Absolute Zero

Absolute Zero

Life is full of gray areas, so it’s refreshing to have some absolutes, things we can count on. One excellent take-it-to-the-bank certainty in this uncertain universe is absolute zero.
Heat is simply the motion of atoms: Something feels hot because you sense the frenzied movement of those little critters. At 98.6 degrees all your body’s atoms are jiggling at about 1,000 miles per hour. They’ll jiggle even faster when you run a fever during your next flu. At the coldest place on Earth (the Antarctic, where a frosty -129 registered in 1983) there’s still plenty of atomic motion. Atoms stop moving only at 459.67 degrees F below zero. Since nothing can go any slower than “stopped,” this is indeed the coldest possible temperature — Absolute Zero.
Until the mid-60s, most astronomers thought that far from any stars, thermometers would register absolute zero throughout the cosmos. Now we know that the heat of the Big Bang, cooled by expansion, produces a five-degree warmth, or 2.73 degrees on the Kelvin scale. (And the universe keeps getting colder all the time: Its background temperature was twice as warm eight billion years ago.)
The universe’s coldest place, its ultimate Minnesota, is right here on Earth, in research laboratories where temperatures less than a BILLIONTH of a degree above A.Z. were created during the past few years. This technological dive to ever-chillier temperatures takes us into an Alice-in-Wonderland realm of bizarre conditions.
As things get cold they can lose all resistance to electrical flow, creating superconductivity. Strange magnetic properties also arise (the Meissner effect) which makes magnets levitate like Hindu swamis. Then there’s superfluidity, where liquid helium defies gravity and flows up the sides of its container, escaping like some resourceful weasel by simply scampering up and out. But with all that, the very weirdest thing that happens as materials approach A.Z. requires a quick rewind to 1924.
Back then, Albert Einstein’s collaboration with Indian physicist Satyendra Nath Bose led to their prediction that if temperatures ever reached A.Z, a new, totally unknown state of matter should appear. This odd consequence of quantum theory was quickly dubbed the Bose-Einstein condensate.
Just a few years earlier, Werner Heisenberg had created his uncertainty principle, which set strange limits on what we can ever know about small particles. We cannot, for example, precisely figure out an electron’s motion AND its position. Pin down one and the other instantly becomes fuzzy.
But what if you chilled those particles to absolute zero where all motion stops? Wouldn’t that do the trick? You’d then know it’s motion (zero) and you’d also see it right in front of you: Voila, position and momentum both revealed. So a good enough freezer should be able to fool quantum laws. Bose and Einstein said: No way. They believed nature would still manage to disguise itself by creating something we’ve never seen before — a new state of existence.
Just ten years ago, researchers succeeded in cooling atoms to within 20 billionths of a degree of A.Z. Sure enough, like magic, the atoms merged into a single blurry blob, a sort of super-atom never before encountered. We still couldn’t know the atoms’ separate qualities because their individualities had vanished into a single quantum state, a new kind of reality. The material wasn’t solid, liquid, gas, or plasma. It had become something else. The Bose Einstein Condensate.
Amazing technological applications usually follow the discovery of a novel configuration of matter or energy. If we could glimpse future household devices utilizing the condensate, they might seem like magic to us now. Their development is held back for the moment only because reaching those ultra-cold temperatures is still so demanding.
Yes, most of the universe, like the Catskills in December, is freezing cold. But stay tuned: Pockets of even greater cold are about to change our lives for the better.

5 thoughts on “Absolute Zero”

  1. Hi Bob, If we chilled something to AZ, wouldn’t the container we chilled it in also “cease to exist” in it’s present form?


  2. The material presently that we can get to within a few billionths of a degree of AZ is suspended and not in contact with anything. That’s part of the process.
    But since the direction of flow is always heat toward cold (that is, kinetic motion influences surrounding atoms, and not the other way’ round) it wouldn’t be a factor anyway. In short, when atoms stop moving (AZ) they don’t make any materials around them stop — it’s the moving atoms in the vicinity (temperature) that wants to influence the material at AZ. Thanks for your comment. — BB

  3. hi I have a question when matter comes close to absolute zero does said matter begin to -in anyway- defy gravity, I seem to remember this in connection with Superfluidity with hydrogen 3.

  4. Hi Bob. You may already have answered my questions but I’ve read none of your previous posts.

    When you mention that “Heat is simply the motion of atoms” I wonder what the atoms must be in motion with respect to that gives what we perceive as heat? If there were but one particle in the universe, nothing could be said about it’s motion (or location)and thus it’s temperature.

    When considering temperature in terms of motion of particles,does motion on a much larger scale come into play? Such as the motion of a cluster of galaxies in which particles reside?

    I’m not sure if cosmic background radiation consists of just energy, just particles, or both. If it consists only of particles (photons?), the above question comes into play. What do particles of CBM move with respect to? (space-time?).If CMB is pure energy, can it move with respect to anything to fulfill the above definition of heat?

    As you can see, I’m unclear as to whether photons (residual electromagnetic radiation comprising the CBM)may be considered as just energy, particles, or both.

    Finally, I’m trying to imagine if a cloud of probabilities, a wave function, can collapse to form a photon moving through space. Is mass suddenly created when a wave function collapses?

    Thank you,
    Bill Horn

  5. Mr. Horn: The only thing constant in the universe is bureaucracy. As been said, when all things get colder, it moves slower, and hotter, it moves faster. Ok, is there a scale on this temp–speed thing on at least most of the periodic scale? As well in deep space cold and hot, is light changing speeds?

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