Posts Tagged ‘sun’
“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.
“Oh dark, dark, dark, amid the blaze of noon, irrevocably dark, total eclipse without all hope of day”*…
Today is the occasion of an annular eclipse, which will pass through eight U.S. states before crossing the Gulf of Mexico and to transit Mexico, Guatemala, Belize, Honduras, Nicaragua, Costa Rica, Panama, Colombia, and Brazil. While some people in the Western Hemisphere will witness a “ring of fire” during the eclipse, many more will experience the phenomenon of crescent sunlight. Rebecca Boyle has advice on how we might approach it…
… This Saturday, for some people in the Western Hemisphere, the Sun will disappear for a few minutes and appear to leave a flaming hole in the sky. Instead of a ball of fire, the Sun will transform into a ring of fire, a strange and wondrous sight. This is an annular solar eclipse, and it happens because the Moon is right smack in front of the Sun.
A solar eclipse only happens during new Moon phases, when we otherwise wouldn’t be able to see our nearest celestial companion. Though we get a new Moon every month, we do not get solar eclipses as often because of our satellite’s oddball path around the planet. Sometimes the Moon casts a shadow just above Earth, and sometimes just below. This weekend, the Moon’s shadow will fall onto Earth, just right for people in parts of the Western Hemisphere to see it.
The annular eclipse is a preview of a more incredible, rarer event next April, when a total solar eclipse will cross the continental United States. There is no experience on Earth like a total eclipse; make plans to see it, if you can. But this weekend’s “ring of fire” eclipse is an event you should try to see first (safely, with eclipse glasses), if you can get yourself into the western U.S. or parts of Central and South America. Here’s a map showing the eclipse path; if you can’t travel to see it in person, you can watch the eclipse online.
Eclipses happen because the Sun and Moon appear to be roughly the same diameter. The Sun is actually about 400 times larger than the Moon, but it is also about 400 times more distant, so they seem like the same size in our sky.
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The Moon’s shadow forms two concentric cones, composed of an inner shadow called the umbra, where the sun is completely obscured, and an outer, broader cone called a penumbra, where sunlight still shines but it is partially blocked. The umbra can be seen in a narrow geographic ribbon across the Americas, and it’s where you will see a full eclipse; under the penumbra, which covers much of the western U.S., Central and South America, you will see a partial eclipse.
Like the gears of a clock, a combination of precise positions and movements initiate an eclipse of the Sun. As Earth spins, day breaks. The Sun and Moon appear to trace a path across the sky. The Sun is not moving (at least not perceptibly); Earth’s rotation makes the star’s position change. The Moon is moving around us while the Earth rotates, so it seems to move too, but it appears to go slower than our star. The partial solar eclipse begins as the Sun catches up to the Moon’s position in our sky. On Saturday morning around 8:06 a.m. Pacific time, people in Eugene, Oregon, will be the first to see the Moon appear to take a bite out of the Sun. The bite will get progressively bigger until the full annular eclipse begins at 9:16 a.m. Pacific time.
The annular eclipse only lasts about four minutes (depending on your precise location under the Moon’s shadow) but the partial eclipse, which will be visible over a much wider geographic area, lasts about an hour and 15 minutes before and afterward. During this phase, shadows cast by objects on Earth will change in unusual ways. One lovely place to be during a partial solar eclipse is underneath a tree, if you can find an evergreen or a deciduous tree that has not dropped its leaves yet. Look at the ground. In the dappled light, you will see crescents everywhere: the crescent Sun.
Sunlight is the heavens reaching down to touch us right where we stand; I think about this when I step into the light. But crescent sunlight is the Moon joining this experience. Its darkness, rather than its light, reaches out to touch us, too…
An informative and lyrical guide to today’s eclipse: “During an Annular Eclipse, Look to the Shadows,” from @rboyle31 in @atlasobscura.
* John Milton, Samson Agonistes
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As we don’t look directly, we might recall that on this date in 1609, Galileo (who has claim to the titles Father of observational astronomy, modern-era classical physics, the scientific method, and modern science) put the telescope to use in his astronomical work. Upon hearing (at age 40) that a Dutch optician had invented a glass that made distant objects appear larger, Galileo crafted his telescope. He continued to improve his device, ultimately achieving 30X magnification, and recorded his observations of the Moon, the moons of Jupiter, the Phases of Venus, Sunspots, The Milky Way, and more. He published his initial telescopic astronomical observations in March 1610 in a brief treatise entitled Sidereus Nuncius (Starry Messenger).
Telescopes were also a profitable sideline for Galileo, who sold them to merchants who found them useful both at sea and as items of trade.
