Lightning, With A Chance Of Antimatter

In a collaborative study appearing in Nature, researchers from Japan describe how gamma rays from lightning react with the air to produce radioisotopes and even positrons — the antimatter equivalent of electrons.

“We already knew that thunderclouds and lightning emit gamma rays, and hypothesized that they would react in some way with the nuclei of environmental elements in the atmosphere,” explains Teruaki Enoto from Kyoto University, who leads the project.

“In winter, Japan’s western coastal area is ideal for observing powerful lightning and thunderstorms. So, in 2015 we started building a series of small gamma-ray detectors, and placed them in various locations along the coast.”

But then the team ran into funding problems. To continue their work, and in part to reach out to a wide audience of potentially interested members of the public as quickly as possible, they turned to the internet.

“We set up a crowdfunding campaign through the ‘academist’ site,” continues Enoto, “in which we explained our scientific method and aims for the project. Thanks to everybody’s support, we were able to make far more than our original funding goal.”

Spurred by their success, the team built more detectors and installed them across the northwest coast of Honshu. And then in February 2017, four detectors installed in Kashiwazaki city, Niigata recorded a large gamma-ray spike immediately after a lightning strike a few hundred meters away.

It was the moment the team realized they were seeing a new, hidden face of lightning.

When they analyzed the data, the scientists found three distinct gamma-ray bursts. The first was less than one millisecond in duration; the second was a gamma-ray afterglow that decayed over several dozens of milliseconds; and finally there was a prolonged emission lasting about one minute.

Enoto explains, “We could tell that the first burst was from the lightning strike. Through our analysis and calculations, we eventually determined the origins of the second and third emissions as well.”

The second afterglow, for example, was caused by lightning reacting with nitrogen in the atmosphere. The gamma rays emitted in lightning have enough energy to knock a neutron out of atmospheric nitrogen, and it was the reabsorption of this neutron by particles in the atmosphere that produced the gamma-ray afterglow.

The final, prolonged emission was from the breakdown of now neutron-poor and unstable nitrogen atoms. These released positrons, which subsequently collided with electrons in annihilation events releasing gamma rays.

“We have this idea that antimatter is something that only exists in science fiction. Who knew that it could be passing right above our heads on a stormy day?” says Enoto.

“And we know all this thanks to our supporters who joined us through ‘academist’. We are truly grateful to all.”

The team still maintains over ten detectors on the coast of Japan, and are continually collecting data. They look forward to new discoveries that may await them, and Enoto hopes to continue seeing the participation of ordinary citizens in research, expanding the bounds of scientific discovery.

How The Earth Stops High-Energy Neutrinos In Their Tracks

For the first time, a science experiment has measured Earth’s ability to absorb neutrinos — the smaller-than-an-atom particles that zoom throughout space and through us by the trillions every second at nearly the speed of light. The experiment was achieved with the IceCube detector, an array of 5,160 basketball-sized sensors frozen deep within a cubic kilometer of very clear ice near the South Pole. The results of this experiment by the IceCube collaboration, which includes Penn State physicists, will be published in the online edition of the journal Nature on November 22, 2017.

“This achievement is important because it shows, for the first time, that very-high-energy neutrinos can be absorbed by something — in this case, the Earth,” said Doug Cowen, professor of physics and astronomy & astrophysics at Penn State. The first detections of extremely-high-energy neutrinos were made by IceCube in 2013, but a mystery remained about whether any kind of matter could truly stop a neutrino’s journey through space. “We knew that lower-energy neutrinos pass through just about anything,” Cowen said, “but although we had expected higher-energy neutrinos to be different, no previous experiments had been able to demonstrate convincingly that higher-energy neutrinos could be stopped by anything.”

The results in the Nature paper are based on one year of data from about 10,800 neutrino-related interactions. Cowen and Tyler Anderson, an assistant research professor of physics at Penn State, are members of the IceCube collaboration. They are coauthors of the Nature paper who helped to build the IceCube detector and are contributing to its maintenance and management.

This new discovery with IceCube is an exciting addition to our deepening understanding of how the universe works. It also is a little bit of a disappointment for those who hope for an experiment that will reveal something that cannot be explained by the current Standard Model of Particle Physics. “The results of this Ice Cube study are fully consistent with the Standard Model of Particle Physics — the reigning theory that for the past half century has described all the physical forces in the universe except gravity,” Cowen said.

