سایت انفجار : The Sky Phenomena That May Have Inspired Artist Georges Seurat

بازی بوم شرطی:بازی انفجار

To artists inspired by what they see in nature, volcanic sunsets are the holy grail of light and color. They transform placid sunsets and post-twilight glows into vibrant bloodbaths of spectral radiance. Yet I’m not writing this to hang on the wall another volcanically inspired sunset painting for us to ponder. Rather, I want to introduce to observers a subtle and little-known daytime phenomenon linked to volcanic activity. It may have, in part, inspired 19th-century Post-Impressionist French artist Georges Seurat (1859–1891) in his attempt to reform Impressionism and illuminate the world with a new form of art: his own version of optical blending of color, called Pointillism.

The Sky As Art

A number of 19th-century artists re-created volcanic sunsets in their paintings. Most touted are the works of English landscape pioneer William Turner, who spent a year painting the vibrant sunsets induced by the weather-altering 1815 eruption of Indonesia’s Mount Tambora — the most powerful volcanic event in recorded history.

William Ascroft of Chelsea, London, captured what are arguably the most faithful representations of sunset skies infused with aerosols from the 1883 eruption of Krakatau (aka Krakatoa; also in Indonesia). He made more than 500 crayon sketches of the changing hues, several of which appear as the frontispiece of the 1888 Royal Society publication, “The eruption of Krakatoa, and subsequent phenomena.” And in 2004, Don Olson of Texas State University added Norwegian artist Edvard Munch’s The Scream (1893) to the tally of paintings inspired by the sunsets observed in the three years following Krakatau’s historic blast.

These artists may not have been alone. In a 2014 paper in the scientific journal Atmospheric Chemistry and Physics, Christos Zerefos of the Academy of Athens in Greece tells how he and his team analyzed red-green ratios in more than 500 paintings from 181 artists, dating from between 1500 and 1900. They recognized the effects of volcanic aerosols (namely, a preponderance of warm hues) in sunset paintings created within a period of three years that followed each of 54 major volcanic events during that time period. These include works by Turner, John Singleton Copley, Edgar Degas and Gustav Klimt. The findings are not surprising. But topping the list is Seurat.

Georges Seurat painted Bathers at Asnières in 1884 at the age of 24. This giant work (118 by 79 inches) shows a riverside spot at the Seine just 4 miles from the center of Paris. Note how he colored the sky to reflect the pollution spewing from the factory smokestack in the distance.
(Credit: Wikimedia Commons)

Science on Canvas

Born in Paris to a wealthy family, Seurat studied drawing at night school before he entered the École des Beaux-Arts in Paris in 1878. During his two-year stay, he became disillusioned with the academic style of painting — the pedantic use of “hidden” brushstrokes and “licked” finishes to smooth the surface of a painting. At the same time, he was growing enamored of the large, separate brushstrokes in French Romantic artist Eugène Delacroix’s murals, and the radical new styles of Impressionist painters Claude Monet, Camille Pissarro and others. Their use of visible brushstrokes and experimental application of color, tone and texture worked together to create a vibrant visual impression of a fleeting moment in life.

More than an artist, Seurat had a keen aptitude for science. He spent hours scouring libraries for books on optics, scientific theories of color and principles of design. Specifically, he was keen on the visual effects of complementary colors and the science behind color perception. He probably learned about those subjects in Principles of Harmony and Contrast of Colours, and Their Applications to the Arts, a book written in 1835 by French chemist Michel-Eugène Chevreul.

Seurat left the academy in 1879 to spend a year of military service in Brest, where, according to biographer Daniel Catton Rich, “he opened his eyes to the luminous effects of sky and quiet water.” He then returned to Paris, where he began to apply his evolving principles of composition and color.

In his quest to discover a new approach to painting, Seurat turned to science, including Chevreul’s law of simultaneous contrast — how one color can change our perception of another color right next to it. Turning away from mixing paint on his palette, he ultimately began applying thousands of small dots of pure color in broken strokes — or small touches set side by side — directly to the canvas in a precise manner, so that the eye mixed the colors instead. His ever-evolving works achieved such an intensity of light that he believed he had discovered the science of painting.

Seurat had not perfected his Pointillist technique when he painted his first large-scale composition, Bathers at Asnières. Finished in 1884, it only flirted with his still-evolving Pointillist style. Still, one can see in the sky the smoggy effects of air pollution from the industrial chimneys in the distance, giving testament to his pursuit of capturing realistic atmospheric optical effects.

A turning point came in the summer of 1884, when Seurat showed the work at the first exhibition of the Group of Independent Artists, of which he was a founding member. That summer he met with younger Neo-Impressionist artist Paul Signac, who pointed out to Seurat that Bathers lacked the luminosity of other Impressionist paintings — the result of his use of muddy earth tones rather than colors of prismatic purity. As Catton Rich notes in his 1958 book, Seurat: Paintings and Drawings, Seurat’s next monumental work — A Sunday Afternoon on the Island of La Grande Jatte (1884) — “explore[s] to the fullest the new laws and principles which he and Signac were developing.”

Seurat preferred to call his new technique “color-luminism” (chromoluminarism), because it gives a painting not only a greater sense of vibrancy but also a shimmering effect, like one experiences on a hot summer’s day as heat rises from a roadway or sidewalk.

Volcanic Influences?

Seurat’s use of the technique of chromoluminarism coincided with the optical effects trailing the August 1883 eruption of Krakatau. It seems almost impossible that Seurat and his fellow optical science-oriented artists of the Neo-Impressionist movement would have ignored the profound post-Krakatau skies — especially because the resulting atmospheric optical effects created the most chromatically vibrant skies recorded for a century. And the vibrancy of light was key to the new artistic movement.

But the Krakatau aerosols also performed light magic in the daytime sky, generating diffuse aureoles of complementary light that radiated most effectively at high noon. Such a sight would have had the capacity to inspire Seurat, especially considering that the artist was keen on the science of diffraction and Rayleigh scattering. It would also be appropriate to suggest that the daytime sky, as painted by the Krakatau eruption, stood before the Neo-Impressionists like a visual muse, inspiring new insights into color and tone that perhaps only science-inspired artists could fully appreciate.

X-ray imaging of Bathers at Asnières reveals that Seurat modified parts of it in the mid-1880s, adding prismatic colors in a Pointillist manner that creates a more vibrant feel. Bathers had not quite been completed by the time Krakatau erupted in August 1883, and the volcano’s associated atmospheric effects only became vividly pronounced over Europe by November of that year. But its optical effects remained intense at least until 1887, and skywatchers continued to record volcanic atmospheric effects to a lesser degree into the early 1900s. Volcanic skies, then, were present throughout the brief heyday of the French Neo-Impressionist movement, which flourished principally from 1886 to 1906. To understand how these optically vibrant skies may have affected Neo-Impressionist thinking, let’s fast-forward 100 years to 1982, the year El Chichón erupted in Mexico.

American artist Frederic Edwin Church captured the 1862 eruption of Cotopaxi, which is about 30 miles south of Quito, Ecuador. Topping out at 19,393 feet, it’s one of the highest volcanoes on Earth.
(Credit: Detroit Institute of the Arts/Wikimedia Commons)

A Flecked Hawaiian Sky

On March 28, 1982, El Chichón, a dormant volcano in Chiapas, Mexico, awoke from 600 years of slumber, erupting violently three times in a week. One of the most important volcanic events of the 20th century, the unexpected blast released 7.5 million metric tons of sulfur dioxide into the stratosphere, warming it by 7.2 degrees Fahrenheit, and cooling the Northern Hemisphere by 0.72 F. The resultant cloud encircled the globe in 20 days and altered Earth’s climate for years afterward.

The stratospheric aerosol cloud initially moved from southern Mexico toward Hawaii, where I was living at the time. In a 1983 Applied Optics paper, Kinsell L. Coulson notes that “a considerable enhancement of intensity” occurred throughout the main part of the day, causing a “diffuse type of aureole” over a large portion of the sky. Mauna Loa Observatory lidar measurements over Hawaii in 1982 revealed a sixfold increase in scattering due to aerosols, and a 25 percent decrease in direct incident radiation.

