World War II computer Colossus that cracked Nazi code
Retired British spy catcher Tony Sale rebuilt Colossus, the world’s first recognisably programmable computer.
Colossus was instrumental in the work of code cracking operations at Bletchley Park in Buckinghamshire during World War II.
It deciphered messages sent by German over the Lorenz Cipher.
(License Plate of a White VW Rabbit)
OK, I am a little embarrassed to be more than fashionably late to the blogohedron party, but this is the 50th anniversary of the laser, and the APS (and some partners) have launched the laserfest website, with lots of stimulating, coherent goodness. Also, Jennifer gives us the festival of lasers
Jennifer points out that
There are several different types of lasers. Solid-state lasers use crystals whose atoms are arranged in a solid matrix, such as ruby. CO2 lasers emit energy in the far-infrared and microwave regions of the spectrum. This type produces intense heat, and is capable of melting through objects. Dr. Evil coveted such a laser when he demanded “sharks with frickin’ laser beams” on their heads to torture Austin Powers to death – only to be foiled because sharks are an endangered species. Imagine his disappointment if, in addition to having to make do with cranky mutated sea bass, they were equipped not with CO2 lasers, but with conventional diode (semiconductor) lasers. These are the type used in pocket laser pointers and CD and DVD players. They are not even remotely lethal.
But beware. Semiconductors aren’t all wimpy — you can get fairly high power diode lasers, and amplifiers that will put out a respectable amount of power. Generally these amplifiers are tapered so the the output beam is larger than the input, so you don’t blow the device up, and the output facet is antireflection coated so that the gain is single-pass (it won’t lase very well on its own). A Watt (or several) of laser power may not be lethal, but it can burn you nicely if it’s focused down, and I have empirical data to back that up. It can also do retinal damage, and that can ruin your whole day.
Remember, kids: Do Not Look Into Laser with Remaining Eye
National Trust on Google Street View
It has engaged Google to take pictures from all around sites including Corfe Castle in Dorset and Fountains Abbey in Yorkshire, which have then be digitally stitched together to give seamless 360 degree images.
You can visit Stonehenge (as I did in 2001), and go where pedestrians are not normally allowed.
Smithsonian.com: Myths of the American Revolution
[M]uch of what we know is not entirely true. Perhaps more than any defining moment in American history, the War of Independence is swathed in beliefs not borne out by the facts. Here, in order to form a more perfect understanding, the most significant myths of the Revolutionary War are reassessed.
Skulls in the Stars: Lord Kelvin vs. the Aether! (1901)
[T]hese speculations resulted in a number of interesting results. For instance, we have noted previously that Earnshaw’s theorem (1839), an important result in electromagnetic theory, arose from an attempt to determine the forces that hold the aether together. In 1902, Lord Rayleigh attempted to detect the aether-induced “length contraction” by measuring the birefringence of moving objects, an ingenious attempt that gave a negative result.
In the broadest sense, a “good” theory is one which raises interesting questions that may inevitably be tested by experiment. Even if it proves to be fundamentally incorrect in the end, it has spurred numerous theoretical and experimental results.
OK, not really.
Dec. 30, 1924: Hubble Reveals We Are Not Alone
Hubble used Leavitt’s formula to calculate that Andromeda was approximately 860,000 light years away. That’s more than eight times the distance to the farthest stars in the Milky Way. This conclusively proved that the nebulae are separate star systems and that our galaxy is not the universe.
Cosmic though it was, the news did not make the front page of The New York Times. The paper did notice the following Feb. 25 that Hubble and a public health researcher split a $1,000 prize ($12,000 in today’s money) from the American Academy for the Advancement of Science.
Letters of Note: “He is a second Dirac, only this time human.”
Robert Oppenheimer’s letter of recommendation on behalf of Richard Feynman.
The reason for telling you about him now is that his excellence is so well known, both at Princeton where he worked before he came here, and to a not inconsiderable number of “big shots” on this project, that he has already been offered a position for the post war period, and will most certainly be offered others. I feel that he would be a great strength for our department, tending to tie together its teaching, its research and its experimental and theoretical aspects. I may give you two quotations from men with whom he has worked. Bethe has said that he would rather lose any two other men than Feyman from this present job, and Wigner said, “He is a second Dirac, only this time human.”
Uncertain Principles: Science Ahead of Its Time?
[T]his does not beg but rather demands the question: are there any examples of truly revolutionary ideas in science? That is, are there scientific theories that jump well ahead of what was “in the air” at the time of their creation, in such a way that they would not have been discovered for decades more if their discoverer had died young in a tragic zeppelin accident?
The economics of pinball at its peak, when it took advantage of programmable electronics that would shortly be its downfall.
In 1980, pinball went digital, multi-ball, and multi-media starting with the game Black Knight. Black Knight brought pinball to a new level, literally speaking because it was among the first games with ramps and elevated flippers, but even more importantly because it brought a new challenge that drew in and solidified a pinball crowd. In doing so it also set the pinball market on a path that would eventually lead to its demise.
I remember Black Knight, and reading a story about how it was developed. The voice synthesizer programming had to be tweaked to make the “s” harder, because “I will slay you” was sounding more like an uncomfortable proposition than a challenge. But even then video games were already beginning to displace pinball machines.