Coldest experiment in the known universe reveals startling discovery

29 Nov 2019

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Millions of times colder than interstellar space, a new experiment has revealed something never seen before in molecules.

A team of scientists from Harvard has pushed science to the limit of absolute zero, creating a never-before seen event where two molecules collide at glacial speeds.

Writing in Science, the team said this was the coldest chemical reaction in the known universe, having been conducted at 500 nanokelvin, or just a few millionths of a degree above absolute zero.

When brought down to such extreme temperatures within an experiment filled with chaotic lasers, the team led by Kang-Kuen Ni was able to see, for the first time, the moment when two molecules meet to form two new molecules. In essence, they captured a chemical reaction in its most critical and elusive act.

First author of the paper, Ming-Guang Hu, said of this discovery: “Probably in the next couple of years, we are the only lab that can do this.”

This work builds on previous research started five years ago to build a new set-up that could achieve the lowest temperature chemical reactions of any currently available technology. But the team did not know this device could see the formation of new molecules.

The coolest thing ever

Understanding chemical reactions is fundamental to our understanding of science, and by looking at how they work at their most basic level, researchers could design combinations the world has never seen.

Such pioneering combinations could have near-endless applications, Ni said, but could include more efficient building blocks for quantum computers or even mould-proof walls.

Until now, attempting to see such chemical reactions – lasting just millionths of a billionth of a second – seemed to be impossible using the most sophisticated imaging technology. For example, using ultra-fast lasers such as fast-action cameras, snapping rapid images of reactions as they occur.

However, this isn’t the case with this new discovery as the extreme temperatures create a “bottleneck effect”, according to Ni. The team’s experiment was able to see the reaction of two potassium rubidium molecules for a few microseconds, millions of times longer than usual and long enough to catch the reaction in the act.

Looking to the future, the team thinks it could use this new testbed to challenge a number of scientific theories, even in the quantum realm.

Colm Gorey was a senior journalist with Silicon Republic