Saturday, May 27, 2017

NASA’s Jupiter Mission Reveals the ‘Brand-New and Unexpected’

Multiple images combined show Jupiter’s south pole, as seen by NASA’s Juno spacecraft from an altitude of 32,000 miles. The oval features are cyclones. Credit NASA/JPL-Caltech/SwRI/MSSS/Betsy Asher Hall/Gervasio Robles
The top and bottom of Jupiter are pockmarked with a chaotic mélange of swirls that are immense storms hundreds of miles across. The planet’s interior core appears bigger than expected, and swirling electric currents are generating surprisingly strong magnetic fields. Auroral lights shining in Jupiter’s polar regions seem to operate in a reverse way to those on Earth. And a belt of ammonia may be rising around the planet’s equator.
Those are some early findings of scientists working on NASA’s Juno mission, an orbiter that arrived at Jupiter last July.
Juno takes 53 days to loop around Jupiter in a highly elliptical orbit, but most of the data gathering occurs in two-hour bursts when it accelerates to 129,000 miles an hour and dives to within about 2,600 miles of the cloud tops. The spacecraft’s instruments peer far beneath, giving glimpses of the inside of the planet, the solar system’s largest.
“We’re seeing a lot of our ideas were incorrect and maybe naïve,” Scott J. Bolton, the principal investigator of the Juno mission, said during a NASA news conference on Thursday.
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Two papers, one describing the polar storms, the other examining the magnetic fields and auroras, appear in this week’s issue of the journal Science. A cornucopia of 44 additional papers are being published in the journal Geophysical Research Letters. The papers describe findings based largely on the first two close passes of Jupiter in which Juno was able to make measurements. Juno has now made five, with the next on July 11, when it is to pass directly over the Great Red Spot.
Infrared images and spectra of Jupiter’s thermal emission based on readings from the Jovian Infrared Auroral Mapper aboard the Juno spacecraft. J.E.P. Connerney et al.
Scientists are puzzled to see that the familiar striped cloud patterns of Jupiter may be only skin deep. An instrument collecting microwave emissions probes the top layers of the atmosphere, but that data does not reflect what is seen in the clouds. “These zones and belts either don’t exist or this instrument isn’t sensitive to it for some reason,” Dr. Bolton said.
The microwave instrument did detect a band of ammonia rising in the equatorial region from at least a couple of hundred miles down — “the most startling feature that was brand-new and unexpected,” Dr. Bolton said.
In measuring the gravitational field, scientists hoped to learn what lies at the center of Jupiter. Some predicted a rocky core, perhaps the size of Earth or several Earths. Others expected no rocky core, but hydrogen, the planet’s main constituent, all the way down. “Most scientists were in one camp or the other,” Dr. Bolton said, “and what we found is neither is true.” Instead, the data suggests a “fuzzy core,” one that is larger than expected, but without a sharp boundary, perhaps partly dissolved.
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A close-up of an enhanced-color image of Jupiter’s clouds obtained by NASA’s Juno spacecraft. Credit NASA/SWRI/MSSS/Gerald Eichstädt/Seán Doran
The magnetic field is also not simple. “What scientists expected was that Jupiter was relatively boring and uniform inside,” Dr. Bolton said. “What we’re finding is anything but that is the truth.”
John E.P. Connerney, a scientist at NASA’s Goddard Space Flight Center in Greenbelt, Md., and the deputy principal investigator on the mission, reported spatial variations in the magnetic field that were much stronger than expected in some areas and much weaker in others.
The magnetic field is generated by the churning of electrically charged fluids at the core. On Earth, that comes from the convection of molten iron in the outer core. On Jupiter, the currents come from hydrogen, which turns into a metallic fluid under crushing pressures.
During a close flyby of Jupiter in August last year, one of Juno’s cameras took this picture, the first to Jupiter’s wispy ring seen from the inside looking out. Credit NASA/JPL-Caltech/Southwest Research Institute
The spatial variations suggest that the dynamo of churning currents is larger than had been thought and may extend beyond the metallic hydrogen region, Dr. Connerney said.
For the magnetic field and gravity measurements, a glitch that has greatly slowed the pace of data gathering could turn out to be beneficial. A final engine burn last October was to put Juno in a 14-day orbit, but a pair of sluggish valves in the fuel system led mission managers to forgo that, and Juno remains in the 53-day orbit instead. The spacecraft is to make the same number of orbits and collect the same amount of data, and the longer mission means that Juno may be able to detect slow changes in the magnetic field.
More surprises were found at the top and bottom of Jupiter.
With Juno’s orbits passing almost directly over the north and south poles, scientists can better study the powerful auroras, which are generated by charged particles traveling along Jupiter’s magnetic field and colliding with molecules in the atmosphere. In Earth’s case, charged particles from the sun speeding outward through the solar system are diverted by the planet’s magnetic field toward the poles, generating light when they collide with air molecules. The expectation was that the same would occur at Jupiter, and it does to some extent.

