Most of what we see in the world belongs to one of four states of matter: gases, liquids, solids, and plasmas. But there is a 5th state of matter, an exotic “super-atom” that has been almost impossible for scientists to observe on Earth.
Researchers announced this week that while onboard the International Space Station they were able to observe this 5th state under the unique conditions of near-absolute zero temperatures and “micro-gravity.” Insights into this exotic matter could someday help solve the mysteries of quantum mechanics, dark energy, and even the elusive “theory of everything.”
The 5th state of matter, called Bose-Einstein condensates (BECs), was first discovered in lab conditions 25 years ago. This unusual “super-atom” forms when atoms of particular kinds of elements (mostly rubidium) reach temperatures near absolute zero (0 Kelvin, minus 273.15 Celsius). The reason BECs are so important is that when they reach this temperature the atoms merge into one homogenous substance that behaves like a quantum object, meaning it exists as both a particle and a wave simultaneously.
BECs thus represent a mysterious and rare liminal region between the microscopic world governed by quantum physics and the macroscopic world governed by gravity. Such a state presents an ideal experimental playground for scientists to dig into the secrets and anomalies of the quantum universe.
However, it is virtually impossible for researchers to observe BECs on Earth because the force of gravity destabilizes the magnetic fields which act as a trellis holding the volatile “super-atom” together. Earth-bound scientists are left with only hundredths of a second before a BEC falls apart.
Researchers aboard the ISS discovered that in the microgravity of orbital space, they could observe BECs in the specially developed Cold Atom Lab for a full second or longer.
“Microgravity allows us to confine atoms with much weaker forces, since we don’t have to support them against gravity,” said Robert Thompson of from the California Institute for Technology, Pasadena.
Microgravity also allowed them to use weaker magnetic fields and colder temperatures, which facilitated the condensates demonstrating more exotic quantum effects.
The observation of the fifth form of matter is considered a groundbreaking achievement that has huge potential ramifications for the study of quantum mechanics and dark energy. Scientists believe that by finally understanding these two fields, they may be able to unite the classical physics of gravity with quantum physics into a “theory of everything.”
“In the past, our major insights into the inner workings of nature have come from particle accelerators and astronomical observatories; in the future, I believe precision measurements using cold atoms will play an increasingly important role,” Thompson said.
In future experiments, researchers hope to try potassium atoms so they can see the result of two BECs merging.
The scientists published their ISS research in the June 11 issue of the journal Nature.