In my studies of the El Chichón-influenced daytime sky, I noticed it had a “nervous” quality, caused by the interplay of minute flecks of complementary colors. This is why I refer to it in my Hawaiian diaries as an Impressionist’s sky. To a casual viewer, the El Chichón aerosols had buffed away the normally crystal-blue sky and replaced it with a frost-glass glare of Pointillist light — light predominantly infused with flecks of blue and orange, with dabs of yellow and white, that scintillated with subtle prismatic effects like tossed confetti. This description is reminiscent of one recorded one month after the Krakatau paroxysm by Captain Parson of the Earnock, who noticed the eastern sky before sunrise appeared “silver grey, changing to light blue, flecked with numerous small cirrus trimming, pink and rosy.”

Some of the color associated with the aerosol umbrella I witnessed was linked to the Bishop’s ring atmospheric phenomenon. This enormous diffraction corona (in this case created by the scattering effects of volcanic aerosols) covered half of the visible sky and displayed the color-contrast aureoles described by Chevreul, though in opposite order — namely, an enormous blue sphere of light surrounded by a vast orange aureole. The volcanic skies seemed to announce the general rule of Neo-Impressionism: “more opposition, more brilliance.”

One painting by Seurat moves me because it recalls the flecked complexity of the El Chichón sky: The Eiffel Tower, a montage of predominantly blue, red and yellow points of color painted from a vantage point that looked to the southeast across the Seine, where such atmospheric optical effects would be expected.

Seurat unveiled this painting in 1889. He began working on it around February 1887, before finalizing the painting in his studio just months ahead of the tower’s completion in 1889. During this period, the Bishop’s ring and other aerosol effects were still present in the atmosphere. As T.W. Backhouse reports in a March 1889 issue of Nature: “I am informed by Miss E. Brown, of Cirencester, that she saw Bishop’s ring in full day-time as recently as last month, not far from 12 o’clock one day.”

Adding to the lingering effects of the Krakatau aerosols were aerosols injected into the atmosphere by the 1886 eruption of Mount Tarawera in New Zealand and the 1888 eruption of Mount Bandai in Japan. So it’s possible that volcanic aerosols from three different eruptions contributed to the atmospheric effects we see in The Eiffel Tower, whose Pointillist style is more boldly laid down than in any previous work by Seurat.

The Point of the Matter?

In the nearly 40 years since the El Chichón eruption, I have witnessed similar large-scale Pointillist effects only rarely: after the 1991 eruption of Mount Pinatubo in the Philippines, and once during totality at the August 2017 total solar eclipse in Oregon, where the sky was affected by rippling waves of smoke from forest fires.

I have observed a similar effect multiple times on a microscale with another diffraction phenomenon: the pollen corona (about 3° in angular extent, compared with nearly 90° in the Bishop’s ring). In one case, I was able to photograph the Pointillist effect in the pollen corona, whereby a blue aureole and outer yellow and orange rings were splintered into a blend of juxtaposed prismatic colors, owing to scattering effects of the airborne particles.

This Pointillist image shows colors of complementary light scattered by pollen grains in a diminutive atmospheric corona. The bright glow is an edge effect from a roof used to block the sun, around which the colorful corona appeared. (Credit: Stephen James O’Meara)

Is it not reasonable, then, to at least consider the possibility that the flecked complementary colors in a volcanically infused daytime sky — which persisted in undulations throughout Seurat’s brief span as an artist — influenced his Pointillist technique?

Unfortunately, we know little about Seurat’s methods. He died tragically of an infection in 1891, at age 31. The artist left behind little in the way of personal letters and diaries; he also didn’t speak much about his technique.

His interest in color theory, however, is well documented. As Jo Kirby and colleagues explain in an article published in a 2003 National Gallery Technical Bulletin titled “Seurat’s Painting Practice: Theory, Development and Technology,” “It is important to realise that nothing in Seurat’s art seems to have been unconsidered.”

Stephen James O’Meara is a contributing editor of Astronomy magazine.

بازی انفجار شرطی
سایت انفجار
سایت شرط بندی انفجار
سایت بازی انفجار

سایت انفجار : چگونه یک سیستم بینایی رایانه برای چین و چروک می تواند انقلابی در توسعه دارو ایجاد کند

بازی بوم شرطی:بازی انفجار

در ارگانیسم های زنده ، نیروهایی که سلول ها را منقبض و کشش می دهند به طرز شگفت آوری نقش مهمی در رشد سلول ها دارند. اکنون فرم جدیدی از میکروسکوپ تنظیم شده است تا با مطالعه چین و چروک هایی که نیروهای سلولی ایجاد می کنند ، بینایی بیشتری فراهم می کند.
بازی انفجار شرطی
سایت انفجار
سایت شرط بندی انفجار
سایت بازی انفجار

سایت انفجار : زندگی ، جهان و ‘Oumuamua

بازی بوم شرطی:بازی انفجار

در جستجوی تمدن های بیگانه ، اولین قدم برای اطمینان از اینکه می فهمیم به دنبال چه چیزی هستیم.
بازی انفجار شرطی
سایت انفجار
سایت شرط بندی انفجار
سایت بازی انفجار

سایت انفجار : چرا این سیگنال اخیر که به نظر می رسد از پروکسیما قنطورس می آید تقریباً چنین نبود

بازی بوم شرطی:بازی انفجار

در تاریخ 29 آوریل 2019 ، تلسکوپ رادیویی پارکز در استرالیا شروع به لیست کردن سیگنال های رادیویی از نزدیکترین همسایه خورشید ، پروکسیما قنطورس ، با فاصله بیش از 4 سال نور کرد. این تلسکوپ به دنبال شواهدی از شراره های خورشیدی بود و بنابراین 30 دقیقه قبل از آموزش مجدد روی یک کوازار دور برای کالیبراسیون مجدد و پس از آن به عقب گوش داد.

در کل ، این تلسکوپ 26 ساعت داده جمع آوری کرده است. اما هنگامی که ستاره شناسان آن را با جزئیات بیشتری تجزیه و تحلیل کردند ، متوجه چیزی عجیب و غریب شدند – یک لحن خالص با فرکانس 982.02 مگاهرتز که پنج بار در داده ها ظاهر شد.

این سیگنال اولین بار سال گذشته در سال گزارش شد روزنامه گاردین، یک روزنامه انگلیسی این مقاله این احتمال را مطرح كرد كه این سیگنال شواهدی از یك تمدن پیشرفته در پروكسیما قنطورس ، یك ستاره كوتوله قرمز است كه شناخته شده است دارای یك سیاره به اندازه زمین است كه در منطقه قابل سكونت خود در حال چرخش است.

اما محققان به طور مداوم این احتمال را نادیده می گیرند و می گویند حداقل ، قبل از نتیجه گیری ، حداقل باید سیگنال را دوباره مشاهده كرد. در واقع ، علیرغم جستجوهای مختلف ، سیگنال دوباره دیده نشده است.

اکنون امیر سراج و آبراهام لوب از دانشگاه هاروارد در کمبریج ، ماساچوست ، احتمال اینکه این سیگنال از یک تمدن مستقر در پروکسیما قنطورس آمده ، حتی بدون مشاهده دیگری را محاسبه کرده اند. آنها می گویند شانس آنقدر کم است که به طور موثر احتمال را رد می کند – به شرط معتبر بودن فرضیاتی که در محاسبات خود ارائه می دهند.

هوش فرازمینی

سیگنال جدید توسط محققان در پروژه Breakthrough Listen ، همکاری بین المللی ستاره شناسان که در جستجوی شواهدی از اطلاعات فرازمینی بودند و توسط میلیاردر یوری میلنر تأمین می شود ، پیدا شد. آنها سیگنال Breakthrough Listen Candidate 1 یا BLC1 را صدا کردند.

این سیگنال جالب است زیرا تن های باریک بطور کلی در طبیعت وجود ندارد ، که بجای آن تمایل به تولید نویز باند پهن دارد. اما BLC1 تمام خصوصیات یک علامت فنی را دارد – یکی از این تمدن ها از تمدنی با توانایی تکنولوژیکی نشات می گیرد.

