In nature, water can be observed in three different phases: liquid, solid and gas. However, for decades, scientists believe that deep within the Earth molecules of this element can take strange shapes that defy all logic.
Now, a strange new state of matter has been discovered for the first time during an experiment at the University of Chicago. Its about super ionic ice which is believed to exist under the conditions of temperature and pressure at the center of the Earth and inside other icy giant planets.
Unlike regular ice from the fridge or popsicles, super ionic ice is black, ultra-hot and weighs even more than normal says geophysicist Vitali Prakapenka, lead author of the research.
This state of matter, which had been theorized three decades ago, was first proven in a 2018 experiment that lasted for nanoseconds. However, in the most recent trial it reached a stable form for microseconds, a fraction of the time enough to appreciate its transformation and be studied in detail.
In the experiment, detailed in an article in the journal Nature Physics, the scientists squeezed a drop of water under pressure from two diamonds – the hardest mineral on Earth – and then subjected the sample to heat from lasers.
This simulation was extreme, since the pressure exceeded 3.5 million times that of the Earth’s atmosphere and the heat was even greater than that of the Sun’s surface. After that step, they detected how the atoms were organized inside of ice using X-rays.
The team was surprised: in this state the ice became less dense and was black. In addition, they ensure that this phase appeared at lower pressures than the previous study showed: at 20 gigapascals of pressure instead of 50.
By definition, water is the inseparable grouping of two hydrogen atoms with one of oxygen, for that reason its chemical name H2O. However, at different temperatures and pressures, such as in the interior of the planet, water can mutate.
For example, scientists have so far described 18 ice phases that could exist inside the Earth. But superionic ice does not share any similar characteristics to other forms of water and for that reason some classify it as a new state of matter.
According to Paprenka, here the two water molecules break apart and cause the hydrogen atoms to flow inside a cubic lattice of oxygen atoms. “It’s like a solid network of oxygen atoms sitting in an ocean of floating hydrogen atoms,” said the study leader.
Due to this “cage” of hydrogen atoms, light cannot pass through the ice and thus gives it its dark appearance.
According to the team, free hydrogen ions from super-ionic ice play a key role in maintaining our planet’s magnetic fields, which prevent dangerous solar radiation. So now they wonder if their presence on other planets such as Neptune, Uranus or even more distant ones can suggest a trace of extraterrestrial life.