Interactive Feature: Jupiter and Its Moons

But Juno also detected charged particles — mostly electrons — traveling in the opposite direction at Jupiter: out of the planet into space. “It’s a 180-degree turnabout from the way we were thinking about those emissions,” Dr. Connerney said.
He said a voltage differential in the atmosphere was drawing the electrons upward.
Earlier photographs of the polar regions were taken from a sharp angle, with details hard to make out. Juno revealed that the clouds there are very different from the usual Jupiter stripes. “What you see is incredibly complex features, the cyclones and anticyclones all over the poles,” Dr. Bolton said.
Planetary scientists had wondered whether Jupiter would have a giant hexagonal pattern like that spotted on Saturn by NASA’s Cassini spacecraft.
On Wednesday, NASA released new images of Saturn’s north polar region, which has changed color in the last four years, possibly because summer has reached the northern hemisphere.
In contrast to the chaotic weather patterns at Jupiter’s poles, a stable hexagonal pattern covers Saturn’s north pole. A comparison of Saturn's north-polar region in 2013, left, and 2017, right. As the gas giant approached its summer solstice, the sun's ultraviolet light led to a yellow-ish haze. NASA/JPL-Caltech/Space Science Institute/Hampton University
In the final stages of Cassini’s mission, which ends in September, it has shifted to a looping elliptical orbit, which will enable similar probing of Saturn’s interior.
“Eventually we will compare,” Dr. Bolton said. “We will really be able to advance our understanding of how these giant planets work.”
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Wednesday, May 24, 2017