تا حد زیادی محتمل ترین منبع زمین است. بیشتر سیگنال های این نوع به سرعت به تداخل رادیویی تلفن های همراه نزدیک ، اجاق های مایکروویو ، اتومبیل های عبوری ، هواپیماها و ماهواره ها و موارد دیگر نسبت داده می شوند.

اما تیم تجزیه و تحلیل این سیگنال هنوز منبع واضحی پیدا نکرده اند. و آنها می گویند که فرکانس سیگنال با گذشت زمان اندکی تغییر می کند ، پدیده ای که مطابق با سیگنال یک بدن چرخان یا مدار است. این باعث افزایش فریب ها شده است.

بنابراین کار سراج و لوب به موقع است. رویکرد آنها مبتنی بر اصل کوپرنیک است ، این ایده که زمین هیچ جای ممتازی در جهان ندارد و در هیچ زمان خاصی نیست ، بنابراین مشاهدات انجام شده از اینجا غیر معمول از مشاهدات انجام شده در هر جای دیگر جهان نیست.

این اصل گذشته ای داستانی دارد. این نام از نام ستاره شناس قرن 14 میلادی ، نیکولاوس کوپرنیکوس گرفته شده است که اظهار داشت زمین در مرکز جهان نمی نشیند و در عوض به دور خورشید می چرخد. تقریباً 30 سال پیش ، ستاره شناس ریچارد گوت از همین اصل استفاده کرد تا با اطمینان 95 درصدی نشان دهد که گونه های ما حداقل 200000 سال اما بیش از 8 میلیون سال زنده نمی مانند.

ایده اصلی این است که بشریت آغاز داشته و سرانجام به پایان خواهد رسید. ما در حال حاضر جایی در جدول زمانی در این بین می نشینیم اما در مکان یا زمان خاصی نیستیم ، خصوصاً در نزدیکی آغاز یا انتها. از نظر ریاضی بعید به نظر می رسد در 2.5 درصد اولیه وجود بشریت و نه در 2.5 درصد نهایی باشیم. بنابراین با اطمینان 95 درصدی ، باید در وسط قرار بگیریم.

سپس فقط مسئله شکاف اعداد است. ما می دانیم که گونه ما حدود 200000 سال قدمت دارد که باید حداقل 2.5 درصد از کل گونه باشد. این با 95 درصد اطمینان حاکی از آن است که بشریت باید حداقل 200000 سال دیگر وجود داشته باشد اما بیش از 8 میلیون سال بیشتر نباشد.

در واقع ، گوت از همان استدلال استفاده كرد تا نشان دهد كه شانس یافتن شواهدی از زندگی هوشمند در جاهای دیگر كهكشان ما بسیار ناچیز است ، حتی اگر تصور كنیم كه این تمدن ها باید وجود داشته باشند. با توجه به اینکه فقط بیش از صد سال است که ما قادر به رادیو هستیم ، احتمال همپوشانی این دوره با قابلیت مشابه تمدن دیگر بسیار ناچیز است. گوت می گوید: “جستجوی هدفمند رادیویی از 1000 ستاره اطراف به احتمال زیاد موفقیت آمیز نخواهد بود.”

سراج و لوب همین استدلال را برای احتمال همپوشانی قابلیت رادیویی تمدن ما با قابلیت تمدن دیگری در پروکسیما قنطورس اعمال می کنند. و اعداد امیدوار کننده نیستند. آنها نتیجه می گیرند که اگر نامزد دستیابی به موفقیت پیشرفت 1 توسط یک تمدن پیشرفته از نظر فناوری تولید می شد ، این امر با هشت مرتبه اندازه اصل کوپرنیک را نقض می کرد. سراج و لوب می گوید: “این امر ، پیشینی گوش دادن به نامزد 1 (BLC1) را به عنوان یک سیگنال رادیویی فناوری از سیستم آلفا قنطورس رد می کند.”

نظریه Panspermia

در واقع ، با توجه به تعداد زیاد سیارات بالقوه قابل سکونت در کهکشان ، این ایده که دو ستاره همسایه باید همزمان از تمدن های پیشرفته میزبانی کنند بسیار غیر ممکن است.

مگر اینکه عوامل دیگری در کار باشد. یکی از این عوامل پان اسپرمیا است – این ایده که زندگی از فضا گرفته شده است. این باعث می شود ستاره های همسایه همزمان زندگی پیشرفته داشته باشند. با این حال ، این استدلال با واقعیت پیچیده است که حیات در زمین حدود 4.5 میلیارد سال پیش قبل از همسایگی خورشید و پروکسیما قنطورس روی زمین ظاهر شده است.

البته ، اصل کوپرنیک نمی تواند این احتمال را که سیگنالی که در پارکز از تمدن دیگری شنیده می شود ، کاملاً نفی کند. فقط احتمال اینکه این یک سیگنال سرگردان از منشا زمینی باشد ، به احتمال زیاد سفارشات زیادی است. در این میان ، تمام اخترشناسان می توانند تلسکوپ های رادیویی خود را به سمت Proxima Centauri برگردانند و منتظر بمانند.

مرجع: اصل کوپرنیک BLC1 را به عنوان یک سیگنال رادیویی فن آوری از سیستم آلفا قنطورس رد می کند: arxiv.org/abs/2101.04118

بازی انفجار شرطی
سایت انفجار
سایت شرط بندی انفجار
سایت بازی انفجار

سایت انفجار : Why Haven’t We Found Alien Life Yet? Blame Our Closed Minds

بازی بوم شرطی:بازی انفجار

This story originally appeared in the December issue of Discover magazine as “Looking for Signs.” Support our science journalism by becoming a subscriber.

Limits don’t sit well with Avi Loeb.

Loeb quickly reels some off to me over the phone (hands-free) during a drive home from work: About 25 billion stars, roughly one-quarter of those that reside in the Milky Way, lie in a habitable zone. He rounds that down to an even 10 billion to keep the calculations simple. “And then there are about a trillion galaxies like the Milky Way,” he says, “which means there are about 1022 [10 billion trillion] planets in the observable universe that could potentially host life as we know it.” In other words, searches for extraterrestrial life have barely scratched the surface. “As in other areas of exploratory science,” Loeb says, “we should investigate thoroughly before making sweeping pronouncements.”

Most of the searching so far, he adds, has been in the radio range, where scientists have examined a tiny fraction of the possible frequencies in an equally tiny fraction of the possible search space. Surveys in optical wavelengths have been much less extensive. For any new technology we develop, Loeb says, we should consider whether, somewhere, an alien civilization might have developed it, too, possibly leaving behind some detectable traces. “As our technology improves, that can help us imagine things we haven’t imagined before and explore things we haven’t searched for before.”

verarubin observatory

The Vera C. Rubin Observatory is expected to start searching the skies in 2022. (Credit: Rubin Obs/NSF/AURA)

When it comes to imagination, Loeb — cited in The New York Times “for his creative and prolific attempts to understand the … universe” — appears to have no shortage. Nor, would it seem, is he lacking in productivity. For over two decades, he has turned out an average of two academic papers each month, in addition to regular essays. He’s director of Harvard’s Institute of Theory and Computation, a member of the President’s Council of Advisors on Science and Technology, founding director of Harvard’s Black Hole Initiative and chair of the Breakthrough Starshot Advisory Committee — an endeavor aimed, among other things, at sending miniature spacecraft to other stars.

Florida Tech physicist Manasvi Lingam described his collaboration with Loeb during a postdoctoral fellowship as “exhilarating.” From 2017 to 2019, Lingam and Loeb wrote 25 research papers and a forthcoming book, Extraterrestrial Life: From Biosignatures to Technosignatures, that provides a wide-ranging discussion of SETI techniques. “With Avi, there’s always a fast turnaround time,” Lingam says. “We always try to look for left-field ideas that are nonetheless testable.”

Loeb is fearless because some of his out-there ideas have been publicly rebuked by other astronomers, says Penn State astronomer Jason Wright.

