BREAKING NEWS: Scientists to Determine Recent Supernovae Responsible for Earth’s Previous Mass Extinction

Dr Brian Thomas, an astrophysicist at Washburn University in Kansas, USA, modeled the biological impacts at the Earth’s surface, based on geologic evidence of nearby supernovae 2.5 million and 8 million years ago. In his latest paper, Thomas investigated cosmic rays from the supernovae as they propagated through our atmosphere to the surface, to understand their effect on living organisms.

How would a nearby supernova affect life on Earth? Thomas laments that supernovae often are exemplified as “supernova goes off and everything dies”, but that is not quite the case. The answer lies in the atmosphere. Beyond sunscreen, the ozone layer protects all biology from harmful, genetically altering ultraviolet (UV) radiation. Thomas used global climate models, recent atmospheric chemistry models and radiative transfer (the propagation of radiation through the layers of the atmosphere) to better understand how the flux of cosmic rays from supernovae would alter Earth’s atmosphere, specifically the ozone layer.

One thing to note is that cosmic rays from supernovae would not blast everything in their paths all at once. The intergalactic medium acts as a kind of sieve, slowing down the arrival of cosmic rays and “radioactive iron rain” (60Fe) over hundreds of thousands of years, Thomas tells Astrobiology Magazine. Higher energetic particles will reach Earth first and interact with our atmosphere differently than lower energy particles arriving later. Thomas’s study modeled the depletion in ozone 100, 300, and 1,000 years after the initial particles from a supernova began penetrating our atmosphere. Interestingly, depletion peaked (at roughly 26 percent) for the 300-year case, beating out the 100-year case.

The high-energy cosmic rays in the 100-year case would zip right through the stratosphere and deposit their energy below the ozone layer, depleting it less, while the less energetic cosmic rays arriving during the 300-year interval would deposit more energy in the stratosphere, depleting ozone significantly.

A decrease in ozone could be a concern for life on the surface. “This work is an important step towards understanding the impact of nearby supernovae on our biosphere,” says Dr Dimitra Atri, a computational physicist at the Blue Marble Space Institute of Science in Seattle, USA.

Thomas examined several possible biologically-damaging effects (erythema, skin cancer, cataracts, marine phytoplankton photosynthesis inhibition and plant damage) at different latitudes as a result of increased UV radiation resulting from a depleted ozone layer. They showed heightened damage across the board, generally increasing with latitude, which makes sense given the changes we see in the fossil record. However, the effects aren’t equally detrimental to all organisms. Plankton, the primary producers of oxygen, seemed to be minimally affected. The results also suggested a small increase in the risk of sunburn and skin cancer among humans.

So, do nearby supernovae result in mass extinctions? It depends, says Thomas. “There is a subtler shift; instead of a ‘wipe-out everything’, some [organisms] are better off and some are worse off.” For example some plants showed increase yield, like soybean and wheat, while other plants showed reduced productivity.  “It fits,” Thomas states, referring to the change in species in the fossil record.

In the future, Thomas hopes to expand on this work and examine possible linkages between human evolution and supernovae.

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Scientists Devise New Method to Locate Dark Matter Axions

Recently, the Department of Energy’s Pacific Northwest National Laboratory (PNNL) researchers, helped shed light on the possible existence of dark matter – called “dark” because it is invisible to today’s telescopes – that may be responsible for gravitational effects that can be detected but not explained by the matter we can observe.

PNNL scientists apply their expertise in physics, chemistry, materials science and engineering to advance our understanding of nuclear and particle physics. Their research delves deep into questions about the universe and its origin, its unseen building blocks, and how the forces within it work together.

The existence of dark matter and its resulting gravitational effects would help to explain how galaxies formed. Scientists are convinced that dark matter far outweighs observable matter in the universe, but there is still much they do not know.

Theories predict that dark matter is composed of fundamental sub-atomic particles that have yet to be discovered, including one dubbed the “axion.” Last month, a large international collaboration of scientists announced the creation of an ultra-sensitive device that can “hear” the telltale signs of dark matter axions while tuning out the electromagnetic “noise” that makes them difficult to detect.

