Research groups at Okayama University and Osaka University have clarified that the origin of the strong magnetic field of Uranus and Neptune is the current flowing through the "metal water" inside the planet.
The main components of Uranus and Neptune, the outermost planets of the solar system, are thought to be water mixed with a small amount of carbon and nitrogen. Also known as "ice planets," these planets are about four times as large and 4 to 15 times as mass as the Earth, and are inside a world of high temperature and pressure.
NASA's Voyager 1980, a spacecraft that reached Uranus and Neptune one after another in the 2s, revealed that these ice planets have a source inside that creates a magnetic field that is dozens of times stronger than Earth. ..In order to create a strong magnetic field, it is necessary for a strong current to continue to flow, but since water, which is the main component of the ice planet, does not conduct much electricity, the mechanism of magnetic field generation has been a mystery for many years.
In this study, with the international cooperation of France and Japan, we conducted an experiment to solve this mystery using two high-intensity laser facilities representing both countries.By preparing a planetary simulated solution containing water as the main component and a little carbon and nitrogen, and irradiating it with a high-intensity laser to strongly compress it, the pressure inside the planet of about 300 million atmospheres was reproduced.However, since this huge pressure can only be maintained for about nanoseconds (one billionth of a second), by shining a measurement laser at the right timing and shooting the intensity of the reflected light with a high-speed camera. , The properties of the aqueous solution were measured.
As a result, it was found that the aqueous solution is in the state of a metal that reflects light.Interestingly, it was also found that the reflectance was significantly increased when carbon was contained compared to the case of pure water.From the above, it is considered that the current flowing in such a metallic fluid is the source of the magnetic field of the ice planet, and the carbon ions affect the properties of water.
It can be said that the existence of "metal water" was demonstrated and the origin of the magnetic field of the ice planet was clarified.
Paper information:[Scientific Reports] Laser-driven shock compression of “synthetic planetaryetch” of water, ethanol, and ammonia
