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Posts Tagged ‘astronomy

“The years teach much the days never know”*…


Hoover Dam

On the western flank of the Hoover Dam stands a little-understood monument, commissioned by the US Bureau of Reclamation when construction of the dam began in 01931. The most noticeable parts of this corner of the dam, now known as Monument Plaza, are the massive winged bronze sculptures and central flagpole which are often photographed by visitors. The most amazing feature of this plaza, however, is under their feet as they take those pictures.

The plaza’s terrazzo floor is actually a celestial map that marks the time of the dam’s creation based on the 25,772-year axial precession of the earth…

Hoover diagram

Alexander Rose, Executive director of The Long Now Foundation, on the star map of “Safety Island,” a Hoover Dam feature that has baffled visitors for decades: “The 26,000-Year Astronomical Monument Hidden in Plain Sight.”

See also “Coventry Doom,” the story of a 15th-century “doom mural” (depiction of the Last Judgement) that remained hidden in plain sight for centuries.

* Ralph Waldo Emerson


As we watch our step, we might send unearthed birthday greetings to Mary Douglas Leakey; she was born on this date in 1913.  An archaeologist and  paleoanthropologist, she made several of the most important fossil finds subsequently interpreted and publicized by her husband, the noted anthropologist Louis Leakey. For every vivid claim made by Louis about the origins of man, the supporting evidence tended to come from Mary’s scrupulous scientific approach.

220px-Mary_Leakey source


Written by LW

February 6, 2019 at 1:01 am

“It is not enough that I succeed, others must fail”*…



Who said “it is not enough that I succeed, others must fail”? According to Tiffany Watt Smith, in this spry book, it might have been Gore Vidal or Genghis Kahn. According to the internet it is either La Rochefoucauld or Somerset Maugham. Having thought about it a bit, it might actually have been me, or perhaps it was Watt Smith herself. The point is that it doesn’t really matter since taking pleasure in another’s misfortune turns out to be a pungent but free-floating feeling that pops up everywhere. The flavours might change – as an academic cultural historian Watt Smith is far from suggesting that emotions are universal across time and place – but there is something familiar to us all about the odd stab of pleasure we get when an enemy or even, God help us, a friend, stumbles.

So it is odd that the English language does not have a word for this grubby little pleasure – instead we have to borrow from the German and call it Schadenfreude (literally “damage-joy”)…

Kathryn Hughes considers that delicious feeling of satisfaction at the “epic fails” of somebody else in a review of Tiffany Watt Smith’s Schadenfreude- the Joy of Another’s Misfortune: “Damage-joy.”

* see above


As we try not to snicker, we might recall that it was on this date in 45 B.C.E. that the Julian Calendar came into effect.  It was the predominant calendar in the Roman world, most of Europe, and in European settlements in the Americas and elsewhere, until it was refined and gradually replaced by the Gregorian calendar, promulgated in 1582 by Pope Gregory XIII.

(The Julian calendar remains useful for some scientific, especially astronomical, purposes, as it provides a linear count of days from a starting point. which was introduced by Joseph Scaliger in 1583.  Julian Day 0 is defined as noon on Monday, January 1, 4713 B.C.E. (in the Julian Calendar).  Regardless of leap years and calendar changes by the Romans or Pope Gregory, the Julian date number enables the easy calculation of the number of days between two dates by simply taking the difference in their Julian day number. This is useful, say, for astronomers’ calculations of the dates of eclipses.  Thus, the Julian day number of a day is defined as the number of days since noon GMT on 1 Jan 4713 B.C.E. in the Proleptic Julian Calendar, and each Julian day number runs from noon to noon.)

122918-03-History-Calendar-768x439 source


Written by LW

January 1, 2019 at 1:01 am

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



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


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.”


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




Written by LW

November 6, 2018 at 2:01 am

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



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


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




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”*…




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…

northern stars

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)


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.



Written by LW

October 16, 2018 at 1:01 am

“And so the Universe ended”*…



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


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”*…




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


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

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