In this project, PNNL used its state-of-the-art microwave engineering and modeling expertise to help design a highly sensitive microwave receiver that “listens” for and identifies the weak axion signal. This same capability underpins the millimeter-wave security scanners used to screen passengers at airports.

In a different collaboration, PNNL is involved in another of the world’s most sensitive dark matter experiments. This one will search for a different class of theorized dark matter particles called weakly interacting massive particles, or WIMPs. Rather than “listening” for these particles, this project seeks to measure WIMP dark matter with a highly sensitive radiation detector.

PNNL researchers are helping to design this detector, which must be made of materials with ultra-low levels of naturally occurring radioactivity so as not to interfere with the measurements they seek.

A New Map For A Birthplace Of Stars

A Yale-led research group has created the most detailed maps yet of a vast seedbed of stars similar to Earth’s Sun.

The maps provide unprecedented detail of the structure of the Orion A molecular cloud, the closest star-forming region of high-mass stars. Orion A hosts a variety of star-forming environments, including dense star clusters similar to the one where Earth’s Sun is believed to have formed.

“Our maps probe a wide range of physical scales needed to study how stars form in molecular clouds, and how young stars impact their parent cloud,” said Yale postdoctoral associate Shuo Kong, first author of a study about the group’s research that appears in the Astrophysical Journal Supplement.

The research team includes astronomers from institutions in the U.S., Chile, Japan, France, Germany, Spain, and the U.K. The team’s principal investigators are Yale astronomy professor Héctor G. Arce, ALMA Observatory scientist John Carpenter, and Caltech astronomy professor Anneila Sargent.

Kong said the team constructed its maps of the Orion A cloud by combining data from a single-dish telescope and an interferometer. The Yale Center for Research Computing assisted in handling the large dataset and producing the images.

The dataset and maps are collectively known as the CARMA-NRO Orion Survey. The name refers to the Combined Array for Research in Millimeter Astronomy (CARMA), an interferometer that was located in California, and the Nobeyama Radio Observatory (NRO) telescope, in Japan.

“Our survey is a unique combination of data from two very different telescopes,” said Yale graduate student Jesse Feddersen, a co-author of the study. “We have combined the zoom of CARMA with the wide-angle of NRO to simultaneously capture the details of individual forming stars and the overall shape and motions of the giant molecular cloud.”

In addition, the maps will help researchers calibrate star formation models for extragalactic studies. “The data we provide here will benefit research on a broad range of evolutionary stages of the star formation process and on the environment stars form,” Arce said.

Yale graduate student María José Maureira is also a co-author of the study.

“The combined observations are a great help for astronomers seeking to understand how fast and efficiently stars form. For example, their maps show the energy released by high-mass stars has a strong impact on the cloud environment,” said Glen Langston, program director at the National Science Foundation. The research was supported by the National Science Foundation.

Hurricanes: Stronger, Slower, Wetter In The Future?

Scientists have developed a detailed analysis of how 22 recent hurricanes would be different if they formed under the conditions predicted for the late 21st century.

While each storm’s transformation would be unique, on balance, the hurricanes would become a little stronger, a little slower-moving, and a lot wetter.

In one example, Hurricane Ike — which killed more than 100 people and devastated parts of the U.S. Gulf Coast in 2008 — could have 13 percent stronger winds, move 17 percent slower, and be 34 percent wetter if it formed in a future, warmer climate.

Other storms could become slightly weaker (for example, Hurricane Ernesto) or move slightly faster (such as Hurricane Gustav). None would become drier. The rainfall rate of simulated future storms would increase by an average of 24 percent.

The study, led by scientists at the National Center for Atmospheric Research (NCAR) and published in the Journal of Climate, compares high-resolution computer simulations of more than 20 historical, named Atlantic storms with a second set of simulations that are identical but for a warmer, wetter climate that’s consistent with the average scientific projections for the end of the century.

A future with Hurricane Harvey-like rains

“Our research suggests that future hurricanes could drop significantly more rain,” said NCAR scientist Ethan Gutmann, who led the study. “Hurricane Harvey demonstrated last year just how dangerous that can be.”

