When wind blows over the snow of Antarctica's Ross Ice Shelf, the surface vibrates and produces a beautiful and eery drone. Colorado State University researchers deployed seismometers to explore the subsurface of the ice shelf and were surprised to learn that their sensors recorded the natural song of the terrain. The frequencies are below the threshold of human hearing and are sped up for audibility in the video above. From the scientific paper:
Ice shelves are the floating buttresses of large glaciers that extend over the oceans and play a key role in restraining inland glaciers as they flow to the sea. Deploying sensitive
seismographs across Earth’s largest ice shelf (the Ross Ice Shelf) for 2 years, we discovered that the shelf
nearly continuously sings at frequencies of five or more cycles per second, excited by local and regional
winds blowing across its snow dune-like topography. We find that the frequencies and other features of
this singing change, both as storms alter the snow dunes and during a (January 2016) warming event
that resulted in melting in the ice shelf’s near surface. These observations demonstrate that seismological
monitoring can be used to continually monitor the near-surface conditions of an ice shelf and other icy
bodies to depths of several meters.
More at Colorado State University News.
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Stephen Hawking's final book, Brief Answers to the Big Questions, was released posthumously Tuesday by his children. Read the rest
According to the explanation of the phrase "like a moth to the flame" at The Phrase Finder, "the word moth was used the the 17th century to mean someone who was apt to be tempted by something that would lead to their downfall." But why do moths have this fatal attraction anyway? National Geographic explains in the above video:
The theory is that these primarily nocturnal insects have evolved to travel by the light of the moon and stars. This way of travel is called transverse orientation. An easy way to think about transverse orientation is to imagine a sailor travelling in the direction of the North Star. In theory, moths similarly follow the light source at a precise position and a precise angle to their bodies. This is how moths would navigate for millions of years … by the light of the moon. What moth evolution couldn’t account for was the proliferation of constant electric light in our modern world. When Thomas Edison patented the lightbulb on January 27, 1880 it was a bad day in moth history. These lightbulbs began to act as artificial moons, confusing moths and overwhelming their senses. Since moths are accustomed to orienting to distant light sources, they can be easily disoriented when a closer light source, like a porch lamp, comes into view.
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Avogadro's Number is 6.022140857 × 1023. That's how many atoms are in 12 grams of carbon-12. One mole of anything has one Avogadro's Number of elementary particles in it. In this video, the Action Lab Man repeats the words "Avogadro's Number," quadrupling the audio track each time until he reaches 6.022140857 × 1023. Each time he utters the words, he includes an interesting fact about the in-progress number. For example 256 is the "Unplayable/unbeatable level in Pac-Man due to an 8-bit integer overflow." And 68,719,476,736 is the "Number of animals eaten by humans each year."
He ends the video by describing what would happen if you gathered together a mole of moles, as found in Randall Munroe's great book, What If? Serious Scientific Answers to Absurd Hypothetical Questions. Read the rest
Stephen Hawking's final paper that he and his colleagues completed just days before his death has now been published. It's titled "Black Hole Entropy and Soft Hair," co-authored with Sasha Haco, Malcolm J. Perry, and Andrew Strominger, about the black hole information paradox. Here is the abstract:
A set of infinitesimal VirasoroL⊗VirasoroR diffeomorphisms are presented which act non-trivially on the horizon of a generic Kerr black hole with spin J. The covariant phase space formalism provides a formula for the Virasoro charges as surface integrals on the horizon. Integrability and associativity of the charge algebra are shown to require the inclusion of `Wald-Zoupas' counterterms. A counterterm satisfying the known consistency requirement is constructed and yields central charges cL=cR=12J. Assuming the existence of a quantum Hilbert space on which these charges generate the symmetries, as well as the applicability of the Cardy formula, the central charges reproduce the macroscopic area-entropy law for generic Kerr black holes.
The Guardian has a translation:
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In the latest paper, Hawking and his colleagues show how some information (contained in an object that falls into a black hole) at least may be preserved. Toss an object into a black hole and the black hole’s temperature ought to change. So too will a property called entropy, a measure of an object’s internal disorder, which rises the hotter it gets.
The physicists, including Sasha Haco at Cambridge and Andrew Strominger at Harvard, show that a black hole’s entropy may be recorded by photons that surround the black hole’s event horizon, the point at which light cannot escape the intense gravitational pull.