Mapping 50 Years of Melting Ice in Glacier National Park

Glacier National Park is losing its glaciers.
The flowing sheets of ice scattered throughout the Montana park shrank by more than a third between 1966 and 2015, according to new data from the United States Geological Survey and Portland State University.
Using aerial and satellite imagery, researchers traced the footprints of 39 named glaciers in the park and surrounding national forest. They found that 10 had lost more than half their area over 50 years.
Ice extent for every glacier in Glacier National Park in 1966 and 2015
Lost 50 percent or more coverage area
Lost 213 acres (54%)
2015 1966
Lost 133 acres (40%)
Lost 129 acres (41%)
Lost 113 acres (45%)
Lost 107 acres (33%)
Lost 98 acres (19%)
Lost 93 acres (26%)
Two Ocean
Lost 87 acres (82%)
Lost 83 acres (18%)
Lost 70 acres (56%)
Lost 65 acres (49%)
Lost 57 acres (41%)
Lost 48 acres (85%)
Lost 44 acres (72%)
Lost 41 acres (57%)
Lost 34 acres (57%)
Lost 34 acres (81%)
Lost 33 acres (41%)
Lost 32 acres (37%)
Lost 28 acres (77%)
Lost 27 acres (27%)
Lost 26 acres (10%)
Lost 25 acres (25%)
Lost 25 acres (33%)
Miche Wabun
Lost 25 acres (49%)
Old Sun
Lost 20 acres (19%)
Lost 19 acres (13%)
Red Eagle
Lost 18 acres (53%)
Lost 17 acres (20%)
Weasel Collar
Lost 14 acres (10%)
Lost 13 acres (42%)
Lost 13 acres (23%)
Lost 13 acres (23%)
Lost 10 acres (36%)
Lost 9 acres (42%)
Lost 9 acres (13%)
North Swiftcurrent
Lost 8 acres (26%)
Lost 7 acres (21%)
Lost 2 acres (24%)
“One of the reasons we study glaciers is because they have a simple, visual and easily understood response to climate,” said Daniel Fagre, a U.S.G.S. research ecologist who led the study. “If it gets warmer or if they get less snow, they shrink.”
Glacier National Park’s eponymous ice sheets have been around for more than 7,000 years, and have survived warmer and cooler periods. But they have been shrinking rapidly since the late 1800s, when North America emerged from the “Little Ice Age,” a period of regionally colder, snowier weather that lasted for roughly 400 years. (At its founding in 1910, the park had at least 150 glaciers, most of which are now gone.)
After the end of the Little Ice Age, glaciers across the western United States, Canada and Europe lost ice as temperatures rebounded. But scientists have attributed more recent melting to human-caused global warming.
“With each decade that we go, more of what we see can be attributed to humans, and less to natural variation,” Dr. Fagre said.
Dr. Fagre noted that even under natural conditions, these small, vulnerable mountain glaciers would have lost ground over the past 50 years — but they would have eventually stabilized at a reduced size. Instead, the park is on track to lose its ice sheets within a generation.

Larger, thinner glaciers have lost the most ground

Agassiz glacier. John Scurlock/U.S.G.S.
Agassiz glacier, pictured above, has lost more ground than any other glacier in the park: over 200 acres.
The relatively large glacier — which covered nearly 400 acres in 1966 — is also relatively thin, making it more vulnerable to rising temperatures.
“The analogy here is, think of the shoreline where the water is shallow and the slope of the beach is flat, and we have a small drop in sea level, which immediately reveals a whole lot of beach. Take that same amount of sea level drop with a steep slope and deep water, and you don't expose much more beach,” said Joel T. Harper, a glaciologist at the University of Montana. “The same is true of these glaciers.”

But smaller, thicker glaciers have lost mass, too

Gem glacier. John Scurlock/U.S.G.S.
Unlike Agassiz, the smallest glacier in the park — appropriately named Gem — has not ceded much ground over the past 50 years. But that doesn’t mean it hasn’t lost ice.
Gem is positioned at the top of a cliff, in a small area on a ledge, which means it never had much room to spread out. The glacier formed by accumulating ice upward, becoming thicker. But Gem has visibly thinned in recent years.
“Repeat photographs show it losing volume over time,” Dr. Fagre said. He added that, today, many of the park’s glaciers were “noticeably thinner than they were in the past.”
The recently published U.S.G.S. data measured only coverage area, but a coming study by Dr. Fagre’s team will measure the glaciers’ volume.
“Both processes are going on: thinning and contracting,” he said.

The park’s most visited glacier lost nearly half its footprint in 50 years

Grinnell glacier. John Scurlock/U.S.G.S.
The park’s most visited glacier, Grinnell, lost 45 percent of its footprint — more than 100 acres — from 1966 to 2015.
“I’ve been going there since 1991 and remember having to choose carefully how to climb up onto the glacier. It was 20 to 30 feet high at the edge,” Dr. Fagre said. “Now it comes only up to your shins.”

