In 1781, the German-born British astronomer William Herschel made Uranus the first planet discovered with the help of a telescope. This cold planet, the third largest in our solar system, remains an enigma 243 years later. And some of what we thought we knew about him turns out to be wrong.
Much of the knowledge about Uranus was gained when NASA’s Voyager 2 robotic spacecraft performed a five-day flyby in 1986. But scientists have now found that the probe visited the planet at a time of unusual conditions – an intense event of solar wind – which led to misleading observations of Uranus and, in particular, its magnetic field.
Solar wind is a high-velocity stream of charged particles emanating from the sun. The researchers looked at eight months of data from the time of Voyager 2’s visit and found that it encountered Uranus just days after the solar wind squeezed its magnetosphere – the planet’s protective magnetic bubble – to about 20% of its size. usual volume.
“We found that the solar wind conditions present during the flyby occur only 4% of the time. The flyby occurred during the maximum peak solar wind intensity for the entire eight-month period,” the physicist said. space plasma Jamie Jasinski of NASA’s Jet Propulsion Laboratory. , lead author of the study published Monday in the journal Nature Astronomy.
“We would have observed a much larger magnetosphere if Voyager 2 had arrived a week earlier,” Jasinski said.
Such a visit would likely demonstrate that Uranus’ magnetosphere is similar to those of Jupiter, Saturn and Neptune, the other giant planets in the solar system, the researchers said.
A magnetosphere is a region of space around a planet where the planetary magnetic field dominates, creating a protective zone against solar radiation and cosmic particles.
Voyager 2’s observations left a misleading impression of Uranus’ magnetosphere, which is devoid of plasma and has unusually intense belts of highly energetic electrons.
Plasma – the fourth state of matter after solids, liquids and gases – is a gas whose atoms have been split into high-energy subatomic particles. Since plasma is a common feature in the magnetosphere of other planets, its low concentration observed around Uranus was interesting.
“The plasma environment of any planetary magnetosphere is generally made up of plasma from the solar wind, plasma from any moons within the magnetosphere, and plasma from the planet’s atmosphere,” Jasinski said.
“On Uranus, we didn’t see plasma coming from the solar wind or the moons. And the measured plasma was very faint,” Jasinski said.
Uranus, blue-green in color due to the methane contained in an atmosphere composed mainly of hydrogen and helium, has a diameter of approximately 50,700 km. It is large enough to contain 63 Earths within it. Among the eight planets of the solar system, only Jupiter and Saturn are larger.
Its unusual tilt makes Uranus appear to orbit the sun like a rolling ball. Uranus, which orbits nearly 20 times farther from the Sun than Earth, has 28 known moons and two sets of rings.
Observations of Voyager 2 suggest that its two largest moons, Titania and Oberon, often orbit outside the magnetosphere. The new study indicates that they tend to remain within the protective bubble, making it easier for scientists to magnetically detect potential underground oceans.
“Both are believed to be prime candidates for hosting liquid water oceans in the Uranian system due to their large size compared to other major moons,” said Jet Propulsion Laboratory planetary scientist and study co-author Corey Cochrane.
Scientists are eager to find out whether the underground oceans of moons in the outer solar system have suitable conditions to support life. NASA launched a spacecraft Oct. 14 on a mission to Jupiter’s moon Europa to answer just that question.
“A future mission to Uranus is critical to understanding not only the planet and magnetosphere, but also its atmosphere, rings and moons,” Jasinski said.
Source: Terra
Rose James is a Gossipify movie and series reviewer known for her in-depth analysis and unique perspective on the latest releases. With a background in film studies, she provides engaging and informative reviews, and keeps readers up to date with industry trends and emerging talents.