Harvey produced more than 4 feet of rain in some locations, breaking records and causing devastating flooding across the Houston area.

The research was funded by the National Science Foundation (NSF), which is NCAR’s sponsor, and by DNV GL (Det Norske Veritas Germanischer Lloyd), a global quality assurance and risk management company.

“This study shows that the number of strong hurricanes, as a percent of total hurricanes each year, may increase,” said Ed Bensman, a program director in NSF’s Division of Atmospheric and Geospace Sciences, which supported the study. “With increasing development along coastlines, that has important implications for future storm damage.”

Tapping a vast dataset to see storms

With more people and businesses relocating to coastal regions, the potential influence of environmental change on hurricanes has significant implications for public safety and the economy.

Last year’s hurricane season, which caused an estimated $215 billion in losses according to reinsurance company Munich RE, was the costliest on record.

It’s been challenging for scientists to study how hurricanes might change in the future as the climate continues to warm. Most climate models, which are usually run on a global scale over decades or centuries, are not run at a high enough resolution to “see” individual hurricanes.

Most weather models, on the other hand, are run at a high enough resolution to accurately represent hurricanes, but because of the high cost of computational resources, they are not generally used to simulate long-term changes in climate.

For the current study, the researchers took advantage of a massive new dataset created at NCAR. The scientists ran the Weather Research and Forecasting (WRF) model at a high resolution (4 kilometers, or about 2.5 miles) over the contiguous United States over two 13-year periods.

The simulations took about a year to run on the Yellowstone supercomputer at the NCAR-Wyoming Supercomputing Center in Cheyenne.

The first set of model runs simulates weather as it unfolded between 2000 and 2013, and the second simulates the same weather patterns but in a climate that’s warmer by about 5 degrees Celsius (9 degrees Fahrenheit) — the amount of warming that may be expected by the end of the century.

Drawing on the vast amount of data, the scientists created an algorithm that enabled them to identify 22 named storms that appear with very similar tracks in the historic and future simulations, allowing the hurricanes to be more easily compared.

As a group, storms in simulations of the future had 6 percent stronger average hourly maximum wind speeds than those in the past. They also moved at 9 percent slower speeds and had 24 percent higher average hourly maximum rainfall rates. Average storm radius did not change.

Each storm unique

“Some past studies have also run the WRF at a high resolution to study the impact of climate change on hurricanes, but those studies have tended to look at a single storm, like Sandy or Katrina,” Gutmann said.

“What we find in looking at more than 20 storms is that some change one way, while others change in a different way. There is so much variability that you can’t study one storm and then extrapolate to all storms.”

But there was one consistent feature across storms: They all produced more rain.

While the study sheds light on how a particular storm might look in a warmer climate, it doesn’t provide insight into how environmental change might affect storm genesis. That’s because the hurricanes analyzed in this study formed outside the region simulated by the WRF model and passed into the WRF simulation as fully formed storms.

Other research has suggested that fewer storms may form in the future because of increasing atmospheric stability or greater high-level wind shear, though the storms that do form are apt to be stronger.

“It’s possible that in a future climate, large-scale atmospheric changes wouldn’t allow some of these storms to form,” Gutmann said. “But from this study, we get an idea of what we can expect from the storms that do form.”

Indonesia Orders Evacuations As The Volatile Mount Merapi Erupts

Indonesian authorities raised the alert for the volatile Mount Merapi volcano on the densely populated island of Java and ordered people within 3 kilometers (2 miles) to evacuate.

Merapi has erupted four times since Monday, sending out a 3,500 meter (11,483 feet) column of volcanic material and dusting the surrounding region in ash.

Sutopo Purwo Nugroho, the national disaster mitigation agency’s spokesman, said some 660 people living within the exclusion zone have evacuated since early Tuesday.

Indonesia’s geological agency raised Merapi’s alert from normal to “beware,” because of its increased activity.

There have been no reports of casualties and operations at Adi Sucipto airport in Yogyakarta have not been affected.

