Category: Top Posts

Lake Michigan Itself Is the Greatest Asian Carp Deterrent

By Eric Betz | September 22, 2017 3:31 pm
Asian carp jump from the water at the mouth of the Wabash River in Ohio. (Credit: U.S. Army Corps of Engineers/Todd Davis)

Asian carp jump from the water at the mouth of the Wabash River in Ohio. (Credit: U.S. Army Corps of Engineers/Todd Davis)

For years, people have been freaking out that Asian carp are about to invade the Great Lakes.

That concern seemed more real than ever this summer after an Illinois fisherman caught a carp in June less than 10 miles from Lake Michigan — beyond the barriers designed to keep them out.

These voracious fish have already decimated Midwestern rivers. They’re filter feeders who feast on plankton — the tiny plants and critters that prop up foodchains. And they eat lots of them. Adult Asian carp eat pounds of the stuff every day. Read More

CATEGORIZED UNDER: Environment, Top Posts

How the Invention of Zero Yielded Modern Mathematics

By Ittay Weiss | September 20, 2017 2:24 pm
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(Credit: Shutterstock)

A small dot on an old piece of birch bark marks one of the biggest events in the history of mathematics. The bark is actually part of an ancient Indian mathematical document known as the Bakhshali manuscript. And the dot is the first known recorded use of the number zero. What’s more, researchers from the University of Oxford recently discovered the document is 500 years older than was previously estimated, dating to the third or fourth century – a breakthrough discovery.

Today, it’s difficult to imagine how you could have mathematics without zero. In a positional number system, such as the decimal system we use now, the location of a digit is really important. Indeed, the real difference between 100 and 1,000,000 is where the digit 1 is located, with the symbol 0 serving as a punctuation mark. Read More

CATEGORIZED UNDER: Space & Physics, Top Posts
MORE ABOUT: mathematics

Cassini’s Bittersweet Symphony

By Shannon Stirone | September 15, 2017 12:27 pm
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Cassini’s final ringscape, taken Sept. 13. (Credit: NASA/JPL-Caltech/Space Science Institute)

The Cassini team members filled the chairs of mission control at NASA’s Jet Propulsion Laboratory in Pasadena, California. As a long-time astronomy journalist, I was invited to witness the end of an era.

At 4:55 a.m. PST, Cassini’s 13-year mission came to a bittersweet end when we lost signal from the spacecraft as it pierced through the cloud tops at Saturn. We’ve gathered in a lecture hall lined with spacecraft models, Voyager, Juno and of course, Cassini. Read More

CATEGORIZED UNDER: Space & Physics, Top Posts
MORE ABOUT: space exploration

Cassini Scientist Would Be Surprised if Life Doesn’t Exist on Enceladus

By Eric Betz | September 14, 2017 12:44 pm
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Enceladus (Credit: NASA)

The Cassini spacecraft has entered its final hours. And with the end nigh, Discover called up the Southwest Research Institute’s Hunter Waite — a Cassini principal investigator — for a look back at how this has redefined our view of where alien life might live in our solar system.

Before reaching Saturn in 2004, astronomers knew little about the gas giant’s many moons. Voyager got a glimpse of the system decades earlier. And Titan — the only known moon with a thick atmosphere — seemed like the best bet for learning about alien life. It seemed a solid proxy for early Earth. So scientists, led by the European Space Agency, landed the Huygens probe the moon’s surface. Read More

CATEGORIZED UNDER: Space & Physics, Top Posts

How the Folsom Point Became an Archaeological Icon

By Stephen E. Nash | August 25, 2017 9:39 am
This broken spear point found between two bison ribs ultimately changed not only the field of archaeology but also the narrative surrounding the arrival of Native Americans in North America. (Credit: DMNS/E-51)

This broken spear point found between two bison ribs ultimately changed not only the field of archaeology but also the narrative surrounding the arrival of Native Americans in North America. (Credit: DMNS/E-51)

The Folsom spear point, which was excavated in 1927 near the small town of Folsom, New Mexico, is one of the most famous artifacts in North American archaeology, and for good reason: It was found in direct association with the bones of an extinct form of Ice Age bison. The Folsom point therefore demonstrated conclusively, and for the first time, that human beings were in North America during the last Ice Age—thousands of years earlier than previously thought.

