Posts Tagged ‘Carl Sagan’
“Pure mathematics is, in its way, the poetry of logical ideas”*…
Alexander Grothendieck is revered in the world of math; outside of it, he’s known for his unusual life, if he’s known at all. Konstantin Kakaes outlines his actual mathematical contributions…
What Albert Einstein was to 20th-century physics, Alexander Grothendieck was to 20th-century mathematics. He is much less well known because math gets technical even more quickly than physics does. But as with Einstein, Grothendieck’s impact came not just from his own results, revolutionary though they were. His work also reoriented his entire discipline in radical new directions.
Grothendieck was intense and ascetic from his early days. Starting in the early 1950s, when he was in his 20s, he produced thousands of pages of formal and informal notes that changed the course of mathematics. Then in 1970, he quit. He left his post at a prestigious research institute just outside of Paris to teach at the provincial university in Montpellier where he studied as an undergraduate. He mostly stopped talking to other mathematicians. In the early 1990s, he moved to a small village in the Pyrenees, where he lived as a hermit.
Mathematicians are still grappling with the innovations he made half a century ago. His work pushed mathematics to a new level of abstraction by focusing on the relationships between objects rather than the objects themselves. “If there is one thing in mathematics which fascinates me more than any other (and undoubtedly always has), it is neither ‘number’ nor ‘size,’ but invariably shape,” he wrote in his memoirs. “And among the thousand and one faces under which shape chooses to reveal itself to us, that which has fascinated me more than any other and continues to do so is the structure hidden in mathematical things.”
His revolutionary mathematics centered around that search for hidden structure…
Read on: “How Alexander Grothendieck Revolutionized 20th-Century Mathematics,” from @kkakaes.bsky.social in @quantamagazine.bsky.social.
For more, see the section on Grothendieck in Benjamin Labatut‘s remarkable When We Cease To Understand the World.
* Albert Einstein
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As we study shape, we might send speculative birthday greetings to a man who, while not technically a mathematician, nonetheless created a famous equation: Frank Drake; he was born this date in 1930. An astronomer and astrophysicist, he formulated the Drake Equation in 1961 to estimate the number of technological civilizations that might exist in the Milky Way galaxy, N = R* × fp × ne× fl × fi × fc × L. Using plausible guesses for the parameters, Drake concluded perhaps 10 planets in our galaxy may have life originating detectable signals. In 1960, Drake led the first search, the two-month Project Ozma to listen for patterns in radio waves with a complex, ordered pattern that might be assumed to represent messages from some extraterrestrial intelligence.
Carl Sagan and Drake designed the plaques on Pioneer 10 and Pioneer 11 for the purpose of greeting and informing any extraterrestrial life that might find the vessels after they left the solar system.
“In the beginning the Universe was created. This has made a lot of people very angry and been widely regarded as a bad move.”*…
In the face of cosmologists who are trying to combine string theory with the theory of cosmic inflation to understand the universe-as-we-find-it, Neil Turok suggests a much simpler explanation. Frank Landymore reports…
Our understanding of the universe, as advanced as it is, remains riddled with paradoxes and huge question marks. Physicists have come up with some pretty heady ideas to explain them — we’ll get to those later — but there just might be a far “simpler” solution to all those holes in cosmology.
As Higgs Chair of Theoretical Physics at the University of Edinburgh Neil Turok explains in an essay for The Conversation, there could be a “mirror” universe that existed before the Big Bang and is a reflection of our own, moving backward in time.
It’s a trippy concept to wrap your head around, but simpler on the physics side of things. It would neatly balance out some of the asymmetries we observe in the universe, provide an answer to dark matter, and supplant some of what Turok would characterize as clumsier leading theories in cosmology, like cosmic inflation and string theory.
“Picturing the big bang as a mirror neatly explains many features of the universe which might otherwise appear to conflict with the most basic laws of physics,” wrote Turok, who published his team’s findings in the journal Annals of Physics. “The progress we have already made convinces me that, in all likelihood, there are alternatives to the standard orthodoxy — which has become a straitjacket we need to break out of.”
The physical laws of the universe should exhibit charge, parity, and time reversal — collectively known as CPT — symmetry, which essentially means every physical interaction can be mirrored. So to break down its implications: every particle should have an anti-particle of the opposite charge, every space has its inversion, and time can be reversed.
Except that’s not what we actually observe. Time only goes forward, and there are more particles than anti-matter particles. As far as we can tell, our universe is not symmetrical.
But: “Our mirror hypothesis restores the symmetry of the universe,” Turok argued. He compared it to looking at your reflection: “The combination of you and your mirror image are more symmetrical than you are alone.”
