Why Did a Huge Pile of Boston Snow Linger Til Mid-July?

For months, Bostonians have marveled — or else recoiled in disgust — at a giant 75-foot-high, 4-acre pile of dirty snow left over from last winter’s record snowfall, which lingered for months in an empty lot on Tide Street in the city’s Seaport district.

The snow mountain actually was a man-made curiosity, the last of 11 such “snow farms” that Boston workers created out of desperation, as the city was inundated with frozen precipitation. The city’s Public Works department’s snowplows worked overtime, clearing the equivalent of 12 trips around the Earth’s equator,and deposited an astonishing 50,000 tons of snow at the snow farm sites.

But unlike the other piles of snow, the big kahuna didn’t melt. In a city filled with historic landmarks, it became a perversely odd sightseeing spot, one that curious passers-by often used as a backdrop for snapshots.

In April, a local resident posted a video of himself skiing down the side of the snow pile, a feat which required him to dodge refuse ranging from rusted lawn chairs to parking cones. (“This post-apocalyptic, sludge-coated amalgamation of snow … was good enough for me,” he commented afterward.)

Boston Mayor Martin J. Walsh even got in on the fun by staging the Boston Snow Melt Challenge, in which residents could guess when the Tide Street mound would finally melt away.

Finally, the Boston Globe reported on Monday morning that the last of the once-giant mound of snow apparently had melted. “Based on my close proximity this morning, it’s really just a pile of trash at this point,” Elise Musumano, an employee at a nearby business, told the Globe.

But you probably have a question lingering in your mind. Why did the giant snow pile last until mid-summer? The reason is that snow and ice don’t just instantly melt when the surface air temperature rises above freezing. As the physics website Splung.com, explains, when a substance is in the solid phase, it requires additional energy to break the bonds holding its molecules in place. That necessary phase-changing energy is called latent heat.

While solar radiation provided a potential source of that energy, getting it to penetrate the snow mound was another thing entirely. As this Boston Globe article explains, the mound was filled with air pockets, which served as an effective insulator. Rain would have helped to break down that insulation by piercing the mound’s surface. But unfortunately, Boston had a spring that was relatively dry as well as being unusually cold.

From Discovery News

Pentaquarks: LHC Has Discovered an Exotic Particle

Now that the Large Hadron Collider (LHC) is smashing protons together at record energies, physicists are hoping to discover new and exotic particles emerge from the collisions. But there are a few unsolved mysteries surrounding different configurations of known subatomic particles that still have to be wrapped up.

And today, CERN announced the discovery of the “pentaquark” — a collection of five quarks bound together to form an exotic state of matter, a particle that has been theorized for some time but other experiments have had a hard time nailing down a true detection.

“The pentaquark is not just any new particle,” said Guy Wilkinson, spokesperson for the LHCb experiment at the LHC, in a CERN press release. “It represents a way to aggregate quarks, namely the fundamental constituents of ordinary protons and neutrons, in a pattern that has never been observed before in over fifty years of experimental searches. Studying its properties may allow us to understand better how ordinary matter, the protons and neutrons from which we’re all made, is constituted.”

Quarks are the subatomic constituents of regular particles, called hadrons. Hadrons come in two varieties, baryons (which contain 3 quarks) and mesons (which contain 2 quarks). Protons and neutrons are baryons where, for example, a proton is composed of 2 “up” quarks and 1 “down” quark; a neutron has 2 “down” quarks and 1 “up” quark.

But in the 1960′s, theorists realized that the Standard Model also allows the formation of 5 quarks in the same particle, known as a pentaquark. But experimental searches for this elusive 5-quark particle kept drawing blanks and any vaguely positive detection was quickly shot down by follow-up experiments.

Now, a strong signal in the LHCb detector has led to the pentaquark’s discovery.

LHCb physicists examined the decay of a baryon known as Lambda b (Λb) into 3 other particles, the J-psi (J/ψ-), a proton and a charged kaon. By using the highly sensitive detector to characterize the masses of these decay products, the physicists were able to see that intermediate states were sometimes involved in their production. They named these intermediate states Pc(4450)+ and Pc(4380)+ and indicate that pentaquarks are at play.

In a nutshell, the physicists noticed a signal emerge from the post-collision noise of particles. This signal, or “excess,” indicated the creation of J/ψ-, protons and kaon in quantities predicted by theories surrounding subatomic decay processes that involve pentaquarks. The decay particles acted as a “fingerprint” of sorts.

