Fun Facts: Physics and Physicists
"For whatever a man may do, he does it in order to annihilate
time, in order to revoke it, and that revocation is called space."
- Hermann Broch
According to string theory, the
universe has not just three
or four dimensions, but eleven dimensions, ten of space and one of time.
We do not observe the extra spatial dimensions because they are curled
tightly around each other.
The Roman poet Lucretius (ca. 94–ca. 55 B.C.) wrote a poem in 56 B.C. describing the views
of Greek philosophers who, like him, thought the universe to be composed of atoms.
This poem is the only record of the beliefs of these early atomists, whose
works were lost due to their unpopular views. Lucretius' poem was lost as
well, but in 1417, however, a copy was discovered. Its views
helped to persuade chemists to consider the atomic theory of matter, a
theory that won out eventually.
The Ancient Greek philosopher Thales noticed that amber decorations on
spinning wheels attracted threads, feathers, and other objects
through what we now know to be static electricity. The Greek word for
amber is elektron, from which William Gilbert, physician
to Queen Elizabeth I, coined the word "electricity".
In 1903, Albert Michelson, one of the 19th century's
top physicists, commented "The more important fundamental laws and
facts of physical science have all been discovered, and these are
so firmly established that the possibility of their ever being
supplemented in consequence of new discoveries is exceedingly remote".
Two years later, Einstein published his revolutionary Theory of Special
Einstein's ideas on relative acceleration were partly inspired by
the free fall of a man who fell off a roof in Berlin. The man, who
survived without injury, told Einstein that he had not felt the effects
In 1905 Albert Einstein wrote his famous Special Theory of
Relativity. It was published in a scientific journal that
same year, but took many years to gain general acceptance.
In fact, it was not verified by actual experiment until 25 years later.
Two years after that paper was published, Einstein
wanted a job as assistant professor of mathematics. This job
required the applicant to submit a thesis paper, so Einstein
submitted his Special Theory of Relativity. The university rejected it.
The quark, a building block of the proton, got its name from
James Joyce's Finnegans Wake, from the line
"Three quarks for Muster Mark! Sure he hasn't got much of a bark".
According to the laws of gravity, the moon technically does not orbit
the Earth. The two bodies actually both orbit around their
common centre of gravity, which is located 1,000 miles
beneath the surface of the Earth and is on a straight line between
the centres of the Earth and moon. The centre of the Earth makes a
small circle around that centre of gravity every 27 1/3
According to the rules of logic, the question "What would happen if an
irresistible force met an immovable object?" is meaningless.
In a universe where one of the above exists, the other cannot by definition.
A "light year" is a measure of distance, not time.
It is defined as
the distance light travels in one year. Light moves at a velocity of about 300,000 kilometres each second, so in one year, it travels about 9,500,000,000,000 kilometres.
To the nearest ten-thousandth of a mile,
light travels at 186,282.3959 miles per second. At that rate,
it takes slightly more than eight minutes to get to Earth from
the sun. However, it takes light hundreds of years to travel
from the sun's centre to its surface. The light must take a
very indirect path to the surface due to the large number of
collisions with particles within the sun.
In 1940, the Tacoma Narrows Bridge (popularly known as "Galloping
Gertie"), which spanned the Puget Sound
south of Seattle, opened. At the time it was the third longest bridge
in the world and narrower than any comparably-sized bridges. Although
the bridge was criticized for being too slender, Leon Moisseiff, the
consulting engineer to the project and an expert on suspension bridges,
assured people that the bridge would be safe. However, only three months after it
opened, the bridge collapsed in a 42 mph wind after going into harmonic
An atomic clock kept at the National Bureau of Standards in Boulder,
Colorado, U.S.A., 1650 metres above sea level, gains about five
microseconds each year relative to an identical clock kept at the
Royal Greenwich Observatory, 25 metres above sea level. The reason
is that gravity gets stronger as one gets closer to the Earth's core,
and, according to Einstein's Theory of Relativity, time is slower in
stronger gravitational fields.
A perpetual motion machine would violate the laws of thermodynamics.
No-one has ever built one, and no-one ever will.
According to the Second Law of Thermodynamics, the amount of entropy
in the universe always increases, which means that eventually, the universe
must run down and life in the universe will cease.
Information about what has fallen into a black hole is stored on the black hole's event horizon.
