Hot Take: Chinese scientists create substance colder than deep space

Chinese scientists have created the coldest substance ever made by humans – and it's colder than deep space.

By cooling a cloud of rubidium atoms down to an equivalent temperature of 9.7 picokelvin, less than a trillionth of a degree above absolute zero, the research team achieved a milestone in quantum physics.

But first, they had to overcome a major hurdle: gravity.

On Earth, gravity constantly pulls atoms downward. Scientists can't pin the elusive little particles down. And if you can't hold them, you can't cool them.

So, the team engineered a "super fridge" – an ultracold atom physics facility – and launched it to the China Space Station. In microgravity, atoms float freely – much like the toothpaste you've seen in astronaut videos – allowing scientists to cool them to extremes impossible in terrestrial labs.

Getting the facility there was an engineering feat in itself. The original ground-based system weighed a massive 10 tonnes and came in at 20 cubic meters. The space version was shrunk down to just 500 kilograms.

Inside this compact facility, lasers trap the atoms in an optical net and slow them down using evaporative and non-adiabatic cooling techniques without needing bulky magnets.

This orbital lab up will allow scientists to develop quantum sensors and atomic clocks capable of measuring Earth's gravity in unprecedented detail, powering atom interferometers for next-generation navigation systems, and providing a fresh way to probe dark matter and the early universe.