“What is the heaviest stable element?” This question,
easily posed, is not so easy to answer. In fact, nobody
knows. This document explores the stability of heavy
elements, the difficulty of experimentally confirming theoretical
predictions of very rare events, and elements whose half-lives are
longer than the lives of all stars in the universe.
Cellular Automata Laboratory
invites you to explore the world of cellular automata with
the aid of high-speed programmable simulators for both
MS-DOS and Windows. Cellular automata rules are defined
by short programs written in Java, C, Pascal, or BASIC; rule
definitions in Java can be compiled even if you don't have
a Java compiler by using a Web-based compilation server.
The accompanying on-line
equivalent to more than 250 printed pages, explains
the theory of cellular automata, how to use the simulator
programs, documents the many
ready-to-run rules included,
describes how to create your own original experiments,
and contains a comprehensive
The only reason Einstein's special theory of relativity seems weird to those
learning it is that the velocities we're familiar with are such a tiny
fraction of the speed of light we've never had a chance to
gain an intuitive sense of relativistic effects. If the speed of
light were 100 kilometres per hour, footballers would have no trouble
dealing with relativistic goal shots. C-ship
uses computer image synthesis to put you aboard a starship entirely
consistent with the laws of physics and lets you look out the window to
experience special relativity with your own eyes.
This "basement science" experiment demonstrates the universality of
gravitation, showing the gravitational attraction between masses of
less than a kilogram. Could Archimedes have discovered universal
gravitation nineteen centuries before Newton? Well, let's see....
An interactive Java applet which illustrates how orbits around compact
objects such as neutron stars and black holes depart drastically from
Kepler's laws, and explains why. Source code for the applet is
Quantum mechanics teaches us that, at the deepest level, uncertainty
rules the universe: there are things we cannot predict, even in
principle. HotBits harnesses this fundamental
uncertainty of nature to generate truly random bits, unlike the
pseudorandom sequences created by an algorithm on a computer.
Along the way, you'll find a discussion of the hardware and
software used to generate the random bytes comprehensive enough
to build your own, and peek under the hood
of quantum mechanics to see why the data are genuinely random,
and some of the implications of all this.
On October 15th, 1991 a proton
with an energy of 3×1020 electron volts slammed into in
the Earth's atmosphere. Let's crunch some numbers…. A
performance comparison with 24th century Galaxy Class
starship technology is presented.
An English language translation of Albert Einstein's 1905 paper which introduced
Special Relativity, as published in the 1923 book
The Principle of Relativity.
This document is
is both a monument of twentieth century physics and
a masterpiece of scientific communication. In addition to
the Web edition,
LaTeX source code
of this document may be downloaded.
has produced a beautiful Adobe Acrobat
of this document--thank you!
An English language translation of Albert Einstein's 1905 paper which
first derived the equivalence of mass and energy,
as published in the 1923 book
The Principle of Relativity.
Starting solely from the principle of relativity for
observers in uniform motion and the constancy of the
speed of light, Einstein employs an elegant kinematical
argument to deduce the most famous equation of twentieth
century physics: the equivalence of mass and energy.
In addition to
the Web edition,
and Adobe Acrobat PDF
files as well as
LaTeX source code
of this document are available.
In April 2013 I had the privilege of visiting CERN: the premier
particle physics laboratory in the world. This
photo essay shows some of the
underground wonders of the largest and most complicated
machine ever built by our species.
Why did such a long interval elapse between the appearance of life on
Earth and the emergence of complex, multicellular organisms? Perhaps
it had little to do with biology and everything to do with the
half-life of a radionuclide forged in the supernova whose debris gave
rise to us all.
It's sometimes said that special relativity has no consequences
in everyday life. Yet there's an effect of special relativity
which is immediately apparent at the glance of an eye and
observed (if not understood) since antiquity—the yellow
gleam of gold.
In 1963, Analog was a large format monthly magazine,
part slick and part pulp, with a cover price of 50 cents. Its
eclectic readership and contents attracted some curious
advertisements, such as this one from Leesona Moos Laboratories
for aerospace devices self-powered by Krypton 85 nuclear batteries.
How many Analog readers in 1963 assumed that in a
couple of years there'd be nuclear flashlight batteries for sale
at the hardware store? This one certainly did.
Due to the finite speed of light, observers in different locations or
moving with respect to one another may see events as occurring in
different orders—simultaneity depends upon your viewpoint.
You've heard the mission control recording of Apollo 11
landing on the Moon, but what did it sound like on board the
demonstrates the relativity of simultaneity and lets you experience
the Eagle's touchdown from a lunar perspective, providing
an insight about Neil Armstrong's first radio transmission after
Thermodynamics confronts special relativity in this
physics puzzle which explains why intergalactic spacecraft
will be streamlined just like in the movies.
A review/rant about Frank Tipler's 1994 book,
The Physics of Immortality.
The 1977 third (and most recent) edition of this book, compiled by
Samuel Glasstone and Philip J. Dolan and published by the
United States Department of Defense and Energy Research and
Development Administration (now Department of Energy) is the
definitive work on nuclear weapons effects. It is presented in a
hybrid form, with an XHTML table of contents which links
to PDF file containing scans of the pages of the book. An
interactive Web edition of the
nuclear bomb effects computer
circular slide rule which accompanied the 1962 edition of
the book is also available.
Relive the chilling calculations of the Cold War with this
interactive edition of the Nuclear Bomb Effects Computer published in
1962 by the United States Atomic Energy Commission. Enter the yield
and range, and the full suite of weapons effects will be displayed
just as on the original pocket slide rule. Nuclear weapons users who
prefer a physical slide rule, either out of nostalgia or an
appreciation for its ability to operate in post-apocalyptic
conditions, will find instructions for making their own.
In 1955 the giant mushrooms sprouted in abundance at the Nevada Test
Site north of Las Vegas. A total of fourteen fission devices were
detonated, with yields as high as 43 kilotons. The "Desert Rock VI"
exercise exposed 8000 troops to nuclear blasts to train them
for combat operations on the nuclear battlefield. This document was
distributed in January 1955 to those living near the Nevada Test Site
to prepare them for the 1955 test series. Illustrated with
delightful 1950s line art, it includes such sage advice as, "Your
best action is not to be worried about fall-out." and
"We can expect many reports that 'Geiger counters were going crazy
here today.' Reports like this may worry people unnecessarily.
Don't let them bother you."
Fast interstellar travel will never be possible with any kind of
rocket, regardless of the energy source (be it chemical, nuclear, or
antimatter), due to the need to carry the rocket's
reaction mass on board. How can a person who coined the maxim
"Never invest in something that violates a conservation law" seriously
entertain the possibility of "propellantless propulsion"? This
brief document speculates on how a "Vacuum Propeller" might be
built which violates no law of physics.