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Posts Tagged ‘Einstein

“The ‘paradox’ is only a conflict between reality and your feeling of what reality ‘ought to be’”*…

One of the most bizarre aspects of quantum physics is that the fundamental entities that make up the Universe, what we know as the indivisible quanta of reality, behave as both a wave and a particle. We can do certain experiments, like firing photons at a sheet of metal, where they act like particles, interacting with the electrons and kicking them off only if they individually have enough energy. Other experiments, like firing photons at small thin objects — whether slits, hairs, holes, spheres, or even DVDs — give patterned results that show exclusively wave-like behavior. What we observe appears to depend on which observations we make, which is frustrating, to say the least. Is there some way to tell, fundamentally, what the nature of a quanta is, and whether it’s wave-like or particle-like at its core?

That’s what Sandra Marin wants to know, asking:

“I wonder if you could help me to understand John Wheeler – the delayed choice experiment and write an article about this.”

John Wheeler was one of the most brilliant minds in physics in the 20th century, responsible for enormous advances in quantum field theory, General Relativity, black holes, and even quantum computing. Yet the idea about the delayed choice experiment hearkens all the way back to perhaps our first experience with the wave-particle duality of quantum physics: the double-slit experiment…

Although Einstein definitively wanted us to have a completely comprehensible reality, where everything that occurred obeyed our notions of cause-and-effect without any retrocausality, it was his great rival Bohr who turned out to be correct on this point. In Bohr’s own words:

“…it…can make no difference, as regards observable effects obtainable by a definite experimental arrangement, whether our plans for constructing or handling the instruments are fixed beforehand or whether we prefer to postpone the completion of our planning until a later moment when the particle is already on its way from one instrument to another.”

As far as we can tell, there is no one true objective, deterministic reality that exists independently of observers or interactions. In this Universe, you really to have to observe in order to find out what you get.

The history and the results of John Wheeler‘s famous “delayed choice” experiments: “Is Light Fundamentally A Wave Or A Particle?

* Richard Feynman

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As we reconsider categories, we might recall that it was on this date in 1404 that King Henry IV signed the “Act Against Multipliers,” stipulating that “None from hereafter shall use to multiply gold or silver, or use the craft of multiplication; and if any the same do, they incur the pain of felony.” Great alarm was felt at that time lest any alchemist should succeed in “transmutation” (the conversion of a base metal into gold or silver), thus undermining the sanctity of the Royal currency and/or possibly financing rebellious uprisings. Alchemy, which had flourished since the time of Bacon, effectively became illegal.

The Act was repealed in 1689, when Robert Boyle, the father of modern chemistry, and other members of the vanguard of the scientific revolution lobbied for its repeal.

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“Sometimes the only way to move forward is to revisit the things in your past that were holding you back”*…

Adobe Flash was the language of choice for a generation of game developers, helping kickstart an indie revolution on the still-young web of the 1990s and 2000s. But it withered on the proprietary and insecure vine, and both web browsers and Adobe have now canned it, threatening countless games and interactive presentations with the memory hole. The Internet Archive comes to the rescue, not only archiving the flash files but emulating the player itself, allowing history to live on.

“The Internet Archive has begun emulating Flash Animations, Games and Toys in a new collection,” wrote archivist Jason Scott on Twitter. “It’s at https://archive.org/details/softwarelibrary_flash and it’s going to be past 1,000 items in 24 hours. You can add your own and get them running, and the animations have never ran smoother or better.”…

From our friends at Boing Boing: “Internet Archive turns on Flash emulation, already has 1000 items to check out.”

* “Barry Allen” (The Flash)

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As we celebrate that what’s old is new again, we might recall that it was on this date in 1915 that Albert Einstein presented the Einstein Field Equation to the Prussian Academy of Sciences.  Einstein soon after elaborated it into the set of 10 equations that account for gravitation in the curved spacetime that he described in his General Theory of Relativity; they are used to determine spacetime geometry.

(German mathematician David Hilbert reached the same conclusion, and actually published the equation before Einstein– though Hilbert, who was a correspondent of Einstein’s, never suggested that Einstein’s credit was inappropriate.)

On the right side of the equal sign, the distribution of matter and energy in space; on the left, the geometry of the space, the so-called metric, a prescription for how to compute the distance between two points.

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“Once we introduce the possibility of applying the quantum principle to the universe, we are forced to consider parallel universes”*…

 

antiverse

 

In the Antarctic, things happen at a glacial pace. Just ask Peter Gorham. For a month at a time, he and his colleagues would watch a giant balloon carrying a collection of antennas float high above the ice, scanning over a million square kilometres of the frozen landscape for evidence of high-energy particles arriving from space.

When the experiment returned to the ground after its first flight, it had nothing to show for itself, bar the odd flash of background noise. It was the same story after the second flight more than a year later.

While the balloon was in the sky for the third time, the researchers decided to go over the past data again, particularly those signals dismissed as noise. It was lucky they did. Examined more carefully, one signal seemed to be the signature of a high-energy particle. But it wasn’t what they were looking for. Moreover, it seemed impossible. Rather than bearing down from above, this particle was exploding out of the ground.

