New research using data from the Voyager 2 mission shows a solar wind event took place during the flyby of Uranus, leading to a mystery about the planet’s magnetosphere that now may be solved.
Key points
- In 1781, German-born British astronomer William Herschel made Uranus the first planet discovered with the aid of a telescope.
- This frigid planet, our solar system’s third largest, remains a bit of an enigma 243 years later.
- NASA’s Voyager 2 flyby of Uranus in 1986 shaped scientists’ understanding of the planet but also introduced unexplained oddities. A recent data dive has offered answers.
- Scientists have now discovered that the probe visited at a time of unusual conditions – an intense solar wind event – that led to misleading observations about Uranus, and specifically its magnetic field.
- The Voyager 2 observations left a misimpression about the magnetosphere of Uranus as lacking in plasma and possessing uncommonly 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.
- Plasma is a common feature in the magnetosphere of other planets so its low concentration observed around Uranus was puzzling.
About Uranus
- Uranus is the seventh planet from the Sun, and it has the third largest diameter of planets in our solar system.
- Uranus, blue-green in color due to the methane contained in an atmosphere comprised mostly of hydrogen and helium, has a diameter of about 31,500 miles (50,700 km).
- It is big enough to fit 63 Earths inside it. Among the solar system’s eight planets, only Jupiter and Saturn are larger.
- Its unusual tilt makes Uranus appear to orbit the sun like a rolling ball.
- Uranus, which orbits almost 20 times further from the sun than Earth does, has 28 known moons and two sets of rings.
- Uranus is the only planet whose equator is nearly at a right angle to its orbit, with a tilt of 97.77 degrees.
- Uranus is also one of just two planets that rotate in the opposite direction than most of the planets. Venus is the other.