But Loeb is rarely deterred by disapproving remarks, saying skepticism “can be a self-fulfilling prophecy.” It’s far better to look, he says, than to assume there’s nothing to be seen. That attitude is apparently shared by NASA. It recently gave Loeb and others the first SETI-related grant in over 30 years that specifically supports innovative search strategies. Here are some of the unconventional notions he and his colleagues have advanced for enlarging the scope of SETI, and perhaps catching a glimpse of E.T. in the process.

Far From the City Lights

Loeb and Princeton University astronomer Edwin Turner are kindred spirits who enjoy batting around speculative ideas. “The conservative impulse that serves science well in some ways doesn’t serve us well when it comes to generating hypotheses,” says Turner. While touring Abu Dhabi a decade ago, and learning that Dubai is so bright it can be seen from outer space, Loeb and Turner started to wonder whether our telescopes could pick up light from an alien city. After some quick calculations, they determined that the Hubble Space Telescope (HST) would be able to detect light pollution from a city on the outer edges of the solar system, well beyond Pluto, and new, more advanced telescopes could extend that range considerably farther.

trappist - nasa

An artist’s concept shows the TRAPPIST-1 planetary system, with its seven Earth-sized, temperate exoplanets orbiting an ultra-cool dwarf star. It’s unusual to have so many planets in the habitable zone. (Credit: NASA/JPL/Caltech)

Although there aren’t any known planets lying in the solar system’s periphery, Loeb and Turner have come up with a method for determining whether a newly discovered light source is natural or artificial. Their technique is based on the principle that light drops off in intensity according to the square of the distance traveled.

Suppose we measure the brightness of a radiant object and repeat that measurement after the object has moved twice as far away from us, heading away from the sun. If the object was natural, such as a previously unknown planet or asteroid, and merely reflecting light from the sun, its brightness would decrease by a factor of 16: Its brightness (as measured from Earth) would have dropped off fourfold during the light’s journey from the sun to the object (since two squared equals four) and another fourfold during its journey back to us. If, on the other hand, the object was a luminous spacecraft, its brightness would drop off only by a factor of four since it produces its own light rather than reflecting it from the sun.

If our measurements of a distant light source indicate a fourfold drop in intensity, we should not immediately start worrying about an alien invasion, says Turner. “But we will want to point other telescopes there and … try to figure out what’s going on.”

Pollution As the Solution to Dilution

In 1990, as the Galileo spacecraft flew past a planet in our solar system, its instruments found evidence of an atmosphere rich in oxygen and methane — signs that the scientific team, led by Carl Sagan, deemed “strongly suggestive of life.” The planet in this case was Earth, and the exercise was mainly a proof of concept. But the HST has already started examining the atmospheres of planets around other stars, called exoplanets. And its successor, the James Webb Space Telescope, which is scheduled for launch in 2021, will soon probe atmospheres of even more distant planets, looking for biological signatures of life.

James webb telescope

(Credit: NASA/Chris Gunn)

In 2014, Loeb and two collaborators, Henry Lin and Gonzalo Gonzalez Abad, decided to flip the switch: Instead of looking for signs of life, they suggested looking for signs of death, or at least serious contamination. “Anthropogenic pollution could be used as a novel biosignature for intelligent life,” wrote the Harvard team, which proposed looking for two chlorofluorocarbon (CFC) gases, tetrafluoromethane and trichlorofluoromethane, that can survive tens of thousands of years and cannot be synthesized by known natural processes.

The James Webb telescope could spot the presence of these molecules in an exoplanet’s atmosphere, the researchers concluded, if concentrations were 10 times current terrestrial levels. Observing high levels of these long-lived pollutants and no signs of life-sustaining molecules like oxygen, Loeb and his coauthors said, “might serve as an additional warning to the ‘intelligent’ life here on Earth about the risks of industrial pollution.”

The Edge Effect

A 2005 paper in the journal Astrobiology by MIT astronomer Sara Seager and three other researchers identified a distinct feature of an Earthlike planet covered with large stretches of vegetation. Plants appear green because they reflect light in the green part of the spectrum, but at higher wavelengths, between the red and infrared range, reflectance shoots up dramatically. A graph of reflectance versus wavelength shows a steep rise at a wavelength of 700 nanometers that creates a pronounced “red edge” — a feature, though not evident to the human eye, that’s readily observable by telescopes with spectral sensitivity.

In 2017, Lingam and Loeb got to wondering: What if an exoplanet was covered by vast tracts of photovoltaic arrays instead of boundless greenery? Massive structures like this, Lingam and Loeb reasoned, would produce an artificial spectral edge analogous to the red edge caused by vegetation, though occurring at different wavelengths (depending, of course, on the materials making up the arrays). They calculated where the spectral edge would lie for silicon-based solar cells — a reasonable choice given silicon’s abundance in the universe — and those composed of other widely used photovoltaic ingredients, including gallium arsenide and perovskite. Future telescopes, such as WFIRST, set to launch in the mid-2020s, would be capable of detecting a “silicon edge,” should it exist.

Lingam and Loeb believe that such an analysis would be particularly powerful when applied to exoplanets that are “tidally locked,” meaning they keep the same orientation with respect to the parent star and therefore have permanently light and dark sides. An inhabited planet equipped with large-scale solar-electric generation could illuminate the dark side, and other installations might release significant amounts of waste heat on the cooler, darker side — developments that could be visible from afar and might remain visible after an alien civilization has gone extinct or migrated to another home.

Although these photovoltaic arrays would undergo wear and tear, Lingam and Loeb wrote in the Monthly Notices of the Royal Astronomical Society, “they can remain functional for a duration of time that is not insignificant by astrophysical standards and would thus represent genuine extraterrestrial artifacts.” If artifacts are someday spotted, they write, it could be an early, if not the first, example of a new field: “interstellar archaeology.”

The Mystery of FRBs

The first fast radio burst (FRB), an intense blast of radio waves emanating from outside our galaxy and lasting just a few milliseconds, was spotted in 2007. Astronomers have since seen more than 100 others. “The popular view is that these bursts come from young neutron stars with very strong magnetic fields,” says Loeb. But that supposition has not been confirmed. And there may not be a single source, he adds, because there are at least two types of bursts — a small minority that repeat and most that do not.


(Credit: Roen Kelly/Discover)

Lingam and Loeb offered a provocative solution to the puzzle: Maybe some of the FRBs are artificial. If that were the case, what would be the purpose of such incredibly powerful bursts? In a 2017 paper in Astrophysical Journal Letters, Lingam and Loeb raise two possibilities: It could be a beacon to broadcast the presence of an alien civilization, which they deem “rather implausible.” Or, it could power large spaceships tugged by even larger (in area, not in mass) light sails. “The optimal frequency for powering the light sail is shown to be similar to the detected FRB frequencies,” they write — a fact that, when combined with other technical arguments, could “lend some credence to the possibility that FRBs might be artificial in origin.”

Naysayers might dismiss this, insisting that “extraordinary claims require extraordinary evidence,” Loeb notes. “I say that they require evidence, but why should they be held to a higher plane? We should not automatically dismiss explanations just because they seem exotic to some people.”

Searching for Artifacts 

“When exploring habitable worlds around other stars, we might … find planets with burnt-up surfaces, abandoned mega-structures or planetary atmospheres rich with poisonous gases and no sign of life,” Loeb has written. One might also see an extensive network of unnatural platforms or satellites orbiting another star — perhaps part of a hypothetical energy-gathering enclosure called a Dyson sphere.

Something like this, if sufficiently large, could be spotted by NASA’s Transiting Exoplanet Survey Satellite (TESS), which looks for dips in the brightness of a star caused by a planet passing in front of it. TESS could also detect dips caused by the passage of giant artificial mega-structures. Officials announced in October 2019 that TESS would collaborate with Breakthrough Listen — a $100 million SETI initiative, the largest and most generously funded in the field’s history.

