On Monday, the New York Times reported that scientists are exploring the possibility of vast oceans on Uranus and Neptune, two distant planets in our solar system that exhibit unusual magnetic field behavior.
Professor Burkhard Militzer, an astronomer at the University of California, Berkeley, published a paper in the Proceedings of the National Academy of Sciences offering a new perspective on the phenomenon. Professor Adam Masters from Imperial College London described the study as “a completely new perspective.”
On Earth, our magnetic field is generated in the core, like a giant magnet with the north and south poles as its axis. A similar phenomenon is observed on other planets, including Jupiter and Saturn, as well as on their moons.
When NASA’s Voyager 2 spacecraft flew by Uranus in 1986, it discovered that the planet’s magnetic axis was significantly tilted. For years, scientists speculated that this distortion resulted from an early shock during the planet’s formation. But in 1989, when Voyager 2 passed Neptune, the same magnetic anomaly was also found on that planet.
Militzer’s paper offers a new explanation. After simulating the movement of 500 different types of atoms, he estimates that both Uranus and Neptune have layers of water about 8,000 km (approximately 4,970 miles) thick. He suggests that these planets may have hydrogen-rich, highly conductive oceans that could significantly shape their magnetic fields. However, this water is likely to exist as a supercritical fluid in which gas and liquid phases are mixed due to the immense pressure, which is about 60,000 times greater than Earth’s.
This supercritical fluid is very different from the carbon-rich liquids found near Earth’s core and from Earth’s water or oil. Uranus’s core is roughly the size of Mercury, while Neptune’s core is larger, comparable to Mars.
Jupiter and Saturn, the gas giants of our solar system, are primarily composed of hydrogen. But Uranus and Neptune are much farther from the Sun, meaning they contain less hydrogen and more heavier elements.
As a result, Uranus and Neptune are unlike Jupiter and Saturn in that they contain both gas and solid matter.
Militzer speculates that these vast oceans may be responsible for the distorted magnetic fields of both planets rather than the traditional core-driven magnetic fields found on Earth and Jupiter.
NASA is considering a mission to send a spacecraft into Uranus’s orbit in the next decade. The goal would be to study the planet’s internal structure and magnetic field and confirm the existence of these mysterious oceans.