Scientists at Queen Mary University in London have made two discoveries about the behaviour of ‘supercritical matter’; matter at the critical point where the differences between liquids and gases seemingly disappear.

As temperatures and pressure increase, so our knowledge about the behaviour of matter decreases. But above the critical point, differences between liquids and gases seemingly disappear, and the supercritical matter was thought to become hot, dense and homogeneous.

By applying two different parameters, the Queen Mary researchers made two key discoveries: that there is a fixed inversion point between the two where matter changes its physical properties from liquid-like to gas-like; and also that this inversion point is remarkably close in all systems studied, which suggests the supercritical matter is intriguingly simple and amenable to new understanding.

Professor Kostya Trachenko said of the results: “The asserted universality of the supercritical matter opens a way to a new physically transparent picture of matter at extreme conditions. This is an exciting prospect from the point of view of fundamental physics as well as understanding and predicting supercritical properties in green environmental applications, astronomy and other areas.

“This journey is ongoing and is likely to see exciting developments in the future. For example, it invites the question of whether the fixed inversion point is related to conventional higher-order phase transitions? Can it be described by using the existing ideas involved in the phase transition theory, or is something new and quite different needed? As we push the boundaries of what is known, we can identify these new exciting questions and start looking for answers.”