The "mantle" of Uranus and Neptune may be made of ice XVIII, which is why they have a peculiar magnetic field.
Ice is something we are very familiar with, and water freezes into ice when the temperature drops below 0 ° C. But are you really familiar with ice? Did you know that so far scientists have discovered 19 types of ice?
Ice's "sibling" brother
You read that right, there are indeed 19 kinds of ice on Earth, and as recently as February 2021, Thomas Loltine, a physical chemist at the University of Innsbruck in Austria, said that he and his team had created the 19th type of ice on Earth, Ice XIX. You must be very strange, usually we see the ice, is not a piece of transparent and colorless solid? How are they divided into 19 species?
On the Earth's surface, atmospheric pressures are 1.0×10 Pa (a standard atmospheric pressure), and under this pressure, water freezes at 0°C. But we know that as the pressure increases, the boiling point of the object will rise, and in the same way, the freezing point of the object will also rise, and the order of atoms inside the object will also change, thus affecting the physicochemical properties of the object, then we can think that a new substance is produced.
Ice I is the kind of ice that can be found everywhere on Earth, oxygen atoms are arranged in a hexagonal arrangement, in which hydrogen atoms are randomly oriented in different spatial directions, and there is no definite order between atoms, so ice I can deform when the pressure changes, which is the reason for glacier flow. But in other pressure and temperature conditions of frozen ice, the arrangement of oxygen atoms will change, some will be square, some will be cage-shaped, and so on. In this way, the spacing between the hydrogen atom and the oxygen atom will change, and when the spacing becomes narrower, it will force the hydrogen atoms between the oxygen atoms to form a fixed order, and this ordered ice is very brittle and will break rather than deform when the pressure changes. In addition, due to changes in the spacing of atoms, the forces between atoms will also change, and these atoms will no longer be as "indifferent" as the hydrogen and oxygen atoms in Ice I, and they may interact with other object atoms, resulting in unexpected effects.
In 1900, the German physical chemist Gustav Tamann proposed that freezing water at different pressures and temperatures can make different ice, and used a high pressure of 200 megapascals and a temperature of -70 ° C ~ -80 ° C to produce the world's second kind of ice - ice II with oxygen atoms arranged in cubes. By further adjusting the temperature and pressure, later generations created Ice III. Until ice XVIII.
When physicists created the Ice XV, they found that it had a different relationship with Ice VI than the other Ice Brothers: they were closer "twins" to each other. The densities of ice XV and ice VI are very similar in that they share the same network of oxygen atom structures, except that the hydrogen atoms in them are not arranged in the same order. This means that only the pressure and temperature conditions need to be changed, and the two ice forms can be converted to each other. This pattern was used by Loltine's team to make ice XIX: by cooling ice XV to -170°C and dramatically increasing the pressure to 2 gigapascals. Conversely, by heating ice XIX at atmospheric pressure, ice XV and ice VI can be obtained. This is another way to make ice brothers, and it's clear that this approach favors the more efficient discovery or creation of new types of ice.
The Ice Brothers are widespread on alien planets
Knowing the types of ice brothers, you must have such doubts, although there are many types of ice, but on the surface of the earth, under normal circumstances, there can only be one kind of ice, other ice is quickly made, and there is no practical effect, why do scientists spend so much effort to make these ices?
Although there is only one type of natural ice on the surface of the Earth, other types of ice may be widespread in the depths of the Earth and on other planets in the universe. Ice deep in the Earth can combine with other materials into new states, and understanding these states is conducive to solving some long-outstanding problems. The existence of ice in the outer planet not only explains some previously unknown planet mysteries, but also proves that there may be water in the outer planet, and water is an indispensable substance for the origin of life. That's what it means to understand the types of ice.
