Posts Tagged ‘Pulsar’
“‘Space-time’ – that hideous hybrid whose very hyphen looks phoney”*…
Space and time seem about as basic as anything could be, even after Einstein’s theory of General Relativity threw (in) a curve. But as Steven Strogatz discusses with Sean Carroll, the reconciliation of Einstein’s work with quantum theory is seeming to suggest that space and time might actually be emergent properties of quantum reality, not fundamental parts of it…
… we’re going to be discussing the mysteries of space and time, and gravity, too. What’s so mysterious about them?
Well, it turns out they get really weird when we look at them at their deepest levels, at a super subatomic scale, where the quantum nature of gravity starts to kick in and become crucial. Of course, none of us have any direct experience with space and time and gravity at this unbelievably small scale. Up here, at the scale of everyday life, space and time seem perfectly smooth and continuous. And gravity is very well described by Isaac Newton’s classic theory, a theory that’s been around for over 300 years now.
But then, about 100 years ago, things started to get strange. Albert Einstein taught us that space and time could warp and bend like a piece of fabric. This warping of the space-time continuum is what we experience as gravity. But Einstein’s theory is mainly concerned with the largest scales of nature, the scale of stars, galaxies and the whole universe. It doesn’t really have much to say about space and time at the very smallest scales.
And that’s where the trouble really starts. Down there, nature is governed by quantum mechanics. This amazingly powerful theory has been shown to account for all the forces of nature, except gravity. When physicists try to apply quantum theory to gravity, they find that space and time become almost unrecognizable. They seem to start fluctuating wildly. It’s almost like space and time fall apart. Their smoothness breaks down completely, and that’s totally incompatible with the picture in Einstein’s theory.
s physicists try to make sense of all of this, some of them are coming to the conclusion that space and time may not be as fundamental as we always imagined. They’re starting to seem more like byproducts of something even deeper, something unfamiliar and quantum mechanical. But what could that something be?….
Find out at: “Where Do Space, Time and Gravity Come From?, ” from @stevenstrogatz and @seanmcarroll in @QuantaMagazine.
* Vladimir Nabokov
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As we fumble with the fundamental, we might send far-sighted birthday greetings to Jocelyn Bell Burnell; she was born on this date in 1943. An astrophysicist, she discovered the first pulsar, while working as a post-doc, in 1957. She then discovered the next three detected pulsars.
The discovery eventually earned the Nobel Prize in Physics in 1974; however, she was not one of the prize’s recipients. The paper announcing the discovery of pulsars had five authors. Bell’s thesis supervisor Antony Hewish was listed first, Bell second. Hewish was awarded the Nobel Prize, along with the astronomer Martin Ryle.
A pulsar— or pulsating radio star– a highly magnetized, rotating neutron star that emits a beam of electromagnetic radiation. The precise periods of pulsars make them very useful tools. Observations of a pulsar in a binary neutron star system were used to confirm (indirectly) the existence of gravitational radiation. The first extrasolar planets were discovered around a pulsar, PSR B1257+12. And certain types of pulsars rival atomic clocks in their accuracy in keeping time.
“I traveled far and wide through many different times”*…
Fifty years ago this month Harold D. Craft, Jr., published a remarkable black-on-white plot in his Ph.D. dissertation at Cornell University. A stacked series of jagged lines displayed incoming radio waves from pulsar CP1919, as detected at Arecibo Observatory in Puerto Rico. Several months later the chart appeared as a full-page visualization in Scientific American, this time with white lines on a field of cyan [above]…
Scientific American
In 1977, the image was included in The Cambridge Encyclopaedia of Astronomy…
… where, two years after that, Factory Records graphic genius Peter Saville discovered it and adapted it as the cover art for Joy Division’s debut album, Unknown Pleasures. He reversed the image from black-on-white to white-on-black, against the band’s stated preference for the original. “I was afraid it might look a little cheap. I was convinced that it was just sexier in black.”
It has, of course, become an icon.
* Joy Division, “Wilderness,” from Unknown Pleasures
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As we tap our toes, we might recall that it was on this date in 1985 that the U.S. Senate held hearings on what they called “porn rock.” The session was convened at the urging of the Parents Music Resource Center, a group founded by Tipper Gore, wife of Senator and later Vice President Al Gore; Susan Baker, wife of Treasury Secretary James Baker; Pam Howar, wife of Washington realtor Raymond Howar; and Sally Nevius, wife of former Washington City Council Chairman John Nevius, and devoted to forcing the music industry to affix Parental Advisory stickers– “warning labels”– to albums and CDs deemed to contain morally challenged material (like the “Filthy Fifteen” songs the group condemned).
