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Thought this was cool: What are some mind-blowing facts about physics?

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In Physics: Ben Golub voted up an answer.

Back in the day, I ended my emails to a physics list at MIT with a random fact. Here’s the list:

The highest temperature ever reached on earth was 4 trillion degrees Celsius. This was in quark-gluon plasma at Brookhaven RHIC.

Prof. Seth Lloyd of MIT, a proponent of the idea that the universe is a computer, calculated that the universe can hold a maximum of 10^120 bits. This bound was calculated by considering the amount of information (entropy) that one can store in a volume before it has the properties of a black hole, whose entropy is proportional to its surface area. The second paragraph of his paper on this result has the most hilarious string of citations I have ever seen (85 in a row):….

Air near the surface of the ocean moves slower than air at higher altitudes due to friction with the water. Albatross can use the a north-south wind speed gradient to fly without flapping their wings when going east-west by moving downwind at higher altitudes to gain speed relative to ground and then moving to a lower altitude before going in their intended direction. (Fact courtesy of Prof. Allan Adams.)

The hypothetical sterile neutrino does not interact via any of the fundamental interactions in the Standard Model except gravity.

The Biot-Savart law is used in aerodynamics to calculate the velocity induced by vortex lines when induced air currents form solenoidal rings around a vortex axis that plays the role of electric current.

Water in the liquid state possesses many molecular interactions which broaden the absorption peak and allow people to eat foods like Pizza Bagels after microwaving them. In the vapor phase, isolated water molecules absorb at around 22 GHz, almost ten times the frequency of the microwave oven.

Quantum effects in the specific heat capacity of hydrogen gas were observed by Maxwell 50 years before quantum theory was developed.

A record high of 83 exoplanets were discovered in 2009 (out of around 531 total). See List of extrasolar planets.

Plasma was first named “plasma” in 1928 by Irving Langmuir because it reminded him of blood plasma.

The sun fuses 620 million metric tons of hydrogen per second.

Since 1967, a second has been defined as the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom. In 1977, the second was lengthened by about 1×10-10 to correct for general relativistic effects above mean sea level. In 1997, the definition was refined to include the phrase, “This definition refers to a caesium atom at rest at a temperature of 0 K.”

Assuming that the Universe continues to expand, it is thought that in 10^19 to 10^20 years the galaxies will evaporate. However, white dwarfs should be able to survive this process. Their subsequent lifetime is on the order of the proton lifetime, which is at least 10^32 years.

Some theories of quantum gravity propose a discrete model of time. One such model suggests the chronon as the basic quantum of time (around 7×10-24 s for an electron)

On March 1, 2010, NASA announced that the moon’s northern pole contains millions of tons of water ice.

The standard value of gravitational acceleration on earth g is from an object in free fall at sea level at a latitude of 45 degrees.

” . . . Additionally, flammable metals with relatively low boiling points such as zinc, whose boiling point of 907°C (1,665°F) is about 1,370°C (2,500°F) below the temperature at which thermite burns, could potentially boil superheated metal violently into the air if near a thermite reaction, where it could then burst into flame as it is exposed to oxygen.” [Wikipedia article on thermite]

Ketchup is a thixotropic, meaning that that the fluid viscosity decreases over time given a constant shear. In other words, fluid motion is initially difficult to start, but once flowing will continue to do so freely. (via Wikipedia)

The energy cost of sending a payload to the stars (i.e., d = infinity) is only 10% more than the cost of sending a payload to Saturn (i.e., d = around 1.2 billion km). See How hard is space travel, in principle? for the calculation.

The approximate power of Galileo space probe’s radio signal (when at Jupiter) as received on earth by a 70-meter DSN antenna is a zeptowatt (10-21 watts). In comparison, the power consumption of a human cell is 10^12 times greater. (via Wikipedia)

The 100 dinar Serbian banknote has Tesla on the front. Check it out! File:100RSD front.jpg

The latest abstract on my physics arxiv RSS feed describes the use of artificial neural network simulation to conclude that the temperature in Antarctica during Captain Robert F. Scott’s death in 1912 was 13 degrees F higher than Scott reported. The last sentence reads, “On the basis of the mentioned evidence I concluded that the real minimum near surface air temperature data was altered by Lt. Bowers and Captain Scott to inflate and dramatize the weather conditions.”

Numerical integrals used to be calculated by drawing the curve and measuring the area underneath using a planimeter. This is how Johnson originally evaluated the voltage gain integrals in his paper on Johnson shot noise (1928).

The sun radiates as a 6000 K blackbody in the optical range but can have a blackbody temperature of over 10^6 K at radio frequencies.

