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Posts Tagged ‘astronomy

“I’m sure the universe is full of intelligent life. It’s just been too intelligent to come here.”*…

 

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Artist’s impression of the first interstellar asteroid/comet, “Oumuamua”

 

Or not…

On October 19th, 2017, the Panoramic Survey Telescope and Rapid Response System-1 (Pan-STARRS-1) in Hawaii announced the first-ever detection of an interstellar asteroid, named 1I/2017 U1 (aka, ‘Oumuamua). In the months that followed, multiple follow-up observations were conducted that allowed astronomers to get a better idea of its size and shape, while also revealing that it had the characteristics of both a comet and an asteroid.

Interestingly enough, there has also been some speculation that based on its shape, ‘Oumuamua might actually be an interstellar spacecraft (Breakthrough Listen even monitored it for signs of radio signals!). A new study by a pair of astronomers from the Harvard Smithsonian Center for Astrophysics (CfA) has taken it a step further, suggesting that ‘Oumuamua may actually be a light sail of extra-terrestrial origin…

As for what an extra-terrestrial light sail would be doing in our solar system, [Harvard astronomers Shmuel Bialy and Prof. Abraham Loeb] offer some possible explanations for that. First, they suggest that the probe may actually be a defunct sail floating under the influence of gravity and stellar radiation, similar to debris from ship wrecks floating in the ocean. This would help explain why Breakthrough Listen found no evidence of radio transmissions.

Loeb further illustrated this idea in a recent article he penned for Scientific American, where he suggested that ‘Oumuamua could be the first known case of an artificial relic which floated into our solar system from . What’s more, he notes that lightsails with similar dimensions have been designed and constructed by humans, including the Japanese-designed IKAROS project and the Starshot Initiative with which he is involved.

“This opportunity establishes a potential foundation for a new frontier of space archaeology, namely the study of relics from past civilizations in space,” Loeb wrote. “Finding evidence for space junk of artificial origin would provide an affirmative answer to the age-old question “Are we alone?”. This would have a dramatic impact on our culture and add a new cosmic perspective to the significance of human activity.”

On the other hand, as Loeb told Universe Today, ‘Oumuamua could be an active piece of alien technology that came to explore our solar system, the same way we hope to explore Alpha Centauri using Starshot and similar technologies”…

More provocative detail at “Could ‘Oumuamua be an extraterrestrial solar sail?

* Arthur C. Clarke

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As we ask if we’re alone, we might recall that it was on this date in 1572 that Wolfgang Schüler first noted a supernova in the W-shaped constellation of Cassiopeia.  It was subsequently seen by other observers, including Tycho Brahe, who included an account of the sighting in his De nova stellaConsequently, the supernova– one of eight visible to the naked eye in historical records– is known as “Tycho’s Supernova.”

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Star map of the constellation Cassiopeia showing the position (labelled I) of the supernova of 1572; from Tycho Brahe’s De nova stella

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Written by LW

November 6, 2018 at 2:01 am

“What is common to many is least taken care of”*…

 

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As an evolutionary biologist who received my PhD in 1975, I grew up with Garrett Hardin’s essay “The Tragedy of the Commons,” published in Science magazine in 1968. His parable of villagers adding too many cows to their common pasture captured the essence of the problem that my thesis research was designed to solve. The farmer who added an extra cow gained an advantage over other farmers in his village but it also led to an overgrazed pasture. The biological world is full of similar examples in which individuals who behave for the good of their groups lose out in the struggle for existence with more self-serving individuals, resulting in overexploited resources and other tragedies of non-cooperation…

Unbeknownst to me, another heretic named Elinor Ostrom was also challenging the received wisdom in her field of political science. Starting with her thesis research on how a group of stakeholders in southern California cobbled together a system for managing their water table, and culminating in her worldwide study of common-pool resource (CPR) groups, the message of her work was that groups are capable of avoiding the tragedy of the commons without requiring top-down regulation, at least if certain conditions are met (Ostrom 1990, 2010). She summarized the conditions in the form of eight core design principles: 1) Clearly defined boundaries; 2) Proportional equivalence between benefits and costs; 3) Collective choice arrangements; 4) Monitoring; 5) Graduated sanctions; 6) Fast and fair conflict resolution; 7) Local autonomy; 8) Appropriate relations with other tiers of rule-making authority (polycentric governance). This work was so groundbreaking that Ostrom was awarded the Nobel Prize in economics in 2009…

David Sloan Wilson on the design principles that can solve the tragedy of the commons: “The Tragedy of the Commons: How Elinor Ostrom Solved One of Life’s Greatest Dilemmas.”