On January 24, 1986, the U.S. interstellar probe Voyager 2 arrived near Uranus and probed some basic conditions of Uranus. In the data sent back by Voyager 2, the researchers found a confusing phenomenon. There are planets in the solar system that have magnetic fields like Earth, which are similar to the geomagnetic fields, with clear south and north poles, and according to the data transmitted by Voyager 2, Uranus's magnetic field is extremely complex, not only the north and south poles, it has multiple magnetic poles, and the direction of magnetic field flow is not consistent with the direction of its rotation. Uranus is not unique, and the same phenomenon has appeared on Neptune.
The reason why the geomagnetic field has a clear pole is because the liquid iron in the core of the earth shows a regular flow, generating a current with a fixed direction, so the direction of the geomagnetic field remains basically stable. The direction of the magnetic fields of Uranus and Neptune is so chaotic that it can only be explained by the fact that there is no regularly operating "generator" in the core of the Earth, and its electric field and current exist in all corners of the shell, so the magnetic field lines produced are different directions. To support this explanation, in 1988, scientists predicted that inside Uranus and Neptune, water would freeze into a new type of ice, Ice XVIII, which is an electrically conductive ice that produces electric and magnetic fields in multiple directions due to extreme pressures and extreme temperatures.
It wasn't until May 2019 that this conjecture was confirmed: scientists at the Lawrence Livermore National Laboratory in the United States successfully created ice XVIII with the help of high-energy lasers and X-rays. On the table top of the laboratory, two opposite diamonds are placed, sandwiched between them with a thin layer of water. When the scientist pressed the button of the laser, 6 huge laser beams produced a series of shock waves of gradually increasing intensity, instantly giving this thin layer of liquid water a pressure equivalent to 4 million times the atmospheric pressure and heating it to a high temperature of up to 2760 ° C, a new oxygen cube of ice formed, which is ice XVIII.
Although ice XVIII melted quickly, X-rays scanned ice XVIII in an instant, recording its atomic structure. According to the data obtained by X-rays, in ice XVIII, oxygen atoms are imprisoned into a square lattice, and the distance between atoms is very close, so some hydrogen atoms can move between adjacent water molecules, as if they are flowing because of their speed. In the process of flow, the electron failed to catch up with the pace of protons, was abandoned in place, and finally participated in the flow of protons that were actually positively charged, so that the ice XVIII generated an electric current, which is why the ice XVIII can conduct electricity. Inside Uranus and Neptune, it may be the "mantle" of ice XVIII,which, due to its peculiar electrical conductivity, prompts the two planets to produce different magnetic fields.
The "Ice Brothers" deep in the Earth's crust
Not only the outer planets, but also some different "ice brothers" exist deep in the earth, which constitute "cages" that bind certain substances. In 2014, scientists at the University of Göttingen in Germany found naturally occurring ice XVI in neon gas hydrates. A gas hydrate is a cage-shaped crystal-like ice in which foreign gas molecules are firmly enclosed by a crystal network formed by hydrogen bonds of water molecules. The researchers extracted the neon gas from the neon gas hydrate, leaving only the crystal structure formed by water molecules, which is ice XVI, which is the least dense of the ice crystal forms, so it can bind the neon gas with a very small mass.
In addition to neon gas hydrates, there are other types of gas hydrates deep in the Earth's crust, such as methane hydrates (immovable ice) found in large quantities in permafrost layers and seabeds. Some scientists envision that if methane from combustible ice could be released for energy use while fixing carbon dioxide in gas hydrates, it would both capture energy and reduce greenhouse gases in the atmosphere. Finding the "Ice Brothers" who can achieve this heavy task may be able to realize this vision.
In addition, in the process of oil and gas transportation, special pressure and temperature environments can easily make some gases and water form gas hydrates, thereby blocking pipelines. The researchers believe that further understanding of gas hydrates could also help solve this problem.
The 19 ice brothers with very different "personalities" may be spread across all corners of the universe and play different roles. In the future, what surprises will ice cubes give us?
The reproduced content represents the views of the author only
Does not represent the position of the Institute of Physics, Chinese Academy of Sciences
Source: Big Tech
Edit: Garrett