In 1999, Jaffe, Busza, and Wilczek at MIT (along with Jack Sandweiss at Yale) co-wrote a paper discussing apocalyptic situations that could arise from high energy relativistic heavy ion collisions, including miniature black holes and the production of a dangerous “strangelet” particle. The abstract ends with the sentence, “Given minimal physical assumptions the continued existence of the Moon, in the form we know it, despite billions of years of cosmic ray exposure, provides powerful empirical evidence against the possibility of dangerous strangelet production.” (See

The sun has cycles of 11, 22, 87, 210, 2300, and 6000 years. (Only the 11 and 22 year cycles are clearly observed.)

In 1996, NASA conducted an experiment with a 20,000-meter conducting tether in space. When the tether was fully deployed during this test, the orbiting tether generated a potential of 3,500 volts. This conducting single-line tether was severed after five hours of deployment. It is believed that the failure was caused by an electric arc generated by the conductive tether’s movement through the Earth’s magnetic field.

George Zweig, one of the physicists who proposed the quark model, originally preferred the name “ace” to “quark.”

In 1997, scientists used a 16 tesla magnetic field to levitate a frog with no apparent ill effects on the frog. (The strongest continuous magnetic field yet produced in a lab is 45 teslas).

The sun is actually yellow, just like everyone thinks it is.

A human being continuously radiates about 1000 watts. A nude person indoors absorbs about 900 watts. Wearing clothes reduces the outgoing heat flux, as observed by rapper Nelly in “Hot in Herre” (2002).

There is not enough mass in the universe to build a Gott time machine.

Velociraptors may have been able to run at 40 mph for short bursts.

The universe is accelerating. (According to Alan Guth when I asked, this is he most important thing one can learn from him.)

In 1912, mathematician Karl Fritof Sundman proved that there exists a series solution in powers of t^(1/3) for the 3-body problem. Unfortunately, this was after Poincare already won King Oscar II’s prize for solving the problem, even though he didn’t.

The coldest measured temperature (450 pK) has a peak black body emittance wavelength of 6400 km.

The raman laser operates by raman scattering of photons. When light hits a substance, it causes the atoms in the substance to vibrate sympathetically. The collision of photons with the substance causes some of the photons to gain or lose energy, resulting in a secondary light of a different wavelength. A Raman laser takes this secondary light and amplifies it by reflecting it and pumping energy into the system to emit a coherent laser beam.

Tycho Brahe lost the bridge of his nose in a duel in 1566 and was said to have pasted a replacement nose of either gold, silver, or copper to his face for the rest of his life.

The Space Pen, used by NASA astronauts since the 1970s, operates from -35 to 120 degrees Celsius and has an estimated shelf life of a century. The ink is forced out by compressed air at nearly 35 psi. (Space Pen)

A subatomic particle with kinetic energy equal to a baseball traveling at 60 mph was observed in 1991. See Oh-My-God particle.

The theory of doubly-special relativity predicts that the speed of light is energy-dependent. (Doubly special relativity)

In 1783, geologist John Michell published a letter postulating that if “the semi-diameter of a sphere of the same density as the Sun were to exceed that of the Sun in the proportion of 500 to 1 . . . all light emitted from such a body would be made to return towards it by its own proper gravity.” He suggested the idea of gravity influencing light nearly 130 years before Einstein but apparently predicted spectral shifts in the wrong direction because he thought that blue light had less energy than red.

A small herd of American bison lives on the grounds of Fermilab, a symbol of Fermilab’s “connection to the American prairie.” [Wikipedia]

The current record for coldest temperature ever achieved by man was set in 1999 by cooling a piece of rhodium metal to 100 picokelvin. While we’re on the topic of rhodium, 1 kg of rhodium costs nearly 2x the MIT yearly tuition, making it the most precious metal.

This one deserves direct quotation. “If a spaghetti stick is uniformly bent until it fractures and ejects a third piece, then the third piece is always ejected outwards from the convex side. When the spaghetti fractures for the first time, the two remaining pieces then spring outwards, and providing there is a sufficiently weak potential fracture site on the opposite side a second fracture occurs, resulting in a third piece being ejected away from the initially convex side.”  (Nickalls, Oliver and Richard; “Linear Spaghetti,” New Scientist, p. 52, 1995)

Air spontaneously ionizes at 2500 kV/m. Fields in lightning storm clouds are usually 10 times less.

The youngest person to receive the Nobel Prize in Physics was William L. Bragg at age 25. I wonder if he Bragged about it.

