Fermi Sees Gamma Rays from ‘Hidden’ Solar Flares

An international science team says NASA’s Fermi Gamma-ray Space Telescope has observed high-energy light from solar eruptions located on the far side of the Sun, which should block direct light from these events. This apparent paradox is providing solar scientists with a unique tool for exploring how charged particles are accelerated to nearly the speed of light and move across the Sun during solar flares.

“Fermi is seeing gamma rays from the side of the Sun we’re facing, but the emission is produced by streams of particles blasted out of solar flares on the far side of the Sun,” said Nicola Omodei, a researcher at Stanford University in California. “These particles must travel some 300,000 miles within about five minutes of the eruption to produce this light.”

Omodei presented the findings on Monday, Jan. 30, at the American Physical Society meeting in Washington, and a paper describing the results will be published online in The Astrophysical Journal on Jan. 31.

Fermi has doubled the number of these rare events, called behind-the-limb flares, since it began scanning the sky in 2008. Its Large Area Telescope (LAT) has captured gamma rays with energies reaching 3 billion electron volts, some 30 times greater than the most energetic light previously associated with these “hidden” flares.

Thanks to NASA’s Solar Terrestrial Relations Observatory (STEREO) spacecraft, which were monitoring the solar far side when the eruptions occurred, the Fermi events mark the first time scientists have direct imaging of beyond-the-limb solar flares associated with high-energy gamma rays.

“Observations by Fermi’s LAT continue to have a significant impact on the solar physics community in their own right, but the addition of STEREO observations provides extremely valuable information of how they mesh with the big picture of solar activity,” said Melissa Pesce-Rollins, a researcher at the National Institute of Nuclear Physics in Pisa, Italy, and a co-author of the paper.

The hidden flares occurred Oct. 11, 2013, and Jan. 6 and Sept. 1, 2014. All three events were associated with fast coronal mass ejections (CMEs), where billion-ton clouds of solar plasma were launched into space. The CME from the most recent event was moving at nearly 5 million miles an hour as it left the Sun. Researchers suspect particles accelerated at the leading edge of the CMEs were responsible for the gamma-ray emission.

Large magnetic field structures can connect the acceleration site with distant part of the solar surface. Because charged particles must remain attached to magnetic field lines, the research team thinks particles accelerated at the CME traveled to the Sun’s visible side along magnetic field lines connecting both locations. As the particles impacted the surface, they generated gamma-ray emission through a variety of processes. One prominent mechanism is thought to be proton collisions that result in a particle called a pion, which quickly decays into gamma rays.

In its first eight years, Fermi has detected high-energy emission from more than 40 solar flares. More than half of these are ranked as moderate, or M class, events. In 2012, Fermi caught the highest-energy emission ever detected from the Sun during a powerful X-class flare, from which the LAT detected high­energy gamma rays for more than 20 record-setting hours.

Fermi Gamma-ray Space Telescope Discovers Most Extreme Blazars Yet

NASA’s Fermi Gamma-ray Space Telescope has identified the farthest gamma-ray blazars, a type of galaxy whose intense emissions are powered by supersized black holes. Light from the most distant object began its journey to us when the universe was 1.4 billion years old, or nearly 10 percent of its present age.

“Despite their youth, these far-flung blazars host some of the most massive black holes known,” said Roopesh Ojha, an astronomer at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “That they developed so early in cosmic history challenges current ideas of how supermassive black holes form and grow, and we want to find more of these objects to help us better understand the process.”

Ojha presented the findings Monday, Jan. 30, at the American Physical Society meeting in Washington, and a paper describing the results has been submitted to The Astrophysical Journal Letters.

Blazars constitute roughly half of the gamma-ray sources detected by Fermi’s Large Area Telescope (LAT). Astronomers think their high-energy emissions are powered by matter heated and torn apart as it falls from a storage, or accretion, disk toward a supermassive black hole with a million or more times the sun’s mass. A small part of this infalling material becomes redirected into a pair of particle jets, which blast outward in opposite directions at nearly the speed of light. Blazars appear bright in all forms of light, including gamma rays, the highest-energy light, when one of the jets happens to point almost directly toward us.

