New calculations suggest that, around 400 million years ago, many coastlines experienced two-week tidal cycles that varied in height by four metres or more. Such a huge range could have stranded fish in tidal pools for a couple of weeks. Only the ones with fins strong enough to muscle themselves out would have been able to journey back into the ocean and survive. Fossil evidence for the earliest known land vertebrates comes from places that had such wide tidal ranges...More information at Nature.
Hundreds of millions of years ago, the Moon was much closer to Earth than it is now. Steven Balbus, an astrophysicist at the University of Oxford, UK, has explored how the Moon’s proximity to Earth might have affected its gravitational pull and influenced life on the planet. In 2014, he suggested that Earth’s tidal ranges would have been greater around the time the first four-limbed vertebrates, or tetrapods, appeared on land...
Showing posts with label science. Show all posts
Showing posts with label science. Show all posts
Ocean tides as evolutionary triggers
"Mother lode of pterosaur eggs"
As reported by the Washington Post:
... a site in China’s Turpan-Hami Basin in Xinjiang has coughed up 215 beautiful, pliable and miraculously three-dimensional eggs — 16 of which contain embryonic remains. The researchers also suspect there could be as many as 300 more eggs within the same sandstone block...Illustration by Zhao Chuang. More about pterosaurs at Wikipedia. And by the way...
What’s more, the egg treasure trove also boasts skeletons from what appear to be hatchlings, juveniles and adults... Pterosaurs ran the gamut from the gigantic, aircraftlike Quetzalcoatlus all the way down to animals about the size of a sparrow, such as Nemicolopterus. Some had the long, pointy snouts we typically associate with the flying reptiles. Others boasted wild and crazy crests...
TYWKIWDBI continues to support Wikimedia/Wikipedia every year and encourages you to do so as well.
The problem with the Nobel prizes
Every year, when Nobel Prizes are awarded in physics, chemistry, and physiology or medicine, critics note that they are an absurd and anachronistic way of recognizing scientists for their work. Instead of honoring science, they distort its nature, rewrite its history, and overlook many of its important contributors...More at The Atlantic. If I am awarded a Nobel prize, I'll share the money with my coauthors and fellows and lab techs...
The wider problem, beyond who should have received the prize and who should not, is that the Nobels reward individuals—three at most, for each of the scientific prizes, in any given year... The paper in which the LIGO team announced their discovery has an author list that runs to three pages. Another recent paper, which precisely estimated the mass of the elusive Higgs boson, has 5,154 authors.
Maybe it should be called "tempafrost"
Excerpts from an article at the New York Times:
Starting just a few feet below the surface and extending tens or even hundreds of feet down, it contains vast amounts of carbon in organic matter — plants that took carbon dioxide from the atmosphere centuries ago, died and froze before they could decompose. Worldwide, permafrost is thought to contain about twice as much carbon as is currently in the atmosphere...
In Alaska, nowhere is permafrost more vulnerable than here, 350 miles south of the Arctic Circle, in a vast, largely treeless landscape formed from sediment brought down by two of the state’s biggest rivers, the Yukon and the Kuskokwim. Temperatures three feet down into the frozen ground are less than half a degree below freezing. This area could lose much of its permafrost by midcentury...“There’s a massive amount of carbon that’s in the ground, that’s built up slowly over thousands and thousands of years,” he said.“It’s been in a freezer, and that freezer is now turning into a refrigerator.”
More at the link.
Percentage eclipse
We're looking forward to an 85% eclipse. We won't get to experience the rush Annie Dillard describes, but it still should be awesome.
Image via.
A detailed discussion of p values
An article in Vox will be of interest primarily to readers who have had a manuscript rejected (or have reviewed and rejected one) because a crucial p value was >0.05
Addendum: see also this article in FiveThirtyEight: "Statisticians Found One Thing They Can Agree On: It’s Time To Stop Misusing P-Values."Most casual readers of scientific research know that for results to be declared “statistically significant,” they need to pass a simple test. The answer to this test is called a p-value. And if your p-value is less than .05 — bingo, you got yourself a statistically significant result.Now a group of 72 prominent statisticians, psychologists, economists, sociologists, political scientists, biomedical researchers, and others want to disrupt the status quo. A forthcoming paper in the journal Nature Human Behavior argues that results should only be deemed “statistically significant” if they pass a higher threshold.“We propose a change to P< 0.005,” the authors write. “This simple step would immediately improve the reproducibility of scientific research in many fields.”...The proposal has critics. One of them is Daniel Lakens, a psychologist at Eindhoven University of Technology in the Netherlands who is currently organizing a rebuttal paper with dozens of authors. Mainly, he says the significance proposal might work to stifle scientific progress.