The 2,968-meter (9,737-foot) mountain is about 30 kilometers (18 miles) from the Yogyakarta city center. About a quarter million people live within a 10 kilometer radius of the volcano, according to figures from authorities in surrounding districts. Its last major eruption in 2010 killed 347 people and caused the evacuation of 20,000 villagers.

Nugroho said climbing on Merapi is prohibited and only disaster agency personnel or related researchers should enter the restricted area.

Indonesia, an archipelago of more than 250 million people, sits on the Pacific “Ring of Fire” and is prone to earthquakes and volcanic eruptions. Indonesian government seismologists monitor more than 120 active volcanoes.

Lava From Hawaii Volcano Enters Ocean, Creating Toxic Cloud

White plumes of acid and extremely fine shards of glass billowed into the sky over Hawaii on Sunday as molten rock from the Kilauea volcano poured into the ocean, creating yet another hazard from an eruption that began more than two weeks ago.

Authorities warned the public to stay away from the toxic steam cloud, which is formed by a chemical reaction when lava touches seawater.

So-called laze — a term combining the words “lava” and haze” — is a mix of hydrochloric acid fumes, steam and fine volcanic glass specks created when erupting lava, which can reach 1,093 degrees Celsius, reacts with sea water, Hawaii County Civil Defense said in a statement.

The warnings also cautioned that reports of toxic sulfur dioxide gas being vented from various points around the volcano had tripled, urging residents to “take action necessary to limit further exposure.”

Further upslope, lava continued to gush out of large cracks in the ground that formed in residential neighbourhoods in a rural part of Hawaii’s Big Island. The molten rock formed rivers that bisected forests and farms as it meandered toward the coast.

At the volcano’s summit, two explosive eruptions unleashed clouds of ash. Winds carried much of the ash toward the southwest.

Joseph Kekedi, an orchid grower who lives and works about five kilometres from where lava dropped into the sea, said luckily the flow didn’t head toward him. At one point, it was about 1.5 kilometres upslope from his property in the coastal community of Kapoho.

He said residents can’t do much but stay informed and be ready to get out of the way.

“Here’s nature reminding us again who’s boss,” Kekedi said.

Hydrochloric acid
Scientists said the steam clouds at the spots where lava entered the ocean were laced with hydrochloric acid and fine glass particles that can irritate the skin and eyes and cause breathing problems.

The laze from the plume spread as far as 24 kilometres west of where the lava met the ocean on the Big Island’s southern coast. It was just offshore and running parallel to the coast, said U.S. Geological Survey scientist Wendy Stovall.

Scientists said the acid in the plume was about as corrosive as diluted battery acid. The glass was in the form of fine glass shards. Getting hit by it might feel like being sprinkled with glitter.

“If you’re feeling stinging on your skin, go inside,” Stovall said. Authorities warned that the plume could shift direction if the winds changed.

The Coast Guard said it was enforcing a safety zone extending 300 metres around the ocean entry point.

Coast Guard Lt. Cmdr. John Bannon said in a statement Sunday that “getting too close to the lava can result in serious injury or death.”

Gov. David Ige told reporters in Hilo that the state was monitoring the volcano and keeping people safe.

“Like typical eruptions and lava flows, it’s really allowing Madame Pele to run its course,” he said, referring to the Hawaiian goddess of volcanoes and fire.

Ige said he was thankful that the current flows weren’t risking homes and hoped it would stay that way.

On Saturday, the eruption claimed its first major injury. David Mace, a spokesperson for the Federal Emergency Management Agency who was helping Hawaii County respond to the disaster, said a man was struck in the leg by a flying piece of lava. He didn’t have further details, including what condition the man was in.

Kilauea has burned some 40 structures, including two dozen homes, since it began erupting in people’s backyards in a neighbourhood on May 3. Some 2,000 people have evacuated their homes, including 300 who were staying in shelters.

In recent days, the lava began to move more quickly and emerge from the ground in greater volume.

Scientists say they don’t know how long the eruption will last.

Hawaii tourism officials have stressed that most of the Big Island remains unaffected by the eruption and is open for business.