For more on the tragedy of the commons, see here— also the source of the cartoon above.

* Aristotle

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As we share and share alike, we might recall that it was on this date in 1937 that we– the entire population of the earth– narrowly avoided total obliteration, as the 500,000 ton asteroid/planetoid 69230 Hermes failed to collide with our planet.  It missed by twice the distance of the Moon… but that’s only three seconds.  (In 1989, the earth had an even closer approach, but by the smaller 4581 Asclepius.)

69230 Hermes

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Written by LW

October 30, 2018 at 1:01 am

“The Bible shows the way to go to heaven, not the way the heavens go”*…

 

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Harmonia Macrocosmica (1660), an atlas of the stars from the Dutch Golden Age of cartography, maps the structure of the heavens in twenty-nine extraordinary double-folio spreads. We are presented with the motions of the celestial bodies, the stellar constellations of the northern hemisphere, the old geocentric universe of Ptolemy, the newish heliocentric one of Copernicus [as above], and Tycho Brahe’s eccentric combination of the two — in which the Moon orbits the Earth, and the planets orbit the Sun, but the Sun still orbits the Earth. The marginal area of each brightly coloured map is a hive of activity: astronomers bent over charts debate their findings, eager youngsters direct their quadrants skywards, and cherubs fly about with pet birds in tow…

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The Northern Stellar Hemisphere of Antiquity

More marvelous maps of the heavens at “The Celestial Atlas of Andreas Cellarius (1660)

* Galileo (quoting a librarian at the Vatican)

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As we look to the stars, we might recall that it was on this date in 1843 that Sir William Rowan Hamilton conceived the theory of quaternions.  A physicist, astronomer, and mathematician who made important contributions to classical mechanics, optics, and algebra, he had been working since the late 1830s on the basic principles of algebra, resulting in a theory of conjugate functions, or algebraic couples, in which complex numbers are expressed as ordered pairs of real numbers.  But he hadn’t succeeded in developing a theory of triplets that could be applied to three-dimensional geometric problems.  Walking with his wife along the Royal Canal in Dublin, Hamilton realized that the theory should involve quadruplets, not triplets– at which point he stopped to carve carve the underlying equations in a nearby bridge lest he forget them.

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Written by LW

October 16, 2018 at 1:01 am

“And so the Universe ended”*…

 

implosion

Conceptual illustration of the Higgs Field that physicists believe permeates the Universe, and that could theoretically bring about its end.

 

Every once in a while, physicists come up with a new way to destroy the Universe. There’s the Big Rip (a rending of spacetime), the Heat Death (expansion to a cold and empty Universe), and the Big Crunch (the reversal of cosmic expansion). My favourite, though, has always been vacuum decay. It’s a quick, clean and efficient way of wiping out the Universe…

Learn more about a possibility that really sucks: “Vacuum decay: the ultimate catastrophe.”

* Douglas Adams, The Restaurant at the End of the Universe

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As we we abhor a vacuum even more than nature does, we might send closely-observed birthday greetings to Jesse Leonard Greenstein; he was born on this date in 1909.  An astronomer who ran Cal Tech’s storied program for decades, he co-discovered (with Maarten Schmidt) the quasar.  While other astronomers had previously observed the bright bodies, Greenstein and Schmidt were the first to to interpret the red shift of quasars and correctly identify them as compact, very distant– and thus very old– objects.  Later, working with Louis Henyey, Greenstein designed and built a new spectrograph and wide-view camera to improve astronomical observations,

greenstein source

 

Written by LW

October 15, 2018 at 1:01 am

“The blazing meteor, when it descends to earth, is only a stone”*…

 

Meteors

 

The odds of being hit by a meteorite are extremely low. You’re far more likely to die in a car crash or a fire than you are to die from a meteorite strike. It’s also more likely that you’ll be killed by lightning or a tornado – both of which are extremely rare. However, there’s bad news too – you have a higher chance of being hit by a meteorite than you do of winning the lottery…

Oh, and avoid the United States (and India)!  See why at: “What Are Your Chances of Being Hit by a Meteorite?

* Henry Wadsworth Longfellow

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As we duck and cover, we might recall that it was on this date in 1969 that a large meteorite fell near Murchison in Victoria, Australia.  Both because it was an observed fall (its bright fireball was seen by many) and because it proved to be rich in organic compounds (an abundance of amino acids), it has been one of the most-studied meteorites.