The largest pinhole camera in the world was built from an abandoned F-18 hangar in California. The resulting photograph measured 108 feet by 85 feet and was developed in an Olympic-sized swimming pool

John A. Wheeler, Feynman’s mentor, believed that all electrons had the same observed mass and charge because they were all the same electron traveling backwards and forwards in time.

The sun’s magnetic poles reverse every 11 years. The next reversal is in 2012.

Researchers at the University of Minnesota have experimentally verified that humans swim in syrup at the about same speed as humans swim in water. Reference:…

Sir David Brewster, best known for being the guy who has a “magic” angle named after him (“magic” is the precise terminology used by Prof. Gedik of 8.03), also invented the sea thermometer. Most people, including myself, do not know what a sea thermometer is because nobody has written a Wikipedia article about it yet.

The Leonids meteor shower of 1833 may have reached 200,000 counts per hour in eastern North America. In Independence, Missouri, the shower was interpreted as a sign that the Mormons should leave.

1 attoparsec per microfortnight is roughly equal to 1 inch per second. (1 parsec = 3.26 light-years, atto- = 10^-18, fortnight = 14 days)

“Tokomak” is a transliteration of the Russian word “tokomak.” (Okay, it looks like the same word but it’s supposed to be written in the Russian alphabet.) “Tokomak” is either short for “toroidal chamber with magnetic coils” or “toroidal chamber with axial magnetic field”.

Dr. Tom Gutierrez at UC Davis wrote a Standard Model Lagrangian that basically summarizes everything that mankind has ever measured in one equation with, like, 29319393 terms. See it here:…

Gamma ray bursts were discovered accidentally while the US government was searching for evidence of the Soviets testing nuclear weapons in space. Their discovery was kept secret for years. (This fact courtesy of Prof. Chakrabarty.)

One (serious) explanation of sonoluminescence is that the light bursts generated by imploding bubbles in a liquid excited by sound are actually due to quantum vacuum radiation. If I’m not mistaken, this means that pistol shrimp (which produce sonoluminescent light by snapping their claws) have the impressive ability to convert virtual photons into real photons.

The radiation from the Crab Nebula (at visible wavelengths!) is actually from electrons moving in a circle of radius 2 AU with a period of 2 hours. Each flash of observable radiation, however, only lasts 10^-15 seconds.

Feynman diagrams are also called Stueckelberg diagrams.

Maxwell’s original formulation of E&M contained 20 equations in 20 variables and probably didn’t fit on a t-shirt.

Oliver Heaviside coined the terms admittance, conductance, impedance, and inductance in E&M theory. More obscurely, he also coined reluctance, which is defined as either magnetic resistance or what you feel before manually computing any integral that involves Coulomb’s law and weirdly shaped wires.

The plot of how much time it takes a double pendulum to flip over as a function of initial angle displacements looks like this:…. (I think my grandmother used to wear a shirt that looked like this, incidentally.)

Microwaves are more efficient on frozen water than liquid water because the molecules aren’t free to rotate in frozen water.

The fastest object ever made by man is the Helios 2, a spacecraft that orbited the sun with an estimated velocity of 153,800 mph at perihelion. That’s 0.0002 times the speed of light.

The shortest time interval ever measured is on the order of 100 attoseconds (10^-16 seconds). In a brilliantly non-obvious article about this in 2004, the BBC wrote, “The advance opens up the possibility of more accurate timekeeping.”

Supposedly the oldest thing ever observed in the universe is a star that exploded 13 billion years ago, when the universe was 600 million years old, which is only slightly older than Harvard.

Metal detectors create magnetic fields, which induce eddy currents in metal objects, which create magnetic fields, which induce annoying beeping sounds in metal detectors.

Ferroliquids are used for cooling in loudspeakers without extra energy input. They’re less magnetic at higher temperatures, so a strong magnet placed near the heat-producing voice coil will attract cold ferrofluid more than hot ferrofluid.

Electric toothbrushes recharge without any exposed contacts. The brush unit and the charge unit each contain half of a transformer. When brought together, a varying magnetic field in one coil induces a current in the other coil, charging the battery by induction.

Homing pigeons can’t navigate on Mercury because Mercury has no magnetic field. Or atmosphere. That’s another reason. (Today is extra special because this fact incorporates both biology and physics, which is like half of the MIT general institute requirements.)

Physics fact of the day: There is current research in the use of nonthermal plasmas to decontaminate fresh produce.

Lightning can reach temperatures five times that of the surface of the sun

See question on Quora

from Ben Golub on Quora:

Written by cwyalpha

十二月 23, 2012 在 4:38 上午

发表在 Uncategorized


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