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Posts Tagged ‘Physics

“At my age, the radiation will probably do me good”*…

 

The “banana equivalent dose” (BED) is a measure of radiation used to illustrate levels of emissions.  Bananas contain lots of potassium, which contains 0.01% potassium-40– which is radioactive.  The radiation exposure from eating a banana is deemed “1 BED,” roughly equivalent to 0.01 millirem (mrem).  (Happily, one would never be able to eat enough bananas to be dangerous, as our bodies excrete the potassium we’re consuming before it can do exposure damage.)

The existence of a clearly-understandable unit of this sort allows for easily-understood apples-to-apples (or, bananas-to-bananas) comparisons…

This is also roughly the exposure from having a single smoke detector.

 

Due to increased altitude; Mt Everest is more like 800 mrem (80,000 bananas) per year.

 

The granite in the walls is mildly radioactive. By comparison, the Vatican is about 800 mrem (80,000 bananas) per year.

 

More fruity comparisons at Mad Art Lab‘s “Yellow Alert

* Sir Norman Wisdom

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As we peel, we might send thoughtful birthday greetings to Richard Philips Feynman; he was born on this date in 1918.  A theoretical physicist, Feynman was probably the most brilliant, influential, and iconoclastic figure in his field in the post-WW II era.

Richard Feynman was a once-in-a-generation intellectual. He had no shortage of brains. (In 1965, he won the Nobel Prize in Physics for his work on quantum electrodynamics.) He had charisma. (Witness this outtake [below] from his 1964 Cornell physics lectures [available in full here].) He knew how to make science and academic thought available, even entertaining, to a broader public. (We’ve highlighted two public TV programs hosted by Feynman here and here.) And he knew how to have fun. The clip above brings it all together.

– From Open Culture (where one can also find Feynman’s elegant and accessible 1.5 minute explanation of “The Key to Science.”)

email readers click here for video

 

Written by LW

May 11, 2015 at 1:01 am

“If we all worked on the assumption that what is accepted as true really is true, then there would be little hope for advance”*…

 

Some guys spend their spare time restoring automobiles, devoting garage space to chocked-up Corvettes and Camaros.  Dave Pares, an adjunct professor at the University of Nebraska- Omaha,  is making his own warp drive.

In theory, a warp drive contracts space in front of a space vessel and expands it at the back. The ship itself speeds along inside what is called a “warp bubble.”  As theoretical physicist Miguel Alcubierre explained in 1994, if such an artificial warping of space — essentially picking up a piece of fabric of space=time at two points and bringing them together — could be accomplished, it would allow a space ship to travel incredible distances incredibly quickly, while avoiding the speed-of-light problem.

NASA has explored the prospect, but been put off by the technical and financial challenges of developing the power source that it believes would be necessary.  But Pares believes he can accomplish warping with low power– indeed, with the voltage available in his garage.

So far, Pares seems primarily to have attracted the attention of UFO enthusiasts; NASA and academic journals have (more and less politely) turned him away.  But retired UN-O physics professor Jack Kasher is cautiously optimistic:

It is so far out there, he’s not going to get funding to do it. If it’s going to be done, it’s going to be done in his garage…  A lot of people are going to flat-out dismiss it off the top, but I think he’s crossed some kind of bridge here, just showing this is possible with reasonable energy.  It wouldn’t surprise me if NASA latches on to this.

In any case, as Kasher notes, at a time when the scientific and technical mainstream had written off manned flight, the Wright Brothers took their first critical steps in their Ohio bike shop.

Read more at “Working toward a warp drive: In his garage lab, Omahan aims to bend fabric of space.”  See also: “No, NASA Did Not Accidentally Invent Warp Drive.”

C.F. also the warp drive’s bizarro twin: the EM Drive (which seems to work in practice… though it doesn’t work in theory).

* Orville Wright

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As we put on our helmets, we might recall that it was on this date in 1949 that Britain’s first “launderette”– self-service, coin-operated laundry– opened on Queensway in London.  The very first coin-op laundry had opened in 1936 in Ft. Worth, Texas (where it was known for a time as a “washateria”).

While these self-service laundries are still known as launderettes in the U.K., they are now widely called “laundromats” in the U.S., Canada, Australia and New Zealand (a genericization of the trademark of the coin-op washers and dryers developed and sold by Westinghouse).

 source

 

Written by LW

May 9, 2015 at 1:01 am

“Time is the longest distance between two places”*…

 

In 1949, on the occasion of Einstein’s seventieth birthday, Gödel presented him with an unexpected gift: a proof of the nonexistence of time. And this was not a mere verbal proof, of the sort that philosophers like Parmenides, Immanuel Kant, and J. M. E. McTaggart had come up with over the centuries; it was a rigorous mathematical proof. Playing with Einstein’s own equations of general relativity, Gödel found a novel solution that corresponded to a universe with closed timelike loops. A resident of such a universe, by taking a sufficiently long round trip in a rocket ship, could travel back into his own past. Einstein was not entirely pleased with Gödel’s hypothetical universe; indeed, he admitted to being “disturbed” that his equations of relativity permitted something as Alice in Wonderland–like as spatial paths that looped backward in time. Gödel himself was delighted by his discovery, since he found the whole idea of time to be painfully mysterious. If time travel is possible, he submitted, then time itself is impossible. A past that can be revisited has not really passed. So, Gödel concluded, time does not exist…

Put yourself in Jim Holt‘s skilled hands for an explanation and an exploration of implications, in “The Grand Illusion.”