Monday, May 22, 2017

Anarchists Fill Services Void Left by Faltering Greek Governance

Elly Antipa, right, a Greek anarcho-communist, with Syrian children in an abandoned school that was occupied by anarchist groups and is now a home for refugees in Athens. Credit Eirini Vourloumis for The New York Times
ATHENS — It may seem paradoxical, but Greece’s anarchists are organizing like never before.
Seven years of austerity policies and a more recent refugee crisis have left the government with fewer and fewer resources, offering citizens less and less. Many have lost faith. Some who never had faith in the first place are taking matters into their own hands, to the chagrin of the authorities.
Tasos Sagris, a 45-year-old member of the Greek anarchist group Void Network and of the “self-organized” Embros theater group, has been at the forefront of a resurgence of social activism that is effectively filling a void in governance.
“People trust us because we don’t use the people as customers or voters,” Mr. Sagris said. “Every failure of the system proves the idea of the anarchists to be true.”
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“People trust us because we don’t use the people as customers or voters,” said Tasos Sagris, a member of the Greek anarchist group Void Network and the “self-organized” Embros theater. Credit Eirini Vourloumis for The New York Times
These days that idea is not only about chaos and tearing down the institutions of the state and society — the country’s long, grinding economic crisis has taken care of much of that — but also about unfiltered self-help and citizen action.
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Yet the movement remains disparate, with some parts emphasizing the need for social activism and others prioritizing a struggle against authority with acts of vandalism and street battles with the police. Some are seeking to combine both.
Whatever the means, since 2008 scores of “self-managing social centers” have mushroomed across Greece, financed by private donations and the proceeds from regularly scheduled concerts, exhibitions and on-site bars, most of which are open to the public. There are now around 250 nationwide.
Some activists have focused on food and medicine handouts as poverty has deepened and public services have collapsed.
In recent months, anarchists and leftist groups have trained special energy on housing refugees who flooded into Greece in 2015 and who have been bottled up in the country since the European Union and Balkan nations tightened their borders. Some 3,000 of these refugees now live in 15 abandoned buildings that have been taken over by anarchists in the capital.
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A group of people in the kitchen of the former school. Credit Eirini Vourloumis for The New York Times
The burst of citizen action is just the latest chapter in a long history for the anarchist movement in Greece.
Anarchists played an active role in the student uprisings that helped bring down Greece’s dictatorship in the mid-1970s, including a rebellion at the Athens Polytechnic in November 1973, which authorities crushed with police officers and tanks, resulting in several deaths.
Since the late 1970s and early 1980s, anarchists have joined leftist groups in occupying portions of Greek universities to promote their thinking and lifestyle; many of those occupied spaces exist today, and some are used as bases by anarchists to fashion the crude firebombs hurled at the police during street protests.
Over the years, anarchists have also backed a spectrum of causes, such as opposing “neoliberal” education reform or campaigning against the 2004 Olympic Games in Athens.
The movement continues to be largely tolerated by the public at large, reflecting a deep distrust of authority among Greeks that has been stoked in recent years by the austerity measures imposed on the debt-racked country by international creditors.
In Athens, the anarchists’ epicenter remains the bohemian neighborhood of Exarchia, where the killing of a teenager by a police officer in 2008 set off two weeks of rioting, helped reinvigorate the movement and produced several guerrilla groups that led to a revival of domestic terrorism in Greece.
The police and the authorities tread lightly in the area.
The police have recently raided some buildings illegally occupied by anarchists, called squats, in Athens, in the northern city of Thessaloniki and on the island of Lesbos, a gateway for hundreds of thousands of migrants over the past two years. But the authorities have stopped short of a blanket crackdown, which would be difficult for the leftist Syriza party of Prime Minister Alexis Tsipras to condone.
In an interview, Public Order Minister Nikos Toskas said that the police sweeps were “systematic,” and that the raids were being carried out “where they are needed.”
The mayor of Athens, Giorgos Kaminis, condemned the squats, saying they have compromised “the quality of life of the refugees.”
