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Posts Tagged ‘time

“‘Space-time’ – that hideous hybrid whose very hyphen looks phoney”*…

Space-time curvature [source: ESA]

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.

Schematic rendering of a pulsar

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Jocelyn Bell Burnell

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Written by (Roughly) Daily

July 15, 2022 at 1:00 am

“A map does not just chart, it unlocks and formulates meaning; it forms bridges between here and there, between disparate ideas that we did not know were previously connected”*…

Friedrich Strass, Der Strom der Zeiten, 1803 [source/zoomable version]

Readers may recall an earlier post on John B. Sparks’ Histomap, a well-known 1931 attempt to visualize the 4,000 year history of global power. Public Domain Review takes a look at Histomap‘s ancestor/inspiration, Friedrich Strass’ Der Strom der Zeiten (published in 1803), and its influence…

In his foundational textbook Elements, the Alexandrian mathematician Euclid defined a line as “breadthless length” — a thing with only one dimension. That’s what lines can do to history when used to plot events: they condense its breadth into pure motion, featuring only those people and places that serve as forces thrusting it forwards along an infinite axis. Early in the nineteenth century, Friedrich Strass proposed a different way to visualize time’s flow. A Prussian historian and schoolteacher, he published his chronological chart in 1803, a massive diagram titled Der Strom der Zeiten oder bildliche Darstellung der Weltgeschichte von den altesten Zeiten bis zum Ende des achtzehnden Jahrhunderts (The stream of the times or an illustrated presentation of world history from the most ancient times until the eighteenth century). The linear timelines that Strass resisted, like those inspired by Joseph Priestley, “implied a uniformity in the processes of history that was simply misleading”, write Anthony Grafton and Daniel Rosenberg. Strass’ stream, by contrast, allowed historical events to “ebb and flow, fork and twist, run and roll and thunder.” It would spawn several imitations as the century drew on…

Capturing history in its organic unfolding: “The Stream of Time,” from @PublicDomainRev. See the original at the David Rumsey Map Collection.

* Reif Larsen

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As we contemplate chronology, we might recall that it was on this date in 1800 that the Library of Congress was established. James Madison has first proposed a national library in 1783. But it wasn’t until 1800, when (on this date) President John Adams signed signed an act of Congress providing for the transfer of the seat of government from Philadelphia to the new capital city of Washington, that the deed was done. The Act appropriated $5,000 “for the purchase of such books as may be necessary for the use of Congress … and for fitting up a suitable apartment for containing them.” Books were ordered from London, creating a collection consisting of 740 books and three maps, which were housed in the new United States Capitol.

But in 1814, during the War of 1812, British forces burned the Capitol Building, and with it, the the collection (by then, around 3,000 volumes). The Library as we know it was created from those ashes. Thomas Jefferson offered to sell his personal library– 6,487 books– as a replacement, Congress accepted, and the Library of Congress grew from there.

The Capitol Building, which housed the Library of Congress, after being burned by the British [source: Library of Congress]

“For himself (and only for a short time) a man may postpone enlightenment in what he ought to know, but to renounce it for posterity is to injure and trample on the rights of mankind”*…

A (small) part of the mechanism of The Clock of the Long Now [source]

The 10,000-year clock is neither a ‘frightening’ ‘distraction,’ as its critics scorn, nor the ‘admirable objective’ its fans claim. It’s something else — a monument to long-term thinking that can unlock a deeper and more thoughtful spirit of interpretive patience. Vincent Ialenti considers The Clock of the Long Now

… Stonehenge was not (to our knowledge) created with the intent of drawing people to think about the far future. However, like the clock, it can also relay a few relatively coherent messages across time. Its monolithic slabs were designed to align with the summer solstice’s sunrise and the winter solstice’s sunset. The clock was likewise designed to synchronize each day at solar noon.

As a result, the architectures of both can exhibit, for future societies, evidence of deliberate human-astronomical calibration. These features could, when encountered by successive generations, foster an ongoing awareness of humanity’s enduring attunement to the heavens. This could serve as a transgenerational reminder that, in the deeper time horizons of the universe, all of us humans are, ultimately, contemporaries — living and dying by the same star.

Long Now’s atmosphere of unhinged creativity and unapologetic eco-pragmatism provided a near-constant drip of bold, stimulating, outside-the-box ideas. There is, to my knowledge, no better setting for pondering the planetary challenges of climate adaptation, nuclear weapons risk and sociopolitical division we will all need to face in the years ahead.

If [Clock designer Danny] Hillis’ clock is a monument to this, then surely it stands for something important. Yet to appreciate why, one must first commit to approaching all timebound commentaries on the clock — including this one — with a patient, non-tempocentric, interpretive ambivalence. Five thousand years from now, after all, it may well be captivating millions, just as Stonehenge does today. What’s certain is that neither its designers nor its critics will live to find out.

The Long Now Foundation (@longnow) and its monumental incitement to take the long view: “Keeping Time Into The Great Beyond,” from @vincent_ialenti in @NoemaMag.

* Immanuel Kant, An Answer to the Question: What Is Enlightenment?

