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[EN VIDÉO] Neptune, such a mysterious blue planet. It's blue like the earth, but that's not because of the water. She…
As Futura explained 14 years ago in the very first article below, in 1981, physicist Marvin Ross of the Lawrence Livermore National Laboratory in California was one of the first to suggest that inside the giant planets Neptune, Neptune and Uranus, we would have been able to find Uranus They are real diamond hearts, which form under the action of the enormous pressure acting on the carbon compounds detected in their atmosphere.
The idea was taken up and developed further in Arthur Clarke's novels after 2001: A Space Odyssey. In 2010: Odyssey 2, following David Bowman's contact with the mythical black monolith left near Jupiter by a race of aliens millions of years ago, the astronaut's mind was uploaded into a network of light streams embedded in the foam structure of a Planets were integrated into space-timespace-time in more than 4 dimensions. Thus dematerialized, the new Bowman wandered through space at will and actually discovered that there was a diamond heart inside the giant planet.
The idea has been further explored through high-pressure physics experiments on Earth, as shown in previous articles below. The latest big problem is presented in a paper published in Nature Astronomy.
An international team of researchers led by Mungo Frost of the SLACSLAC National Accelerator Laboratory in California exploited the European diamond showers in icy giants such as Neptune and Uranus, of course, but also their cousins in the world of exoplanets.
The experiments conducted are broadly as follows.
This video shows the principle of diamond anvil cells to recreate in the laboratory the conditions that exist in the depths of the planets, here in the Earth's mantle, by placing very small pieces of magnetic iron oxide between the tips of two diamonds. The diamonds were pressed together to create pressures of up to 90 GPa. An infrared laser beam can then heat the sample to up to 1,000 °C. To translate into French, click on the white rectangle at the bottom right, then click on the mother, then “Subtitles” and “Auto translate”. © Carnegie Science
Neptune on Earth with diamond anvil cells
We start by using a plastic sheet made from a hydrocarbon compound of polystyrene and polystyrene, which we compress to pressures similar to those found inside these planets using the famous diamond anvil cells. The film lies between the tips of two transparent artificial diamonds that are transparent to X-rays. With them we can heat the plastic film to several thousand degrees.
Ultimately, a whole range of pressures and temperatures are accessible, reproducing those found at different depths. The new thing about the experiments carried out is that they last longer than the previous ones. The same X-rays that heated the material to over 2,200 degrees Celsius also showed the formation of diamonds in the plastic film.
The researchers then found that diamond could be formed at lower temperatures and pressures than they thought. We might conclude that diamond rains must form in relatively shallow layers of the atmosphere of the solar system's ice giants, but also of the mini-Neptunes outside.
That's an interesting discovery in itself, but physicists say there's more, as explained in a press release from SLAC.
A layer of conductive ice in convection?
We know that Uranus and Neptune have surprising magnetic fields compared to those of Earth, almost resembling those of a bar magnet slightly tilted from the rotation axis of our blue planet. In the ice giants, not only are the magnetic fields tilted by tens of degrees relative to the axis of rotation, but the axis of the magnetic dipole itself does not pass through the center of the two giants.
In the case of the Earth, we know that the magnetic field is generated by a so-called self-exciting dynamo in the liquid, convective and turbulent part of the core of our planet, all influenced by its rotation, which explains the close relationship between the axis of rotation and the axis of the magnetic field . In the case of Uranus and Neptune, the situation is inevitably different than on Earth, although it is based on similar physics to the one we know how to explore in the laboratory with the VKS experiment.
It now seems plausible that the key to the puzzle lies in the existence of diamond showers that begin at relatively shallow depths inside Uranus and Neptune. They would lead to the formation of a convection envelope, also flat, as they descend from the outer layers into the inner layers of the planet, causing ice flows. Specifically, the new results show that diamonds form on a layer of conductive ice, which they stir up as they fall. The resulting currents would then enable the formation of a self-exciting dynamo.
Article by Laurent SaccoLaurent Sacco published on August 28, 2017
There would actually be showers of diamonds on giant planets like Neptune or Uranus. This is confirmed by experiments in the field of high pressure physics.
The current models of the internal structure of the giant planets of our solar system are heirs to those proposed by the American astrophysicist of German origin Rupert Wildt in the 1940s and 1950s. However, these models need to be clarified thanks to experiments on high pressure physics and numerical simulations, learned numerical simulations on the computer. These models are also based on purely theoretical work. So, in the early 1980s (see article below), American researchers came to the conclusion that the cores of giant planets, especially Neptune and Uranus, could contain colossal amounts of diamonds in solid form. The challenge now is to test this prediction in the laboratory on Earth by conducting experiments with materials compressed using laser beams at very high pressure.