* Tennessee Williams, The Glass Menagerie

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As we check our watches, we might recall that it was on this date in 1925 that Clarence Birdseye first tested frozen peas with consumers at a Chester, NY grocery store.  Birdseye had already patented a range of “flash-freezing” processes and devices, inspired by his experiences as a biologist and trapper in Labrador earlier in the century.  He had noticed that while slow freezing creates ice crystals in frozen foods– crystals that, when thawed, create sogginess– meat exposed to the extremely cold temperatures in the Canadian North– frozen essentially instantly– didn’t create internal ice, and were as tasty when thawed months later as fresh.  Birdseye created quick-frozen vegetables and meats as a storable option to fresh, and in 1930 offered a range of 26 frozen meats and vegetables.

source

 

Written by LW

November 3, 2014 at 1:01 am

“Photons have mass? I didn’t even know they were Catholic”*…

 

On Tuesday, the Nobel Committee announced the winners of the the Nobel Prize in Physics for 2014.

Isamu Akasaki, 85, left, Hiroshi Amano, 54, and Shuji Nakamura, 60, won “for the invention of efficient blue light-emitting diodes which has enabled bright and energy-saving white light sources”– an award that speaks to current concerns over energy efficiency, climate change, and improving living conditions in developing economies:

In the spirit of Alfred Nobel the Prize rewards an invention of greatest benefit to mankind; using blue LEDs, white light can be created in a new way. With the advent of LED lamps we now have more long-lasting and more efficient alternatives to older light sources…

As about one fourth of world electricity consumption is used for lighting purposes, the LEDs contribute to saving the Earth’s resources. Materials consumption is also diminished as LEDs last up to 100,000 hours, compared to 1,000 for incandescent bulbs and 10,000 hours for fluorescent lights.

The LED lamp holds great promise for increasing the quality of life for over 1.5 billion people around the world who lack access to electricity grids: due to low power requirements it can be powered by cheap local solar power…

[Read more in the Nobel press release]

The Committee’s choice was clearly a worthy one.  Still, as a reminder that the field is a very competitive one, it’s worth (re-)visiting the expert predictions that immediately preceded the award.  Thompson-Reuters’ annual Science Watch predictions named three potential winners (or groups– the award can go to up to three); while they’ve been right four of the last ten years, and all of their candidates did amazing– and amazingly-important– work, they missed this year.  Ditto, the expert panel whose prognostications were reported last Friday by Scientific American.

But maybe most fundamentally, it’s worth noting (quizzically, as SciAm does) that since the Prize was first awarded in 1901, only two women have won: Marie Curie (who was a double Laureate, also winning in Chemistry) and more recently, Maria Goeppert-Mayer, who won in 1963.

* Woody Allen

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As we size up the sociology of science, we might recall that this was a bad day for inclusiveness in Massachusetts in 1635: the General Court of the then-Colony banished Roger Williams for speaking out for the separation of church and state and against the right of civil authorities to punish religious dissension and to confiscate Indian land.   Williams moved out to edge of the Narragansett Bay, where with the assistance of the Narragansett tribe, he established a settlement at the junction of two rivers near Narragansett Bay, located in (what is now) Rhode Island. He declared the settlement open to all those seeking freedom of conscience and the removal of the church from civil matters– and many dissatisfied Puritans came. Taking the success of the venture as a sign from God, Williams named the community “Providence.”

Williams stayed close to the Narragansett Indians and continued to protect them from the land greed of European settlers. His respect for the Indians, his fair treatment of them, and his knowledge of their language enabled him to carry on peace negotiations between natives and Europeans, until the eventual outbreak of King Philip’s War in the 1670s. And although Williams preached to the Narragansett, he practiced his principle of religious freedom by refraining from attempts to convert them.

Roger Williams statue, Roger Williams Park, Providence, R.I.

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Written by LW

October 9, 2014 at 1:01 am

“Correlation does not imply causation”*…

 

From stat-enthusiast (and full-time law student) Tyler Vigen, entertaining examples of patterns that map in compelling– but totally-inconsequential– ways…

More (and larger) examples at the sensational Spurious Correlations.

