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Posts Tagged ‘astronomy

“If and when all the laws governing physical phenomena are finally discovered, and all the empirical constants occurring in these laws are finally expressed through the four independent basic constants, we will be able to say that physical science has reached its end”*…

The fine-structure constant was introduced in 1916 to quantify the tiny gap between two lines in the spectrum of colors emitted by certain atoms. The closely spaced frequencies are seen here through a Fabry-Pérot interferometer.

As fundamental constants go, the speed of light, c, enjoys all the fame, yet c’s numerical value says nothing about nature; it differs depending on whether it’s measured in meters per second or miles per hour. The fine-structure constant, by contrast, has no dimensions or units. It’s a pure number that shapes the universe to an astonishing degree — “a magic number that comes to us with no understanding,” as Richard Feynman described it. Paul Dirac considered the origin of the number “the most fundamental unsolved problem of physics.”

Numerically, the fine-structure constant, denoted by the Greek letter α (alpha), comes very close to the ratio 1/137. It commonly appears in formulas governing light and matter. “It’s like in architecture, there’s the golden ratio,” said Eric Cornell, a Nobel Prize-winning physicist at the University of Colorado, Boulder and the National Institute of Standards and Technology. “In the physics of low-energy matter — atoms, molecules, chemistry, biology — there’s always a ratio” of bigger things to smaller things, he said. “Those ratios tend to be powers of the fine-structure constant.”

The constant is everywhere because it characterizes the strength of the electromagnetic force affecting charged particles such as electrons and protons. “In our everyday world, everything is either gravity or electromagnetism. And that’s why alpha is so important,” said Holger Müller, a physicist at the University of California, Berkeley. Because 1/137 is small, electromagnetism is weak; as a consequence, charged particles form airy atoms whose electrons orbit at a distance and easily hop away, enabling chemical bonds. On the other hand, the constant is also just big enough: Physicists have argued that if it were something like 1/138, stars would not be able to create carbon, and life as we know it wouldn’t exist.

Physicists have more or less given up on a century-old obsession over where alpha’s particular value comes from; they now acknowledge that the fundamental constants could be random, decided in cosmic dice rolls during the universe’s birth. But a new goal has taken over.

Physicists want to measure the fine-structure constant as precisely as possible. Because it’s so ubiquitous, measuring it precisely allows them to test their theory of the interrelationships between elementary particles — the majestic set of equations known as the Standard Model of particle physics. Any discrepancy between ultra-precise measurements of related quantities could point to novel particles or effects not accounted for by the standard equations. Cornell calls these kinds of precision measurements a third way of experimentally discovering the fundamental workings of the universe, along with particle colliders and telescopes…

In a new paper in the journal Nature, a team of four physicists led by Saïda Guellati-Khélifa at the Kastler Brossel Laboratory in Paris reported the most precise measurement yet of the fine-structure constant. The team measured the constant’s value to the 11th decimal place, reporting that α = 1/137.03599920611. (The last two digits are uncertain.)

With a margin of error of just 81 parts per trillion, the new measurement is nearly three times more precise than the previous best measurement in 2018 by Müller’s group at Berkeley, the main competition. (Guellati-Khélifa made the most precise measurement before Müller’s in 2011.) Müller said of his rival’s new measurement of alpha, “A factor of three is a big deal. Let’s not be shy about calling this a big accomplishment”… largely ruling out some proposals for new particles

A team in Paris has made the most precise measurement yet of the fine-structure constant, killing hopes for a new force of nature: “Physicists Nail Down the ‘Magic Number’ That Shapes the Universe.”

[TotH to MK]

* George Gamow

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As we ponder precision, we might spare a thought for Persian polymath Omar Khayyam; the mathematician, philosopher, astronomer, epigrammatist, and poet died on this date in 1131.  While he’s probably best known to English-speakers as a poet, via Edward FitzGerald’s famous translation of the quatrains that comprise the Rubaiyat of Omar Khayyam, Omar was one of the major mathematicians and astronomers of the medieval period.  He is the author of one of the most important works on algebra written before modern times, the Treatise on Demonstration of Problems of Algebra (which includes a geometric method for solving cubic equations by intersecting a hyperbola with a circle).  His astronomical observations contributed to the reform of the Persian calendar.  And he made important contributions to mechanics, geography, mineralogy, music, climatology, and Islamic theology.

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“Earth is a small town with many neighborhoods in a very big universe”*…

… full of very large objects. From @nealagarwal, a scroll-able comparison of the size of the objects that surround us in in the universe: “Size of Space.”

(Listen to outer space here.)

For other nifty visualizations, visit his site and check out, e.g., “The Deep Sea.”