The Folsom discovery marked the end of a long series of sometimes serendipitous, sometimes deliberate actions by an intriguing cast of characters. As such, it helps us understand that archaeology—like most fields of study—has very few “Eureka!” moments in which a brilliant sage comes upon an insight that suddenly changes the world. Instead, archaeology is cumulative, often slow, and painstaking. And while an individual artifact can indeed be important, it’s context (where it was found) and association (what it was found with) are often more important than the object itself.

Lucky Break

The story begins in 1908. In the late afternoon heat of August 27, an unusually strong summer thunderstorm dropped 13 inches of rain—75 percent of the yearly average—on Johnson Mesa, northwest of Folsom. The resulting flash flood swept through the town and the usually dry drainages in the vicinity. In so doing, it exposed buried features and artifacts that hadn’t seen the light of day in thousands of years.

A local cowboy named George McJunkin soon went out to inspect and repair fence lines broken by the flood. McJunkin was a fascinating character. Born into slavery in Midway, Texas, in 1851, he migrated west in 1868 to escape his awful past, and in Folsom he found a welcoming community. Though effectively self-taught as a naturalist, McJunkin maintained a collection of artifacts and specimens amassed during the long hours he spent chasing cattle. While surveying along Wild Horse Arroyo after the flash flood in 1908, he noticed large bones eroding out of a newly exposed wall at the base of the arroyo some 10 feet below the surface.

For 14 years after he made the discovery—until his death in 1922—McJunkin either kept the Folsom Site a secret or (more likely) was unable to convince anyone of its scientific importance. But on December 10, 1922, Carl Schwachheim, a naturalist and collector from nearby Raton, visited the Folsom Site with local banker Fred Howarth. Both must have known McJunkin; the community is very small even today. Perhaps McJunkin’s death had inspired them to finally visit the hard-to-reach site.

Recognition At Last

On January 25, 1926, Schwachheim and Howarth made a business trip to Denver. While there, they stopped by the Colorado Museum of Natural History (now the Denver Museum of Nature & Science [DMNS], where I work) to discuss the site and its contents with scientific experts. First they met director Jesse Dade Figgins, who told them to send bones to the museum for conclusive identification. Once they did so several weeks later, honorary curator of paleontology Howard Cook confirmed that the bones were from an extinct form of Ice Age bison, Bison antiquus. Cook’s identification and Figgins’ authorization finally set institutional and scientific wheels in motion.

A flash flood in 1908 exposed this profoundly important archaeological site near Folsom, New Mexico. (Credit: DMNS/02-2048A.1)

A flash flood in 1908 exposed this profoundly important archaeological site near Folsom, New Mexico. (Credit: DMNS/02-2048A.1)

Cook and Figgins went to the Folsom Site in early spring of 1926 to develop a plan of action; Schwachheim’s excavation team entered the field in May. Their goal was to secure an exhibition-quality bison skeleton for the museum—they had no way (yet) of knowing that the site contained evidence of ancient humans. Indeed, most scientific experts at the time thought that Native Americans had been in North America for only a few thousand years.

In mid-July, Schwachheim’s team discovered the base of a broken stone spear point. Unfortunately, they found it in a pile of the soil that had been removed by mule teams in order to gain access to the bone bed. As such, they could not prove it was directly associated with Ice Age mammals.

When told of the discovery, Figgins immediately recognized its scientific importance and potential. He told Schwachheim in no uncertain terms: If the team finds other points in the bone bed they should be left exactly where they are so that the deposit can be examined by specialists. Disappointingly, none were discovered that year.