Listen’s ground-based telescopes would focus on potentially habitable planets identified by TESS. Loeb cites the example of Tabby’s Star: Discovered in 2016, two years before the TESS launch, it exhibited a peculiar dimming pattern, prompting some to speculate that it was surrounded by some kind of alien structure. It turns out that our view was blocked by an oddly shaped disk of dust, Loeb says, but that’s the kind of irregularity TESS scientists would be looking for.

Searching for Interstellar Visitors

On Oct. 19, 2017, an astronomer using Hawaii’s Pan-STARRS telescope discovered an object moving past the sun at 196,000 miles per hour, so fast that it almost surely originated from outside the solar system. The object, dubbed ‘Oumuamua — Hawaiian for “first scout from a distant place” — was initially classified as an asteroid and then a comet and more recently as a chunk of hydrogen ice. 


Interstellar visitor ‘Oumuamua has defied easy classification — Loeb has suggested it’s an artificial lightsail — but a team of astronomers concluded in 2019 that it’s a natural object. (Credit: Auntspray/Shutterstock)

But Loeb has analyzed all of these ideas and finds that they still leave some questions unanswered. He doesn’t see a plausible way that a “large hydrogen iceberg” could form. And even if it did, he says, an object like that could not survive its interstellar journey to the solar system because hydrogen evaporates so readily. Furthermore, ‘Oumuamua has unusual features that don’t match those of asteroids or comets: For one thing, it’s extremely elongated, about 10 times longer than it is wide. The object’s acceleration is also unexplained, as there’s no sign of outgassing, propulsion caused by the release of gas that’s normally seen in comets. Loeb and Shmuel Bialy of Harvard suggested that ‘Oumuamua was being pushed and sped up by solar radiation, in which case it must be shaped more like a thin pancake than a cigar as was commonly assumed. That raised the possibility that ‘Oumuamua “might be a lightsail of artificial origin” — a case they made in a November 2018 paper in Astrophysical Journal Letters.

In a July 2019 article in Nature Astronomy, an international team of 14 astronomers reached a different conclusion, contending that ‘Oumuamua is a natural object, despite its peculiar properties.

In the meantime, a second interstellar visitor, Comet Borisov, was discovered in 2019, whipping around the sun at 110,000 mph. This object is “clearly not artificial,” Loeb says, “because it looks like any other comet we’ve seen before.” But there soon should be many more interlopers to look at. The Pan-STARRS observatory has given us the capacity to survey the entire sky, and the Vera C. Rubin Observatory, expected to begin an even broader survey in 2022, “will be much more sensitive,” Loeb says, “a bigger and better telescope that could potentially detect an ‘Oumuamua-type object every month.”

When it comes to SETI, evidence ultimately carries the day, Loeb insists. “We should collect evidence without prejudice, without assuming we know the truth in advance, and see what we learn.” On the other hand, he says, we should be open-minded and allow for some risk-taking in our pursuit of that evidence. As the physicists Giuseppe Cocconi and Philip Morrison wrote in 1959, one year before SETI began: “The probability of success is difficult to estimate, but if we never search, the chance of success is zero.”

Steve Nadis is a contributing editor to Discover.

بازی انفجار شرطی
سایت انفجار
سایت شرط بندی انفجار
سایت بازی انفجار

سایت انفجار : تئوری بازی شکار تمدن های بیگانه را فقط روی یک ستاره متمرکز می کند

بازی بوم شرطی:بازی انفجار

این س ofال که آیا باید به ستاره ها پیام ارسال شود ، با مشکل روبرو است. ترس بزرگ ، تمدن پیشرفته تری را با نیت شیطانی جذب می کند. چرا باید ریسک کرد؟

در حقیقت ، مفسران مختلف اظهار داشته اند كه این ترس ممكن است پارادیوكس معروف فرمی را توضیح دهد كه می پرسد چرا از تمدنهای دیگر چیزی نشنیده ایم. پاسخ این است که یا افراد دیگری وجود ندارد یا بهترین استراتژی برای بقا سکوت است که مبادا تمدن پیشرفته تری شما را پیدا کند و نابود کند.

اما یک سوال جالب این است که آیا پارادوکس را می توان به روش دیگری حل کرد؟ اکنون ایمون کرینز در دانشگاه منچستر انگلیس می گوید با استفاده از تئوری بازی برای تعیین بهترین روش جستجو و برقراری ارتباط با تمدن های فرازمینی از پارادوکس جلوگیری می شود.

همین استراتژی همچنین زمینه نامزدهای سیاره فراخورشیدی را که ارزش بررسی دقیق برای تماس احتمالی را دارند به طرز چشمگیری محدود می کند. در حقیقت ، كرینز می گوید این روند جستجو برای سیارات فراخورشیدی قابل سكونت را كاهش می دهد كه باید فقط برای تماس با یكی در نظر گرفته شود.

نظریه بازی

ایده اصلی در رویکرد کرینز قابلیت شناسایی متقابل است. این تصور این است که بارورترین راه برای جستجوی زندگی بیگانه جستجوی مکان هایی است که یک مشاهده گر شانس دیدن آنها را داشته باشد. او می گوید: "قابلیت شناسایی متقابل یک رویکرد نظری بازی است که هدف آن افزایش احتمال برقراری ارتباط بین دو تمدن دارای توانایی SETI است."

البته هر دو طرف به اطلاعات مختلفی دسترسی خواهند داشت. این امر توسط عواملی مانند درخشندگی ستاره مادر تعیین می شود که می تواند سیگنال را از سیاره ، مدار سیاره خارج و غیره باتلاق یا پنهان کند. بنابراین قابلیت شناسایی متقابل همیشه متقارن نیست.

همچنین ممکن است تمدن دیگری به دنبال همان نوع سیگنالی نباشد که ما بدنبال آن هستیم. در واقع ، می تواند اطلاعاتی وجود داشته باشد که وجود ما را آشکار می کند و ما از آنها بی خبریم. اگر تمدن دیگری به دنبال این باشد ، بعید است که با آنها ارتباط برقرار کنیم.

بنابراین بهترین استراتژی محدود کردن جستجوهای ما به سیارات فراخورشیدی است که به شما اجازه می دهد تمدن به همان روشی که ما به دنبال آنها هستیم ، به دنبال ما باشد. در این صورت ، هر دو اطلاعات مشترکی دارند. کرینز این "اطلاعات مخرج مشترک" را می نامد.

با پیدا کردن چنین سیاره فراخوانی ، این سوال پیش می آید که چه کسی باید با چه کسی تماس بگیرد. هر دو طرف ممکن است تصمیم بگیرند که اختیار قسمت بهتری از شجاعت است و سکوت اختیار کنند. اما در غیر این صورت ، پس تئوری بازی پیشنهاد می کند که طرفی که بیشترین اطلاعات مخرج را دارد ابتدا باید صحبت کند. "مسئولیت انتقال به عهده حزب با برتری است [common denominator information] درباره طرف دیگر ، "می گوید Kerins.

این حداقل تئوری است. Kerins ادامه می دهد تا آن را در بایگانی سیارات فراخورشیدی ناسا اعمال کند که در حال حاضر شامل 74 سیاره فراخورشیدی در مناطق قابل سکونت ستاره های اصلی آنها است.

طبق قانون قابلیت شناسایی متقابل ، بهترین مکان برای جستجوی سایر تمدن ها در زیرمجموعه سیارات فراخورشیدی است که می توانند زمین را با همان روش مشاهده کنند. محبوب ترین راه برای لکه بینی سیارات فراخورشیدی جستجوی کم نور شدن ستاره اصلی هنگام عبور یک سیاره از مقابل آن است.

واضح است که فقط کسری از سیارات فراخورشیدی دیگر با منظومه شمسی همسو می شوند تا زمین را از مقابل خورشید ببینند. ستاره شناسان این منطقه را منطقه ترانزیت زمین می نامند. و معلوم شد که ما فقط سیاره فراخورشیدی قابل سکونت را در این منطقه می شناسیم.

این K2-155d است. این یک ابر زمین است که در منطقه قابل سکونت ستاره ای به نام K2-155 در صورت فلکی گاو می چرخد. با استفاده از تلسکوپ فضایی کپلر در سال 2018 به همراه دو سیاره خواهر که در منطقه قابل سکونت نیستند کشف شد.

