A new study published in the journal Nature Astronomy says German scientists have succeeded in replicating the process of diamond rain formation similar to that on Neptune on a laboratory scale.

Unlike Earth or Mars, Neptune is a gaseous planet made up of gas giants instead of rocks. Going 7,000 km deep from the planet’s surface, the extreme heat and pressure cause the methane to turn into diamond crystals and fall like hail into the planet’s core. According to scientists, these diamonds can weigh millions of carats or hundreds of kilograms.

Previously, the creation of diamonds was only hypothetical, and this time German scientists have confirmed its feasibility. Dominik Kraus, lead author of the study at the Helmholtz Zentrum Dresden-Rossendorf laboratory, said. “The moment I saw the results of the experiment was one of the best moments in my scientific career.”

The team used the Linac Coherent Light Source instrument at SLAC National Accelerator Laboratory to transmit shock waves to the polystyrene specimen. Polystyrene is a perfect replica of the elements that exist in the ice cores of gaseous planets because it is made up of many chains of carbon and hydrogen.

Under the shock waves, nearly every atom in the sample turned into a nano-sized diamond. This is just an experiment on a miniature scale compared to the process that occurs on planets. The researchers think that the diamonds that form inside Neptune are many times larger in size. Depending on the mass and composition of the two planets, they can produce diamonds with a weight of up to 200 kg.

The study also marks the first time that scientists have been able to observe diamonds forming in real time. Previous research also simulated diamond formation under similar conditions but was unable to observe the process. A laboratory X-ray free-electron laser allows researchers to record what happens in a specimen over time up to a millionth of a billionth of a second.