Lightning In The Eyewall Of A Hurricane Beamed Antimatter Toward The Ground

Hurricane Patricia, which battered the west coast of Mexico in 2015, was the most intense tropical cyclone ever recorded in the Western Hemisphere. Amid the extreme violence of the storm, scientists observed something new: a downward beam of positrons, the antimatter counterpart of electrons, creating a burst of powerful gamma-rays and x-rays.

Detected by an instrument aboard NOAA’s Hurricane Hunter aircraft, which flew through the eyewall of the storm at its peak intensity, the positron beam was not a surprise to the UC Santa Cruz scientists who built the instrument. But it was the first time anyone has observed this phenomenon.

According to David Smith, a professor of physics at UC Santa Cruz, the positron beam was the downward component of an upward terrestrial gamma-ray flash that sent a short blast of radiation into space above the storm. Terrestrial gamma-ray flashes (TGFs) were first seen in 1994 by space-based gamma-ray detectors. They occur in conjunction with lightning and have now been observed thousands of times by orbiting satellites. A reverse positron beam was predicted by theoretical models of TGFs, but had never been detected.

“This is the first confirmation of that theoretical prediction, and it shows that TGFs are piercing the atmosphere from top to bottom with high-energy radiation,” Smith said. “This event could have been detected from space, like almost all the other reported TGFs, as an upward beam caused by an avalanche of electrons. We saw it from below because of a beam of antimatter (positrons) sent in the opposite direction.”

One unexpected implication of the study, published May 17 in the Journal of Geophysical Research: Atmospheres, is that many TGFs could be detected via the reverse positron beam using ground-based instruments at high altitudes. It’s not necessary to fly into the eye of a hurricane.

“We detected it at an altitude of 2.5 kilometers, and I estimated our detectors could have seen it down to 1.5 kilometers. That’s the altitude of Denver, so there are a lot of places where you could in theory see them if you had an instrument in the right place at the right time during a thunderstorm,” Smith said.

Despite the confirmation of the reverse positron beam, many questions remain unresolved about the mechanisms that drive TGFs. Strong electric fields in thunderstorms can accelerate electrons to near the speed of light, and these “relativistic” electrons emit gamma-rays when they scatter off of atoms in the atmosphere. The electrons can also knock other electrons off of atoms and accelerate them to high energies, creating an avalanche of relativistic electrons. A TGF, which is an extremely bright flash of gamma-rays, requires a large number of avalanches of relativistic electrons.

“It’s an extraordinary event, and we still don’t understand how it gets so bright,” Smith said.

The source of the positrons, however, is a well known phenomenon in physics called pair production, in which a gamma ray interacts with the nucleus of an atom to create an electron and a positron. Since they have opposite charges, they are accelerated in opposite directions by the electric field of the thunderstorm. The downward moving positrons produce x-rays and gamma-rays in their direction of travel when they collide with atomic nuclei, just like the upward moving electrons.

“What we saw in the aircraft are the gamma-rays produced by the downward positron beam,” Smith said.

First author Gregory Bowers, now at Los Alamos National Laboratory, and coauthor Nicole Kelley, now at Swift Navigation, were both graduate students at UC Santa Cruz when they worked together on the instrument that made the detection. The Airborne Detector for Energetic Lightning Emissions (ADELE) mark II was designed to observe TGFs up close by measuring x-rays and gamma-rays from aircraft flown into or above thunderstorms.

Getting too close to a TGF could be hazardous, although the risk drops off rapidly with distance from the source. The gamma-ray dose at a distance of one kilometer would be negligible, Smith said. “It’s hypothetically a risk, but the odds are quite small,” he said. “I don’t ask pilots to fly into thunderstorms, but if they’re going anyway I’ll put an instrument on board.”

Smith’s group was the first to detect a TGF from an airplane using an earlier instrument, the ADELE mark I. In that case, the upward beam from the TGF was detected above a thunderstorm. For this study, the ADELE mark II flew aboard NOAA’s Hurricane Hunter WP-3D Orion during the Atlantic hurricane season.