اولین تماس

اما آیا باید با آنها تماس بگیریم یا برعکس؟ رویکرد نظری بازی کرینز پاسخ می دهد. از آنجا که K2-155d یک ابر زمین در اطراف یک ستاره نسبتاً درخشان است ، برای ما بیشتر از زمین برای آنها قابل مشاهده است. او می گوید: "در این حالت ، مسئولیت نظریه بازی به عهده ما است تا به K2-155d منتقل شود."

بنابراین اگر تمدنی در K2-155d از حساب مشابهی استفاده می کند ، باید منتظر تماس ما باشد. اینکه آیا ما آن تماس را برقرار می کنیم یا خیر هنوز یک سوال دشوار است.

این رویکرد نظری بازی هنوز کاندیدایی را که مسئولیت تماس با ما را دارد مشخص نمی کند. اما کرینز می گوید این به این دلیل است که ستاره های درخشندگی کمتری که به احتمال زیاد میزبان این نامزدها هستند هنوز به خوبی بررسی نشده اند.

البته این با گذشت زمان تغییر خواهد کرد. در واقع ، او محاسبه می کند که کهکشان راه شیری هزاران سیاره فراخورشیدی را هم در منطقه قابل سکونت و هم در منطقه ترانزیتی زمین که می توانند معیارهای تئوری بازی را برای تماس بالقوه داشته باشند ، در خود جای دهد.

البته ، هیچ یک از اینها به معنای وجود تمدن در هر یک از این سیارات فراخورشیدی نیست. فقط اگر این کار را انجام دهند ، بهترین فرصت تماس را دارند.

در حال حاضر ، فقط یک مسئله زمان است که ما یک سیاره فراخورشیدی را پیدا می کنیم که مسئولیت آن با ما است و می توانند با ما تماس بگیرند. تنها کاری که باید انجام دهیم تماشا و انتظار است. البته مگر اینکه آنها همین کار را انجام دهند.

مرجع: قابلیت شناسایی متقابل: یک استراتژی هدفمند SETI که از پارادوکس SETI جلوگیری می کند arxiv.org/abs/2010.04089

بازی انفجار شرطی
سایت انفجار
سایت شرط بندی انفجار
سایت بازی انفجار

سایت انفجار : Cropland vs Climate Change: A Conversation with Wolfgang Busch

بازی بوم شرطی:بازی انفجار

For billions of years, plants and their ancestors, the cyanobacteria, have been powerful agents of change on Earth. They pumped out oxygen and squirreled away carbon dioxide, transforming the chemistry of the biosphere. They colonized land and allowed animal life to follow, changing the course of evolution.

Now molecular biologist Wolfgang Busch wants to recast plants into agents of stability, offsetting the tremendous amount of climate-warming carbon dioxide that humans are pouring into the environment. As part of the Harnessing Plants Initiative at the Salk Institute in La Jolla, California, Busch is working on a bold scheme to modify major crop plants so that they grow deeper, bigger root systems, leaving those carbon-rich roots embedded in the soil after harvest time. While we humans get to work cutting back on our carbon emissions, the plants will be busily lending a hand.

A fundamental challenge with this idea is that the shallow roots of crops normally rot and release much of their carbon over the course of the year. The Harnessing Plants team, under the direction of Joanne Chory, has come up with a clever solution. The researchers are modifying plants so that they produce suberin (the primary ingredient in cork) in their roots. Suberin stubbornly resists decomposition, so the roots masses of these “Salk Ideal Plants” could remain in the soil for an extremely long time without sending their carbon back into the air.

Many different parts of the plan have to come together just right for the Harnessing Plants Initiative to work. The plants have to bury carbon efficiently and effectively. The modified crops have to provide all the same seed yield as before. Farmers need to embrace these crops on a global scale. And the rest of the world still needs to keep working on cutting carbon emissions, since plants alone won’t save our bacon.

On the other hand, the humongous scale of agriculture provides a unique opportunity for large-scale decarbonization. Busch and his colleagues are therefore plowing full-speed ahead (with some COVID speed bumps along the way) to see whether carbon-sequestering corn and wheat can help us turn down the heat from climate change while also recharging the planet’s carbon-depleted soils. An edited version of my conversation with Busch follows.

What drew you to the idea of using plants as a way of burying carbon dioxide in the ground?

I’ve been conducting research on the genetic and molecular basis of root growth since a long time. I started my own lab almost 10 years ago in Vienna. Then I moved three and a half years ago to the Salk Institute. My main interest has long been the factors in plant genes that determine whether roots grow deep or shallow, and how they respond to the environment.

Just around the time when I was negotiating with the institute, Elizabeth Blackburn [Salk’s president at the time] asked the faculty, “What’s the most important question that you’d like to address with your fundamental research?” The plant faculty group came up with an answer after considering: Plants are very good at catching carbon, so they thought about how to make this ability useful for addressing climate change. Which they thought, and I thought, was the world’s most pressing problem.

And that fit in with the work you were already doing?

It was a very good coincidence. The main effort at Salk [the Harnessing Plants Initiative] is related to the root system. We’re trying to put more carbon in the root system, to make it deeper with more root mass, and to produce molecules such as suberin that keep the carbon longer in the soil. It fits very well my interests. I have been worried about climate
change since I was in middle school. The Harnessing Plants Initiative gives us all the opportunity to merge our research expertise with what we consider the most pressing problem.

Lots of people talk about planting trees, but this is the first I’ve heard of using crops to fight climate change. Where did the idea come from?

We had an evolving thought process. At first, we thought about using plants to sequester carbon on marginal lands, and we focused on the things that can grow that can grow on those marginal lands. We would do a good thing for the soil there, and for carbon sequestration.

But soon we realized that it’s all about acreage. Focusing on [small amounts of] marginal land, we’d have only a small potential to increase its ability to sequester carbon. Plus, every plant species is different in its lifestyle, and if you have to work with the genetics of many different a species, it’s a lot of effort.

Then it became obvious that we should be focusing on crops, because there are only a handful of species that populate a vast area. There’s more than 600 million hectares worldwide for the four most prevalent crops. There’s also an existing distribution system. You already have people planting and updated seeds every year. You already have a system of incentives that are market-driven, but also government-driven, like crop insurance.

Each year, human activity releases 18 gigatons more carbon dioxide than the Earth can absorb. Enhanced plants could take up some of that excess. (Credit: Salk/HPI)

Human activity releases 18 gigatons more carbon dioxide than the Earth can absorb. Enhanced plants could take up some of that excess. (Credit: Salk/HPI)

With all of that acreage to work with, how much could re-engineered crops do to offset human carbon emissions?

We did a back of the envelope calculation. Taking into account published biomass data and the acreage of the planted crops, how much biomass do they yield above ground? Taking into account root to mass fractions, how much of the plant is root and how much is shoot?

We ran these numbers on five target crops that we think we can deal with: corn, soy, wheat, rice, canola. We considered that at some point in the future, 70 percent of the target crops could be enhanced for carbon-sequestration traits. Then we asked, what would happen if we could stabilize 30 percent of the biomass in the root mass?

If you run the numbers, you end up with 5.5 gigatons of CO2 [per year], which is roughly 30 percent of the annual surplus [anthropogenic emissions] that is leaked in the atmosphere. I have to say, this is just a very rough calculation, but it showed us that if we could make plants better, it would have a global impact. Even if only 10 percent of the biomass is stabilized, you have 1.8 gigatons [of CO2 sequestered].

Essentially, it looked like we could offset 10 percent to 30 percent of the surplus of CO2 that is currently emitted in the atmosphere each year. So, that was to us encouraging.

Those are huge numbers, but to get there you’d also have to make a huge change in the crops we grow. What are the steps to make that happen?

That, basically, is the question driving us. We and others have to do much more research to know how much can we actually sequester. There are so many unknowns. We need to know the residence time of carbon [how long it stays buried]. Soil chemistry and local microbiomes will play a role.