Caltech researchers developed the illusion above to illustrate postdiction, a sensory phenomenon "in which a stimulus that occurs later can retroactively affect our perceptions of an earlier event." From Caltech Matters:
"Illusions are a really interesting window into the brain," says first author Noelle Stiles (PhD '15), a visitor in biology and biological engineering and a postdoctoral scholar–research associate at USC. "By investigating illusions, we can study the brain's decision-making process. For example, how does the brain determine reality with information from multiple senses that is at times noisy and conflicting? The brain uses assumptions about the environment to solve this problem. When these assumptions happen to be wrong, illusions can occur as the brain tries to make the best sense of a confusing situation. We can use these illusions to unveil the underlying inferences that the brain makes...."
Postdictive processing has been demonstrated within individual senses, but this work focuses on how the phenomenon can bridge multiple senses. The key to both of the new illusions is that the audio and visual stimuli occur rapidly, in under 200 milliseconds (one-fifth of a second). The brain, trying to make sense of this barrage of information, synthesizes the stimuli from both senses to determine the experience, using postdiction to do so.
Read more in the researchers' scientific paper: "What you saw is what you will hear: Two new illusions with audiovisual postdictive effects" (PLoS ONE)
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Gone, obviously. Tom Scocca:
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Using our advanced technology, it is possible to look up the beaches in the National Oceanic and Atmospheric Administration’s Sea Level Rise Viewer, and to imagine what will happen if we visit them, or try to visit them, in the future—when the sea levels have risen three feet, or six feet, or more, if you want. You can use your pocket phone-computer to watch them move ahead through time below.
Jupiter's frozen moon Europa has a massive ocean below the surface that could potentially harbor life. To find out, NASA is in the early stages of building a robotic lander to explore the moon in the mid-2020s. Now though, Cardiff University researcher Daniel Hobley and colleagues suggest that touching down on Europa could be tricky due to fields of massive ice spikes jutting up as high as 50 feet. From Science
Such spikes are created on Earth in the frigid tropical peaks of the Andes Mountains, where they are called “penitentes,” for their resemblance to devout white-clad monks. First described by Charles Darwin, penitentes are sculpted by the sun in frozen regions that experience no melt; instead, the fixed patterns of light cause the ice to directly vaporize, amplifying minute surface variations that result in small hills and shadowed hollows. These dark hollows absorb more sunlight than the bright peaks around them, vaporizing down further in a feedback loop.
From the research paper in the scientific journal Nature:
We estimate that penitentes on Europa could reach 15 m in depth with a spacing of 7.5 m near the equator, on average, if they were to have developed across the interval permitted by Europa’s mean surface age. Although available images of Europa have insufficient resolution to detect surface roughness at the multi-metre scale, radar and thermal data are consistent with our interpretation. We suggest that penitentes could pose a hazard to a future lander on Europa.
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Very quickly. Before it, and you, freeze.
On Cyprien Verseux's Twitter account, wonderful snapshots of fun with food on the bleak, frozen ice sheets of Antarctica. Read the rest
NASA's Voyager 2 space probe, launched in 1977 on a grand tour of the solar system, may be nearing interstellar space. Carrying a message for extraterrestrials, the iconic Golden Record, the Voyager 2 is now about 11 billion miles (about 17.7 billion kilometers) from Earth and still sends data back daily from its various sensors. Most recently, it has detected an increase in higher-energy cosmic rays that originate outside our solar system. This increase in the rate of cosmic rays indicates that the Voyager 2 may soon break through the heliosphere, the "bubble" of charged particles generated by our sun, and cross into interstellar space. Voyager 1 entered interstellar space in 2012.
From the Jet Propulsion Laboratory:
The fact that Voyager 2 may be approaching the heliopause six years after Voyager 1 is also relevant, because the heliopause moves inward and outward during the Sun's 11-year activity cycle. Solar activity refers to emissions from the Sun, including solar flares and eruptions of material called coronal mass ejections. During the 11-year solar cycle, the Sun reaches both a maximum and a minimum level of activity.
"We're seeing a change in the environment around Voyager 2, there's no doubt about that," said Voyager Project Scientist Ed Stone, based at Caltech in Pasadena. "We're going to learn a lot in the coming months, but we still don't know when we'll reach the heliopause. We're not there yet -- that's one thing I can say with confidence."
In a decade or so, Voyager 1 and 2 will run out of power and go silent. Read the rest
The UN's International Panel on Climate Change is an interdisciplinary expert body comprised of leading scientists who study climate change; they issue periodic reports summarizing the best peer-reviewed science on climate change and making recommendations as to what must be done to avert the most catastrophic outcomes; their latest report is the gravest yet, where even the most optimistic projections of the panel predict disruption and hardship for tens of millions of people, within our lifetimes.