Previously, the most distant blazars detected by Fermi emitted their light when the universe was about 2.1 billion years old. Earlier observations showed that the most distant blazars produce most of their light at energies right in between the range detected by the LAT and current X-ray satellites, which made finding them extremely difficult.

Then, in 2015, the Fermi team released a full reprocessing of all LAT data, called Pass 8, that ushered in so many improvements astronomers said it was like having a brand new instrument. The LAT’s boosted sensitivity at lower energies increased the chances of discovering more far-off blazars.

The research team was led by Vaidehi Paliya and Marco Ajello at Clemson University in South Carolina and included Dario Gasparrini at the Italian Space Agency’s Science Data Center in Rome as well as Ojha. They began by searching for the most distant sources in a catalog of 1.4 million quasars, a galaxy class closely related to blazars. Because only the brightest sources can be detected at great cosmic distances, they then eliminated all but the brightest objects at radio wavelengths from the list. With a final sample of about 1,100 objects, the scientists then examined LAT data for all of them, resulting in the detection of five new gamma-ray blazars.

Expressed in terms of redshift, astronomers’ preferred measure of the deep cosmos, the new blazars range from redshift 3.3 to 4.31, which means the light we now detect from them started on its way when the universe was between 1.9 and 1.4 billion years old, respectively.

“Once we found these sources, we collected all the available multiwavelength data on them and derived properties like the black hole mass, the accretion disk luminosity, and the jet power,” said Paliya.

Two of the blazars boast black holes of a billion solar masses or more. All of the objects possess extremely luminous accretion disks that emit more than two trillion times the energy output of our sun. This means matter is continuously falling inward, corralled into a disk and heated before making the final plunge to the black hole.

“The main question now is how these huge black holes could have formed in such a young universe,” said Gasparrini. “We don’t know what mechanisms triggered their rapid development.”

In the meantime, the team plans to continue a deep search for additional examples.

“We think Fermi has detected just the tip of the iceberg, the first examples of a galaxy population that previously has not been detected in gamma rays,” said Ajello.

ANNOUNCEMENT: Mitch Battros Guest On ‘The Conspiracy Show’ with Richard Syrett

Join me this Sunday (Jan. 22nd) for my guest appearance on Richard Syrett’s Conspiracy Show. Our focus will be on the latest news and research concerning the coming full magnetic pole shift. In addition, we will discuss the latest research on the cause of cyclical climate change the Earth has seen its whole life.

We will certainly touch on the Sun-Earth connection, but we will go much further than this to show newly found intricacies between our solar system and galaxy identifying cyclical expansions and contractions – which I might suggest mirrors that of a living entity in the way of “inhaling” and exhaling”. Showtime is 11 PM eastern – 8 PM pacific.
Radio Stations – Click Here

The Elements of Life Mapped Across Milky Way

To say “we are stardust” may be a cliche, but it’s an undeniable fact that most of the essential elements of life are made in stars.

“For the first time, we can now study the distribution of elements across our Galaxy,” says Sten Hasselquist of New Mexico State University. “The elements we measure include the atoms that make up 97% of the mass of the human body.”

The new results come from a catalog of more than 150,000 stars; for each star, it includes the amount of each of almost two dozen chemical elements. The new catalog includes all of the so-called “CHNOPS elements” – carbon, hydrogen, nitrogen, oxygen, phosphorous, and sulfur – known to be the building blocks of all life on Earth.

This is the first time that measurements of all of the CHNOPS elements have been made for such a large number of stars.

How do we know how much of each element a star contains? Of course, astronomers cannot visit stars to spoon up a sample of what they’re made of, so they instead use a technique called spectroscopy to make these measurements. This technique splits light – in this case, light from distant stars – into detailed rainbows (called spectra). We can work out how much of each element a star contains by measuring the depths of the dark and bright patches in the spectra caused by different elements.