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As we resolve to be good ancestors, we might spare a thought for another long-term thinker, Pierre Teilhard de Chardin; he died on this date in 1955.  A Jesuit theologian, philosopher, geologist, and paleontologist, he conceived the idea of the Omega Point (a maximum level of complexity and consciousness towards which he believed the universe was evolving) and developed Vladimir Vernadsky‘s concept of noosphere.  Teilhard took part in the discovery of Peking Man, and wrote on the reconciliation of faith and evolutionary theory.  His thinking on both these fronts was censored during his lifetime by the Catholic Church (in particular for its implications for “original sin”); but in 2009, they lifted their ban.

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“Torture the data, and it will confess to anything”*…

Source: @piechartpirate

Add movement to a bar chart, and you’ve got yourself an audience-pleaser. These so-called “bar chart races” are not popular with data visualization experts– but what do experts know?…

I’m not a betting man. But I do enjoy a good bar chart race — a popular way to visually display and compare changing data over time. Bars lengthen and shorten as time ticks away; contenders accordingly hop over each other to switch places in the ranking. Will your favorite keep their lead? Look at that surprise challenger rush to the front! Meanwhile, furious battles are waged for the middle and even the lower spots on the list.

Bar chart races are a spectacular way to animate certain types of information, but the so-called dataviz community is skeptical. Many data visualization specialists complain that bar chart races are like a sugar rush: a lot of entertainment, but very little analysis. Big on grabbing attention, small on conveying causality. Instead of good seats at the data ballet, you get standing room only at the information dog track.

Well, all that may be true. But when is the last time you’ve been glued to a statistic about global coffee production? Bar chart races are fun to watch, not least because you can pick a favorite early on and get to see them win — or lose. In other words, you’re emotionally invested in the animation in a way that’s lacking from static stats.

Bar chart races are used for just about any dataset that can be quantified over time: best-selling game consoles, most trusted brands, highest grossing movies…

Any dataset that can be quantified over time can be turned into a contest that is both exciting and (a little bit) enlightening: from @VeryStrangeMaps, 10 examples of “Bar chart races: short on analysis, but fun to watch,” for example…

Ronald Coase

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As we ruminate on representation, we might check our watches: it was on this date in 1918 that the Standard Time Act (AKA, the Calder Act) became effective. Passed by Congress earlier in the year, it implemented across the U.S. both Standard time (the creation of time zones anchored in UTC, the successor to GMT) and Daylight Saving Time.

U.S. Time Zones (somewhat revised from the original division)

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“For the moment we might very well can them DUNNOS (for Dark Unknown Nonreflective Nondetectable Objects Somewhere)”*…

When does one give up on a hypothesis?…

In 1969, the American astronomer Vera Rubin puzzled over her observations of the sprawling Andromeda Galaxy, the Milky Way’s biggest neighbour. As she mapped out the rotating spiral arms of stars through spectra carefully measured at the Kitt Peak National Observatory and the Lowell Observatory, both in Arizona, she noticed something strange: the stars in the galaxy’s outskirts seemed to be orbiting far too fast. So fast that she’d expect them to escape Andromeda and fling out into the heavens beyond. Yet the whirling stars stayed in place.

Rubin’s research, which she expanded to dozens of other spiral galaxies, led to a dramatic dilemma: either there was much more matter out there, dark and hidden from sight but holding the galaxies together with its gravitational pull, or gravity somehow works very differently on the vast scale of a galaxy than scientists previously thought.

Her influential discovery never earned Rubin a Nobel Prize, but scientists began looking for signs of dark matter everywhere, around stars and gas clouds and among the largest structures in the galaxies in the Universe…

But… over the past half century, no one has ever directly detected a single particle of dark matter. Over and over again, dark matter has resisted being pinned down, like a fleeting shadow in the woods. Every time physicists have searched for dark matter particles with powerful and sensitive experiments in abandoned mines and in Antarctica, and whenever they’ve tried to produce them in particle accelerators, they’ve come back empty-handed. For a while, physicists hoped to find a theoretical type of matter called weakly interacting massive particles (WIMPs), but searches for them have repeatedly turned up nothing.

With the WIMP candidacy all but dead, dark matter is apparently the most ubiquitous thing physicists have never found. And as long as it’s not found, it’s still possible that there is no dark matter at all. An alternative remains: instead of huge amounts of hidden matter, some mysterious aspect of gravity could be warping the cosmos instead…

Dark matter is the most ubiquitous thing physicists have never found; Ramin Skibba (@raminskibba) wonders if it isn’t time to consider alternative explanations: “Does dark matter exist?” in @aeonmag.

* Bill Bryson on dark matter, in A Short History of Nearly Everything (2003)

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As we interrogate the invisible, we might send observant birthday greetings to Val Logsdon Fitch; he was born on this date in 1923. A particle physicist, he shared the 1964 Nobel Prize in Physics with his collaborator James Cronin for their experiments proving that some subatomic reactions do not adhere to fundamental symmetry principles (and are therefore indifferent to the direction of time).

By examining the decay of K-mesons, they proved that a reaction run in reverse does not retrace the path of the original reaction, which showed that the reactions of subatomic particles are not indifferent to time. Thus the phenomenon of CP violation was discovered… and thus was demolished the faith that physicists had previously had that natural laws were universally governed by symmetry.

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