Schwachheim’s team returned to the site in 1927 with the exact same directive: Newly discovered points were to be left precisely where they were found until specialists could be called in. On August 29, the moment of truth finally arrived: They exposed a complete spear point between two bison ribs.

According to plan, Schwachheim telegrammed Figgins, who then contacted prominent archaeologists to announce the discovery and ask them to come see, and hopefully confirm, for themselves. Serendipitously, two of those archaeologists, though based on the East Coast, were already in Pecos, New Mexico—only 200 miles away from Folsom.

The wait, though less than a week in duration, must’ve been excruciating for Schwachheim and his team. They had worked for months under difficult conditions and now had to wait for specialists to confirm what they already knew—they had made a major scientific discovery. Over the next several weeks Alfred Vincent Kidder, Frank H.H. Roberts, and other specialists confirmed the initial field assessment: The point was indeed directly associated with the bison, proving that Native Americans had hunted large mammals during the last Ice Age. That Folsom point instantly became an icon, and it remains prominently on display at DMNS, still in its original sediment block.

Barnum Brown and Carl Schwachheim at bison Quarry, Folsom, New Mexico. Brown and Schwachheim are sitting at site of arrowhead in situ. (Credit: Jesse Dade Figgins)

Carl Schwachheim (left) shows the Folsom point, in its original excavation context, to visiting paleontologist Barnum Brown on September 4, 1927 (Credit: Jesse Dade Figgins)

The One That Mattered

The now iconic Folsom point was in fact the third spear point found at the Folsom Site. In addition to the broken point found in the soil pile in July 1926, Schwachheim’s team discovered a second point on July 14, 1927. For some reason, they ignored Figgins’ explicit directive and sent it, encased in a large block of sediment, to Denver. Figgins confirmed their discovery in the lab, but he knew from personal experience that they still needed a point in the field in order to convince the experts.

In 1924, Figgins had been involved in a remarkably similar project at the Lone Wolf Creek Site in central Texas. He had discovered Stone Age spear points in the laboratory, in sediment blocks that had been sent to the museum, just like the second point from Folsom. But he never found a point in the field at Lone Wolf Creek, which is why he was so adamant in his directive to Schwachheim’s team. Figgins must have been infuriated when their sediment block arrived in Denver in 1927. But he, like any good scientist, was patient, discerning, and critical.

The expert in-field confirmation that Figgins sought for so long, and eventually obtained, is the sole reason that the term “Folsom” is now given to a site, an artifact type, and a world-famous archaeological culture. By comparison, the Lone Wolf Creek Site is unknown, has no eponymous artifact type, and there is no archaeological culture bearing its name. Such is the nature of science.

Although the discovery and confirmation chapters of the Folsom story took place in both the field and the laboratory, it did not include research on museum collections. And it failed to answer some (now) basic archaeological questions: How old was the site, in years? How many animals were killed? Where did the raw material for the Folsom points come from? As we shall see in my next post, the Folsom story is still being written through the use of new analytical techniques and the reanalysis of archives and artifacts curated by museums.

[This work first appeared on SAPIENS under a CC BY-ND 4.0 license. Read the original here.]

CATEGORIZED UNDER: Living World, Top Posts
MORE ABOUT: archaeology

Does It Snow on Mars?

By David Rothery, The Open University | August 22, 2017 10:08 am
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What Mars could have looked like during an ice age 400,000 years ago. (Credit: NASA/JPL)

Given that there are ambitious plans to colonize Mars in the near future, it is surprising how much we still have to learn about what it would be like to actually live on the planet. Take the weather, for instance. We know there are wild fluctuations in Mars’s climate – and that it is very windy and at times cloudy (though too cold and dry for rainfall). But does it snow? Might settlers on Mars be able to see the red planet turn white? A new study surprisingly suggests so.

