JUST IN: Scientists Seem To Be Very Interested In Cosmic Rays

There is a great deal of interest in galactic cosmic rays coming from our best space agencies and top universities. As evidenced by several recently published studies, the interest is in the relatively new understanding associated with the paradoxical effect between solar minimum and cosmic ray acceleration.

A second focused interest is the physical effects of higher rates of radiation on humans and animals. Commercial airlines are flying at lower altitudes, and pilots and flight attendants have reduced their number of long flights as well as over polar region flights.

A closer watch has been placed on the Earth’s weakening magnetic field, which of course has always been our greatest defense against charged particles. I think it also important to highlight the ongoing interest and new studies on transcranial magnetic stimulation and its effect on the brain, much of which is related to emotions.

Is it time to go underground? Should we bring out the aluminum hats and umbrellas? No, not yet anyway. I would suggest this generation and the next is not likely to be burdened with such things, but perhaps a hundred years from now there may be inter-planetary travel.

Coming in next newsletter, I will be placing perhaps five or so of the latest published studies for you to perhaps grasp and contemplate on this fascinating direction of research. Not just from looking into the future, but looking into the past.

Then of course, there will be a few of you already have an understanding of this science of cycles. Perhaps you may have even found a source who has produced the inside story on how this puzzle plays out – maybe even since 2012 :-).

Cheers, Mitch

Flux Measurement Of Light Nuclei In Cosmic Rays with CALET Experiment

The CALET Cosmic Ray experiment, led by Professor Shoji Torii from Waseda University in Japan, along with collaborators from LSU and other researchers in the U.S. and abroad, have successfully carried out the high-precision measurement of cosmic-ray electron spectrum up to 3 tera electron volts (TeV) by using the CALorimetric Electron Telescope (CALET) on the Japanese Experimental Module, the Exposed Facility on the International Space Station (ISS). This experiment is the first to make direct measurements of such high energy electrons in space.

The CALET experiment is funded by the Japanese Space Agency (JAXA), the Italian Space Agency (ASI), and NASA. John Wefel, professor emeritus in LSU’s Department of Physics and Astronomy, serves as the spokesperson for the U.S. CALET team, which includes LSU (lead U.S. institution), NASA Goddard Space Flight Center, Washington University, and the University of Denver. Other LSU researchers working with the project are PhD student Nick Cannady, research associates Doug Granger and Amir Javaid, former LSU undergraduate Anthony Ficklin, and professors of physics and astronomy Greg Guzik and Mike Cherry.

“High energy electrons are difficult to measure, but important because they potentially provide information about nearby astrophysical sources of high energy radiation and/or dark matter,” said Cherry. The CALET team published its first results in Physical Review Letters.

“The initial results provide a hint of anticipated structure in the high energy spectrum, which may indicate the presence of a nearby source of high energy particles like a pulsar or the annihilation of dark matter.”

CALET was installed on the ISS in August 2015 and has been accumulating scientific data since October 2015 with a goal of five years of operation. CALET is the first Japanese-led space-based mission dedicated to cosmic ray observations.

The origin and acceleration of cosmic rays are still one of the cosmic mysteries, and cosmic-ray electrons are one of the most important targets of high-energy cosmic ray research. However, in order to observe high-energy electrons, it is required to have (1) high-precision energy measurement of each cosmic ray particle, (2) sensitivity to detect the very rare electron flux, and (3) the capability to identify electrons buried under the over 1,000 times higher flux of cosmic ray protons. Thus the measurement of electrons above 1 TeV has been a difficult goal to achieve.

The calorimeter of CALET, with its unique and crucial capabilities, enables scientists to perform accurate measurement of cosmic-ray electrons into the TeV region thanks to the long-term exposure available on the ISS.

This measurement demonstrates the ability of CALET to do a precise direct measurement of electrons above 1 TeV that was difficult for past experiments. With five years of observations, CALET will achieve nearly six times higher statistics compared to this first result, and will allow for reduction of the systematic uncertainties, including that from the detector response.

