Now you see it, now you don't ⬇️
low enough that it scattered less light. If they can cool the cloud even closer to absolute zero , they say it will become completely invisible."What we've observed is one very special and simple form of Pauli blocking, which is that it prevents anfrom what all atoms would naturally do: scatter light," study senior author Wolfgang Ketterle, a professor of physics at MIT,."This is the first clear observation that this effect exists, and it shows a new phenomenon in physics.
Because at the spooky quantum level there only are a finite number of energy states, this forces electrons in atoms to stack themselves into shells of higher energy levels that orbit ever farther around atomic nuclei. It also keeps the electrons of separate atoms apart from each other because, according to a 1967co-authored by the famed physicist Freeman Dyson, without the exclusion principle all atoms would collapse together while erupting in an enormous release of energy.
But cool a gas down, and you have a different story. Now the atoms lose energy, filling all of the lowest available states and forming a type of matter called a Fermi sea. The particles are now hemmed in by each other, unable to move up to higher energy levels or drop down to lower ones.