Mars is clearly cold enough for snow. It has ice – the amount of which has varied significantly over time. When its axis is tilted at only a small angle relative to its orbit, its surface is ice-free except for the polar caps. This is the situation today, when its axial tilt is 25⁰ (similar to Earth’s 23⁰ axial tilt). However, possibly because Mars lacks a large moon to stabilize its spin, there have been times when its spin axis was tipped over by up to 60⁰ – allowing the polar ice caps to spread, maybe even to the extent that there was abundant ice near the equator.

NASA’s Phoenix Mars Lander didn’t see snow on the ground. (Credit: NASA/JPL-Caltech/University of Arizona/Texas A&M University)

Mars emerged from its most recent ice age about 400,000 years ago. Since then, its polar caps have been small, and any ice surviving near the equator has been buried under dust.

The planet’s atmosphere is of low pressure and very dry. Although it is still possible for clouds to form at an altitude of several kilometers, until now it has been generally believed that any true snowfall would not reach the ground. The clouds, resembling Earth’s cirrus clouds, are believed to form when the small amount of water vapor in the atmosphere condenses (directly from vapor to ice) onto grains of dust lofted skywards during storms.

Winter Wonderland?

Being only a few micrometers in size, ice particles falling from the clouds would would drop at about only a centimeter a second. This allows more than enough time for them to evaporate before reaching the ground (strictly speaking, the process should be called “sublimation”, because the ice goes directly to vapor, without melting first). Overnight and seasonal frost spotted on Mars have been explained by water-ice particles falling quickly because they had been made temporarily larger and heavier by an outer coating of frozen carbon dioxide from the atmosphere.

Seasonal frost (or snowfall?) in gullies on a crater wall on Mars, at 60⁰ N. This view is about 800 metres wide. (Credit: NASA/JPL/University of Arizona)

The new study, published in Nature Geoscience, has found a way in which tiny specks of water-ice could travel down to the ground without this strange frozen carbon dioxide coat. If correct, this would mean genuine snow on Mars – just like that on Earth. The team used measurements from two orbiting spacecraft (the Mars Global Surveyor and Mars Reconnaissance Orbiter) to study how temperature varies with height in the Martian atmosphere. They found that at night, the lower atmosphere below ice clouds can become unstable, because it becomes less dense below than above.

This leads to rapid downdrafts of air, traveling at about 10 meters per second, which could carry ice crystals to the surface too quickly for them to “evaporate”. However, the snow layer would probably be thin and not last too long before it sublimes back into the atmosphere – where it could form new clouds and snowfall.

The phenomenon is similar to what is known on Earth a “microburst”, when a localized 60mph (97km per hour) downdraft below a thunderstorm can be powerful enough to flatten trees. The same process can also be responsible for intense snowfall at a particular location, by carrying snowflakes groundward in a blast, punching through the near-surface layer of air that would normally be warm enough to melt them.


A microburst on Earth.

Snow has not yet been observed in the process of actually reaching the ground on Mars, but it has been seen falling through the sky. NASA’s Phoenix lander, which landed at 68⁰ N in 2008 and became famous for finding ice below the surface when it scraped the dirt away, studied the sky above too. It used a LIDAR (like radar but relying on reflections from a laser beam) to probe the atmosphere, and on at least two nights observed curtains of falling snow hanging below the cloud layer.

Frost or a light dusting of snow seen at the Viking 2 lander site, Utopia Planitia, Mars. (Credit: Vandencbulek Eric, CC BY)

The ConversationIf a downdraft powerful enough had occurred, then maybe one morning Phoenix would have woken up to a winter wonderland, instead of the usual red landscape – at least for a few hours.

 

This article was originally published on The Conversation. Read the original article.