The goal of the project is to push the energy limit to 20 TeV and to obtain the precise energy spectrum, hopefully making it possible to demonstrate definitively the presence of nearby astrophysical cosmic ray sources and/or to reveal the nature of dark matter.

Chinese Space Probe Detects Signal Hinting at ‘Dark Matter’ via Cosmic Rays

The universe is mostly made up of dark matter – a non-luminous material that scientists cannot directly observe. It’s five times more abundant than ordinary matter, which makes it one of the greatest scientific mysteries.

Scientists have been trying to crack it for decades, and Wukong’s recent measurement of energy distribution of cosmic ray electrons with energies as high as 5 tera electron Volts may shed light on this.

Researcher said this data might suggest that dark matter is not necessarily “dark”, meaning that with more data, they might be one step closer to discovering what it really is.

The annihilation and decay of dark matter particles in the Milky Way and nearby galaxies is expected to leave relics in high-energy cosmic rays and gamma rays. By observing these cosmic and gamma rays when they propagate to Earth’s neighborhood, scientists can, in turn, determine their properties and origins.

“Dark matter is not visible, but when it annihilates or decays, it produces ordinary particles that can be detected and studied,” explained Chang Jin, deputy director of Purple Mountain Observatory at the Chinese Academy of Sciences. “Wukong is able to detect, and most importantly, distinguish different particles, which can help us study them.”

“The explorer weighs 1.4 tons and the heaviest compartment is the BGO crystal calorimeter, used to detect energy of particles,” Wu Ji, director of the National Space Science Center and the Chinese Academy of Sciences, said. “Our team has developed the world’s longest crystal bars, which we’ve installed inside Wukong to expand the area of data collection.”

During the first 17 months of exploration, Wukong was able to detect 1.5 million cosmic ray electrons out of a total of 25 billion events, with unprecedented low particle background contamination and high-energy resolution.

Since it’s launch in December 2015, Wukong has recorded about 3.5 billion cosmic ray events, with a maximum event energy exceeding 100 trillion electron volts.

The satellite is expected to record more than 10 billion cosmic ray events in the next few years. By collecting more data, scientists are hoping they will gain new insight into the nature of dark matter.

Oldest Ice Core Ever Drilled Outside The Polar Regions

The oldest ice core ever drilled outside the polar regions may contain ice that formed during the Stone Age — more than 600,000 years ago, long before modern humans appeared.

Researchers from the United States and China are now studying the core — nearly as long as the Empire State Building is tall — to assemble one of the longest-ever records of Earth’s climate history.

What they’ve found so far provides dramatic evidence of a recent and rapid temperature rise at some of the highest, coldest mountain peaks in the world.

At the American Geophysical Union meeting on Thursday, Dec. 14, they report that there has been a persistent increase in both temperature and precipitation in Tibet’s Kunlun Mountains over the last few centuries. The change is most noticeable on the Guliya Ice Cap, where they drilled the latest ice core. In this region, the average temperature has risen 1.5 degrees Celsius (2.7 degrees Fahrenheit) in the last 50 years and the average precipitation has risen by 2.1 inches per year over the past 25 years.

Lonnie Thompson, Distinguished University Professor in the School of Earth Sciences at The Ohio State University and co-leader of the international research team, said that the new data lend support to computer models of projected climate changes.

“The ice cores actually demonstrate that warming is happening, and is already having detrimental effects on Earth’s freshwater ice stores,” Thompson said.

Earth’s largest supply of freshwater ice outside of the Arctic and Antarctica resides in Tibet — a place that was off limits to American glaciologists until 20 years ago, when Ohio State’s Byrd Polar and Climate Research Center (BPCRC) began a collaboration with China’s Institute of Tibetan Plateau Research. There, glaciologist Yao Tandong secured funding for a series of joint expeditions from the Chinese Academy of Sciences.