* Ron Garan

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As we internalize insignificance, we might send distantly-observed birthday greetings to Harlow Shapley; he was born on this date in 1885. An astronomer known as “the Modern Copernicus,” he did important work first at the Mt. Wilson Observatory, and then as head of the Harvard College Observatory. He boldly and correctly proclaimed that the globulars outline the Galaxy, and that the Galaxy is far larger than was generally believed and centered thousands of light years away in the direction of Sagittarius: he discovered of the center of our Galaxy, and of our position within it.

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Written by LW

November 2, 2020 at 1:01 am

“Loki’d!”*…

January 2, 1961: 100,000 spectators filled Pasadena’s Rose Bowl stadium to watch the Minnesota Golden Gophers take on the Washington Huskies in the New Year’s Day game (played that year on January 2 because the 1st fell on a Sunday). Millions more watched around the nation, crowded in front of tv sets in living rooms, restaurants, and bars.

NBC was providing live coverage of the game. At the end of the first half the Huskies led 17 to 0, and the audience settled in to watch the half-time show for which the Washington marching band had prepared an elaborate flip-card routine.

Sets of variously colored flip cards and an instruction sheet had been left on seats in the section of the stadium where the Washington students were located. When the students heard the signal from the cheerleaders, they were each supposed to hold up the appropriate flip card (as designated by the instruction sheet) over their head. In this way different gigantic images would be formed that would be visible to the rest of the stadium, as well as to those viewing at home. The Washington band planned on displaying a series of fifteen flip-card images in total.

The flip-card show got off to a well-coordinated start. Everything went smoothly, and the crowd marvelled at the colorful images forming, as if by magic, at the command of the cheerleaders. It wasn’t until the 12th image that things began to go a little wrong. This image was supposed to depict a husky, Washington’s mascot. But instead a creature appeared that had buck teeth and round ears. It looked almost like a beaver.

The next image was even worse. The word ‘HUSKIES’ was supposed to unfurl from left to right. But for some reason the word was reversed, so that it now read ‘SEIKSUH’.

These strange glitches rattled the Washington cheerleaders. They wondered if they might have made some careless mistakes when designing the complex stunt. But there was nothing for them to do about it now except continue on, and so they gave the signal for the next image.

What happened next has lived on in popular memory long after the rest of the 1961 Rose Bowl has been forgotten. It was one of those classic moments when a prank comes together instantly, perfectly, and dramatically.

The word ‘CALTECH’ appeared, held aloft by hundreds of Washington students. The name towered above the field in bold, black letters and was broadcast to millions of viewers nationwide.

For a few seconds the stadium was plunged into a baffled silence. Everyone knew what Caltech was. It was that little Pasadena technical college down the road from the Rose Bowl stadium. What no one could figure out was what its name was doing in the middle of Washington’s flip-card show. Throughout the United States, a million minds simultaneously struggled to comprehend this enigma.

In fact, only a handful of people watching the game understood the full significance of what had just happened, and these were the Caltech students who had labored for the past month to secretly alter Washington’s flip-card show…

More on one of the great pranks of all time: “The Great Rose Bowl Hoax,” via The Museum of Hoaxes.

See also this explication of one of the more successful imitators.

* Tom Hiddleston

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As we treasure tricksters, we might recall that on this date in 2006 the City Councils of Reykjavik and its neighboring municipalities agreed to turn off all the city lights in the capital area for half an hour, while a renowned astronomer talked about the stars and the constellations on national radio.

(Ten years later they dimmed again to allow unpolluted viewing of the Northern Lights.)

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Written by LW

September 28, 2020 at 1:01 am

“I’m envious of people who can sleep as long as they want. I have the circadian rhythm of a farmer.”*…

After World War II, scientists began studying the internal clocks of animals in earnest. They discovered that mammals and other creatures are ruled by their own, internal body clock, what is commonly referred to today as a biological clock. The German physician and biologist Jürgen Aschoff wondered if this might also be true of humans. In the early 1960s, as head of a new department for biological timing at the Max Planck Institute for Behavioral Physiology, Aschoff and his research partner Rütger Wever designed an experiment to find out.

To study the inner workings of human biological clocks, Aschoff built a soundproof underground bunker in the foothills of a mountain deep in the Bavarian countryside, just up the road from the well-known beer-brewing monastery Kloster Andechs. Through a series of investigations that included 200 subjects and spanned two decades, Aschoff’s bunker experiments would become a pioneering study in the field of chronobiology, changing the way we think about time today…

What Is Chronobiology? Does it explain why we’re having so much trouble sleeping? Find out here.