* a maxim widely repeated in science and statistics; also rendered: (P&Q)≠(P→Q)٧(Q→P).  It addresses the post hoc, ergo propter hoc (“affirming the consequent”) logical fallacy

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As we think before we leap, we might send energetic (really energetic) birthday greetings to Enrico Fermi; he was born on this date in 1901.  A physicist who is best remembered for (literally) presiding over the birth of the Atomic Age, he was also remarkable as the last “double-threat” in his field:  a genius at creating both important theories and elegant experiments.  As recently observed, the division of labor between theorists and experimentalists has since been pretty complete.

The novelist and historian of science C. P. Snow wrote that “if Fermi had been born a few years earlier, one could well imagine him discovering Rutherford’s atomic nucleus, and then developing Bohr’s theory of the hydrogen atom. If this sounds like hyperbole, anything about Fermi is likely to sound like hyperbole.”

 source

 

Written by LW

September 29, 2014 at 1:01 am

“The cosmos is within us. We are made of star-stuff. We are a way for the universe to know itself”*…

 

Did you ever wonder where you came from? That is the stuff that’s inside your body like your bones, organs, muscles…etc.  All of these things are made of various molecules and atoms. But where did these little ingredients come from? And how were they made?…

Find the answer at “How much of the human body is made up of stardust?

* Carl Sagan

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As we hum along with Hoagy Carmichael, we might recall that it was on this date in 1958 that the first American edition of Vladimir Nabakov’s Lolita was released.  Finished in 1953, Nabakov was turned down by publishers ranging from Simon & Schuster to New Directions, all concerned about its subject matter.  Nabakov turned to Maurice Girodias and his Olympia Press, and published in France in 1955.  Though it received almost no critical attention on release, Graham Greene called in “one of the three best novels of 1955″ in a year-end wrap-up published in the Sunday Times— provoking a response in the Sunday Express that the novel was one “one of the filthiest” ever.  Surprisingly to many, the novel’s American launch elicited no official response.  But it registered hugely with the reading public: it went into a third printing within days and became the first novel since Gone with the Wind to sell 100,000 copies in its first three weeks.  Lolita is included on Time‘s “List of the 100 Best Novels in the English language from 1923 to 2005,” and it is fourth on the Modern Library’s 1998 “List of the 100 Best Novels of the 20th century.”

Cover and half-title page of a presentation copy of the first American edition, inscribed by Nabokov to his wife, Vera ( “Verina verae Nab Aug. 1958 Ithaca”) and embellished with a delicately-rendered butterfly.

source

 

Written by LW

August 18, 2014 at 1:01 am

“Mathematics is the art of giving the same name to different things”*…

 

A few years back, 12 million of us clicked over to watch the “Pachelbel Rant” on YouTube. You might remember it. Strumming repetitive chords on his guitar, comedian Rob Paravonian confessed that when he was a cellist, he couldn’t stand the Pachelbel Canon in D. “It’s eight quarter notes that we repeated over and over again. They are as follows: D-A-B-F♯-G-D-G-A.” Pachelbel made the poor cellos play this sequence 54 times, but that wasn’t the real problem. Before the end of his rant, Paravonian showed how this same basic sequence has been used everywhere from pop (Vitamin C: “Graduation”) to punk (Green Day: “Basket Case”) to rock (The Beatles: “Let It Be”).

This rant emphasized what music geeks already knew—that musical structures are constantly reused, often to produce startlingly different effects. The same is true of mathematical structures in physical theories, which are used and reused to tell wildly dissimilar stories about the physical world. Scientists construct theories for one phenomena, then bend pitches and stretch beats to reveal a music whose progressions are synced, underneath it all, in the heart of the mathematical deep.

Eugene Wigner suggested a half-century ago that this “unreasonable effectiveness” of mathematics in the natural sciences was “something bordering on the mysterious,” but I’d like to suggest that reality may be more mundane. Physicists use whatever math tools they’re able to find to work on whatever problems they’re able to solve. When a new song comes on, there’s bound to be some overlap in the transcription. These overlaps help to bridge mutations of theory as we work our way toward a lead sheet for that universal hum…

Read the harmonious whole at “How Physics is Like Three-Chord Rock.”

* Henri Poincare

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As we hum the tune eternal, we might send astronomical birthday greetings to Allan Rex Sandage; he was born on this date in 1926.  An astronomer, he spent his career first at the Palomar Observatory, then at the Carnegie Observatory in Pasadena, where at the outset, he was a research assistant to Edwin Hubble, whose work Sandage continued after Hubble’s death.  Sandage was hugely influential on his field; he is probably best remembered for determining the first reasonably accurate value for the Hubble constant (there ate those chords again) and the age of the universe— and for discovering the first quasar (again, those chords).

 source

 

Written by LW

June 18, 2014 at 1:01 am

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