Neutrinos first were formed at the beginning of the universe, and they continue to be produced by stars throughout space and by nuclear reactors on Earth. “Understanding how neutrinos interact is key to the operation of IceCube,” explained Francis Halzen, principal investigator for the IceCube Neutrino Observatory and a University of Wisconsin-Madison professor of physics. “We were of course hoping for some new physics to appear, but we unfortunately find that the Standard Model, as usual, withstands the test,” Halzen said.

IceCube’s sensors do not directly observe neutrinos, but instead measure flashes of blue light, known as Cherenkov radiation, emitted after a series of interactions involving fast-moving charged particles that are created when neutrinos interact with the ice. By measuring the light patterns from these interactions in or near the detector array, IceCube can estimate the neutrinos’ energies and directions of travel. The scientists found that the neutrinos that had to travel the farthest through Earth were less likely to reach the detector.

Most of the neutrinos selected for this study were more than a million times more energetic than the neutrinos produced by more familiar sources, like the Sun or nuclear power plants. The analysis also included a small number of astrophysical neutrinos, which are produced outside the Earth’s atmosphere, from cosmic accelerators unidentified to date, perhaps associated with supermassive black holes.

“Neutrinos have quite a well-earned reputation of surprising us with their behavior,” says Darren Grant, spokesperson for the IceCube Collaboration, a professor of physics at the University of Alberta in Canada, and a former postdoctoral scholar at Penn State. “It is incredibly exciting to see this first measurement and the potential it holds for future precision tests.”

In addition to providing the first measurement of the Earth’s absorption of neutrinos, the analysis shows that IceCube’s scientific reach extends beyond its core focus on particle physics discoveries and the emerging field of neutrino astronomy into the fields of planetary science and nuclear physics. This analysis also is of interest to geophysicists who would like to use neutrinos to image the Earth’s interior in order to explore the boundary between the Earth’s inner solid core and its liquid outer core.

“IceCube was built to both explore the frontiers of physics and, in doing so, possibly challenge existing perceptions of the nature of universe. This new finding and others yet to come are in that spirt of scientific discovery,” said James Whitmore, program director in the National Science Foundation’s physics division. Physicists now hope to repeat the study using an expanded, multiyear analysis of data from the full 86-string IceCube array, and to look at higher ranges of neutrino energies for any hints of new physics beyond the Standard Model.

Iceland’s Biggest Active Volcano Shows Signs Of Reawakening

Iceland’s biggest active volcano is being kept under close surveillance amid signs it is waking up after centuries of slumber.

A new 1km-wide caldera – a basin-shaped volcanic depression – has been discovered by scientists in Öræfajökull, which translates as “wasteland”, in the south of the island.

The Icelandic Met Office has also received reports of the surrounding area smelling of sulphur, while geothermal water has been released from the volcano into a river on the surrounding glacier, reports Iceland Magazine.

Scientists believe this water caused a section of the volcano to collapse, producing the new caldera.

Although scientists say there are no imminent signs of an eruption, Iceland’s Civil Protection Agency has declared an uncertainty phase – a warning that there may be a threat in the near future – while its Met Office has issued a yellow warning.

Bryndís Ýr Gísladóttir, natural resource specialist at the Met Office, told newspaper Morgunbladid: “We issued a yellow warning for security reasons because we actually don’t know that much about Öræfajökull glacier, nor how it behaves because its last eruption occurred in 1727, and 1362 before that.”

Öræfajökull features Iceland’s highest peak and is thought to be one of the most powerful volcanoes in Europe. It is responsible for the country’s second deadliest eruption after a steam blast in 1362 deposited 10 cubic kilometres of debris across farmland and killed all inhabitants across dozens of farms.

Although still sparsely populated, the region can attract thousands of tourists at the height of the holiday season. The Icelandic Civil Protection Agency estimates there would only be a 20-minute warning before any eruption.

The volcano last erupted in 1727, and as a result volcanologists have a limited ability to predict when any eruption would occur.

With the growing seismic and geothermal activity of recent weeks, monitoring of the volcano is being increased.

Several Villages Hit By Volcanic Ash After Mt. Agung Erupts In Bali

Volcanic ash has fallen onto a number of villages surrounding Mount Agung in Bali following an eruption at the island’s tallest volcano on Tuesday afternoon, less than a month after the alert level was lowered.

