Gas giant planets are difficult to conceive. What is beneath the opaque clouds of planets like Uranus or Neptune? More gas? A solid core perhaps? Is there a defined limit or just a succession of different layers?
An ocean? A new study has pointed out the possibility that Uranus or Neptune hide oceans behind their clouds of hydrogen and helium. According to the results obtained by creating a computer simulation of the interior of these planets, successive layers could be found in them, some formed by hydrocarbons, others by water.
Layers that, as if they were water and oil, do not intermingle under the dense atmosphere of these frozen giants. The presence of these bodies of water could be linked to the unique magnetic fields of these planets in our solar system.
Different magnetic fields. When the Voyager 2 mission made its approach to this area of the solar system, it became the first (and still the only one) probe to approach Uranus and Neptune. In his approach he was able to study these planets, as well as their magnetic field, which was somewhat peculiar as we discovered at the time.
The Earth’s magnetic field, which arises as a result of the convective movements of the iron in its core, is dipolar, so it has a flow that oscillates between the north and south poles. Observations from the Voyager 2 probe showed us that the ice giants did not have a dipole field, but rather disorganized magnetic fields.
This led experts to assume that Uranus and Neptune had interiors divided into layers of compounds that did not mix with each other, preventing large-scale convective movements as occurs in the interior of the Earth. The challenge since then was to explain what the compounds in question were.
Simulating the interior. The new study has been based on computer simulations to be able to study what circumstances and compounds could explain this curious circumstance. These simulations showed layers of water, methane and ammonia, separated from each other in different layers, a circumstance facilitated by the escape of hydrogen atoms in the methane and ammonia layers as a consequence of pressure. Calculations based on this simulation imply the possible existence of a layer of water about 8,000 km thick on these planets.
“We now have, I would say, a good theory of why Uranus and Neptune have really different (magnetic) fields from those of Earth, Jupiter and Saturn,” study author Burkhard Militzer explained in a press release. “We haven’t known this before. “It’s like water and oil, only the oil stays down due to the loss of hydrogen.”
Militzer published the details of his analysis in an article in the journal Proceedings of the National Academy of Sciences.
A mission for the frost giants. The publication of the study has coincided with the appearance of another article, this one in the journal Geophysical Research Letterswhich speculated on the possibility that the gravitational interaction between Uranus and its moons could help a future mission to the ice giant to find evidence of oceans hidden in these satellites.
Uranus and Neptune are most interesting to astronomers since these types of planets are among the most common exoplanets we know of in our galaxy. Knowing this, it is not surprising that a few months ago a study carried out among astronomers found a certain consensus in the community about the need to organize a mission to Uranus in the next decade.
This mission would require launching a probe in the first half of the 2030s to take advantage of favorable orbital dynamics that would allow the spacecraft to reach the ice giant in just over a decade. There, not only the planet but also its moons could be closely studied and the possibility that one or others contain oceans of liquid water.
In WorldOfSoftware | The moons of Uranus guard secret oceans. And we know this thanks to data from 40 years ago
Image | NASA/JPL-Caltech