Extrapolating our universe backward in time through the Big Bang, “we found its mirror image, a pre-bang universe in which (relative to us) time runs backward and antiparticles outnumber particles,” Turok wrote.
This could also solve the mystery of dark matter, an invisible substance thought to make up 85 percent of all matter in the universe. Under the mirror hypothesis, weak, subatomic particles called neutrinos would be the ideal candidate to explain it.
Since we’ve only observed left-handed neutrinos, perhaps yet-unseen right-handed could even exist in the mirror universe.
What’s more, this could also tidily explain why the universe appears to be so uniform and flat. The prevailing theory is that a period of accelerated, faster-than-light expansion called cosmic inflation was responsible for shaping how the universe is today — but we’re yet to observe the large gravitational waves this would have produced.
With a handy mirror universe, however, “statistical arguments explain why the universe is flat and smooth and has a small positive accelerated expansion, with no need for cosmic inflation,” Turok wrote.
Of course, there’s a lot more needed to bear out this intriguing hypothesis. But Turok argues that, even if disproven, it demonstrates that there could be more straightforward explanations than what the Standard Model offers…
A mirror of our own, going backwards in time: “Physicist Says There’s Another Universe Hiding Behind the Big Bang,” from @futurism.
Turok’s full essay– longer and more detailed, but very accessible– is here.
* Douglas Adams, The Restaurant at the End of the Universe
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As we size up symmetry, we might send lofty birthday greetings to another ponderer of the cosmos, Carl Edward Sagan; he was born on this date in 1934. An astronomer, cosmologist, astrophysicist, astrobiologist (his contributions were central to the discovery of the high surface temperatures of Venus), he is best remembered as a popularizer of science– via books like The Dragons of Eden, Broca’s Brain and Pale Blue Dot, and the award-winning 1980 television series Cosmos: A Personal Voyage (which he narrated and co-wrote), the most widely-watched series in the history of American public television (seen by at least 500 million people across 60 different countries).
He is also remembered for his contributions to the scientific research of extraterrestrial life, including experimental demonstration of the production of amino acids from basic chemicals by radiation.
(Readers can enjoy a loving riff on Cosmos here.)
“To create something from nothing is one of the greatest feelings”*…
Something from nothing? Not exactly. As Charlie Wood explains, it’s even weirder…
For their latest magic trick, physicists have done the quantum equivalent of conjuring energy out of thin air. It’s a feat that seems to fly in the face of physical law and common sense.
“You can’t extract energy directly from the vacuum because there’s nothing there to give,” said William Unruh, a theoretical physicist at the University of British Columbia, describing the standard way of thinking.
But 15 years ago, Masahiro Hotta, a theoretical physicist at Tohoku University in Japan, proposed that perhaps the vacuum could, in fact, be coaxed into giving something up.
At first, many researchers ignored this work, suspicious that pulling energy from the vacuum was implausible, at best. Those who took a closer look, however, realized that Hotta was suggesting a subtly different quantum stunt. The energy wasn’t free; it had to be unlocked using knowledge purchased with energy in a far-off location. From this perspective, Hotta’s procedure looked less like creation and more like teleportation of energy from one place to another — a strange but less offensive idea.
“That was a real surprise,” said Unruh, who has collaborated with Hotta but has not been involved in energy teleportation research. “It’s a really neat result that he discovered.”
Now in the past year, researchers have teleported energy across microscopic distances in two separate quantum devices, vindicating Hotta’s theory. The research leaves little room for doubt that energy teleportation is a genuine quantum phenomenon.
“This really does test it,” said Seth Lloyd, a quantum physicist at the Massachusetts Institute of Technology who was not involved in the research. “You are actually teleporting. You are extracting energy.”…
“Physicists Use Quantum Mechanics to Pull Energy out of Nothing,” from @walkingthedot in @QuantaMagazine.
Vaguely related (and fascinating): “The particle physics of you.”
* Prince
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As we demolish distance, we might send insightful birthday greetings to Brain Cox; he was born on this date in 1968. A physicist and former musician (he was keyboardist for Dare and D:Ream), he is a professor of particle physics in the School of Physics and Astronomy at the University of Manchester, and a fellow at CERN (where he works on the ATLAS experiment, studying the forward proton detectors for the Large Hadron Collider there).
But Cox is most widely known as the host/presenter of science programs, perhaps especially the BBC’s Wonders of the Universe series, and for popular science books, such as Why Does E=mc²? and The Quantum Universe— which (he avers) were inspired by Carl Sagan and for which Cox has earned recognition as the natural successor to David Attenborough and Patrick Moore.
