Science Alert reports:

Even the seemingly empty vacuum of space isn’t completely cold.

The Universe was born some 13.8 billion years ago in a state so hot and dense that the leftover radiation still permeates every one of its nooks and crannies.

The average background temperature of space hovers around 2.7 kelvins – that’s -270.45 degrees Celsius, or -454.81 Fahrenheit.

Now, scientists have made something with an equivalent temperature 280 billion times lower – shattering the previous record in humanity’s quest to get as close as possible to absolute zero.

Aboard China’s Tiangong space station in Earth orbit, physicists have achieved a record equivalent temperature of just 9.7 picokelvins – or 0.0000000000097 kelvins – “which is, to our knowledge, the lowest equivalent temperature ever measured,” the researchers write in a paper published in Science.

Absolute zero – or zero kelvins – is the theoretical lower limit temperature can reach in the Universe. At that point, thermal energy physically cannot plunge any lower. It’s like the speed of light – a fundamental limit that the laws of physics simply cannot cross.

Unlike the speed of light, however, absolute zero is impossible to reach. The closer scientists get, the harder it becomes to remove the remaining thermal energy, until reaching the limit would require a cooling process that could never be completed.

But that hasn’t stopped physicists from trying – and the closer they get, the weirder matter begins to behave. [Continue reading…]