Astronomers in the Sloan Digital Sky Survey have made these observations using the APOGEE (Apache Point Observatory Galactic Evolution Experiment) spectrograph on the 2.5m Sloan Foundation Telescope at Apache Point Observatory in New Mexico. This instrument collects light in the near-infrared part of the electromagnetic spectrum and disperses it, like a prism, to reveal signatures of different elements in the atmospheres of stars. A fraction of the almost 200,000 stars surveyed by APOGEE overlap with the sample of stars targeted by the NASA Kepler mission, which was designed to find potentially Earth-like planets. The work presented today focuses on ninety Kepler stars that show evidence of hosting rocky planets, and which have also been surveyed by APOGEE.

While the Sloan Digital Sky Survey may be best known for its beautiful public images of the sky, since 2008 it has been entirely a spectroscopic survey. The current stellar chemistry measurements use a spectrograph that senses infrared light – the APOGEE (Apache Point Observatory Galactic Evolution Experiment) spectrograph, mounted on the 2.5-meter Sloan Foundation Telescope at Apache Point Observatory in New Mexico.

Jon Holtzman of New Mexico State University explains that “by working in the infrared part of the spectrum, APOGEE can see stars across much more of the Milky Way than if it were trying to observe in visible light. Infrared light passes through the interstellar dust, and APOGEE helps us observe a broad range of wavelengths in detail, so we can measure the patterns created by dozens of different elements.”

The new catalog is already helping astronomers gain a new understanding of the history and structure of our Galaxy, but the catalog also demonstrates a clear human connection to the skies. As the famous astronomer Carl Sagan said, “we are made of starstuff.” Many of the atoms which make up your body were created sometime in the distant past inside of stars, and those atoms have made long journeys from those ancient stars to you.

While humans are 65% oxygen by mass, oxygen makes up less than 1% of the mass of all of elements in space. Stars are mostly hydrogen, but small amounts of heavier elements such as oxygen can be detected in the spectra of stars. With these new results, APOGEE has found more of these heavier elements in the inner Galaxy. Stars in the inner galaxy are also older, so this means more of the elements of life were synthesized earlier in the inner parts of the Galaxy than in the outer parts.

While it’s fun speculate what impact the inner Galaxy’s composition might have on where life pops up, we are much better at understanding the formation of stars in our Galaxy. Because the processes producing each element occur in specific types of stars and proceed at different rates, they leave specific signatures in the chemical abundance patterns measured by SDSS/APOGEE. This means that SDSS/APOGEE’s new elemental abundance catalog provides data to compare with the predictions made by models of galaxy formation.

Jon Bird of Vanderbilt University, who works on modelling the Milky Way, explains that “these data will be useful to make progress on understanding Galactic evolution, as more and more detailed simulations of the formation of our galaxy are being made, requiring more complex data for comparison.”

“It’s a great human interest story that we are now able to map the abundance of all of the major elements found in the human body across hundreds of thousands of stars in our Milky Way,” said Jennifer Johnson of The Ohio State University. “This allows us to place constraints on when and where in our galaxy life had the required elements to evolve, a sort ‘temporal Galactic habitable zone'”.

New Study Highlights Charged Particles Role In Creating Upper Atmosphere Discharge Similar to Terrestrial Lightning

Scientists from NASA and three universities have presented new discoveries about the way heat and energy move and manifest in the ionosphere, a region of Earth’s atmosphere that reacts to changes from both space above and Earth below.

themosphere_sprites_scienceofcycles_m

Far above Earth’s surface, within the tenuous upper atmosphere, is a sea of particles that have been split into positive and negative ions by the Sun’s harsh ultraviolet radiation. Called the ionosphere, this is Earth’s interface to space, the area where Earth’s neutral atmosphere and terrestrial weather give way to the space environment that dominates most of the rest of the universe – an environment that hosts charged particles and a complex system of electric and magnetic fields. The ionosphere is both shaped by waves from the atmosphere below and uniquely responsive to the changing conditions in space, conveying such space weather into observable, Earth-effective phenomena creating the aurora, disrupting communications signals, and sometimes causing satellite problems.