“The water issues created by melting ice on the Third Pole, along with that from the Arctic and Antarctica, have been recognized as important contributors to the rise in global sea level. Continued warming in these regions will result in even more ice melt with the likelihood of catastrophic environmental consequences,” Yao noted.

The name “Third Pole” refers to high mountain glaciers located on the Tibetan Plateau and in the Himalaya, in the Andes in South America, on Kilimanjaro in Africa, and in Papua, Indonesia — all of which have been studied by the Ohio State research team.

Of particular interest to the researchers is a projection from the Intergovernmental Panel on Climate Change that future temperatures on the planet will rise faster at high altitudes than they will at sea level. The warming at sea level is expected to reach 3 degrees Celsius by the year 2100, and possibly double that, or 6 degrees Celsius, at the highest mountain peaks in the low latitudes.

“The stable isotopic records that we’ve obtained from five ice cores drilled across the Third Pole document climate changes over the last 1,000 years, and contribute to a growing body of evidence that environmental conditions on the Third Pole, along with the rest of the world, have changed significantly in the last century,” Thompson said. “Generally, the higher the elevation, the greater the rate of warming that’s taking place.”

Around the world, hundreds of millions of people depend on high-altitude glaciers for their water supply. The Guliya Ice Cap is one of many Tibetan Plateau ice caches that provide fresh water to Central, South, and Southeast Asia.

“There are over 46,000 mountain glaciers in that part of the world, and they are the water source for major rivers,” Thompson said.

In September and October of 2015, the team ventured to Guliya and drilled through the ice cap until they hit bedrock. They recovered five ice cores, one of which is more than 1,000 feet long.

The cores are composed of compressed layers of snow and ice that settled on the western Kunlun Mountains year after year. In each layer, the ice captured chemicals from the air and precipitation during wet and dry seasons. Today, researchers analyze the chemistry of the different layers to measure historical changes in climate.

Based on dating of radioactive elements measured by scientists at the Swiss research center ETH Zurich, the ice at the base of the core may be at least 600,000 years old.

The oldest ice core drilled in the Northern Hemisphere was found in Greenland in 2004 by the North Greenland Ice Core Project and was dated to roughly 120,000 years, while the oldest continuous ice core record recovered on Earth to date is from Antarctica, and extends back 800,000.

Over the next few months, the American and Chinese research teams will analyze the chemistry of the core in detail. They will look for evidence of temperature changes caused by ocean circulation patterns in both the North Atlantic and tropical Pacific Oceans, which drive precipitation in Tibet as well as the Indian monsoons. For instance, one important driver of global temperatures, El Niño, leaves its chemical mark in the snow that falls on tropical glaciers.

Ultimately, researchers hope the work will reveal the linkages that exist between ice loss in tropical mountain glaciers and climate processes elsewhere on the planet. Thompson, Yao, and German ecologist Volker Mosbrugger are co-chairing a Third Pole Environment Program to focus on basic science and policy-relevant issues.

“The more we study the different components of the environment of the Third Pole, the better we understand climate change and its linkages among Earth’s three polar regions,” Yao said.

Mars Mission Sheds Light On Habitability Of Distant Planets

How long might a rocky, Mars-like planet be habitable if it were orbiting a red dwarf star? It’s a complex question but one that NASA’s Mars Atmosphere and Volatile Evolution mission can help answer.

“The MAVEN mission tells us that Mars lost substantial amounts of its atmosphere over time, changing the planet’s habitability,” said David Brain, a MAVEN co-investigator and a professor at the Laboratory for Atmospheric and Space Physics at the University of Colorado Boulder. “We can use Mars, a planet that we know a lot about, as a laboratory for studying rocky planets outside our solar system, which we don’t know much about yet.”

At the fall meeting of the American Geophysical Union on Dec. 13, 2017, in New Orleans, Louisiana, Brain described how insights from the MAVEN mission could be applied to the habitability of rocky planets orbiting other stars.

