Where is the coldest known place in the Universe? It may sound strange, but today, it is here on Earth: in 1995, in a laboratory in M.I.T. (Massachusetts Institute of Technology), the German physicist Wolfgang Ketterle and his colleagues have cooled a sodium gas to the lowest temperature ever recorded, only half-a-billionth of a degree above absolute zero.
But, soon, this record will be broken. NASA is going to launch a facility to the International Space Station (ISS) that will contain a spot 10 billion times colder than outer space. The new Cold Atom Laboratory (CAL) facility, which will operate in microgravity, could help answer some big questions in modern physics, allowing researchers to dive deep into the quantum realm in a way that would never be possible here on Earth.
Inside the Cold Atom Lab, scientists will use lasers and magnetic traps to slow atoms down until they are almost motionless (see notes 1). Then, the atoms can form a distinct state of matter called Bose-Einstein condensate (BEC) (see notes 2). In this state, the wave characteristics of matter become more noticeable.
On Earth, the pull of gravity causes atoms to settle toward the ground, ad the freely evolving BECs are typically only observable for fractions of a second. But, inside the CAL, ultra-cold atoms can hold their wave-like forms longer while in a freefall (microgravity), giving scientists more time to observe and understand physics at its most basic level.
The quest for ever colder temperatures has been a major theme of physics for over a century, leading to such breakthroughs such as the discovery of superfluidity and superconductivity, and more recently to the development of laser cooling techniques and the observation of dilute atomic-gas Bose-Einstein Condensates (BEC) and super-fluid Fermi gases.
Beyond the great interest in the scientific aspects of these phenomena, the result of the experiments currently planned for this facility could potentially lead to a number of improved technologies, including sensors, quantum computers, and atomic clocks used in spacecraft navigation.
The “true” Coldest Known Place in the Universe
According to the Guinness Book of World Records, besides laboratory-created temperatures, “the coldest place in the universe is in the Boomerang Nebula, a cloud of dust and gases 5,000 light years from Earth. It has a temperature of -272°C (-457.6°F). It is formed by the rapid expansion of gas and dust flowing away from its central aging star. This cold region of the nebula was discovered in 1995 by astronomers using from data obtained by the 49 ft wide Swedish-European Space Observatory-Submillimeter radio telescope in La Silla, Chile. In the areas coldest spots, the gases are believed to be expanding at 370,000 mph (595,457 km/h or 165,404.8 meters per second). Colder temperatures have been achieved in laboratories on Earth.”
Update (July 30, 2018): The coldest place in the Universe is now on the ISS
- Absolute zero is the lower limit of any possible temperature. Nothing can be cooler than it – in fact, it is unreachable. More scientifically, it is the lower limit of the thermodynamic temperature scale, a state at which the enthalpy and entropy of a cooled ideal gas reach its minimum value, taken as 0. Absolute zero is the point at which the fundamental particles of nature have minimal vibrational motion, retaining only quantum mechanical, zero-point energy-induced particle motion. It is taken as -273.15°C (-459.67°F), which is determined by extrapolating the ideal gas law. The corresponding Kelvin and Rankine temperature scales set their zero points at absolute zero by definition.
- A Bose-Einstein condensate (BEC) is a state of matter of a dilute gas of bosons cooled to temperatures very close to absolute zero. Under such conditions, a large fraction of bosons occupy the lowest quantum state, at which point microscopic quantum phenomena, particularly wavefunction interference, become apparent. A BEC is formed by cooling a gas of extremely low density, about one-hundred-thousandth the density of normal air, to ultra-low temperatures. This state was first predicted, generally, in 1924-25 by the Indian physicist Satyendra Nath Bose (1 January 1894 – 4 February 1974) and Albert Einstein.
- “The Coolest Spot in the Universe” on NASA’s Cold Atom Laboratory (CAL) website
- “NASA’s Atomic Fridge Will Make the ISS the Coldest Known Place in the Universe” on motherboard.vice.com
- Absolute zero on Wikipedia
- Bose-Einstein condensate (BEC) on Wikipedia
- The coldest place in the Universe on guinnessworldrecords.com
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