“Benefiting from the large data set provided by the LHC, and the excellent precision of our detector, we have examined all possibilities for these signals, and conclude that they can only be explained by pentaquark states,” said Tomasz Skwarnicki, a LHCb physicist from Syracuse University, New York. “More precisely the states must be formed of two ‘up’ quarks, one ‘down’ quark, one ‘charm’ quark and one ‘anti-charm’ quark.”

Read more at Discovery News

Big Day for Little Pluto: Probe Makes Flyby

After tearing through space for 9.5 years, putting 3 billion miles on its odometer, NASA’s low-cost New Horizons spacecraft made it past Pluto, the last major unexplored piece of real estate in the solar system -- or so scientists hope.

Confirmation that New Horizons survived its brush by Pluto and its five known moons won’t come until 8:53 p.m. EDT Tuesday. But that didn’t stop the celebrations at New Horizons mission control center at the Johns Hopkins University Applied Physics Lab outside Baltimore.

“It’s truly a mark in human history,” said NASA’s associate administrator for science John Grunsfeld. “It’s been an incredible voyage.”

As New Horizons approached Pluto, scientists began realizing they were looking at a far more active world than initially imagined. The probe relayed its closest view yet on Monday before going into radio silence for the flyby. NASA released the image on Tuesday.

“What we’ve seen already from Pluto is that it’s a complex, interesting world,” Grunsfeld told reporters after the flyby.

With 99 percent of New Horizons flyby data still onboard the spacecraft, mission managers and scientists have a nervous wait ahead.

“Hopefully it survived the passage, we’re counting on that,” said lead scientist Alan Stern, with the Southwest Research Institute in Boulder, Colo.

New Horizons was on track to fly within 7,750 miles of Pluto at 7:49 a.m. EDT. Mission operations manager Alice Bowman said the latest data from the spacecraft showed it would arrive 72 seconds early, well within the targeted time for the planned encounter.

From Discovery News

Human Hands More Primitive than Chimp Hands

Given our inherent human-centric viewpoint, we tend to think that our species is more advanced in all respects than other animals, but new research finds that human hands are more primitive than those of our closest primate ancestors: chimpanzees.

The study, published in the latest issue of the journal Nature Communications, determined that while human hand proportions have changed little from those of the last common ancestor of chimps and humans, the hands of chimps and orangutans have evolved quite a bit.

“The findings suggest that the structure of the modern human hand is largely primitive in nature, rather than, as some believe, the result of more recent changes necessary for stone tool-making,” Kurtis Hiatt, a spokesperson for The George Washington University, told Discovery News.

Sergio Almécija, a scientist in the university’s Center for the Advanced Study of Human Paleobiology, led the study, which was co-authored by Jeroen Smaers and William Jungers. Smaers and Jungers are researchers at Stony Brook University, where the research was conducted.

The researchers came to their conclusions after analyzing the hands of humans, chimps and orangutans, as well as the remains of hands for early apes like Proconsul heseloni and the hands of human ancestors, such as Ardipithecus ramidus and Australopithecus sediba.

Almécija and his team discovered that human hands today are not that different from those of the early human ancestors.

“Human hands are marked by a relatively long thumb when compared to the length of their four other fingers — a trait that is often cited as one of the reasons for the success of our species because it facilitates a ‘pad-to-pad precision grip,’” Hiatt said.

Conversely, chimp hands are much longer and narrower. Since the thumb is not as long, it just meets up with the palm, while the chimp’s other four fingers extend upward. As a result, chimps and orangutans do not have opposable thumbs as we do.

Gorillas also appear to have inherited our more primitive hand structure. Like human hands, gorilla hands have five fingers, including an opposable thumb. Gorilla feet are similar to ours too. Each gorilla foot has five toes, but their big toe is opposable and can move much more flexibly than ours can.

Almécija and his colleagues suspect that all living primates survived a late Miocene (12 to 5 million years ago) extinction event by specializing to exist in certain habitats. While chimps and orangutans became tree-climbing specialists, humans evolved to become more terrestrial. Gorillas did too.

Read more at Discovery News

Clear Horizons? Now For Your Pluto Space Weather Report

Pluto may be, on average, 40 times further away from the sun than Earth, but that doesn’t mean it doesn’t experience the sun’s outbursts. And it just so happens that, although it’s extremely difficult to gauge the location and intensity of solar particle clouds at 3.7 billion mile away, a NASA supercomputer has taken on the task and arrived at a space weather report of sorts just in time for New Horizons’ flyby.