At least five villages were affected by the ash, including Pidpid, Nawakerti, Bukit Galah, Sebudi and Abang Village. The villages are located within the danger zone of the volcano, kompas.com reported.

Authorities from the Energy and Mineral Resources Ministry’s Volcanology and Geological Hazard Mitigation Center (PVMBG) visited the villages following reports from local residents’ to authorities at the Mount Agung monitoring station.

“The PVMBG Emergency Response Team found [volcanic] ash, however, the intensity of the ash [falling on the villages] is still light,” head of mitigation sub-directorate at PVMBG, Devi Kemal, said on Tuesday evening.

Devi further advised residents not to panic and follow the authorities instructions. “Everyone should remain calm and follow PVMBG recommendations,” Devi said.

Mount Agung, which has been experiencing increased activity in recent months, erupted and spewed black smoke at 5:05 p.m. on Tuesday, with the height of the smoke reaching more than 700 meters from the peak of the mountain.

Residents are advised to stay away from areas within a 6 kilometer radius of the volcano. The volcano’s status is set at the third highest alert level, the National Disaster Mitigation Agency (BNPB) has previously said.

The alert level for the volcano that had forced more than 100,000 residents to flee was lowered late last month, from the highest level to the third highest level, although authorities said there was still a chance of eruption.

Smart People Have Better Connected Brains

Differences in intelligence have so far mostly been attributed to differences in specific brain regions. However, are smart people’s brains also wired differently to those of less intelligent persons? A new study supports this assumption. In intelligent persons, certain brain regions are more strongly involved in the flow of information between brain regions, while other brain regions are less engaged.

Understanding the foundations of human thought is fascinating for scientists and laypersons alike. Differences in cognitive abilities — and the resulting differences for example in academic success and professional careers — are attributed to a considerable degree to individual differences in intelligence. A study just published in Scientific Reports shows that these differences go hand in hand with differences in the patterns of integration among functional modules of the brain. Kirsten Hilger, Christian Fiebach and Ulrike Basten from the Department of Psychology at Goethe University Frankfurt combined functional MRI brain scans from over 300 persons with modern graph theoretical network analysis methods to investigate the neurobiological basis of human intelligence.

Already in 2015, the same research group published a meta-study in the journal Intelligence, in which they identified brain regions — among them the prefrontal cortex — activation changes of which are reliably associated with individual differences in intelligence. Until recently, however, it was not possible to examine how such ‘intelligence regions’ in the human brain are functionally interconnected.

Earlier this year, the research team reported that in more intelligent persons two brain regions involved in the cognitive processing of task-relevant information (i.e., the anterior insula and the anterior cingulate cortex) are connected more efficiently to the rest of the brain (2017, Intelligence). Another brain region, the junction area between temporal and parietal cortex that has been related to the shielding of thoughts against irrelevant information, is less strongly connected to the rest of the brain network. “The different topological embedding of these regions into the brain network could make it easier for smarter persons to differentiate between important and irrelevant information — which would be advantageous for many cognitive challenges,” proposes Ulrike Basten, the study’s principle investigator.

In their current study, the researchers take into account that the brain is functionally organized into modules. “This is similar to a social network which consists of multiple sub-networks (e.g., families or circles of friends). Within these sub-networks or modules, the members of one family are more strongly interconnected than they are with people from other families or circles of friends. Our brain is functionally organized in a very similar way: There are sub-networks of brain regions — modules — that are more strongly interconnected among themselves while they have weaker connections to brain regions from other modules. In our study, we examined whether the role of specific brain regions for communication within and among brain modules varies with individual differences in intelligence, i.e., whether a specific brain region supports the information exchange within their own ‘family’ more than information exchange with other ‘families’, and how this relates to individual differences in intelligence.”

The study shows that in more intelligent persons certain brain regions are clearly more strongly involved in the exchange of information between different sub-networks of the brain in order for important information to be communicated quickly and efficiently. On the other hand, the research team also identified brain regions that are more strongly ‘de-coupled’ from the rest of the network in more intelligent people. This may result in better protection against distracting and irrelevant inputs. “We assume that network properties we have found in more intelligent persons help us to focus mentally and to ignore or suppress irrelevant, potentially distracting inputs,” says Basten. The causes of these associations remain an open question at present. “It is possible that due to their biological predispositions, some individuals develop brain networks that favor intelligent behaviors or more challenging cognitive tasks. However, it is equally as likely that the frequent use of the brain for cognitively challenging tasks may positively influence the development of brain networks. Given what we currently know about intelligence, an interplay of both processes seems most likely.”