CATEGORIZED UNDER: Space & Physics, Top Posts
MORE ABOUT: Mars

On the Shores of Lake Erie, Endangered Birds Catch a Lucky Break

By Hannah Gavin | August 16, 2017 2:11 pm
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Endangered piping plovers are a precocial species, which means they mobile after emerging their egg. (Credit: Shutterstock)

Protecting species in peril doesn’t happen overnight. Rather, it’s all about stringing together small wins that, in the long-term, make all the difference. A little luck can also go far.

When waves surged on the Pennsylvania coast of Lake Erie early this summer, it could easily have been the end for a nest of piping plover eggs caught in the water’s path. Fortunately, a dynamic team of biologists, zookeepers and volunteers swooped into action, rescuing the eggs and rearing them at a quiet facility at the tip of the Michigan mitten.

Recently, young birds from those very eggs were released, in the hopes that they will join the 75 nesting pairs of birds sustaining this endangered population.

A Piping Plover Nest in Distress

The day was sunny, but all was not well on the Pennsylvania coast of Lake Erie.

As a pair of piping plover parents anxiously hopped about, waves swept over a shoreline nest and carried four eggs from their sandy home. Washed into shallow waters ten feet afield, the would-be shorebirds seemed to have met their demise.

Unbeknownst to them, regional wildlife diversity biologist Tim Hoppe was at the same moment searching cabinets for Tupperware and cotton balls – the construction materials for an impromptu egg container. In fact, an entire team of adoptive plover parents was mobilizing in what Pennsylvania Game Commission wildlife biologist Cathy Haffner describes as “basically a flurry of texting!”

Earlier the same morning, shared electronic communications had been celebratory: the first piping plovers to nest on Erie’s Pennsylvania shores in 60 years had just successfully hatched their chicks. Come afternoon, however, things turned more somber. A bird monitor noticed water and wind threatening the state’s second, un-hatched nest.

It was Sunday, and business offices were closed, but the monitor got in touch with Catherine, who contacted Tim. He arrived at the beach just in time to pluck the washed-out eggs from the water. A trip to a local tractor supply, 10 minutes before closing, yielded an incubator that would keep the eggs warm for the night.

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Plover eggs stay warm and safe in an incubator until hatching. (Courtesy: Bonnie Van Dam, Detroit Zoological Society)

Safe Haven

The rescue was novel in Pennsylvania, but similar scenarios have played out for years in the Midwest. In fact, Catherine did her graduate research with University of Minnesota ornithologist Francesca Cuthbert, who first incorporated captive rearing programs into the Great Lakes Piping Plover Conservation efforts. When they first began rescuing abandoned and washed-out eggs, Dr. Cuthbert and her team borrowed time in a 20-by-20-foot room.

The efforts have expanded, and today the Detroit Zoological Society’s Associate Curator of Birds, Bonnie Van Dam, oversees the captive-rearing arm of the conservation efforts. Her team of zookeepers is based at the University of Michigan Biological station each summer. They knew just what to do when this summer’s Pennsylvania eggs arrived in Michigan after a long road trip.

They watched, turned, and weighed the eggs daily. They supervised hatching, which takes up to four days for a given egg. Then they monitored the new chicks, taking weights and delivering worms and observing behaviors.

“We (zookeepers) are basically professional animal stalkers!” laughs Bonnie.

Actually, she notes, piping plover chicks are generally quite independent. Altricial birds, such as robins and condors, are born naked and helpless. Piping plovers, in contrast, are a precocial species, meaning they are relatively mature and mobile after emerging their egg. Just 4 to 6 hours after hatching, each bird resembled a feathered cotton ball on unsteady toothpick legs, scooting toward worms and crickets. With siblings and mirrors for company, and feather dusters for warmth, the chicks were safe.

Back to Nature

Fast forward 20 days, and the plovers had progressed from sand-filled bathtubs, via a kiddie pool, to a lakeside enclosure. They were nearing graduation. Zookeeper Matt Porter predicted the birds were on schedule to be released in just a few days provided there weren’t any setbacks.

