane explained in a statement, a planet’s rings contain many clues about the planet’s history. They can help scientists understand which objects may have collided with a planet in the past, or perhaps the type of event that formed them.
“To us astronomers, they’re the blood spatter 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 researchers say they do not plan to end their astronomical investigation at Jupiter; their next stop is Uranus, which also has puny rings. The researchers speculate that Uranus, which appears to be tipping on its side, may be missing 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 even discover them until 1979, when the Voyager spacecraft passed by the gas giant. There are three faint rings, all made of dust particles ejected from nearby moons—a main ring 20 miles thick and 4,000 miles wide, a donut-shaped inner ring more than 12,000 miles thick and so-called “gossamer ” ring that actually consists of three much smaller rings made up of microscopic debris from the nearby moons.
NASA itself has expressed astonishment at the whippy rings that accompany our solar system’s most conspicuous magnificence—especially at the size of the particles that make them up.
“These grains are so small that a thousand of them put together are only one millimeter long,” writes NASA. “That makes them as small as the particles in cigarette smoke.”
In contrast, the rings of Saturn are famously beautiful, and some of the particles in these rings are “as big as mountains”. When the Cassini spacecraft finally got a closer look at Saturn’s rings, it found “spokes” longer than Earth’s diameter and potentially made of ice — as well as jets of water from Saturn’s moon Enceladus, which would provide much of the material in the planet’s E ring.
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