We know that the [plant root] traits that we are working on can make a difference, but we want to get to more quantitative models. We’ve started field research — collaborations
with soil scientists, soil biochemists, soil geochemists — to systematically study these questions. Time is short, so we are developing our [engineered plant] traits and coming up with a better quantification at the same time.

This month we are starting two field trials. We wanted to have more, but COVID makes it really hard. Next year we want to have 10 field sites, and then 15, maybe more, depending on whether we can get additional funding. We will be planting our first plants in a couple weeks. One of our field trials will be located in Yuma, Arizona; one will close to the Central Valley in California. Those are with commercial partner field sites. In the long term, we want to work with a couple of universities on this.

Plants absorb CO2 as they grow, then release it as they decompose. Engineered "ideal" plants would store carbon for many decades in deep roots. (Credit: Salk/HPI)

Plants absorb CO2 as they grow, then release it as they decompose. Engineered “ideal” plants would store carbon for many decades in deep roots. (Credit: Salk/HPI)

What about the central issue of how long the carbon stays buried? Can cropland hold the carbon in place long enough to be useful?

So, we know from the literature that deeper rooting leads to slow decomposition rates. And suberin or potentially other stable compounds go into long-lived carbon pools, which can have interactions with the soil minerals. These pools are considered to be stable from decades to centuries.

Centuries! I had no idea.

The root depth and the root depth distribution are important factors in how much carbon you can put into the long-lived carbon fractions in the soil, including suberin. We know it will be dependent on soil chemistry. The quantities and the residence time [of the buried carbon] will very much depend on these variables. That’s why we need to get the experiments going, to be able to quantify these things better.

Right, I was also wondering about total quantity of carbon that farmland can absorb. Can you keep burying more carbon there, year after year?

One fundamental consideration is that the soil carbon content has been reduced dramatically over the past century in industrialized, monoculture agriculture. We know there’s a huge potential, because if the soil carbon was there before, we can at least replenish it. I can’t give you a specific number until we do more modeling. But there is definitely many years of potential carbon sequestration that can happen.

How far along are you in developing and testing the engineered, deep-root plants you would need for agricultural carbon sequestration?

In the first year [of field experiments], we are not planting any genetically changed plants. We are basically taking crops that we know and quantifying different properties of rooting under field conditions. We estimate that our first [suberin-enhanced] test lines will hit the field site next year. The bulk of our studies of the potential of our changes will come in three years, say.

Have you done studies yet to make sure that suberin-enhanced crops are just as good as the ones the farmers are planting now — similar in yield, quality and so

That’s a very important and interesting question. What we are currently trying to do is to have a first pass at answering these questions with the help of our collaboration partners. We are looking to see whether there are trade-offs.

A trade-off that one would be worried about would be the root mass to yield allocation [with the increase in root mass coming at the cost of the harvest]. I think there is ample evidence from the literature that it’s not a fixed trade-off. We’re going to try a lot of different strains. We’re going to evaluate the genetic recipe to store more carbon in the roots, and at the same time we will also measure the yield.

Despite COVID, we just finished the construction of a 10,000-square-foot greenhouse that will allow us to grow the crops we are interested in — corn, soy, wheat, rice, canola — in field-like conditions. Not true field condition, but field-like.

Wolfgang Busch (right) with his postdoc Takehiko Ogura, examining one of his green test subjects. (Credit: Salk Institute)

Wolfgang Busch (right) with his postdoc Takehiko Ogura, examining one of his green test subjects. (Credit: Salk Institute)

Let’s be optimistic and assume the experiments go well. How do you get farmers planting carbon-sequestering crops on the scales needed to have a meaningful impact?

We have started talking to many different agribusiness companies. We are all active scientists in the [Harnessing Plants] initiative. We get invited to talk a lot, we go to a lot of conferences. Most of the companies in this space are very aware of our activities. Some of them have expressed interest in talking more about the specific issues that are important to them.

We know we won’t get the scale we need without partnering with big seed companies and big ag [agribusiness]. Without seed companies that will allow us to distribute seeds to the farmers, and without the farmers who are interested, this project will never fly. We’re also talking to NGOs [non-governmental organizations], because some crops and some parts of the world are not dominated by the big ag companies. We’re trying to spread the word so that NGOs and companies come to us, but we are also talking to as many of them as we can, to see if we can get together.

In the future, there might be market incentives when it comes to things like carbon credits or other ways that governments might reimburse farmers to store carbon in the soil. We’re
exploring all this, because this is more than just a science project. We really want this to succeed.

What about the consumer side? I’m picturing a future in which some customers might seek out products that have a stamp that says “this was made with greenhouse-fighting crops” or something like that.

That would be wonderful if it could be a consumer choice. We are thinking about this, too.
We have this term, the “Salk ideal plant.” It would be wonderful if that would be a label that consumers at some point could say, “Okay, I’m going to make this choice.”

How does the Harnessing Planet Initiative fit in with related concepts, like using partially burned plants (biochar) to increase the carbon content of soils? Are these
potentially synergistic approaches?

Absolutely. Just before the COVID lockdown in California, we had a conference called Plant
Carbon Drawdown 2020 at Salk. We wanted to bring together scientists who think about all these different solutions for sequestering carbon, like biochar, enhanced rock weathering, forestry, and enhanced carbon absorption in the oceans and in wetlands.

A lot of these approaches could be important. We just come at the issue from a genetics
perspective because genetics has revolutionized agriculture multiple times. There’s a huge potential to make a global impact by changing plants in a manner that’s beneficial for humans. But then, everything else, like no-till agriculture [allowing more organic material
to stay in the ground], and supplementing soils with different materials, is also wonderful. The more approaches, the better.

Who is supporting this type of research? Do you get any state or federal funding?

Not yet. We’re reaching out to funding agencies to see if that would fit in. The [government] funding is not currently structured in a way that you could say, “Oh, we want to do carbon sequestration using plants.” We’re pretty much ahead of the curve. But we’re hoping that by providing data and evidence that we can actually do it, we make it possible for the federal government to spend money on this, and to allow other groups to work on this.

We were lucky to get Audacious funding [funded by the TED nonprofit] last year: a large grant to do what we think we have to do, and to show others that there is a potential. Part of where I see us as hopefully having a big impact is to show not only scientists, but also potential funding agencies and the government that there’s something else [for agricultural funding] beyond crop yield and stress resilience. That we should, as a society, put money into this because it’s really important, and also realistic.

Your idea to remake agricultural crops around the globe is, as you say, rather far ahead of the curve. What are the obstacles you’re most concerned about?

I think the main unknown is, if we change the crop plants, will there be a trade-off? Will there be something that a farmer will not like about it? Until we have the data, we don’t know. But we know that we don’t need to change the traits radically. Even a small improvement would help. We think that there’s not a lot of question that we can make a large impact just by making roots deeper and having more suberin in them. So, we are optimistic about that.

Another unknown is whether governments will be convinced that addressing climate change is something important. Will they take real action on changing the incentives in our systems to make a positive impact?

Personally, I hope there will be an incentive system for storing carbon in the soil, and good protocols for quantifying this. It really depends on governments all around the planet. There are already a lot of incentives given to farmers in the big agricultural regions; it’s just a shift in the type of incentives. Countries could say, “We don’t really care about providing incentives for drawing down carbon.” That’s a risk. On the other hand, I’m hopeful, because it seems that governments are more and more willing to think about this.

Clearly you wouldn’t be devoting your energy to a project like this if you weren’t fundamentally hopeful the world will step up and address climate change.

Yeah. We are all really enthusiastic and motivated here! I’m thrilled to be doing this every day.

For more science news and ideas, follow me on Twitter: @coreyspowell

بازی انفجار شرطی
سایت انفجار
سایت شرط بندی انفجار
سایت بازی انفجار

بازی انفجار : نظریه عجیب Coronavirus از فضا

سایت بازی انفجار,بازی, انفجار

نظریه های غیرمعمول زیادی در مورد منشأ SARS-CoV-2 ، ویروس مسئول COVID-19 وجود دارد. از ادعا ها مبنی بر اینکه ویروس یک بیوجاون است ، به این عقیده که انتقال 5G در پشت همه گیر است ، هیچ کمبودی در ایده های باورنکردنی وجود ندارد.