That strange finding was made in 2016. Since then, all sorts of suggestions rooted in known physics have been put forward to account for the perplexing signal, and all have been ruled out. What’s left is shocking in its implications. Explaining this signal requires the existence of a topsy-turvy universe created in the same big bang as our own and existing in parallel with it. In this mirror world, positive is negative, left is right and time runs backwards. It is perhaps the most mind-melting idea ever to have emerged from the Antarctic ice ­­– but it might just be true…

Strange particles observed by an experiment in Antarctica could be evidence of an alternative reality where everything is upside down: “We may have spotted a parallel universe going backwards in time.”

* Michio Kaku

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As we consider our alternatives, we might recall that it was on this date in 1912, in his “Manuscript on the Special Theory of Relativity,” that Einstein first identified the fourth dimension as time… or so it is widely accepted.  Some physicists believe that Einstein was making a subtler– and much more complicated– suggestion, “x4 = ict”: that the fourth dimension, not “physical” like the other three, but emergent (in a way “understandable” as time) as the fourth dimension expands from the other three at the rate of “c.”

Screen Shot 2020-04-12 at 1.59.50 PM source

 

 

Written by LW

April 15, 2020 at 1:01 am

“Human DNA spreading out from gravity’s steep well like an oilslick”*…

 

200116-Earth

 

Could the Earth be a life-exporting planet? That’s the curious question examined in a recent paper written by Harvard University astronomers Amir Siraj and Abraham Loeb.

The researchers take a novel twist on the controversial notion of panspermia – the idea, propelled into the mainstream in the early 1970s by astronomers Fred Hoyle and Chandra Wickramasinghe, that life might have started on Earth through microbes arriving from space.

The theory is generally discounted, although eminent astrophysicists such as Stephen Hawking conceded it was at least possible, and a major paper published in 2018 revived the topic big-time.

In their [late December, 2019] paper, Siraj and Loeb reverse the standard assumption about the direction of the microbial journey and ask whether it is possible to that at some point Earth-evolved bacteria could have been propelled away from the planet, possibly to be deposited somewhere else in the Milky Way…

Astronomers suggest microbes might hitch lifts on interstellar asteroids.  More on the hypothesis and the evidence that supports it at “Earth bacteria may have colonised other solar systems.”  Read the underlying paper at arXiv.

* William Gibson, Neuromancer

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As we ponder the polarity of proliferation, we might recall that it was on this date in 1921 that Albert Einstein startled his audience at the Prussian Academy of Sciences in Berlin by suggesting the possibility that the universe could be measured.  His talk, “Geometry and Experience” (text here), applied some results of the relativity theory to conclude that if the real velocities of the stars (as could be actually measured) were less than the calculated velocities, then it would prove that real gravitations’ great distances were smaller than the gravitational distances demanded by the law of Newton.  From that divergence, the finiteness of the universe could be proved indirectly, and could even permit the estimation of its size.

Later that year, Einstein was announced as the 1921 Nobel Laureate in Physics, an award he accepted the following year.

Bildnis Albert Einstein (1879-1955)

Einstein in 1921

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Happy Birthday, Dante, Mozart, and Lewis Carroll!

 

“The missing link in cosmology is the nature of dark matter and dark energy”*…

 

Familiar visible matter can be thought of as the privileged percent—actually more like 15 percent—of matter. In business and politics, the interacting 1 percent dominates decision making and policy, while the remaining 99 percent of the population provides less widely acknowledged infrastructure and support—maintaining buildings, keeping cities operational, and getting food to people’s tables. Similarly, ordinary matter dominates almost everything we notice, whereas dark matter, in its abundance and ubiquity, helped create clusters and galaxies and facilitated star formation, but has only limited influence on our immediate surroundings today…

The common assumption is that dark matter is the “glue” that holds together galaxies and galaxy clusters, but resides only in amorphous clouds around them. But what if this assumption isn’t true and it is only our prejudice—and ignorance, which is after all the root of most prejudice—that led us down this potentially misleading path?…

Indeed,  Harvard theoretical physicist and cosmologist Lisa Randall asks, “Does dark matter harbor life?

* Stephen Hawking

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As we reach reflexively for a flashlight, we might send particular birthday greetings to Abraham Pais; he was born on this date in 1918.  After earning his Ph.D. in physics in Holland five days before a Nazi deadline banning Jews from receiving degrees, he went into hiding– and worked out ideas in quantum electrodynamics (later shared with Niels Bohr) that became the building blocks of the theory of elemental particles.  He was later a colleague of Robert Oppenheimer and Albert Einstein at the Institute for Advanced Studies at Princeton.

Pais was also an widely-respected historian of science.  Among his many works were a biography of Bohr and (the work for which he’s best remembered as a historian) Subtle Is the Lord: The Science and Life of Albert Einstein, which is considered the definitive Einstein biography.

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Written by LW

May 19, 2017 at 1:01 am

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