For a period of 15 days, a cooled copper mass enclosed in a cryostat container may very well have been the coldest object in the Universe. At -273.144 degrees Celsius, it nearly achieved absolute zero. The technique, which resulted a world record, could produce important new insights into exotic particle physics.
Prior to this, no experiment on Earth has ever cooled a similar mass or volume to temperatures this low. Remarkably, the conditions created in the lab are not thought to appear anywhere in nature. So, unless some extraterrestrial civilization was conducting a similar experiment, it was the coldest object in the Universe for over two weeks.
The copper mass, which weighed 880 pounds (400 kg), was brought to an achingly low temperature of 6 milliKelvins, or -273.144 degrees Celsius. That's crazy if you think about it; absolute zero (or 0 Kelvin) is only a mere 0.006 degrees away at -273.15 C.
The feat happened at the Cryogenic Underground Observatory for Rare Events (CUORE), a particle physics lab in Italy where an international group of scientists are working, including those from the U.S., China, Spain, and France. The copper was encased in a cryostat container, which according to the researchers is "the only one of its kind in the world, not only in terms of its dimensions, extreme temperatures and cooling power, but also for the selective materials and for the building techniques that both guarantee very low levels of radioactivity."
On it's own it's a remarkable achievement, but the implications to particle physics are quite profound. As noted by an Italian National Institute for Nuclear Physics release:
CUORE is seeking to observe a hypothesized rare process called neutrinoless double-beta decay. Detection of this process would allow researchers to demonstrate, for the first time, the transformation of antineutrinos to neutrinos, thereby offering a possible explanation for the abundance of matter over anti-matter in our Universe. These transitions are only possible if the neutrinos are so-called Majorana particles, as suggested by Italian physicist Ettore Majorana in 1930s. The experiment will also be sensitive to the miniscule value of the neutrino mass.
CUORE, which is designed to work in ultra-cold conditions at the temperatures of around 10 mK (i.e. ten thousandths of a degree above absolute zero), consists of tellurium dioxide crystals serving as bolometers (radiation detectors which measure energy by recording tiny fluctuations in detector's temperature).
[ INFN ]
All images: INFN.