One of the latest experiments in this area was carried out using a visible-emitting laser and the Matter in Extreme Conditions (MEC) instrument connected to the SLAC free-electron laser, the Linac Coherent Light Source (LCLS). . The aim was to apply intense pressure using shock waves generated by the impact of laser pulses on a plastic material, in this case polystyrene (made up of a mixture of hydrogen atoms, hydrogen and carbon, which is found in very large quantities on giant planets). generate, especially in the form of methane).
Rain of diamonds weighing millions of carats
The aim of the American and German researchers at the Helmholtz Center Dresden-Rossendorf was not only to recreate the pressure and temperature conditions inside the giant planets, but also to recreate the chemical reactions that take place there. Better yet, they wanted to watch these reactions live. Therefore, in parallel with the creation and propagation of shock waves in the plastic, it was exposed to laser pulses in the X-ray range for a few femtoseconds (femtoseconds). This allowed physicists to put into practice an X-ray diffraction technique called “femtosecond,” which, in a sense, allows taking snapshots of the reactions produced. This allowed them to determine that nanodiamonds are actually forming, but also determine their size and observe how they grow over time.
As the researchers explain in an article published in Nature, the results obtained represent the first clear observation of the formation of diamonds at high pressure in an environment with conditions similar to those inside the planet Neptune (at pressures of about 150 gigapascals and temperatures of the order of 5,000 Kelvin) in accordance with theoretical predictions.
Did you know ?
In jewelry, the carat is a unit of mass for gemstones. It is equivalent to 200 mg or 5 carats per 1 gram. It should not be confused with the jeweler's carat, which indicates the degree of purity of a precious metal, such as gold.
The diamonds synthesized in these experiments are in the nanometer range. However, evidence suggests that the diamonds formed inside giant planets such as Uranus and Neptune are actually much larger, reaching several million carats in weight. Over millennia, these diamonds must slowly sink into the layers of ice that surround the rocky hearts of the giant planets. In the end, real diamond layers will most likely have to form around the hearts of these giants, from diamond rains that form 10,000 kilometers below the surface of Uranus and Neptune.
These experiments are interesting not only from the perspective of high-pressure materials and astrophysics, whether we are talking about the giant planets of the Solar System or similar exoplanets located elsewhere in the Milky Way. In fact, this nanodiamond synthesis technique could have interesting technological applications in the field of medicine or electronics; Such nanodiamonds are now produced and commercialized by explosion. A synthesis route using lasers could therefore offer more interesting prospects from a cost perspective. This work could also have application in the field of controlled inertial fusion, where thermonuclear fuel spheres containing deuterium and covered with plastic layers are used.
Article by Laurent Sacco published on January 20, 2010
Nearly thirty years ago, two researchers showed that the cores of giant planets like Neptune and Uranus could contain colossal amounts of diamond in solid form. Experiments now show that we can imagine oceans of liquid diamond covered in icebergs…
When the Beatles sang “Lucy in the Sky with Diamonds,” they probably didn't know that there were actually nanodiamonds floating in interstellar space and even found in some meteorites. In 1981, Marvin Ross was one of the first to suggest that real diamond hearts could form inside the giant planets Neptune and Uranus under the effect of the enormous pressure acting on the carbon compounds detected in their atmospheres.
The idea was taken up and developed further in Arthur Clarke's novels after 2001: A Space Odyssey. After David Bowman's contact with the black monolith left by a race of aliens near Jupiter millions of years ago, the astronaut's mind had been uploaded into a network of light streams, embedded in the foam structure of a space-time with more than 4 dimensions. Thus dematerialized, the new Bowman wandered through space at will and actually discovered that there was a diamond heart inside the giant planet.
The idea that a star could have a heart of diamond is not the speculation of an uninhibited theorist. For example, we have long known that the core of a white dwarf carbon must crystallize over time and as the star cools. However, in 2004, a group of astrophysicists studying the pulsations of a white dwarf located about 50 light-years away in the constellation Centaur (BPM 37093) announced that the methods of asteroseismology led to the realization that a significant portion of the White dwarfs have actually crystallized in the form of diamond.
Today, a group of researchers at Lawrence Livermore National Laboratory published in Nature the results of studies that examined the melting point of carbon at high pressures. Typically, a liquid phase of diamond is not observed in the laboratory because it transforms into graphite before fusion begins. However, by applying pressures on the order of 40 million atmospheres using laser beams, it is possible to achieve a phase transition that emanates from solid diamond instead of graphite.
To their surprise, once the liquid was extracted and the pressure dropped to 11 million atmospheres and the temperature also dropped to 50,000 K, the researchers observed that not only did fragments of the solid diamond reappear, but they also floated on the surface like icebergs fluid.
Neptune and Uranus consist of about 10% carbon and conditions similar to those above must exist at great depths on these planets. So huge diamond icebergs could be floating on liquid carbon.