How many statisticians does it take to ensure at least a 50 percent chance of a disagreement about p-values? According to a tongue-in-cheek assessment by statistician George Cobb of Mount Holyoke College, the answer is two … or one. So it’s no surprise that when the American Statistical Association gathered 26 experts to develop a consensus statement on statistical significance and p-values, the discussion quickly became heated.Continued at the link.
It may sound crazy to get indignant over a scientific term that few lay people have even heard of, but the consequences matter. The misuse of the p-value can drive bad science (there was no disagreement over that), and the consensus project was spurred by a growing worry that in some scientific fields, p-values have become a litmus test for deciding which studies are worthy of publication. As a result, research that produces p-values that surpass an arbitrary threshold are more likely to be published, while studies with greater or equal scientific importance may remain in the file drawer, unseen by the scientific community.
The results can be devastating...
The Pentagon Will Continue To Tap Some Of Science And Technology's Greatest Minds To Help Innovate U.S. Military Capabilities And Culture,
Astrophysicist Neil deGrasse Tyson interacts with Pepper, a social humanoid robot, during the Clinton Global Initiative's annual meeting in New York, Sept. 28, 2015.
VOA: Top Scientists, Tech Experts to Innovate Military Under Trump Administration
THE PENTAGON — The Pentagon has tapped some of science and technology's greatest minds to help innovate U.S. military capabilities and culture, and members of the panel say they will continue serving in the Trump administration if asked.
Eric Schmidt, the chairman of the board and chairman of Google's parent company, Alphabet, said he expects everyone to stay on to serve under retired General James Mattis, if the board is invited to continue its work.
"No one has told me they are leaving," Schmidt told reporters Monday at the Pentagon after the first board meeting since the presidential election.
Read more ....
WNU Editor: No surprises here. America's top minds have always worked with the military to give them a heads up on emerging technologies (Einstein and the atomic bomb) to today's leaders from Silicon Valley and elsewhere.
CRISPR explained
This is really quite amazing. Those for whom an audio presentation is too linear and TLDR can browse a summary of the contents at this Radiolab page.
- CRISPR is the sort of thing that gets drunk biologists at parties overly excited
- CRISPR is a breakthrough approach to gene therapy that can turn Chihuahua into a Great Dane (and much much more)...
"The world is running out of helium." Not.
The discovery of a previously-unknown helium gas field resulted in a number of stories reminding us how critically low the world's helium reserves are.
For the first time ever, researchers have tracked and located a helium gas field. And the discovery, presented Tuesday during the Goldschmidt geochemistry conference in Japan, could help allay fears about a global helium shortage, which could affect such sectors as medicine and manufacturing...That was the understanding I had had for years. That's why I understood the U.S. maintains its National Helium Reserve. But the claim of a world shortage of the gas is hogwash, according to this report in Wired:
Even though helium is one of the most abundant elements in the universe, there’s concern that it may be running dry here on planet Earth.
Most of the world’s helium comes from natural gas, where it can exist in very small quantities. A good source will be about 3 percent helium, but more often helium hovers between 0.1 percent and 0.5 percent—nothing compared to the relatively astronomical 10 percent pocket found in Tanzania. But worldwide, helium is about a thousand times less lucrative than gas, so even though removing (inert) helium makes the gas burn better, companies don’t usually bother to take it out. “Normally, it’s an afterthought,” says Samuel Burton, assistant field manager at the Federal Helium Program. “It’s something that they don’t even consider because the natural gas makes so much more money for them.”
When helium’s price goes up—like it has for most of the past few years—natural gas companies are incentivized to sell extracted helium on its own. Countries like Qatar mine so much natural gas that even though it has relatively little helium, they can crank out a decent percentage of the world’s demand as an afterthought...