* Moby

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As we hit the hay, we might spare a thought for Urbain Le Verrier; he died on this date in 1877. An astronomer and mathematician who specialized in celestial mechanics, he’s best remembered for predicting the existence and position of the planet Neptune using only mathematics. Le Verrier sent the coordinates to Johann Gottfried Galle at the New Berlin Observatory, asking him to verify. Galle found Neptune in the same night he received Le Verrier’s letter– this date in 1846. The planet was within 1° of the predicted position.

Urbain Le Verrier

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Written by LW

September 23, 2020 at 1:01 am

“Doomsday is quite within our reach, if we will only stretch for it”*…

 

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Ah, to have planned for a comet apocalypse in the Belle Epoque! Looks like a wild time, according to all the 19th and 20th century postcards with folks soaring through the skies, bum over noggin, towards a starry death. Out of all the (ultimately) anti-climactic close comet calls, the 1910 approach of Halley’s Comet takes the cake. Not only did it lead to the first ever photograph of a comet, and the actual gathering of “spectroscopic ” data, but because the anticipation of its arrival caused a media frenzy. Stores started selling “anti-comet pills.” Papers put out ads for escape submarine rentals. One cult considered sacrificing a virgin…

It’s hard for us science laypeople to fathom the workings of space, let alone its errant pebbles. Although, Halley’s never been just a random fly bye event; by 1705, its orbital period of 75 or so years was confirmed by the English astronomer, Edmond Halley, bringing us both the comet’s eponymous name and a new tradition: once, maybe even twice in a lifetime, the comet’s 24-million-mile long tail would become visible to the naked eye. Fun fact: he might not have had his breakthrough, if he hadn’t consulted a friend and fellow scholar named Isaac Newton.

But people started to wonder – were there consequences of such seemingly close contact? One account of its 1835 passing describes a “vapour trail” in the sky…

When Halley was next slated to return, it was at the beginning of a new century in 1910, when advancements in media and technology had radically accelerated the circulation of people and ideas, and major breakthroughs were being made in the automobile and radio industries; the world had seen the first airplanes and photographs – including the photographs of astronomical objects. That meant it was finally, hopefully, the moment to capture an image of the comet when it neared earth in one of its shortest return cycles yet, a mere 74 years. It had one man in particular, a French scientist named Camille Flammarion, feeling rather worried. Flammarion was a prominent, and above all colourful presence in the astronomy scene. He ran the journal L’Astronomie, as well as his own private, castle-like observatory in Juvisy-sur-Org, France, which you can still visit today…

As an author, he penned both scientific essays and science fiction with a talent for poetic turns of a phrase. Readers loved it; critics tended to roll their eyes at his tendency for sensationalism. “This end of the world will occur without noise, without revolution, without cataclysm,” he wrote in L’atmosphère : météorologie populaire in 1888, “Just as a tree loses leaves in the autumn wind, so the earth will see in succession the falling and perishing of all its children, and in this eternal winter, which will envelop it from then on, she can no longer hope for either a new sun or a new spring. She will purge herself of the history of the worlds.” Yikes.

The incoming of Halley’s comet, he said, contained a poisonous cyanogen gas that “would impregnate the atmosphere and possibly snuff out all life on the planet.” When The New York Times ran a story on his assertion, the fear amplified on a global scale in the tabloids. One science writer, Matt Simon, said folks were so frightened, they began sealing up the keyholes of their houses to “keep the poison out of their homes.”… Comet pills, comet shelters, comet soap, and even submarine rentals became the norm for doomsday preppers… Even fashion took a turn. It wasn’t uncommon to find both amateur and professional-grade comet buttons, broaches and jewellery…

“I came in with Halley’s comet in 1835,” Mark Twain famously wrote in 1909, decreeing that he fully expected “to go out with it in 1910,” which, to his credit, he did. Was Twain’s death a feat of willpower, coincidence, or fate? Who knows. But it was one in a series of events that used the comet as a launching pad for a kind of self-fulfilling prophecy. Some cited the event as the cause of death of King Edward VII. The civil unrest surrounding the comet even helped spark China’s Xinhai Revolution in 1911, which effectively ended the last dynasty…

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Halley in April 1910, from Harvard’s Southern Hemisphere Station, taken with an 8-inch Bache Doublet

 

It’s the end of the world as they knew it: “Doomsday Prepping in the Belle Epoque.”

* Loudon Wainwright III

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As we eye the sky, we might send far-seeing birthday greetings to James Ferguson; he was born on this date in 1797.  Working at the U.S. Naval Observatory with a 9.6 inch refractor telescope, made the first discovery of an asteroid from North America (31 Euphrosyne).

150px-James_Ferguson_(astronomer) source

 

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