As discussed in the video below, it takes around 5 months for a coronal mass ejection (CME) to travel from the sun to the orbit of Pluto (as a comparison, CMEs take between hours to a couple of days to reach Earth), but interplanetary space is a complex environment and it takes some extreme computing power to simulate these energetic clouds of magnetized plasma over those distances.

CMEs are launched from the sun’s highly magnetized lower corona (the sun’s atmosphere) and are composed of ionized particles that can interact with planetary magnetic fields. Should a CME be “geoeffective” when encountering our planet’s magnetosphere, for example, a geomagnetic storm can be triggered, producing spectacular aurorae at high latitudes.

Pluto is much further away from the sun, and by the time a CME reaches the dwarf planet, the plasma will have been stretched out and much less dense than a CME encountering Earth — so the CME is more of a “gentle breeze” by this point. It is currently unknown whether Pluto possesses a magnetic field, but space weather will undoubtedly affect the dwarf planet’s surface, depositing solar plasma, possibly driving some interesting chemistry.

As for the New Horizons flyby, don’t expect anything spectacular in the way of space weather. On July 14, it seems that CME activity should be extremely low during flyby, with a higher density front encountering Pluto later, which could impact the small world’s tenuous atmosphere.

“Our simulation estimates that during the New Horizon approach, Pluto might be immersed in a region with very low solar wind densities, lasting for about one month,” Dusan Odstricil, of NASA's Goddard Space Flight Center in Greenbelt, Md., told Spaceweather.com. “This will be followed by a large merged region, which could significantly compress Pluto’s atmosphere.”

Read more at Discovery News

Confirmed: Pluto is Reigning King of the Kuiper Belt

New measurements made by NASA’s New Horizons spacecraft confirm Pluto actually is the reigning king of the Kuiper Belt, with a diameter that surpasses the size of Eris, another so-called “dwarf planet” in the solar system’s backyard.

“That settles the debate about the largest object in the Kuiper Belt,” New Horizons lead scientist Alan Stern, with the Southwest Research Institute in Boulder, Colo., told reporters Monday.

The observations, relayed as New Horizons neared Pluto after a 9.5-year, 3 billion mile journey, show that Pluto spans about 1,473 miles in diameter. Scientists suspect the maximum diameter for Eris, which circles the sun about three times farther than Pluto, is 1,445 miles.

Pluto’s size has been somewhat of a mystery because the planet’s atmosphere makes it somewhat blurry against the light of background stars, which are used as measurement tools.

With a slightly larger diameter than predicted, Pluto is a little less dense, with a higher percentage of ice and a little less rock. The measurement also means Pluto’s troposphere, its lowest layer of atmosphere, is closer to the ground than some computer models predict.

Early analysis of New Horizons data also shows that more of Pluto’s nitrogen atmosphere is escaping into space, or an unknown transport mechanism is ramping-up the process. On Tuesday, New Horizons will be able to see if Pluto is sharing any of its atmosphere with its primary moon and orbital partner Charon.

The discoveries are just a hint of what scientists expect from New Horizons as it punches through the Pluto system Tuesday morning, then looks back at its quarry for several more hours.

“This science is already mouth-watering,” Stern said.

Although within 650,000 miles of Pluto, the difference between what New Horizons’ cameras saw on Monday and what they will image when the spacecraft passes about 7,750 miles from Pluto (and about 18,000 miles from Charon) on Tuesday. Image resolution will jump from 15 kilometers per pixel to less than 100 meters, an improvement of more than two orders of magnitude, Stern said.

Read more at Discovery News

Pluto's Moon Charon Hosts Craters and Monster Canyon

While all eyes are on Pluto, NASA’s New Horizons mission is also beaming back intriguing views of the dwarf planet’s largest moon, Charon.

A starkly different color to Pluto, Charon seems to have its own highly complex geology featuring large craters and a spectacular canyon, which is longer and miles deeper than Earth’s Grand Canyon. In short, Charon is shaping up to be the second arena of discovery as New Horizons prepares for close approach to the Pluto system hours from now.

“This is the first clear evidence of faulting and surface disruption on Charon,” said William McKinnon, deputy lead scientist with New Horizon’s Geology and Geophysics investigation at Washington University in St. Louis, Mo. “New Horizons has transformed our view of this distant moon from a nearly featureless ball of ice to a world displaying all kinds of geologic activity.”

The largest chasm looks like a deep scar in the moon’s southern hemisphere and the most prominent crater, measuring approximately 60 miles (a little under 100 kilometers) is seen close to its south pole.