“No one knows who they are controlled by and what conditions people being put up in occupied buildings live in,” he said in a response to a reporter’s questions.
The anarchists say their squats are a humane alternative to the state-run camps now filled with more than 60,000 migrants and asylum seekers. Human rights groups have broadly condemned the camps as squalid and unsafe.
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Ms. Antipa, right, with Abdulah Arifay, a Syrian refugee, on the rooftop of the school, where a chicken coop has been set up. Credit Eirini Vourloumis for The New York Times
In Exarchia, one of the squats includes a former state secondary school that was abandoned because of structural problems. Established last spring with the help of anarchists, the squat is now home to some 250 refugees, mostly from Syria, who have set up a chicken coop on the roof. Many more refugees are on a “waiting list” for other occupied buildings.
The squats function as self-organized communities, independent from the state and nongovernmental organizations, said Lauren Lapidge, 28, a British social activist who came to Greece in 2015 at the peak of the refugee crisis and is actively involved with several occupied buildings.
“They are living organisms: Kids go to school, some were born in the squat, we’ve had weddings inside,” she said.
Another initiative in Exarchia involves anarchists and local residents who have moved a cargo container into the neighborhood’s central square, calling it a political kiosk, from which they distribute food and medicine and sell anarchist literature.
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Vassiliki Spathara is part of a group of anarchists who set up a cargo container in the main square of Exarchia, dubbing it a political kiosk. Credit Eirini Vourloumis for The New York Times
Vassiliki Spathara, 49, a painter and anarchist living in Exarchia, said the initiative was necessary because the local authorities would not intervene “even to replace light bulbs” in the square, known as a haunt for drug dealers, though activity has abated recently.
“The authorities want to downgrade the area because it’s the only place in Athens that has an organized, anti-establishment identity,” Ms. Spathara said.
Mayor Kaminis said the local authorities were cooperating with residents “to rejuvenate the area,” and insisted that Exarchia residents had the same rights as all Athenians.
Yet in Greece’s crumbling political landscape, anarchists appear to be styling themselves as a political alternative to the government.
“We want people to fight back, in all ways, from taking care of refugees to burning banks and Parliament,” said Mr. Sagris, the member of Void Network and the Embros theater group, which raises money to fund squats housing refugees. “Anarchists use all tactics, violent and nonviolent.”
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A memorial for Alexandros Grigoropoulos in Exarchia. He was 15 when he was shot by the police in 2008, setting off riots in Athens. Credit Eirini Vourloumis for The New York Times
He noted, however, that anarchists had a “moral obligation” to make sure that tragedies — like the deaths of three people in May 2010 when an Athens bank was firebombed during an anti-austerity rally — did not happen again. Though anarchists were blamed, none were convicted in a trial that ended with three bank executives convicted of manslaughter through neglect resulting from safety oversights. (They were released on bail, pending an appeal.)
Another anarchist group, Rouvikonas, is looking beyond violence, though its members have made a cause of raiding and vandalizing state offices and businesses.
Last week, members of the group, armed with large wooden sticks festooned with black anarchist flags, conducted a night patrol of a large park in central Athens, saying the police had not intervened to stop the drug trade and prostitution involving young migrants.
Mr. Toskas, who oversees the Greek police force, said the authorities had made a major dent in the drug trade in Exarchia. “Some anarchist groups want to say that they got rid of drugs in the area so that they can control it,” he said.
Rouvikonas members recently applied to a local court to found a “cultural society”— to help organize fund-raising events — and on Saturday the group presented its “political identity” at a squat in Exarchia. (Anarchists insist they are not forming a political party.)
“Anarchists obviously cannot form a political party,” said Spiros Dapergolas, 45, a graphic designer who belongs to Rouvikonas. “But we have our own means to enter the political center,” he said. “We want to get bigger.”
The group’s long-term aim is “militant unionism,” Mr. Dapergolas said. But, he conceded, it is not easy for people to organize themselves. In the meantime, he said, “what Rouvikonas is doing can be done by anyone.”