“The commonality between science and art is in trying to see profoundly – to develop strategies of seeing and showing”*…
Working with her scientist husband, Orra Hitchcock produced illustrations on bolts of linen that manifest original knowledge about extinction, stratigraphy, and their evidentiary features in the surrounding landscape– and trained eager young students to recognize and describe geological and natural-historical phenomena…
After meeting and falling in love with Edward Hitchcock, her employer at Massachusetts’ Deerfield Academy, Orra (née White) married him in 1821, beginning a lifetime of professional collaboration while raising a family amid piles of rocks and research tomes. Highly trained, white, and wealthy, she was far from an oddity in nineteenth-century education. Like many other women of her class, Hitchcock received extensive instruction in the arts and sciences, making a name by working alongside, not beneath, a man who had easier access to academic opportunities. Variously lauded as “an anomaly” and “the most remarkable” of their era, her scientific illustrations have rarely been considered on their own terms — admired for the natural historical and religious knowledge they contain — without being made an exemplar of the broader category of “women’s work”.
Moving to Amherst when Edward was appointed Professor of Chemistry and Natural History, the couple embarked on a decades-long exploration of the Connecticut River Valley’s botany and geology. While Edward lectured to eager young students about the principles of nature, from the depths of oceans to the granite veins of the earth, Orra produced more than sixty hand-colored scientific illustrations on poster-sized linen swaths designed to be hung on classroom walls.
Ranging from extinct mammals like Megatherium (a genus of giant ground sloth [below]) through lithic strata to fossilized footprints, the collection is striking for its modern abstraction, anticipating the later works of George Maw. Although some of Hitchcock’s geological illustrations seem far from “accurate” in their specificity (or lack thereof), her devotion to clear and concise visual communication bespeaks a deep-seated understanding of complex scientific principles…
An appreciation: “Orra White Hitchcock’s Scientific Illustrations for the Classroom (1828–40),” from @PublicDomainRev.
* Edward Tufte
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As we picture it, we might send sharply-observant birthday greetings to Cecilia Helena Payne-Gaposchkin; she was born on this date in 1900. An astrophysicist and astronomer, she was the first– in her Radcliffe (Harvard) PhD thesis in 1927– to apply the laws of atomic physics to the study of the temperature and density of stellar bodies: the first to conclude that hydrogen and helium are the two most common elements in the universe and the first to suggest that the Sun is primarily (99%) composed of hydrogen. During the 1920s, the accepted explanation of the Sun’s composition was a calculation of around 65% iron and 35% hydrogen. Her thesis adviser, astronomer Henry Norris Russell, reached a similar conclusion via his own observations several years later, and (while he made brief mention of Payne’s work) was for a time credited with the discovery. But in 1947, astronomer Fred Hoyle confirmed her original claim.
She spent her entire career at Harvard. In 1956 she became the first woman to be promoted to full professor from within the faculty at Harvard’s Faculty of Arts and Sciences. Later, with her appointment to the Chair of the Department of Astronomy, she also became the first woman to head a department at Harvard.
Her students included Helen Sawyer Hogg, Joseph Ashbrook, Paul W. Hodge, and Frank Drake (the creator of the Drake Equation)– all of whom made important contributions to astronomy.
“An imbalance between rich and poor is the oldest and most fatal ailment of all republics”*…
… so, how we measure it matters…
In 2015, Greece, Thailand, Israel, and the UK were equally unequal. That is, all four countries had the same Gini coefficient, a common measure of income inequality.
The number suggests that the spread of incomes in the four nations was the same. However, a close look at the poorest and wealthiest in those societies reveals a very different picture. The ratio between income held by the richest 10% and the poorest 10% ranged significantly, from 13.8 in Greece to 4.2 in the UK.
The fact is, just because the Gini coefficient is so well known doesn’t mean it’s a particularly useful measurement. Its appeal comes from its simplicity—a number between 0 and 1 that can encapsulate a complex distribution in a single figure—as well as its popularity. It is also regularly published and updated by powerful international organizations like the OECD, the World Bank, and the International Monetary Fund.
However, it has a number of serious limitations. So many, in fact, that the World Inequality Database, one of the world’s leading sources of income inequality data, steers clear. And it’s not alone. While some economists defend the Gini coefficient’s continued use, most agree that as a way to understand income inequality, it’s insufficient on its own…
A primer on the dominant measure of economic inequality, and on some alternatives/supplements to it: “Gini coefficient: An introduction.”
* Plutarch
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As we aim to understand, we might note that today is the Summer Solstice, the day on which the earth’s north pole is maximally tilted toward sun, and there are more hours of daylight than on any other day of the year (in the Northern Hemisphere; in the Southern, it is the Winter Solstice, the shortest day). The June solstice is the only day of the year when all locations inside the Arctic Circle experience a continuous period of daylight for 24 hours. And perhaps more immediately, it is the “official” start of Summer.
(The 21st is the traditional date; in the event, the solstice falls on the 20th, 21st, or 22nd– this year, on the 20th… still, the traditional date is the one folks tend to mark.)
