Voyager 2’s defining passage of Uranus may have been distorted by a rare cosmic event

Voyager 2’s defining passage of Uranus may have been distorted by a rare cosmic event

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When the Voyager 2 spacecraft became the first and only mission to fly by Uranus in 1986, defining the way astronomers understand the ice giant. But the data collected by the probe also introduced new mysteries that have continued to puzzle scientists in the decades since the historic flyby.

Now, a new look at the data has revealed that Voyager 2 happened to zoom past the distant planet during a rare event, suggesting that scientists’ current understanding of the planet may have been shaped – and skewed – by an unusual stellar coincidence.

The study’s findings, published Monday in the journal Nature Astronomymay have solved some of the riddles posed by Voyager 2’s strange Uranus measurements.

“The spacecraft saw Uranus in conditions that occur only about 4% of the time,” lead study author Jamie Jasinski, a space plasma physicist at NASA’s Jet Propulsion Laboratory in Pasadena, California, said in a statement.

The study results could also reinforce the idea that Uranus remains a largely misunderstood world, as astronomers’ basic knowledge of the planet emerged from an extraordinary anomaly.

Voyager 2’s flyby of the side-spinning Uranus revealed previously unknown rings and moons around the planet.

But the spacecraft’s observations of Uranus’ magnetosphere were very different from astronomers’ expectations, and scientists considered the planet an outlier among the other major planets in our solar system, such as Jupiter, Saturn and Neptune.

Magnetospheres are the protective bubbles around planets like Earth, which have magnetic cores and magnetic fields, and are driven by the planet’s magnetic field. These magnetic bubbles protect the planets from solar wind, a stream of energetic particles and gas that continuously flows from the sun.

Understanding how magnetospheres around other planets function not only helps scientists plan exploration missions, it also provides insight into how Earth’s magnetosphere works.

Voyager 2 data showed that Uranus’ magnetosphere was home to unexpectedly powerful electron radiation belts. Their intensity was comparable to the enormous radiation bands around Jupiter.

As the largest planet in our solar system, Jupiter has a magnetic field 20,000 times stronger than Earth’s. NASA. The magnetic field captures charged particles and accelerates them to high speeds. The fast-moving particles release energy in the form of intense radiation that bombards Jupiter’s nearest moons.

However, there was no obvious source for energetic particles to drive and amplify the intensity of the belts around Uranus because there seemed to be a lack of plasma or ionized gas, which was strange because plasma is a common element in magnetospheres around other planets. .

Voyager 2’s observations of Uranus’ magnetosphere defied astronomers’ understanding of how magnetic fields trap energetic particles and their radiation.

The astronomers were surprised by the lack of plasma, because five of Uranus’ icy moons exist in the magnetosphere, and they should have produced ions in the magnetic bubble that surrounds Uranus and some of its moons. This strange discovery led Voyager scientists to conclude that the moons must be completely inactive.

But a new analysis of Voyager 2 data showed that Uranus experienced a rare cosmic event just before the flyby.

Days before the flyby, an intense solar wind was unleashed by the sun, stirring up space weather throughout the solar system. The solar wind hit Uranus and dramatically compressed the magnetosphere, likely pushing out plasma. But the solar wind also made Uranus’ magnetosphere more dynamic by feeding it with electrons, strengthening the planet’s radiation belts, the new study said.

The first panel of this artist's concept shows how Uranus' magnetosphere (the protective bubble) behaved before Voyager 2's flyby. The second panel shows that an unusual kind of solar weather occurred at the same time as the spacecraft's flyby, causing Scientists got a distorted view of Uranus' magnetosphere.

“If Voyager 2 had arrived just a few days earlier, it would have observed a completely different magnetosphere on Uranus,” Jasinski said.

It’s likely that without any anomalies, Uranus’ magnetosphere would have looked the same as the magnetic bubbles around the other giant planets in our solar system, the study authors said.

The findings also suggest that some of Uranus’s moons could be geologically active, as they likely released ions into the magnetosphere before the solar wind temporarily carried the particles away.

“We emphasize that our understanding of the Uranus system is very limited, and our analysis shows that any conclusions from the Voyager 2 flyby are also preliminary,” the authors wrote in their study. “We suggest that discoveries made by the Voyager 2 flyby should not be given any typical character with respect to the magnetosphere of Uranus.”

The flyby of Uranus “was full of surprises” and researchers immediately began looking for a way to explain the unexpected data, said Linda Spilker, project scientist for the twin Voyager probes at JPL, who served as one of the mission scientists for Voyager during the mission. 2 served. that time. Spilker was not involved in the new research.

“Voyager 2’s measured magnetosphere was just a snapshot,” Spilker said in a press release statement. “This new work explains some of the apparent contradictions, and it will once again change our view of Uranus.”

If astronomers’ knowledge of Uranus is based on a flight performed under rare conditions, it suggests there may be good reasons to revisit the ice giant. The James Webb Space Telescope has already helped reveal new information about Uranus, including highlighting the usually hidden information rings, moons, weather and atmosphere.

Fortunately, sending a special mission to study Uranus in the future has become a priority for NASA, according to a report released in 2022.

The planetary decadal research advised the first devotee Uranus Orbiter and probe as the next big NASA mission. After launching as early as the early 2030s, the proposed spacecraft would make an orbital tour of the ice giant during flybys and deliver a probe to explore its atmosphere.

Meanwhile, the long-lived Voyager 2 has continued its journey and is currently nearly 13 billion miles from Earth, exploring interstellar space. His unique perspective contributes to helping astronomers understand the unknown region beyond our solar system.


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