“There is actually so much helium that’s flooding the market that it’s not in short supply at all,” Burton says. And as for the future, “I’ve seen a lot of talk about this global shortage of helium—that’s actually not the case. In the United States, we’ve got at least 20 years of known supplies that are easily, readily available.”
The surface of Europa
Today's Astronomy Picture of the Day, from NASA:
An enhanced-color view, this image covers a 350 by 750 kilometer swath across the surface of Jupiter's tantalizing moon Europa. The close-up combines high-resolution image data with lower resolution color data from observations made in 1998 by the Galileo spacecraft. Smooth ice plains, long fractures, and jumbled blocks of chaos terrain are thought to hide a deep ocean of salty liquid water beneath.
Reflected radiation
I was startled to see this photo of a Hiroshima victim in a book I read recently about the Manhattan Project. The Wikipedia entry on effects of nuclear explosions reads as follows:
Burns visible on a woman in Hiroshima during the blast, darker colors of her kimono at the time of detonation correspond to clearly visible burns on skin touching parts of the garment exposed to thermal radiation. Since kimonos are not form fitting attire, some parts were not directly touching her skin are visible as breaks in the pattern.It took me a moment to realize that the burns in the photo are not radiation burns (which would never be affected by clothing), but thermal ones. Still, it's startling to see the degree to which the color of fabric affects the transmission of heat.
When thermal radiation strikes an object, part will be reflected, part transmitted, and the rest absorbed. The fraction that is absorbed depends on the nature and colour of the material. A thin material may transmit a lot. A light colored object may reflect much of the incident radiation and thus escape damage. The absorbed thermal radiation raises the temperature of the surface and results in scorching, charring, and burning of wood, paper, fabrics, etc. If the material is a poor thermal conductor, the heat is confined to the surface of the material.
Water ice confirmed on the surface of a comet
This apparently isn't unexpected, as this Reddit thread discusses. But it still boggles my own mind, since I spent the first half-dozen decades of my life believing that water in any form would sublimate instantly and could therefore not exist in an object traveling through a vacuum.
And it is water ice, btw, not frozen methane of ammonia.
Are there more stars in the sky of the Southern Hemisphere?
Again I quote from Borges' essay "The Divine Comedy," the content of which was a lecture he gave in Buenos Aires in 1977:
They [Ulysses and his crew] sail and leave behind Ceuta and Seville, enter the open sea, and turn toward the left... Then he tells us, "in the night I saw all the stars of the other hemisphere" - our hemisphere, the Southern, full of stars. (The great Irish poet Yeats speaks of the "starladen sky." That is untrue in the Northern Hemisphere, where there are few stars compared to ours.)I suppose I could search the answer online, but there must be a reader out there who has lived in both hemispheres, or who has a sufficient knowledge of astronomy to answer the question.
Are record-LOW temperatures near Greenland ominous?
Most areas of the globe are experiencing above-average temperatures. So why are scientists especially concerned about an anomalous area of record-LOW temperatures near Greenland?
First of all, it’s no error. I checked with Deke Arndt, chief of the climate monitoring branch at NOAA’s National Centers for Environmental Information, who confirmed what the map above suggests — some parts of the North Atlantic Ocean saw record cold in the past eight months...More at the link and in Wikipedia:
And there’s not much reason to doubt the measurements — the region is very well sampled. “It’s pretty densely populated by buoys, and at least parts of that region are really active shipping lanes, so there’s quite a lot of observations in the area,” Arndt said. “So I think it’s pretty robust analysis.”..
There is strong evidence — not just from our study — that this is a consequence of the long-term decline of the Gulf Stream System, i.e. the Atlantic ocean’s overturning circulation AMOC, in response to global warming.
In 2005, British researchers noticed that the net flow of the northern Gulf Stream had decreased by about 30% since 1957. Coincidentally, scientists at Woods Hole had been measuring the freshening of the North Atlantic as Earth becomes warmer. Their findings suggested that precipitation increases in the high northern latitudes, and polar ice melts as a consequence. By flooding the northern seas with lots of extra fresh water, global warming could, in theory, divert the Gulf Stream waters that usually flow northward, past the British Isles and Norway, and cause them to instead circulate toward the equator. If this were to happen, Europe's climate would be seriously impacted.
