One of the most peculiar things about Uranus and Neptune is their magnetic fields. Each of these planets has a hot mess of magnetospheres, deviated and wildly tilted from their spin axis in a way not seen on any other planet.
It’s not entirely clear why, but thanks to a team of researchers from China and Russia, we might have a new piece of the puzzle: a really strange, ionized form of water called aquodiium that could exist deep within the extremely high-pressure interiors of these houses. strange, icy worlds.
Akvodium consists of a normal water molecule with two additional protons, giving it a net positive charge that – in sufficient quantities – could create a planetary magnetic field similar to that of Uranus and Neptune.
They are produced by planetary magnetic fields far out into space around the planets. However, they are generated deep within the planet by moving charges, although the exact mechanism may vary.
On Earth, it’s an iron-nickel alloy that spins around the core, spins, flows, and is electrically conductive, converting all that kinetic energy into streams of electrons. in what is called a dynamo. For Jupiter and Saturn, scientists think it’s metallic hydrogen that provides a conduit for the flowing electrons.
Earth, Jupiter, and Saturn have relatively ordered magnetic fields that resemble those of a giant bar magnet running along the planet’s axis of rotation, its field lines neatly connecting the north and south poles like a cage.
In contrast, the magnetic poles of Uranus and Neptune are tilted 59 and 47 degrees from their spin axes, and the magnetic field lines are constantly changing and shifting. And they are not actually concentrated in the cores of the planets.
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One possible explanation is that the magnetic fields could be generated by an ionically conducting fluid in which the ions are the charge carriers rather than the fluid acting as a conductor for the electrons.
“Hydrogen surrounding Jupiter’s rocky core at these locations [high-pressure] conditions is a liquid metal: It can flow, the way molten iron flows in the interior of the Earth, and its electrical conductivity is due to the free electrons shared by all hydrogen atoms compressed together,” explains theoretical chemist, mineralogist and physicist Artem Oganov. from the Skolkovo Institute of Science and Technology in Russia.
“In Uranus, we think that the hydrogen ions themselves – i.e. the protons – are the free charge carriers.”
So the question is which ions? Some, like ammonium, are obvious choices. But could the water molecules of the planets also play a more significant role in this process?
A team of researchers led by physicist Jingyu Hou of Nankai University in China went back to first principles combined with models of how molecules can evolve and delved into a concept called chemical hybridization.
This is when the orbital elements of an atom are mixed or combined to form an atom that can bond in new ways. There are different types of hybridization, but one relevant here is sp3 hybridization, where four orbitals form a tetrahedral arrangement around a central nucleus.
Each of the four points of the tetrahedron has either a lone electron capable of bonding with another atom, or an electron pair that cannot form bonds with other atoms.
Oxygen has two single electrons and two electron pairs in its outer shell. If you attach a hydrogen atom to each of the available valence electrons, you get H2O – water.
Sometimes hydrogen without its electron—also known as a plain old proton—will attach itself to one of the electron pairs to form a molecule called a hydronium ion.
“The question was: Can you add another proton to the hydronium ion to fill in the missing piece? Such a configuration is energetically very unfavorable under normal conditions, but our calculations show that there are two things that can cause this,” says the physicist. Xiao Dong from Nankai University.
“First, very high pressure forces matter to shrink in volume, and sharing a previously unused electron pair of oxygen with a hydrogen ion (proton) is an elegant way to do this: like a covalent bond with hydrogen, except for both electrons in the pair. Second, you need lots of protons available, and that means an acidic environment, because that’s what acids do—they supply protons.”
Scientists performed computational modeling and under conditions similar to those believed to exist inside Uranus and Neptune, this happened. At temperatures around 3,000 degrees Celsius (5,430 Fahrenheit) and pressures of 1.5 million atmospheres, protons attach to hydronium to form H4O2 – aquodium.
It’s still theoretical, of course. More detailed observations of the two most distant planets will be needed to investigate this possibility further; but the findings give us a new way to understand the blue freaks that are Uranus and Neptune.
And they also have implications for chemistry in general, representing, the researchers write, “an important addition to traditional physical and chemical theories such as the valence-shell model of electron pair repulsion, proton transfer, and acid-base theory.”
The research was published in Physical overview C.