Many of these effects are not well-understood, leaving the ionosphere, for the most part, a region of mystery. Scientists from NASA’s Goddard Space Flight Center in Greenbelt, Maryland, the Catholic University of America in Washington, D.C., the University of Colorado Boulder, and the University of California, Berkeley, presented new results on the ionosphere at the fall meeting of the American Geophysical Union on Dec. 14, 2016, in San Francisco.

One researcher explained how the interaction between the ionosphere and another layer in the atmosphere, the thermosphere, counteract heating in the thermosphere – heating that leads to expansion of the upper atmosphere, which can cause premature orbital decay. Another researcher described how energy outside the ionosphere accumulates until it discharges – not unlike lightning – offering an explanation for how energy from space weather crosses over into the ionosphere. A third scientist discussed two upcoming NASA missions that will provide key observations of this region, helping us better understand how the ionosphere reacts both to space weather and to terrestrial weather.

Changes in the ionosphere are primarily driven by the Sun’s activity. Though it may appear unchanging to us on the ground, our Sun is, in fact, a very dynamic, active star. Watching the Sun in ultraviolet wavelengths of light from space – above our UV light-blocking atmosphere – reveals constant activity, including bursts of light, particles, and magnetic fields.

Occasionally, the Sun releases huge clouds of particles and magnetic fields that explode out from the Sun at more than a million miles per hour. These are called coronal mass ejections, or CMEs. When a CME reaches Earth, its embedded magnetic fields can interact with Earth’s natural magnetic field – called the magnetosphere – sometimes compressing it or even causing parts of it to realign.

It is this realignment that transfers energy into Earth’s atmospheric system, by setting off a chain reaction of shifting electric and magnetic fields that can send the particles already trapped near Earth skittering in all directions. These particles can then create one of the most recognizable and awe-inspiring space weather events – the aurora, otherwise known as the Northern Lights.

But the transfer of energy into the atmosphere isn’t always so innocuous. It can also heat the upper atmosphere – where low-Earth satellites orbit – causing it to expand like a hot-air balloon.

“This swelling means there’s more stuff at higher altitudes than we would otherwise expect,” said Delores Knipp, a space scientist at the University of Colorado Boulder. “That extra stuff can drag on satellites, disrupting their orbits and making them harder to track.”

This phenomenon is called satellite drag. New research shows that this understanding of the upper atmosphere’s response to solar storms – and the resulting satellite drag – may not always hold true.

“Our basic understanding has been that geomagnetic storms put energy into the Earth system, which leads to swelling of the thermosphere, which can pull satellites down into lower orbits,” said Knipp, lead researcher on these new results. “But that isn’t always the case.”

Sometimes, the energy from solar storms can trigger a chemical reaction that produces a compound called nitric oxide in the upper atmosphere. Nitric oxide acts as a cooling agent at very high altitudes, promoting energy loss to space, so a significant increase in this compound can cause a phenomenon called overcooling.

“Overcooling causes the atmosphere to quickly shed energy from the geomagnetic storm much quicker than anticipated,” said Knipp. “It’s like the thermostat for the upper atmosphere got stuck on the ‘cool’ setting.”

That quick loss of energy counteracts the previous expansion, causing the upper atmosphere to collapse back down – sometimes to an even smaller state than it started in, leaving satellites traveling through lower-density regions than anticipated.

A new analysis by Knipp and her team classifies the types of storms that are likely to lead to this overcooling and rapid upper atmosphere collapse. By comparing over a decade of measurements from Department of Defense satellites and NASA’s Thermosphere, Ionosphere, Mesosphere Energetics and Dynamics, or TIMED, mission, the researchers were able to spot patterns in energy moving throughout the upper atmosphere.