220px-Murchison_crop source

 

Written by LW

September 28, 2018 at 1:01 am

“The truth is not always beautiful, nor beautiful words the truth.”*…

 

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Does anyone who follows physics doubt it is in trouble? When I say physics, I don’t mean applied physics, material science or what Murray-Gell-Mann called “squalid-state physics.” I mean physics at its grandest, the effort to figure out reality. Where did the universe come from? What is it made of? What laws govern its behavior? And how probable is the universe? Are we here through sheer luck, or was our existence somehow inevitable?

In the 1980s Stephen Hawking and other big shots claimed that physics was on the verge of a “final theory,” or “theory of everything,” that could answer these big questions and solve the riddle of reality. I became a science writer in part because I believed their claims, but by the early 1990s I had become a skeptic. The leading contender for a theory of everything held that all of nature’s particles and forces, including gravity, stem from infinitesimal, stringy particles wriggling in nine or more dimensions.

The problem is that no conceivable experiment can detect the strings or extra dimensions…

John Horgan examines physicist Sabine Hossenfelder‘s claim that desire for beauty and other subjective biases have led physicists astray: “How Physics Lost Its Way.”

* Lao Tzu, Tao Te Ching

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As we contemplate certainty, we might recall that it was on this date in 1595 that Johann Kepler (and here) published Mysterium cosmographicum (Mystery of the Cosmos), in which he described an invisible underlying structure determining the six known planets in their orbits.  Kepler thought as a mathematician, devising a structure based on only five convex regular solids; the path of each planet lay on a sphere separated from its neighbors by touching an inscribed polyhedron.

It was a beautiful, an elegant model– and one that fit the orbital data available at the time.  It was, nonetheless, wrong.

Detailed view of Kepler’s inner sphere

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Written by LW

July 9, 2018 at 1:01 am

“Life can only be understood backwards; but it must be lived forwards”*…

 

If you wanted to hear the future in late May, 1968, you might have gone to Abbey Road to hear the Beatles record a new song of John Lennon’s—something called “Revolution.” Or you could have gone to the decidedly less fab midtown Hilton in Manhattan, where a thousand “leaders and future leaders,” ranging from the economist John Kenneth Galbraith to the peace activist Arthur Waskow, were invited to a conference by the Foreign Policy Association. For its fiftieth anniversary, the F.P.A. scheduled a three-day gathering of experts, asking them to gaze fifty years ahead. An accompanying book shared the conference’s far-off title: “Toward the Year 2018”…

More amazing than science fiction,” proclaims the cover, with jacket copy envisioning how “on a summer day in the year 2018, the three-dimensional television screen in your living room” flashes news of “anti-gravity belts,” “a man-made hurricane, launched at an enemy fleet, [that] devastates a neutral country,” and a “citizen’s pocket computer” that averts an air crash. “Will our children in 2018 still be wrestling,” it asks, “with racial problems, economic depressions, other Vietnams?”

Much of “Toward the Year 2018” might as well be science fiction today. With fourteen contributors, ranging from the weapons theorist Herman Kahn to the I.B.M. automation director Charles DeCarlo, penning essays on everything from “Space” to “Behavioral Technologies,” it’s not hard to find wild misses. The Stanford wonk Charles Scarlott predicts, exactly incorrectly, that nuclear breeder reactors will move to the fore of U.S. energy production while natural gas fades. (He concedes that natural gas might make a comeback—through atom-bomb-powered fracking.) The M.I.T. professor Ithiel de Sola Pool foresees an era of outright control of economies by nations—“They will select their levels of employment, of industrialization, of increase in GNP”—and then, for good measure, predicts “a massive loosening of inhibitions on all human impulses save that toward violence.” From the influential meteorologist Thomas F. Malone, we get the intriguing forecast of “the suppression of lightning”—most likely, he figures, “by the late 1980s.”

But for every amusingly wrong prediction, there’s one unnervingly close to the mark…

Those uncannily-accurate predictions, and their backstories, at “The 1968 book that tried to predict the world of 2018.”

* Søren Kierkegaard

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As we ponder posterity, we might send static-y birthday greetings to Robert Woodrow Wilson; he was born on this date in 1936.  An astronomer, he detected– with Bell Labs colleague Arno Penzias– cosmic microwave background radiation: “relic radiation”– that’s to say. the “sound “– of the Big Bang.  Their 1964 discovery earned them the 1978 Nobel Prize in Physics.

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