اما یک نظریه COVID-19 چنان چشمگیر است که باعث می شود دیگران با مقایسه خسته کننده به نظر برسند: پیشنهادی که تاج ویروس از فضا آمده است.

در این پست ، من درباره این ایده شگفت انگیز و تاریخ به همان اندازه عجیب و غریب آن بحث خواهم کرد.

تئوری ویروس فضایی کار گروهی از محققان است ، به ویژه ادوارد جی استیل و ن. چاندرا ویکرامایزه. این گروه از زمان شروع همه گیری ، ده مقاله در این زمینه منتشر کرده است ، اما این مقاله از 14 ژوئیه استدلال دقیق ترین ارائه می دهد.

استیل و همکاران. پیشنهاد می کند COVID-19 در 11 اکتبر سال 2019 به شهاب سنگی رسید که به عنوان یک آتش نشانی روشن بر فراز شهر سونگیان در شمال شرقی چین مشاهده شد.

آنها پیشنهاد می کنند که شهاب سنگ ممکن بوده است "یک شهاب سنگ شکننده و سست نگهدارنده و دارای یک محموله از تریلیون ها ویروس / باکتری و سایر سلولهای منبع اصلی."

نویسندگان اعتراف می کنند که شهاب سنگیونگ در بیش از 2 هزار کیلومتری شمال شرقی ووهان واقع شده است ، جایی که اولین موارد COVID-19 گزارش شده است ، اما آنها با این فرضیه برخورد می کنند با این فرضیه که قطعه متفاوتی از شهاب وارد منطقه ووهان می شود:

یک شهاب سنگ اصلی بسیار بزرگتر به راحتی می توانست قبل از احتراق این رویداد آتشنشانی ، قطعات آن را پراکنده و پراکنده کند. یک فرض معقول این است که آتش بس که 2،000 کیلومتری شمال ووهان را لرزاند ، ممکن است بخشی از لوله گسترده ای از زباله ها باشد که بخش عمده ای از آن در استراتوسفر سپرده شده است تا بر فراز ووهان بیفتد.

نیازی به گفتن نیست ، این تئوری نیست که هیچ مدرکی برای آن وجود دارد. هیچ مدرکی مبنی بر وجود ویروس یا باکتری (یا زندگی دیگر) در فضا وجود ندارد و استیل و همکاران. هیچ مدرک مستقیمی مبنی بر ورود coronavirus از آسمانها ارائه نکنید.

اما معلوم می شود که تئوری زندگی (و بیماری) از فضا چیز جدیدی نیست. این تئوری نامیده می شود لوزالمعده و تعداد معدودی از محققان ، از جمله استیل و ویکراماشینگ ، چندین دهه است که از آن حمایت می کنند.

Panspermia ، به طور کلی ، این ایده است که زندگی از فضا به زمین رسیده است ، و همچنان ادامه دارد. این ایده به کلیه یونانیان باستان برمی گردد ، اما به شکل مدرن آن به دهه 1970 و کار دو اخترشناس ، فرد هویل (1915-2001) و چاندرا ویکرامایزینگ برمی گردد.

هویل یک ستاره شناس مشهور بود که در طول حرفه خود مشاجرات زیادی را به دنبال داشت. وی شاید بیشتر به خاطر آمدن اصطلاح "بیگ بنگ" شناخته شود - اگرچه برخلاف اکثریت قریب به اتفاق همکارانش ، وی هرگز اعتبار نظریه بیگ بنگ را نپذیرفت. Wickramasinghe دانشجوی دکترای هویل بود.

در حالی که آنها داستان را بیان می کنند ، هویل و ویکرامینشینه در حالی که سعی در توضیح چگونگی جذب غبار بین ستاره ای داشتند ، از پانسرمیا تصور کردند. آنها متوجه شدند که اگر گرد و غبار از باکتریها تشکیل شده باشد ، این الگوی مشاهده شده از جذب نور را تولید می کند.

Hoyle و Wickramasinghe سرانجام به ایده کهکشان کاملاً پر از میکروارگانیسم ها ، موجود در دنباله دارها و شهاب سنگها و همچنین ابرهای گرد و غبار رسیدند.

panspermia - http://cosmology.com/Panspermia4.html

نمودار "حلقه تقویت کننده برای میکروارگانیسم های اولیه در کهکشان". (اعتبار: Napier & Wickramasinghe 2010 مجله کیهان شناسی)

در حالی که موجودات موجود در فضا عمیق به تنهایی نمی توانند زنده باشند ، هویل و ویکرامایز معتقد بودند که میکروارگانیسم های فضایی می توانند در صورت ورود به یک سیاره مناسب ، مانند زمین - دوباره فعال شوند و احتمالاً موجودات بومی را نیز آلوده کنند.

Hoyle و Wickramasinghe در سال 1979 بازگرداندن عنوان "بیماری هایی از فضا" به عنوان عنوان یکی از کتاب های خود نوشتند. آنها در ادامه به دنبال منشا بین سیاره ای برای چندین شیوع بیماری ، از جمله SARS اصلی در سال 2003 و آنفولانزا بودند.

من فکر می کنم کهکشان کهکشانی با زندگی جذاب است. من آن را باور نمی کنم ، و panspermia توسط اکثر دانشمندان رد می شود ، اما مطمئناً یک ایده جسورانه و خلاق بود. ممکن است واقعیت نداشته باشد ، اما در بدترین حالت ، این علمی تخیلی خوب است.

با این حال ، تلاشهای اخیر برای توضیح COVID-19 به عنوان ناشی از فضا ، جالب توجه و خطرناک به نظر می رسد.

COVID از فضا یک فرضیه جالب نیست. این تئوری به وضوح فقط تلاشی برای متناسب کردن COVID-19 در مدل panspermia موجود است - هیچ چیز جدید یا خلاق در مورد آن وجود ندارد.

صادقانه بگویم، حتی اگر شما به panspermia اعتقاد دارید ، من نمی توانم ببینم چرا فکر می کنید COVID-19 از فضا آمده است. ویروس SARS-CoV-2 برخی از عوامل بیماری زای عجیب و غریب نیست. این بسیار شبیه به اولین ویروس SARS ، و با coronaviruses های مختلف پستانداران ، به ویژه ویروس های خفاش است. بنابراین حتی اگر شما به ویروس های فضایی اعتقاد دارید ، این ویروس است که به وضوح منشاء زمین دارد.

COVID- از فضا نیز یک فرضیه خطرناک است. استیل ، Wickramasinghe و همکاران. گفته اند كه COVID-19 از فرد به شخص دیگر مسری نیست (یا فقط بندرت). براساس این عقیده ، آنها (در ماه فوریه) پیشنهاد کردند كه COVID-19 عمدتاً چین را تحت تأثیر قرار دهد و هنگامی كه گرد و غبار پراکنده شود ، از بین می رود. آنها همچنین نوشتند که هیچ نکته ای برای جستجوی واکسن وجود ندارد:

بنابراین ، ایجاد واکسن به نام "COVID-19" که در زمان نوشتن اخبار بسیار زیاد است ، می تواند هدر رفته از بودجه پرداخت کننده مالیات عمومی باشد ، اگر در مقیاس پیش بینی شده توسط دولت ها و مراکز ملی کنترل بیماری انجام شود.

واضح است که اگر کسی این ایده را جدی گرفت ، برای سلامتی عمومی بسیار خطرناک خواهد بود. خوشبختانه ، فکر نمی کنم کسی چنین کند.

با این حال ، من می گویم که نظریه coronavirus-from-space هنوز قابل باورتر از برخی دیگر از تئوری های COVID-19 است. به عنوان مثال ، باور اینکه کرونا ویروس در اثر انتقال 5G ایجاد می شود ، حتی علمی کمتر از اعتقاد ورود به یک شهاب سنگ باعث می شود. یک شهاب سنگ میتوانستاز نظر تئوری ، ویروس را حمل می کنید ، اما امواج رادیویی نمی توانند.

بازی انفجار شرطی
بهترین سایت بازی انفجار
بازی انفجار