“Overcooling is most likely to happen when very fast and magnetically-organized ejecta from the Sun rattle Earth’s magnetic field,” said Knipp. “Slow clouds or poorly-organized clouds just don’t have the same effect.”

This means that, counterintuitively, the most energetic solar storms are likely to provide a net cooling and shrinking effect on the upper atmosphere, rather than heating and expanding it as had been previously understood.

Competing with this cooling process is the heating that caused by solar storm energy making its way into Earth’s atmosphere. Though scientists have known that solar wind energy eventually reaches the ionosphere, they have understood little about where, when and how this transfer takes place. New observations show that the process is localized and impulsive, and partly dependent on the state of the ionosphere itself.

Traditionally, scientists have thought that the way energy moves throughout Earth’s magnetosphere and atmosphere is determined by the characteristics of the incoming particles and magnetic fields of the solar wind – for instance, a long, steady stream of solar particles would produce different effects than a faster, less consistent stream. However, new data shows that the way energy moves is much more closely tied to the mechanisms by which the magnetosphere and ionosphere are linked.

“The energy transfer process turns out to be very similar to the way lightning forms during a thunderstorm,” said Bob Robinson, a space scientist at NASA Goddard and the Catholic University of America.

During a thunderstorm, a buildup of electric potential difference – called voltage – between a cloud and the ground leads to a sudden, violent discharge of that electric energy in the form of lightning. This discharge can only happen if there’s an electrically conducting pathway between the cloud and the ground, called a leader.

Similarly, the solar wind striking the magnetosphere can build up a voltage difference between different regions of the ionosphere and the magnetosphere. Electric currents can form between these regions, creating the conducting pathway needed for that built-up electric energy to discharge into the ionosphere as a kind of lightning.

“Terrestrial lightning takes several milliseconds to occur, while this magnetosphere-ionosphere ‘lightning’ lasts for several hours – and the amount of energy transferred is hundreds to thousands of times greater,” said Robinson, lead researcher on these new results. These results are based on data from the global Iridium satellite communications constellation.

Because solar storms enhance the electric currents that let this magnetosphere-ionosphere lightning take place, this type of energy transfer is much more likely when Earth’s magnetic field is jostled by a solar event.

The huge energy transfer from this magnetosphere-ionosphere lightning is associated with heating of the ionosphere and upper atmosphere, as well as increased aurora.

Looking Forward

Though scientists are making progress in understanding the key processes that drive changes in the ionosphere and, in turn, on Earth, there is still much to be understood. In 2017, NASA is launching two missions to investigate this dynamic region: the Ionospheric Connection Explorer, or ICON, and Global Observations of the Limb and Disk, or GOLD.

“The ionosphere doesn’t only react to energy input by solar storms,” said Scott England, a space scientist at the University of California, Berkeley, who works on both the ICON and GOLD missions. “Terrestrial weather, like hurricanes and wind patterns, can shape the atmosphere and ionosphere, changing how they react to space weather.”

ICON will simultaneously measure the characteristics of charged particles in the ionosphere and neutral particles in the atmosphere – including those shaped by terrestrial weather – to understand how they interact. GOLD will take many of the same measurements, but from geostationary orbit, which gives a global view of how the ionosphere changes.

Both ICON and GOLD will take advantage of a phenomenon called airglow – the light emitted by gas that is excited or ionized by solar radiation – to study the ionosphere. By measuring the light from airglow, scientists can track the changing composition, density, and even temperature of particles in the ionosphere and neutral atmosphere.

ICON’s position 350 miles above Earth will enable it to study the atmosphere in profile, giving scientists an unprecedented look at the state of the ionosphere at a range of altitudes. Meanwhile, GOLD’s position 22,000 miles above Earth will give it the chance to track changes in the ionosphere as they move across the globe, similar to how a weather satellite tracks a storm.

“We will be using these two missions together to understand how dynamic weather systems are reflected in the upper atmosphere, and how these changes impact the ionosphere,” said England.