Science is too important not to be a part of a popular culture.
“What I desire of a poem is a clear understanding of motive”*…
I’m not a Hollywood scriptwriter, but if I were, I know what screenplay I’d write. Imagine a violent murder at the epicenter of early Santa Clara Valley—soon to be renamed Silicon Valley in the popular imagination—and an innocent man sent to Death Row at San Quentin. But a famous literary critic emerges as the super sleuth who gets him freed, amid dark evocations of scandal involving corrupt politicians and murky underworld figures.
You don’t need to imagine it, because it really happened. It’s like the movie Chinatown—in fact, it took place during the same era as that scrumptiously vintage film—but with intriguing literary twists and turns. And, like Chinatown, it possesses all the same overtones of a brutal California origin myth. It would make a riveting film. But in this case the story is true.
On Memorial Day in 1933, a woman’s [Allene Lamson’s] naked body was found, apparently bludgeoned to death, in her Stanford campus home. Within an hour of their arrival on the crime scene, the police had already decided that the husband [David Lamson]—always the prime suspect in a case of this sort—must be the murderer.
…
The police never took any other explanation seriously. A student named John Venderlip had seen a suspicious character near the Lamson home the morning of the crime, as well as the night before. But no effort went into investigating this lead. The possibility of accidental death was ruled out, too, although it would later play a decisive role in the case.
This web of speculation and insinuation proved sufficient to get a conviction after a three-week trial that was front page news day after day. The jury only deliberated for eight hours before delivering a guilty verdict. The judge handed out the death penalty—a court-mandated hanging within 90 days. And David Lamson was sent off to San Quentin to await his imminent execution on Death Row.
And that would seem to be the end of the story. But it wasn’t. And the main reason for this surprising turn into the biggest crime story of its day was a mild-mannered poet and literary critic named Yvor Winters…
In the 1930s, Yvor Winters legitimized literary studies at Stanford—but Hollywood should make a movie about his skills as an amateur detective. A remarkable story from the remarkable Ted Gioia (@tedgioia): “When a Famous Literary Critic Unraveled Silicon Valley’s Most Sensational Murder Case.”
And for further (entertaining, but wholly fictional) accounts of a literary critic’s sleuthing, see Edmund Crispin‘s Gervase Fen novels…
* Yvor Winters
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As we consider the clues, we might remind our selves that if the history of the universe was condensed into a year, the Milky Way would form on this date (May 15), life on earth would appear on September 21, and the dinosaurs would go extinct on December 30. Modern humans would evolve on December 31 at 11:52 PM and Columbus would discover America at 11:59:58 PM. (For more detail: the Cosmic Calendar)
“To declare that Earth must be the only planet with life in the universe would be inexcusably bigheaded of us”*…
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If any intelligent life in our galaxy intercepts the Voyager spacecraft, if they evolved the sense of vision, and if they can decode the instructions provided, these 116 images are all they will know about our species and our planet, which by then could be long gone…
When Voyager 1 and Voyager 2 launched into space in 1977, their mission was to explore the outer solar system, and over the following decade, they did so admirably.
With an 8-track tape memory system and onboard computers that are thousands of times weaker than the phone in your pocket, the two spacecraft sent back an immense amount of imagery and information about the four gas giants, Jupiter, Saturn, Uranus, and Neptune.
But NASA knew that after the planetary tour was complete, the Voyagers would remain on a trajectory toward interstellar space, having gained enough velocity from Jupiter’s gravity to eventually escape the grasp of the sun. Since they will orbit the Milky Way for the foreseeable future, the Voyagers should carry a message from their maker, NASA scientists decided.
The Voyager team tapped famous astronomer and science popularizer Carl Sagan to compose that message. Sagan’s committee chose a copper phonograph LP as their medium, and over the course of six weeks they produced the “Golden Record”: a collection of sounds and images that will probably outlast all human artifacts on Earth…
More (including an interactive decoding of the symbols on the disc) at “The 116 photos NASA picked to explain our world to aliens.”
And for an update on NASA”s attempts at interstellar communication, check here.
* Neil DeGrasse Tyson, Death By Black Hole
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As we contemplate co-habitation of the universe, we might send out-of-this-world birthday greetings to Alan B. Shepard; he was born on this date in 1923. A naval aviator and test pilot, he was selected in the first class of American astronauts, the “Mercury Seven”; in 1961, he piloted the first American manned mission, “Freedom 7,” becoming the first American (and second man, after Yuri Gagarin) into space. Ten years later, he was part of the Apollo 14 crew, piloting the lunar module for Nasa’s third successful moon landing.
Shepard during the “Freedom 7” flight
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