In this observation captured by the mission’s Long Range Reconnaissance Imager (LORRI) in July 11, bright rays can be seen surrounding the crater, indicating that the impact occurred relatively recently in geological timescales. These rays were formed when an impactor scoured into Charon’s surface, blasting bright ejecta across the darker landscape.

The New Horizons team are particularly interested in the surprising darkness of the crater’s floor according to a press release issued on Sunday. One theory is that when Charon was hit, the impactor exposed darker layers of icy material below the surface. Another possibility is that the material inside the crater is the same material on the surface of the moon, but has taken the form of larger grain sizes, which reflect less light.

Read more at Discovery News

Rare Harpy Eagle Chick Captured in New Pics

Harpy eagles nesting high above the understory of the Peruvian rainforest have been captured in a series of stunning new photos.

One of the eagles is a mama bird, while the other is an adorable eagle chick.

Because the giant bird of prey lives in the darkest portions of the rainforest and hunts its quarry in dead silence, many Peruvian Amazon birders can go their entire lives without seeing one, said nature photographer Jeff Cremer, who photographed the eagles.

“It’s about as rare as seeing a unicorn,” Cremer told Live Science.

Rare creatures

Harpy eagles (Harpia harpyja) are imposing creatures. The massive birds can be up to 3 feet (0.9 meters) tall, with wingspans reaching 6 feet (1.8 m), Cremer said. Like stealth bombers, the birds of prey glide silently; they move through the shadows of the rainforest, hunting sloths, monkeys and even an occasional deer, Cremer said. To better hunt their prey, the eagles can turn their heads 180 degrees to face upward while flying through the dense rainforest, and can also fluff up their white head feathers, creating an acoustic funnel to direct sound to their ears.

When they do capture an unsuspecting animal, the eagles crush it, killing it instantly with their huge talons, which can produce hundreds of pounds of force, Cremer added.

“They have claws the size of an adult grizzly bear,” Cremer told Live Science.

But the eagles are tough to spot, because they build their nests in the dark region between the forest’s understory and canopy, high up in the trees, where the limbs just begin to branch out. In addition, logging and illegal mining have sharply reduced the harpy eagle’s natural habitat and the majestic hunter is now considered near threatened by the International Union for the Conservation of Nature. As a result, seeing a harpy eagle chick in the wild in this region is incredibly rare, Cremer said.

Baby bird

Guides at the Tambopata Research Center in Peru first became aware of the birds of prey after noticing a nest high up in the trees. The guides also saw a harpy eagle fly over their heads, carrying the head of a half-eaten sloth to the nest, which contained a single chick. After monitoring the nest, Cremer and his colleagues decided to climb up to take photos.

Getting those pictures was no easy feat. The nest was perched high in the branches of an ironwood tree, about 100 feet (30 m) above the ground, so the team had to toss a slingshotlike rope up to the branches and then ascend using special climbing gear.

Read more at Discovery News

Amazing flare from a black hole in a distant galaxy

Five billion years ago, a great disturbance rocked a region near the monster black hole at the center of galaxy 3C 279. On June 14, the pulse of high-energy light produced by this event finally arrived at Earth, setting off detectors aboard NASA's Fermi Gamma-ray Space Telescope and other satellites. Astronomers around the world turned instruments toward the galaxy to observe this brief but record-setting flare in greater detail.

"One day 3C 279 was just one of many active galaxies we see, and the next day it was the brightest thing in the gamma-ray sky," said Sara Cutini, a Fermi Large Area Telescope scientist at the Italian Space Agency's Science Data Center in Rome.

3C 279 is a famous blazar, a galaxy whose high-energy activity is powered by a central supermassive black hole weighing up to a billion times the sun's mass and roughly the size of our planetary system. As matter falls toward the black hole, some particles race away at nearly the speed of light along a pair of jets pointed in opposite directions. What makes a blazar so bright is that one of these particle jets happens to be aimed almost straight at us.

"This flare is the most dynamic outburst Fermi has seen in its seven years of operation, becoming 10 times brighter overnight," said Elizabeth Hays, a Fermi deputy project scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland. Astronomers think some change within the jet is likely responsible for the flare, but they don't know what it is.

The brightest persistent source in the gamma-ray sky is the Vela pulsar, which is about 1,000 light-years away. 3C 279 is millions of times farther off, but during this flare it became four times brighter than Vela. This corresponds to a tremendous energy release, and one that cannot be sustained for long. The galaxy dimmed to normal gamma-ray levels by June 18.

