Experiments on a microscopic scale have helped scientists shed new light on the chemical make-up of the solar system’s largest planets.

Researchers have used advanced laboratory techniques to reveal how hydrogen and helium – which make up most of Jupiter and Saturn – behave under the extreme pressures found inside the planets.

The findings suggest the gases do not react with each other inside Jupiter and Saturn, where pressures can be more than two and a half million times higher than Earth’s atmosphere, experts said.

The discovery comes after previous research suggested the gases do react under such high pressure.

The team from the University of Edinburgh team made the discovery by inserting tiny mixtures of hydrogen and helium into a device, known as a diamond anvil cell, used to create very high pressures.

A laser beam was then shone on to the high-pressure mixtures, creating distinct patterns of scattered light that reveal the structure of the molecules in each sample.

Using this technique, known as Raman spectroscopy, the experts found that hydrogen and helium are very unreactive, with no chemical bonds formed between them even under immense pressure.

Dr Robin Turnbull, of the university’s School of Physics and Astronomy, who led the study, said: “We hope that these results will prompt further investigations into the behaviours of elemental gas mixtures under extreme conditions.

“It’s important to remain critical of your own work and of the work of others.”

The study, published in the journal Physical Review Letters, also involved researchers at the Centre for High Pressure Science and Technology Advanced Research in China and the Carnegie Institution for Science in the US.

It was funded by the Engineering and Physical Sciences Research Council and the European Research Council.