Not coincidentally, today is also National Daylight Appreciation Day.
“The grid is awesomely complex. It is the largest machine in the world.”*…
Solar Flare (upper left), May 28, 2020
The Sun emitted its largest solar flare since 2017 on Friday, indicating that our star may be awakening from a quiet period that has lasted several years. Though the flare erupted on the opposite side of the Sun from Earth, NASA’s Solar Dynamics Observatory was able to detect its glow above the solar surface, which is visible in the upper left corner of the above image…
Solar flares, sudden bursts of light blasted out by the Sun, are sometimes accompanied by arcing ejections of hot plasma from the star. These flashes normally show up in the same area as sunspots, which are dark patches of the solar surface that are slightly cooler than other parts of the Sun.
Our star experiences solar cycles that last about 11 years and are timed by the number of sunspots visible on the surface: peak activity correlates to the largest numbers of sunspots in a cycle, while a relatively spotless Sun is considered to be in hibernation. The last cycle started in 2008, and produced a major solar storm in 2012.
These storms also cause extremely bright and vivid auroras, popularly called the Northern and Southern Lights, as the glut of charged particles from a more energetic Sun illuminates the skies. However, past incidents show that extremely powerful flares and ejections—which blast out powerful surges of X-ray and UV radiation—can also scramble satellite systems and even cause energy failures on Earth, such as a blackout in March 1989 that left millions of people in Québec without power… (source and more info)
Indeed, after the 1989 event, earth had a near miss when the effects of a much more powerful storm barely passed us by…
Back in 2012, the Sun erupted with a powerful solar storm that just missed the Earth but was big enough to “knock modern civilization back to the 18th century,” NASA said.
The extreme space weather that tore through Earth’s orbit on July 23, 2012, was the most powerful in 150 years, [see here for info on that earlier storm] according to a statement posted on the US space agency website Wednesday.
However, few Earthlings had any idea what was going on.
“If the eruption had occurred only one week earlier, Earth would have been in the line of fire,” said Daniel Baker, professor of atmospheric and space physics at the University of Colorado…. (source and more info)
The damage, should another huge solar storm hit, could be massive– but wouldn’t be evenly distributed…
This map shows 100-year storm-induced voltages on the national electric power grid
A new study about solar-induced power outages in the U.S. electric grid finds that a few key regions—a portion of the Midwest and Eastern Seaboard—appear to be more vulnerable than others…
Solar flares and other solar-mass ejections that travel through space can slam into Earth’s atmosphere and generate powerful electric and magnetic fields. These magnetic storms can occasionally be intense enough to interfere with the operation of high-voltage electricity lines.
Depending on the geology of a given region, the currents a geomagnetic storm induces in the power lines can destabilize the power grid’s operation and cause damage to (or even destroy) transformers….
Utilities in those [most vulnerable] regions need to know that power disturbances and outages—and possibly blown transformers—are more likely in the case of a big solar storm hitting Earth.
In a worst-case scenario… portions of the electric grid without enough backup transformers and other equipment could find themselves unable to operate until they can swap in backup systems. Of course, if there are not enough transformers and other devices, many in the hardest-hit regions could be without power for days or weeks until equipment could be delivered or built from scratch…
The worst-case scenario, the one that keeps grid experts up at night, happened last in 1859. It originated in a solar flare that blasted off the solar surface on 1 September 1859 and was observed by the English amateur astronomers Richard Carrington and Richard Hodgson.
Fortunately, when the “Carrington Event” hit Earth, the world had precious little electric infrastructure to disturb. It was mostly telegraph wires along railway lines that felt any high-voltage surges.
“There’s some expectation that if we were to have a repeat of the 1859 storm, it could have some substantial effects on the electric power grid and other technology that modern society depends upon,” [USGS research geophysicist Jeffrey] Love said. And because so many of today’s electrical systems are built around computer chips that are not robust to high-voltage surges, the fear is that a modern-day Carrington event could also blow out some portion of our computerized world… (source and more info)
What can we do about it? We can urge utilities (and their regulators) to expand and extend the emergency transformer stockpile (Grid Assurance) and to shore up the grid’s resilience to electromagnetic pulses.
As though we need one more thing about which to be concerned…
* The Grid: The Fraying Wires Between Americans and Our Energy Future
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As we have a sunny day, we might spare a thought for Joseph Ritter von Fraunhofer; he died on this date in 1826. A physicist and optical lens manufacturer, he made optical glass and achromatic telescope objective lenses, invented the spectroscope, and developed diffraction grating. But he is perhaps best remembered for his discovery of the dark absorption lines in the spectrum of the sun (created by selective absorption of those wavelengths by the atoms of different elements)– now, appropriately, known as Fraunhofer lines.
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