Unexpected Atmospheric Vortex Behavior On Saturn’s Moon Titan

A new study led by a University of Bristol earth scientist has shown that recently reported unexpected behaviour on Titan, the largest moon of Saturn, is due to its unique atmospheric chemistry.

Titan’s polar atmosphere recently experiences and unexpected and significant cooling, contrary to all model predictions and differing from the behaviour of all other terrestrial planets in our solar system.

Titan is the largest moon of Saturn, is bigger than the planet Mercury, and is the only moon in our solar system to have a substantial atmosphere.

Usually, the high altitude polar atmosphere in a planet’s winter hemisphere is warm because of sinking air being compressed and heated — similar to what happens in a bicycle pump.

Puzzlingly, Titan’s atmospheric polar vortex seems to be extremely cold instead.

Before its fiery demise in Saturn’s atmosphere on September 15, the Cassini spacecraft obtained a long series of observations of Titan’s polar atmosphere covering nearly half of Titan’s 29.5 earth-year long year using the Composite Infrared Spectrometer (CIRS) instrument.

The Cassini/CIRS observations showed that while the excepted polar hot spot did begin to develop at the start of winter in 2009, this soon developed into a cold spot in 2012, with temperatures as low as 120 K being observed until late 2015.

Only in the most recent 2016 and 2017 observations has the expected hot-spot returned.

Lead author Dr Nick Teanby from the University of Bristol’s School of Earth Sciences, said: “For Earth, Venus, and Mars, the main atmospheric cooling mechanism is infrared radiation emitted by the trace gas CO2 and because CO2 has a long atmospheric lifetime it is well mixed at all atmospheric levels and is hardly affected by atmospheric circulation.

“However, on Titan, exotic photochemical reactions in the atmosphere produce hydrocarbons such as ethane and acetylene, and nitriles including hydrogen cyanide and cyanoacetylene, which provide the bulk of the cooling.”

These gases are produced high in the atmosphere, so have a steep vertical gradient, meaning that their abundances can be significantly modified by even modest vertical atmospheric circulations.

Therefore, winter polar subsidence led to massive enrichments of these radiatively active gases over the southern winter pole.

Researchers used the temperature and gas abundances measured with Cassini, coupled with a numerical radiative balance model of heating and cool rates, to show that trace gas enrichment was large enough to cause significant cooling and extremely cold atmospheric temperatures.

This explains earlier observations of strange hydrogen cyanide ice clouds that were observed over the pole in 2014 with Cassini’s cameras.

Dr Teanby added: “This effect is so far unique in the solar system and is only possible because of Titan’s exotic atmospheric chemistry. “A similar effect could also be occurring in many exoplanet atmospheres having implications for cloud formation and atmospheric dynamics.”

Ice Shapes The Landslide Landscape On Mars

How good is your Martian geography? Does Valles Marineris ring a bell? This area is known for having landslides that are among the largest and longest in the entire solar system. They make the perfect object of study due to their steep collapse close to the scarp, extreme thinning, and long front runout. In a new research paper published in EPJ Plus, Fabio De Blasio and colleagues from Milano-Bicocca University, Italy, explain the extent to which ice may have been an important medium of lubrication for landslides on Mars. This can in turn help us understand the geomorphological history of the planet and the environment of deposition.

The authors noted that the landslides in Valles Marineris are of similar shape as ice-lubricated landslides on Earth. In their paper, they feed these observations, combined with remote sensing measurements showing the presence of massive ice under the soil, into a numerical simulation exploring the possibility that such landslides were lubricated by ice.

They then explore two possible scenarios to explain what happens to landslides rocks: one in which ice is only present at the base, and another in which ice impregnates the soil. To reproduce the vertical collapse of landslide material in the landslide scarp area and the extreme thinning and runout in the front, the model must take into account the presence of ice in the calculations.

The authors, therefore, demonstrate how the presence of ice, exposed on the ground or in the collapsing slope, could affect the shape and velocity of these landslides. The calculated velocity of landslides are often well in excess of 100 m/s and up to 200 m/s at peak. The authors then compare the results of the numerical simulations with real images and elevation profiles, allowing them to draw conclusions regarding the influence of the climate on shaping Martian landscapes.