The rapid fading is why astronomers rush to collect data as soon as they detect a blazar flare. "Our priority is to make observations while the object is still bright," said Masaaki Hayashida, a Fermi team member at the University of Tokyo's Institute for Cosmic Ray Research. "Once it's over, we can start trying to understand the mechanisms powering it."

The Italian Space Agency's AGILE gamma-ray satellite first reported the flare, followed by Fermi. Rapid follow-up observations were made by NASA's Swift satellite and the European Space Agency's INTEGRAL spacecraft, which just happened to be looking in the right direction, along with optical and radio telescopes on the ground.

3C 279 holds a special place in the history of gamma-ray astronomy. During a flare in 1991 detected by the EGRET instrument on NASA's then recently launched Compton Gamma Ray Observatory (CGRO), which operated until 2000, the galaxy set the record for the most distant and luminous gamma-ray source known at the time. "Although we didn't expect to find the galaxy so bright, we soon had a much greater surprise," recalled Robert Hartman, who led the first gamma-ray study of 3C 279 with CGRO and is now a member of the Fermi team at Goddard. "Its brightness varied substantially, becoming four times brighter within 10 days."

Read more at Science Daily

'Planet' Pluto Has Complex and Interesting Geology

As NASA’s New Horizons spacecraft barrels toward Pluto, rapidly approaching its close encounter on July 14, long-distance reconnaissance by the probe is revealing a fascinating surface geology.

Far from being a bland, uniform surface, the dwarf planet seems to play host to a complex array of geological features that planetary scientists are already trying to decipher.

“We’re close enough now that we’re just starting to see Pluto’s geology,” said Curt Niebur, New Horizons program scientist at NASA Headquarters in Washington, D.C., in a Friday news release.

Of particular interest is the “whale” feature that can be seen covering the lower-left region of Pluto’s globe in this Long Range Reconnaissance Imager (LORRI) observation. Although it’s too early to tell, this dark shape seems to be some kind of plain, starkly contrasting with the surrounding, brighter landscape.

Niebur is particularly interested in the gray region immediately above the whale’s “tail”: “It’s a unique transition region with a lot of dynamic processes interacting, which makes it of particular scientific interest.”

“Among the structures tentatively identified in this new image are what appear to be polygonal features; a complex band of terrain stretching east-northeast across the planet, approximately 1,000 miles long; and a complex region where bright terrains meet the dark terrains of the whale,” added New Horizons principal investigator Alan Stern. “After nine and a half years in flight, Pluto is well worth the wait.”

The imagery coming from New Horizons is becoming more and more detailed as the probe approaches. This particular LORRI image was captured on July 9 from a distance of 3.3 million miles (5.4 million kilometers), but even from this distance the camera is able to deliver a resolving power of 17 miles per pixel.

On Tuesday, New Horizons will make its historic close approach to Pluto and its moons, giving us a close-up view of the last of the “classical” nine planets of the solar system to be explored by a robotic flyby mission. There is little doubt that this encounter, and the science it will gather, will not only enrich our understanding of the very early formation of our solar system (Pluto is an ancient “open book” of geological record), it will also stir the debate surrounding Pluto’s planetary status.

In 2006, Pluto suffered what was widely regarded as a “demotion” of sorts, when it was re-catagorized by the International Astronomical Union (IAU) from being a “planet” to a “dwarf planet.” The motivation for this reclassification focused on the new and exciting Kuiper Belt discoveries that were cropping up as observational techniques became more sophisticated. Rather than the classical “nine planets,” astronomers found themselves swamped with a solar system possibly containing hundreds of planets.

Unfortunately for Pluto, it became a rounding error and fell into a new group of planetary bodies: dwarf planets.

Over the years, the “Pluto debate” has ebbed and flowed in the public and scientific arena with polarized opinions on both sides focusing on what is considered to be a planet and what isn’t. The definition of a planet (using the IAU’s golden rules for what a planet is) will, however, seem completely archaic when New Horizons beams back a growing archive of close-up observations of this alien world after flyby (the mission is expected to take months to transmit all of its Pluto close encounter data, according to Stern).

For what it’s worth, I think that we are currently exploring a completely different class of planetary body, not based on its physical size, but on its unique configuration. Largest moon Charon doesn’t orbit Pluto; Pluto and Charon orbit a common point (known as a “barycenter”) in space above Pluto’s surface. Charon’s mass is so large that on each orbit, it tugs Pluto off-center, causing it to wobble. As discussed in previous Discovery News articles, the case for the Pluto-Charon system being a “binary planet” is an interesting one.

Read more at Discovery News