Three musicians– Frank Zappa, John Denver, and Dee Snyder– testified in opposition to the proposal at the hearing… which was in the end moot, as the industry, afraid of negative publicity, agreed voluntarily to begin the labeling.
It is unclear that the “Tipper sticker” was/is effective in preventing children from being exposed to explicit content. Some, citing the “forbidden-fruit effect,” suggest that the sticker in fact increases record sales, arguing as Philip Bailey of Earth, Wind & Fire has: “for the most part [the sticker] might even sell more records… all you’ve got to do is tell somebody this is a no-no and then that’s what they want to go see.”
“Behold the hands”*…
Is gesture a universal language? When lost for words, we point, wave, motion and otherwise use our hands to attempt to indicate meaning. However, much of this form of communication is intuitive and is not generally seen to be, by itself, an effective substitution for speech.
John Bulwer (1606 – 1656), an English doctor and philosopher, attempted to record the vocabulary contained in hand gestures and bodily motions and, in 1644, published Chirologia, or the Naturall Language of the Hand alongside a companion text Chironomia, or the Art of Manual Rhetoric, an illustrated collection of hand and finger gestures that were intended for an orator to memorise and perform whilst speaking.
For Bulwer, gesture was the only from of speech that was inherently natural to mankind, and he saw it as a language with expressions as definable as written words…
More of the backstory (and more examples) at “Chirologia, or The Natural Language of the Hand (1644).”
* “Behold the hands, how they promise, conjure, appeal, menace, pray, supplicate, refuse, beckon, interrogate, admire, confess, cringe, instruct, command, mock and what not besides, with a variation and multiplication of variation which makes the tongue envious.” – Montaigne
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As we gesticulate, we might recall that it was on this date in 1967 that Jocelyn Bell Burnell and Antony Hewish discovered the first pulsar— or pulsating radio star– a highly magnetized, rotating neutron star that emits a beam of electromagnetic radiation.
The precise periods of pulsars make them very useful tools. Observations of a pulsar in a binary neutron star system were used to confirm (indirectly) the existence of gravitational radiation. The first extrasolar planets were discovered around a pulsar, PSR B1257+12. And certain types of pulsars rival atomic clocks in their accuracy in keeping time.
Schematic rendering of a pulsar
“A computer once beat me at chess, but it was no match for me at kick boxing”*…
J. Presper Eckert, foreground left, and John W. Mauchly, leaning against pole, are pictured with the Electronic Numerical Integrator and Computer (ENIAC) at the University of Pennsylvania in 1946. Mauchly and Eckert were the masterminds behind ENIAC, arguably the first modern computer. When it was fully operational, ENIAC filled up a room 30 x 50 feet and weighed 50 tons. Every second it was on, it used enough electricity to power a typical Philadelphia home for a week and a half.
The ENIAC— or least a good bit of it– has been saved…
Eccentric billionaires are tough to impress, so their minions must always think big when handed vague assignments. Ross Perot’s staffers did just that in 2006, when their boss declared that he wanted to decorate his Plano, Texas, headquarters with relics from computing history. Aware that a few measly Apple I’s and Altair 880’s wouldn’t be enough to satisfy a former presidential candidate, Perot’s people decided to acquire a more singular prize: a big chunk of ENIAC, the “Electronic Numerical Integrator And Computer.” The ENIAC was a 27-ton, 1,800-square-foot bundle of vacuum tubes and diodes that was arguably the world’s first true computer. The hardware that Perot’s team diligently unearthed and lovingly refurbished is now accessible to the general public for the first time, back at the same Army base where it almost rotted into oblivion…
Read the whole story– and see more photos of computing, v1.0– at “How the World’s First Computer Was Rescued From the Scrap Heap.”
* Emo Philips
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As we praise the preservationists, we might recall that it was on this date in 1967 that Jocelyn Bell Burnell and Antony Hewish observed the first pulsar– “pulsating radio star.” A highly-magnetized, rotating neutron star, a pulsar emits a beam of electromagnetic radiation that can only be detected on Earth when it is being beamed in our direction (so seems, from Earth’s vantage, to be pulsing). Pulsars have short, regular rotational periods, so produce the pulses that we detect at very precise intervals.
Schematic view of a pulsar. The sphere in the middle represents the neutron star, the curves indicate the magnetic field lines, the protruding cones represent the emission beams and the green line represents the axis on which the star rotates.
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