MAVEN carries a suite of instruments that have been measuring Mars’ atmospheric loss since November 2014. The studies indicate that Mars has lost the majority of its atmosphere to space over time through a combination of chemical and physical processes. The spacecraft’s instruments were chosen to determine how much each process contributes to the total escape.

In the past three years, the Sun has gone through periods of higher and lower solar activity, and Mars also has experienced solar storms, solar flares and coronal mass ejections. These varying conditions have given MAVEN the opportunity to observe Mars’ atmospheric escape getting cranked up and dialed down.

Brain and his colleagues started to think about applying these insights to a hypothetical Mars-like planet in orbit around some type of M-star, or red dwarf, the most common class of stars in our galaxy.

The researchers did some preliminary calculations based on the MAVEN data. As with Mars, they assumed that this planet might be positioned at the edge of the habitable zone of its star. But because a red dwarf is dimmer overall than our Sun, a planet in the habitable zone would have to orbit much closer to its star than Mercury is to the Sun.

The brightness of a red dwarf at extreme ultraviolet (UV) wavelengths combined with the close orbit would mean that the hypothetical planet would get hit with about 5 to 10 times more UV radiation than the real Mars does. That cranks up the amount of energy available to fuel the processes responsible for atmospheric escape. Based on what MAVEN has learned, Brain and colleagues estimated how the individual escape processes would respond to having the UV cranked up.

Their calculations indicate that the planet’s atmosphere could lose 3 to 5 times as many charged particles, a process called ion escape. About 5 to 10 times more neutral particles could be lost through a process called photochemical escape, which happens when UV radiation breaks apart molecules in the upper atmosphere.

Because more charged particles would be created, there also would be more sputtering, another form of atmospheric loss. Sputtering happens when energetic particles are accelerated into the atmosphere and knock molecules around, kicking some of them out into space and sending others crashing into their neighbors, the way a cue ball does in a game of pool.

Finally, the hypothetical planet might experience about the same amount of thermal escape, also called Jeans escape. Thermal escape occurs only for lighter molecules, such as hydrogen. Mars loses its hydrogen by thermal escape at the top of the atmosphere. On the exo-Mars, thermal escape would increase only if the increase in UV radiation were to push more hydrogen to the top of the atmosphere.

Altogether, the estimates suggest that orbiting at the edge of the habitable zone of a quiet M-class star, instead of our Sun, could shorten the habitable period for the planet by a factor of about 5 to 20. For an M-star whose activity is amped up like that of a Tasmanian devil, the habitable period could be cut by a factor of about 1,000 — reducing it to a mere blink of an eye in geological terms. The solar storms alone could zap the planet with radiation bursts thousands of times more intense than the normal activity from our Sun.

However, Brain and his colleagues have considered a particularly challenging situation for habitability by placing Mars around an M-class star. A different planet might have some mitigating factors — for example, active geological processes that replenish the atmosphere to a degree, a magnetic field to shield the atmosphere from stripping by the stellar wind, or a larger size that gives more gravity to hold on to the atmosphere.

“Habitability is one of the biggest topics in astronomy, and these estimates demonstrate one way to leverage what we know about Mars and the Sun to help determine the factors that control whether planets in other systems might be suitable for life,” said Bruce Jakosky, MAVEN’s principal investigator at the University of Colorado Boulder.

Chemical Tipping Point Of Magma Determines Explosive Potential Of Volcanoes

Volcanic eruptions are the most spectacular expression of the processes acting in the interior of any active planet. Effusive eruptions consist of a gentle and steady flow of lava on the surface, while explosive eruptions are violent phenomena that can eject hot materials up to several kilometres into the atmosphere.

The transition between these eruptions represents one of the most dangerous natural hazards.

Understanding the mechanisms governing such transition has inspired countless studies in Earth Sciences over the last decades.

In a new study led by Dr Danilo Di Genova, from the University of Bristol’s School of Earth Sciences, an international team of scientists provide evidence, for the first time, that a subtle tipping point of the chemistry of magmas clearly separates effusive from explosive eruptions worldwide.