Recent calculations by those who study quantum gravity theory and superstrings have confirmed what Stephen Hawking and his collaborators proposed a decade or more ago. Evidently, the information contained in matter that falls into a black hole is by some curious means encoded in the pattern of frozen quantum fields at the horizon. This raises some interesting possibilities that we could resurrect clocks, humans, spacecraft, and whole planets into something like their pristine form if we could magically reverse the in-fall and collapse process. Many believe that this mathematical result means that we have reached a watershed moment in history in understanding the connection between quantum mechanics and gravitation theory. Quantum mechanics deals with statements about the information that we can extract about a quantum mechanical process involving
observation. Now this same information language can be applied to configurations of the gravitational field and space-time itself.
While light has no mass, it has weight. Weight is a measurement of
the pull of gravity on something, and light can be bent by gravity.
The sky is blue because of refraction. The sun's light is of all colours
of the rainbow, mixed together to make white light. The reds and yellows
pass through air easily, but some of the blue portion of sunlight is
scattered in every direction by air molecules. This scattering causes
the sky to be blue.
An article in the April 26, 1993 article of Physical Review
Letters, titled "First Measurement of the Left-Right Cross-Section
Asymmetry in the Boson Production by e+ e-
Collisions", had 407 authors.
It is not possible to hear in space. Because there is no atmosphere in space to conduct the sound, it would not carry. So, the object would make a noise, but it would not carry to any receiver, and no one would hear it.
There is sound in space. Sound is a pressure wave, and as long as there is some kind of gaseous medium, there is the possibility of forming pressure waves in it.
In space, the interplanetary medium is a very dilute gas at a density of about 10 atoms per cubic centimeter, and the speed of sound in this medium is about 300 kilometers per second. Typical disturbances due to solar storms and "magneto-sonic turbulence" at the Earth's magnetopause have scales of hundreds of kilometers, so the acoustic wavelengths are enormous. Human ears would never hear them, but we can technologically detect these pressure changes and play them back for our ears to hear by electronically compressing them.
Since the 1950s, physicists have discovered over 200 different kinds of particles.
The difference between the appearance of a real object and its
reflection in a mirror is that the clockwise and counterclockwise
directions are switched.
Newton's Third Law of Motion states that for every action there is an equal and opposite reaction.
When an airplane travels at a speed faster than sound, density waves of sound emitted by the plane accumulate in a cone behind the plane. When this shock wave passes, a listener hears a sonic boom.
It is not known exactly what gravity is. We can define what it is as a field of influence, and with general relativity we can define a language which states that it is a property of our real world that is mathematically equivalent to not just the geometry of space-time, but equivalent to space-time itself. Some
think that it is made up of particles called gravitons, which flit about at the speed of light just
as photons do. In any true fundamental sense, we do not know what gravity is, we only know how it operates in various corners of our universe. Without gravity, there would be no space and time.
Around one percent of the static on a television set tuned between stations
is a relic of the Big Bang.
Ordinary matter consists almost entirely (99.9999999999999%) of empty space.
Bell's Theorem states that certain measurements made on one particle
can instantaneously affect the measurements made on a second particle that,
in theory, could have been removed to the opposite side of the galaxy,
with no physical connection between the two.
The size of Earth is roughly the geometric mean of the size of the
universe and the size of an atom, and the mass of a human is roughly the
geometric mean of the mass of Earth and the mass of the proton.
In 1988, the United States Department of Energy spent $1,400,000 sending
the entire 25-pound, 8,800-page environmental impact statement on the
Superconducting Super Collider (SSC) to 16,000 citizens who had expressed
interest in the project. However, all that was required by law was to mail a
summary of that statement.
One of the most interesting demonstrations of the quantum mechanical
nature of light is the double-slit experiment. In this experiment, light
is shone through two slits on an opaque plate onto a screen. If one slit is
open, the light impacts the screen with greatest intensity at the centre,
fading as one moves away from the centre. One might think that, if both
slits are open, the result would be the sum of the intensities from the
individual slits, but what actually occurs is that an interference pattern is
produced, showing that light has wave properties. Even more unusual, if you
only fire one photon at the apparatus at a time (and replace the screen
with a photographic plate), an interference pattern is still produced, so it
would appear as if an individual photon is able to travel through both slits
and interfere with itself. If you place a detector at each slit, you will
observe that each photon only goes through one slit—but the pattern
is now just the sum of the intensities from the individual slits, without
any interference pattern.