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Members of the Great Lakes Piping Plover Conservation Team trek down sand dunes to a lakeside release site. (Credit: Hannah Gavin)

They certainly looked ready to go as they ran from waves, squatted among plants, and flew in the longest stretches a 5-meter enclosure would allow. Still, how would they fare, far from their protectively netted home?

Research shows that captive-reared plovers are responsive to potential predators, so the same inborn knowledge that leads them to eat and fly will help defend them upon release. Unfortunately, captive reared plovers produce fewer successful offspring than their wild-reared counterparts. Still, a 2008 study reported that the captive-reared Great Lakes plovers constituted up to 3 percent of the birds in the total population. Plus, more chicks have been successfully reared each summer of the ensuing decade.

Letting Go

Come release day, all chicks get a final weigh-in. Then they are loaded into a plastic pet crate, and zookeepers part with the birds they’ve come to know and love.

Plover banding duo Stephanie Schubel and Sarah Saunders secure the crate in the rear seat of a car, and head for the big lakes. Plover peeps sound out in waves, as if the birds keep re-remembering their excitement about impending freedom.

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Freedom! A newly released piping plover explores the beach. (Credit: Hannah Gavin)

On the beach, the crate is opened and the plovers depart with little sentiment. Watching them soar, it’s hard to remember the peril they endured early on. Without help, the Pennsylvania eggs would never have hatched. Even with help, their road wasn’t smooth. Of the nest’s four eggs, one was cracked during the washout. Another was whole, but never hatched; the tumble rendered the embryo unviable. Circumstances certainly weren’t ideal even for the two remaining eggs.

But, Bonnie points out, dealing under non-ideal circumstances is central to the Great Lakes Piping Plover Recovery efforts. As the newly released plover chicks swoop along the beach to independence, they are a living testament to the team’s success in doing just that.

CATEGORIZED UNDER: Living World, Top Posts
MORE ABOUT: animals

Why Are Oddly Satisfying Videos So…Satisfying?

By Nathaniel Scharping | August 15, 2017 11:58 am

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If you’ve never seen a master lathe operator at work, I highly recommend it. Deft movements and practiced flourishes turn a block of spinning wood into a bedpost, top, bowl or some other circular object, each motion peeling away curls of wood to uncover the beauty hidden inside.

It’s hard to explain why the motions feel so right, but there is an undeniable allure to the work, as if it scratches an itch you didn’t know you had. Read More

CATEGORIZED UNDER: Mind & Brain, Top Posts
MORE ABOUT: senses

Wait, What Happened in Cuba?

By Carl Engelking | August 11, 2017 4:15 pm
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The American embassy in Havana, Cuba. (Credit: Shutterstock)

U.S.-Cuban relations have taken an unusual turn after several U.S. diplomats, and at least one Canadian diplomat, experienced hearing damage after being targeted by a covert “sonic device” in Havana.

Huh? A what?

On Wednesday, U.S. officials who spoke to the Washington Post on the condition of anonymity revealed that in the fall of 2016, at least five U.S. diplomats began experiencing unexplainable hearing loss and other physical symptoms while serving at the embassy in Havana—so severe, they returned home to the U.S. for medical treatment. One U.S. diplomat will need to use a hearing aid as a result of their injuries, CNN reports. Read More

CATEGORIZED UNDER: Technology, Top Posts
MORE ABOUT: gadgets

Crucial Steps Ahead for Flying Cars

By Christina Reed | July 25, 2017 12:33 pm
aero-mobil

An artist’s conception of the AeroMobil flying car. (Credit: AeroMobil)

Flying cars are up against a wall — literally. Turning aircraft into street-safe machines requires manufacturers to prove their safety standards in crash tests. So at least one expensive prototype needs to get smashed to smithereens, while its dummy passengers survive. This is no small financial hurdle, and for a decade the industry has been just a few years away from getting models street-certified. Read More

CATEGORIZED UNDER: Technology, Top Posts
MORE ABOUT: transportation
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