Posts Tagged ‘radiation’
“It is clear that there is no classification of the Universe that is not arbitrary and full of conjectures. The reason for this is very simple: we do not know what kind of thing the universe is.”*…
… Still, scientists try. Ethan Siegel on the current state of play– with special attention to whether or not our cosmic landscape is endless or not, and why the Universe is so uniform on large scales, but so non-uniform on smaller scales…
13.8 billion years ago, our Universe as we know it began with the hot Big Bang, which gave rise to a primordial soup of particles and antiparticles that led to the planets, stars, and galaxies we know today. The hot Big Bang itself was set up by a preceding phase known as cosmic inflation, but only the final tiny fraction-of-a-second gets imprinted onto our observable Universe. What we can observe about the Universe is finite, but what about the unobservable parts that lie beyond it: are they finite or infinite? What the data can tell us is limited, but here’s what we think and why…
Read on to find out: “Is the Universe finite or infinite?” from @StartsWithABang in @bigthink.
* Jorge Luis Borges, in “The Analytical Language of John Wilkins”
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As we stargaze, we might send sunny birthday greetings to Herbert Friedman; he was born on this date in 1916. A physicist and astronomer, he made seminal contributions to the study of solar radiation. Friedman joined the Naval Research Laboratory in 1940 and developed defense-related radiation detection devices during WW II. In 1949, he obtained the first scientific proof that X rays emanate from the sun, when he directed the firing into space of a V-2 rocket carrying a detecting instrument. Through subsequent rocket astronomy, he also produced the first ultraviolet map of celestial bodies, and gathered information for the theory that stars are being continuously formed, on space radiation affecting Earth, and on the nature of gases in space. Friedman also made fundamental advances in the application of x rays to material analysis.
“Better to see something once than to hear about it a thousand times”*…
In recent years, the Zone, a highly restricted area in northern Ukraine that surrounds the site of the 1986 nuclear disaster, has become a tourist hotspot. Each morning, tour buses queue at the entry checkpoint where a souvenir shop plastered with nuclear warning symbols peddles neon keyrings and radiation suits. The guides’ t-shirts read: “Follow me and you will survive”. In fact, the dangers are minimal. Along their tightly demarcated routes, these visitors will be exposed to less radiation than during a routine x-ray.
Existing in the shadows of this highly commodified industry is the secretive subculture of the “stalkers”: mostly young Ukrainian men who sneak into the Zone illegally to explore the vast wilderness on their own terms. The name originates from the 1972 Russian science fiction novel Roadside Picnic. Written by brothers Arkady and Boris Strugatsky, it tells the story of contaminated “zones” created on Earth by aliens, in which rogue stalkers roam, hoping to recover valuable alien technology. The book inspired Andrei Tarkovsky’s 1979 cult-classic film Stalker.
Beyond youthful rebellion, the motivations of the modern stalkers are complex, and speak to the national trauma that resulted from a tragedy whose effects will be felt for generations. And now there is another side to the practice. Enterprising stalkers have started offering their own “illegal tours” to travellers seeking a less restricted (and therefore more dangerous) experience of the Exclusion Zone. I joined one such tour in an effort to discover why visitors might chose a stalker over an official guide. Can a subculture that is so tied to deep wells of personal and national loss really offer something of value to an outsider?…
Accompany Aram Balakjian on a beautifully-photographed expedition through the forbidden area: “Into the Zone: 4 days inside Chernobyl’s secretive ‘stalker’ culture.”
* Uzbek proverb
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As we take the tour, we might recall that it was on this date in 2000, via an announcement by then Secretary of Energy Bill Richardson, and after decades of denial, that a U.S. government study conceded that cancer and premature deaths of workers at 14 nuclear weapons plants since WW II were caused by radiation and chemicals.
“Now I am become Death, the destroyer of worlds”*…
Your correspondent is old enough to remember the Cold War and the Civil Defense efforts (booklets, films, duck-and-cover drills) aimed at “preparing” us for atomic conflict. It’s a sad sign of our times that they’re re-emerging: “Where to Hide If a Nuclear Bomb Goes Off In Your Area.”
(If there’s a silver lining in this fallout-laced cloud, it’s that it’s re-directing attention to a problem– a threat– that never actually went away; c.f., Ploughshares.)
* J. Robert Oppenheimer
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As we enter the Twilight Zone, we might recall that it was on this date in 1903 that The Times (London) newspaper reported that Marie and Pierre Curie communicated to the Academy of Sciences that the recently discovered Radium…
… possesses the extraordinary property of continuously emitting heat, without combustion, without chemical change of any kind, and without any change to its molecular structure, which remains spectroscopically identical after many months of continuous emission of heat … such that the pure Radium salt would melt more than its own weight of ice every hour … A small tube containing Radium, if kept in contact with the skin for some hours … produces an open sore, by destroying the epidermis and the true skin beneath … and cause the death of living things whose nerve centres do not lie deep enough to be shielded from their influence.
That same year the Curies (and Antoine Henri Becquerel) were awarded the Noble Prize in Physics for their work on radioactivity and radiation.
Marie and Pierre Curie
“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”
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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
In lieu of a graduation address…
… from xkcd:
As we avoid looking too closely at the faces of our watches, we might recall that it was on this date in 1921 at the White House that President Warren G. Harding presented Marie Curie with a gram of radium (worth $100,000 at the time). Curie died in 1934 of aplastic anemia contracted from exposure to radiation. Her laboratory is preserved at the Musée Curie. But because of their levels of radioactivity, her papers are considered too dangerous to handle, and are kept in lead-lined boxes; those who wish to consult them must wear protective clothing.
Curie, with Harding at the White House (source)
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