Moreover, they demonstrate that variabilities at the nanoscale of magmas can dramatically increase the explosive potential of volcanoes.

Dr Di Genova said: “The new experimental data, thermodynamic modelling and analysis of compositional data from the global volcanic record we presented in our study provide combined evidence for a sudden discontinuity in the flow behaviour of rhyolitic magmas that guides whether a volcano erupts effusively or explosively.

“The identified flow-discontinuity can be crossed by small compositional changes in rhyolitic magmas and can be induced by crystallisation, assimilation, magma replenishment or mixing.

“Composition-induced flow behaviour variations may also originate from changes in magmas intrinsic parameters such as temperature, pressure or oxygen fugacity.”

These can result in revitalization of a previously “locked” magma chamber via chemical fluidification or may hinder efficient degassing and lead to increased explosive potential via chemical “stiffening” of a magma.

Furthermore, the study showed how the sudden precipitation of iron-bearing nanocrystals, which have been recently found in volcanic rocks, can increase the explosive potential of a magma via both depletion of iron in the melt structure and providing nucleation points for gas bubbles which drive explosive eruption.

Residual Strain Despite Mega Earthquake

On Christmas Day 2016, the earth trembled in southern Chile. In the same region, the strongest earthquake ever measured occurred in 1960. A comparison of data from seismic and geodetic measurements during and after both earthquakes shows that the energy released by the 2016 quake accumulated over more than 56 years. According to this, the 1960 quake, despite its immense strength, must have left some strain in the underground. The study has now been published in the journal Geophysical Journal International.

On 22 May 1960, an earthquake shook the southern Chilean continental margin on a length of about 1,000 kilometers. Estimates suggest that around 1,600 people died as a direct result of the quake and the following tsunami, leaving around two million people homeless. With a strength of 9.5 on the moment magnitude scale, the Valdivia earthquake from 1960 still ranks number one on the list of strongest earthquakes ever measured.

More than half a century later, on 25 December 2016, the earth was trembling around the southern Chilean island of Chiloé. With a strength of 7,5 Mw this event can be described as rather moderate by Chilean standards. But the fact that it broke the same section of the Chilean subduction zone as the 1960 earthquake is quite interesting for scientists. As researchers from the GEOMAR Helmholtz Centre for Ocean Research Kiel and the Universidad de Chile have now published in the journal Geophysical Journal International, part of the energy of the 2016 quake apparently dates back to before 1960. “So, the 1960 quake, despite its immense strength, must have left some strain in the underground, ” says Dr. Dietrich Lange, geophysicist at GEOMAR and lead author of the study.

To understand why Chile is being hit so frequently by heavy earthquakes, one has to look at the seabed off the coast. It belongs to the so-called Nazca plate, a tectonic plate, which moves eastwards with a rate of 6.6 cm per year. Off the Chilean coast it collides with the South American plate and is submerged beneath it. In this process, strains build up between the plates – until they break and the earth trembles.

During such an earthquake, the strain is released within minutes. During the 1960 earthquake for example, the plates shifted by more than 30 meters against each other. As a result, landmasses were lifted up or down several meters with a fundamental change of Chilean landscapes and coastline. “The scale of the slip also gives information about the accumulated energy between the two plates,” explains Dr. Lange.

From the time interval (56 years), the known speed of the Nazca plate, and further knowledge of the subduction zone, the German-Chilean team has calculated the accumulated energy and thus the theoretical slip of the 2016 earthquake to about 3.4 meters. But the analysis of seismic data and GPS surveys showed a slip of more than 4.5 m. “The strain must have had accumulated for more than 56 years. It is older than the last earthquake in the same region,” says Dr. Lange.

Similar results have recently been obtained in another subduction zones. Along with them, the new study suggests that for risk assessment in earthquake-prone areas, not just a single seismic cycle from one earthquake to the next should be considered. “The energy can be greater than that resulting from the usual calculations, which can, for example, have an impact on recommendations for earthquake-proof construction,” says Dr. Lange.