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Now seems like a fine time to read this Scientific American article titled The Art of Lying by Theodor Schaarschmidt. According to a study conducted by UC Santa Barbara psychologist Bella M. DePaulo and referenced in the article, people make up around two stories every day. Apparently, children "initially have difficulty formulating believable lies, but proficiency improves with age. Young adults between 18 and 29 do it best. After about the age of 45, we begin to lose this ability." From Scientific American:
Current thinking about the psychological processes involved in deception holds that people typically tell the truth more easily than they tell a lie and that lying requires far more cognitive resources. First, we must become aware of the truth; then we have to invent a plausible scenario that is consistent and does not contradict the observable facts. At the same time, we must suppress the truth so that we do not spill the beans—that is, we must engage in response inhibition. What is more, we must be able to assess accurately the reactions of the listener so that, if necessary, we can deftly produce adaptations to our original story line. And there is the ethical dimension, whereby we have to make a conscious decision to transgress a social norm. All this deciding and self-control implies that lying is managed by the prefrontal cortex—the region at the front of the brain responsible for executive control, which includes such processes as planning and regulating emotions and behavior.
"The Art of Lying" (Scientific American)
image: screenshot of Pinocchio film trailer, public domain
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If you are a woman who struggles with the pain of recurring urinary tract infections, a new study suggests that drinking more water could help. Read the rest
Based on a new study of the safety and abuse potential of psilocybin, the hallucinogenic drug in magic mushrooms, Johns Hopkins University School of Medicine researchers recommend that "psilocybin should be re-categorized from a schedule I drug—one with no known medical potential—to a schedule IV drug such as prescription sleep aids, but with tighter control."
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In 1960, my friend Frank Drake launched Project Ozma, the first modern scientific search for extraterrestrial intelligence (SETI). Frank used the National Radio Astronomy Observatory (image above) in Green Bank, West Virginia to listen for interstellar radio transmissions that might be a signature of ETs. Nearly 60 years and countless scans later, we still haven't heard anything. Why? Space is big. Massive. In a 2010 paper, the SETI Institute's Jill Tarter and her colleagues described their ongoing calculations of a “cosmic haystack" where we're searching for an extraterrestrial needle.
"If you build a mathematical model, the amount of searching that we've done in 50 years (as of 2008) is equivalent to scooping one 8-ounce glass out of the Earth's ocean, looking and seeing if you caught a fish," Tarter told NPR. "No, no fish in that glass? Well, I don't think you're going to conclude that there are no fish in the ocean. You just haven't searched very well yet. That's where we are."
Now, Penn State astronomer Jason Wright and colleagues have refined the "cosmic haystack" model to include additional factors involving likely frequencies and bandwidth along with the latest large SETI searches. Even still, they "conclude that the fraction of it searched to date is also very small: similar to the ratio of the volume of a large hot tub or small swimming pool to that of the Earth's ocean."
From Science News:
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Converting the volume to liters for the sake of analogy, the researchers concluded that SETI has covered the equivalent of 7,700 liters out of 1.335 billion trillion liters of water in Earth’s oceans.
In the late 19th century, artist/astronomer Étienne Léopold Trouvelot (1827-1895) painted thousands of stunning works illustrating the beauty and science of the known planets, comets, and celestial phenomena. The Huntington Library near Los Angeles holds 15 of Trouvelot's chromolithographs that were published in 1882 in two portfolios, the Trouvelot Astronomical Drawings:
Initially, the Astronomical Drawings portfolios were sold to astronomy libraries and observatories as reference tools, but as early 20th-century advances in photographic technology allowed for more accurate and detailed depictions of the stars, planets, and phenomena, Trouvelot’s prints were discarded or sold to collectors.
Radiant Beauty: E. L. Trouvelot’s Astronomical Drawings (The Huntington)
See more at Graphicine: "ETIENNE TROUVELOT – ASTRONOMICAL DRAWINGS" (Thanks Anotherone!)
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Last week, the Japanese Aerospace Exploration Agency landed two tiny rovers on the asteroid Ryugu where they'll "hop" across the rock as part of a mission to collect samples that the Hayabusa2 mothership will return to Earth. Here are new images from the asteroid that's 289 million kilometers (180 million miles) away from Earth. Far fucking out.
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