View Full Version : Humans are hottest and coldest of all

2006-Apr-23, 05:07 PM
While recently searching for information on highest and lowest temperatures, I found an old thread on bautforum. In light of the new information I dug up via my search, I thought I'd post what I found and hopefully reinvigorate the discussion:

Hey everyone,

I did a little research this morning, and from what I can gather, humans have indeed created the hottest collection of matter -- in a sizeable quantity -- that exist anywhere in the known universe today. See the Sandia Article. We have also created the coldest temperatures in the known universe (see last article).

Beyond that, the RHIC collider in long-island has created a fireball with "temperatures" that go back to the early moments of the big-bang -- far hotter than any mass existing in an equivelant volume anywhere in the universe today. The volume we're talking about is 5 femtometers (insy, binsy, but hey, it's still something). The temperature is 2 trillion degrees Kelvin or (in energy units) 175 MeV. When CERN goes online in 2007/08, they should exceed these energies by a magnitude of 50 -- yoiks!!

John, Dad, thoughts? I fully understand that large-scale structures, when measured as a whole, carry vastly more energy and are therefore in an entirely different realm. But if we're comparing equivelant volumes, then the quark-gluon "liquid" in the RHIC collider reached higher energies than any other equivelant volume in the existing universe today, muchless the majority of time, going back to the early moments of the big bang. True? Have a look at these articles. They're fascinating if you ask me!

Highest Temperatures:
At the Relativistic Heavy Ion Collider (RHIC) on Long Island, the four large detector groups agreed, for the first time, on a consensus interpretation of several year’s worth of high-energy ion collisions: the fireball made in these collisions -- a sort of stand-in for the primordial universe only a few microseconds after the big bang -- was not a gas of weakly interacting quarks and gluons as earlier expected, but something more like a liquid of strongly interacting quarks and gluons (PNU 728).

http://www.bnl.gov/RHIC/images/ev2_front1.jpg (http://www.bnl.gov/RHIC/images/ev2_front1.jpg)
A picture of the gold/gold nuclei collision at full energy at RHIC

Let's look at what happened. In the RHIC accelerator itself two beams of gold ions, atoms stripped of all their electrons, are clashed at several interaction zones around the ring-shaped facility. Every nucleus is a bundle of 197 protons and neutrons, each of which shoots along with an energy of up to 100 GeV. Therefore, when the two gold projectiles meet in a head-on "central collision" event, the total collision energy is 40 TeV (40 trillion electron volts). Of this, typically 25 TeV serves as a stock of surplus energy---call it a fireball---out of which new particles can be created. Indeed in many gold-gold smashups as many as 10,000 new particles are born of that fireball. Hubble-quality pictures of this blast of particles (http://www.bnl.gov/RHIC/full_en_images.htm), shows the aftermath of the fireball, but not the fireball itself.

The outward streaming particles provide all the tomographic evidence for determining the properties of the fireball. To harvest this debris, the RHIC detectors must be agile and very fast. The recreation of the frenzied quark era is ephemeral, lasting only a few times 10-24 seconds. The size of the fireball is about 5 femtometers, its density about 100 times that of an ordinary nucleus, and its temperature about 2 trillion degrees Kelvin or (in energy units) 175 MeV. RHIC was built to create that fireball. But was it the much-anticipated quark-gluon plasma? The data unexpectedly showed that the fireball looked nothing like a gas. For one thing, potent jets of mesons and protons expected to be squirting out of the fireball, were being suppressed.
http://www.aip.org/pnu/2005/split/728-1.html (http://www.aip.org/pnu/2005/split/728-1.html)

Scientists at Sandia National Laboratories have produced superheated gas exceeding temperatures of 2 billion degrees Kelvin, or 3.6 billion degrees Fahrenheit.
This is hotter than the interior of our Sun, which is about 15 million degrees Kelvin, and also hotter than any previous temperature ever achieved on Earth, they say.
http://www.livescience.com/technology/060308_sandia_z.html (http://www.livescience.com/technology/060308_sandia_z.html)

The protons in the center of neutron stars are believed to become superconducting at 100 million K, so these are the real high-T_c champs of the universe.

Some really hot things:
The centre of the Sun: 15,600,000 K
The corona (outer atmosphere) of the Sun: over 1,000,000 K
The tenuous electron gas in clusters of galaxies: 100,000,000 K
Accretion disks around stellar mass black holes: over 1,000,000 K

W is a very rare type of intensely hot star, with surface temperatures up to 50,000 K. There is only one example in the sky that is visible to the naked eye, in the Suhail al Muhlif system in the constellation Vela.
http://www.glyphweb.com/esky/concepts/spectralclassification.html (http://www.glyphweb.com/esky/concepts/spectralclassification.html)

Lowest Temperatures:

Lancaster University´s Ultralow Temperature Physics Group has twice achieved the lowest temperature in the known universe, coming within a few millionths of a degree above absolute zero.

The work of the Lancaster ULT Group concerns the behaviour of materials at the lowest accessible temperatures. This means down to temperatures of 5mK, i.e. to within a few millionths of a degree above absolute zero. Our current interests lie mostly in the behaviour of the quantum fluid, superfluid helium 3. (Helium 3 is the light isotope of helium). This material at the lowest temperatures is completely ordered.
http://www.lancs.ac.uk/users/spc/research/condmatt/ult/ultpage.html (http://www.lancs.ac.uk/users/spc/research/condmatt/ult/ultpage.html)