The Super Blood Moon Eclipse
Scientific American: Sunday's "Supermoon" Total Lunar Eclipse: When and Where to See It
The evening of September 27 will be the fourth time in the last 17 months that the moon becomes immersed in the Earth's shadow.
On the evening of Sept. 27, the moon will once again become immersed in the Earth's shadow, resulting in a total lunar eclipse─the fourth such event in the last 17 months,
As with all lunar eclipses, the region of visibility for Sunday's blood-moon lunar eclipse will encompass more than half of our planet. Nearly 1 billion people in the Western Hemisphere, nearly 1.5 billion throughout much of Europe and Africa and perhaps another 500 million in western Asia will be able to watch as the Harvest Full Moon becomes a shadow of its former self and morphs into a glowing coppery ball.
WNU Editor: I have been an amateur astronomer since I was a teen .... so I love this stuff. The last time that I saw such an eclipse was in my teenage years .... and the memory of seeing a red moon in the night sky is something that still sticks with me today. If you have a chance to see it please do .... it will be something that you will never forget.
The CIA Invented Cough Syrup
io9: Why the CIA Invented Cough Syrup
Much of the cough syrup on the shelves today owes a little something to the US Navy and the CIA. One of its main effective ingredients was developed by a project funded by both agencies. Learn why.
Dextromethorphan (DM), a major ingredient in many cough syrups, is not entirely uncontroversial. At high doses it can produce hallucinations and get people high. What it doesn’t do is get people pleasantly high. Forums dedicated to drug use include entries like, “Worst thing I’ve done,” and “Terrified of Dying.” That sounds like one of the projects the CIA would engage on during its MKUltra evil phase.
Actually, this drug was developed well before that phase. It was invented, with the support of the Navy, to fix a practical problem. People in the field, or in a war, or stuck on a boat, needed to function even when they were sick. This meant they needed the best medication, and the best medication in the early 1950s was codeine. Anyone with even the slightest acquaintance with codeine knows the problem there. Codeine always makes people high. It also makes them sleepy, and just as a bonus it is physically addictive. Everyone needed an alternative.
WNU Editor: You learn something new everyday.
A shiny spot on the dwarf planet Ceres
Even more impressive on the gif of planetary rotation.
The latest images from Nasa’s Dawn spacecraft reveal a pair of bright spots on Ceres, a 590-mile-wide dwarf planet, with the brightest of the two reflecting at least 40% of the sunlight that falls on it.The Reddit thread discusses this phenomenon and the concept and calculation of albedo. Also interesting that a 590-mile wide planet "holds enough frozen water to fill all the lakes on Earth."
Scientists are unsure what the bright patches are, but given that frozen water makes up at least a quarter of the bulk of Ceres, the odds are high that they are patches of primordial ice.
There are other possibilities though. The bright spots might be the work of volcanic eruptions on Ceres that blast ice out from the body’s interior. Yet another explanation could be the materials that make up the object. Some asteroids shine brightly because of their mineral constituents. Known as enstatite asteroids, they are rich in magnesium silicates, which can reflect nearly half of the light they receive.
Limpet teeth - nature's strongest natural material
"Spider silk is famous for its amazing toughness, and until recently a tensile strength of 1.3 gigapascals (GPa) was enough to earn it the title of strongest natural material. However, researchers report online today in the Journal of the Royal Society Interface that the record books need to be updated to properly recognize the incredible strength of the limpet teeth. Marine snails known as limpets (Patella vulgata) spend most of their lives scraping a set of small teeth along rocks in shallow ocean waters, looking for food. The constant grinding would be enough to quickly reduce most natural materials to nubs, but the limpets’ teeth boast a tensile strength of between 3 and 6.5 GPa..."Microphotograph via the Washington Post, which offers these observations:
The teeth also bested several man-made materials, including Kevlar, a synthetic fiber used to make bulletproof vests and puncture-proof tires. The amount of weight it can withstand, Barber told the BBC, can be compared to a strand of spaghetti used to hold up more than 3,300 pounds, the weight of an adult female hippopotamus.The original publication is here.
Their secret is in the size of their fibers, which are 1/100th the diameter of a human hair. The ultra-thin filaments avoid the holes and defects that plague larger strands — including man-made carbon fibers — meaning any structure they compose is also flawless, regardless of how big it gets.