Scientists link sun jets to the sunspot cycle

Researchers discover a once unknown link between plasma jets in the sun’s interior and the sunspot cycle.

A team of scientists from the Center of Excellence in Space Sciences India, and the Tata Institute of Fundamental Research in Mumbai recently uncovered a once unknown link between plasma jets inside of the sun and the sunspot cycle that may foreshadow the hemisphere of the sun’s unequal activity.

Plasma material at different locations inside the sun revolves at different rates powering a dynamo mechanism that creates the magnetic sunspots. According to researchers Lekshmi B., Dibyendu Nandi, and H.M. Antia, asymmetries in plasma jets just below the sun’s surface precede asymmetries in Sunspot activity by about a year.

This discovery has no valid theoretical explanation so far. “The strength of the sun’s torsional oscillation is very small compared to the differential rotation thus making it difficult to measure. Our careful analysis covering 16 years of both ground- and space-based observations has allowed us to discover this link,” said graduate student Lekshmi B.

The team used helioseismology techniques to observe oscillations on the sun’s surface that the propagation of acoustic waves in the interior produces. The process involved using helioseismic techniques to change and tease out plasma velocity in the sun’s two hemispheres.

They probed only the near-surface bands of faster and slower rotation. However, the current consensus is that magnetic fields that form sunspots exist deeper inside the sun. The sunspot cycle asymmetry is across the vast depth of the sun’s convection zone linking the deep and the near-surface layers of the sun.

Drawing reveals white solar flare observed in 1886

Nature of teen’s observation wasn’t recognized until now.

A teenage amateur astronomer viewed a rare white solar flare from Spain on September 10, 1886, and accurately drew an image of what he saw that survives to this day.

Originally published in the French journal L’Astronomie, the drawing is discussed in a paper co-authored by Jorge Sanchez Almeida of the Instituto de Astrofisica de Canarias (IAC) and published in the journal Solar and Stellar Astrophysics.

Juan Valderrama y Aguilar, who was 17 in 1886, discussed his observation of the rare solar flare in greater detail in his private journal, Almeida noted.

White solar flares are flares of extremely high energy that produce flashes in visible light as well as in ultraviolet light and X-rays.

“White-light flares correspond to the most extreme of this phenomenon, where so much energy is dumped into the corona and chromosphere [of the Sun] that the energy propagates downward to the photosphere, heating it up, and producing the excess brightness that we observe in white light,” Almeida explained.

While most solar flares emit some visible light, sensitive equipment is usually needed to detect it. Yet Valderrama successfully saw it using just a 2.5-inch- (six-cm-) diameter telescope.

In his journal, he describes the sunspot from which the flare erupted.

“A huge, beautiful sunspot was formed from yesterday to today. By looking at it carefully, I noticed an extraordinary phenomenon on her, on the penumbra to the west of the nucleus, and almost in contact with it, a very bright object was distinguishable, producing a shadow clearly visible on the sunspot penumbra. This object had an almost circular shape, and a light beam came out from its eastern part that crossed the sunspot to the south of the nucleus, producing a shadow on the penumbra that was lost in the large mass of faculae surrounding the eastern extreme of the sunspot,” he wrote.

Faculae are bright regions on the Sun’s surface linked to sunspots.

The first sightings of solar flares were made by British astronomer Richard Carrington in 1859 and by Italian astronomer Pietro Angelo Secchi in 1872.

“It is extraordinary that in Spain of the 19th century, a 17-year-old kid would make such a scientific discovery, and it is even more impressive that he had the courage of submitting it for publication to a foreign scientific journal,” Almeida emphasized.

Almeida and study co-author Manuel Vazquez are writing a biography of Valderrama, who directed the meteorological observatory in Madrid.

Tiny solar flares may be heating up the Sun’s corona

Origin of coronal X-ray emissions could be key to answering a question that has long baffled scientists.

Tiny solar flares previously undetectable from Earth may be heating up the Sun’s corona or outer atmosphere, and might be responsible for it being hotter than the Sun’s surface, according to a new study by an international group of scientists from the US, Switzerland, and Japan.

Scientists have long been puzzled as to why the corona is so much hotter than the Sun’s surface. They have been unable to sufficiently investigate the phenomenon because they lacked instruments that could measure activity in its surface and atmosphere.

In their latest study, the research team collected data using the Focusing Optics X-ray Solar Imager (FOXSI-2) sounding rocket, a rocket payload composed of seven telescopes specifically designed to study the solar surface, to test their theory that very small flares on the Sun’s surface could be heating up the corona.

FOXSI studies solar radiation and particle acceleration in the corona by observing and collecting X-ray data over periods of just six to seven minutes.

The first FOXSI rocket was launched in 2012 and the second, from which the research team collected data, was launched two years later.

According to the researchers’ theory, these flares, which are actually small explosions, infuse the corona with heat. Until now, even the most sophisticated instruments could not detect such small solar flares.

Solar flares are known to emit X-rays, so the scientists focused on coronal X-ray emissions. These were found to be highly energetic, lending support to the theory.

No standard solar flares were visible in the part of the Sun studied with FOXSI-2. This means the X-rays detected have to be coming from nanoflares, composed of superheated plasma, within the corona.

FOSXI-3, a sounding rocket with even more sensitive equipment capable of detecting the faintest X-rays, is scheduled for launch next year, the researchers note, adding it might find further support for their theory.

Further assistance could come from the planned launch of a satellite specifically designed to detect nanoflares.

To actually prove their theory correct, scientists will need to successfully pinpoint the source of the X-rays being emitted from the corona.

Findings of the study have been published in the journal Nature Astronomy.

 

 

 

Solar storm that caused auroras on Mars observed by Mars orbiters, rover

High radiation levels detected on Mars for two days following solar storm.

A powerful solar storm that caused global auroras on Mars was observed by NASA spacecraft orbiting Mars, especially the Mars Atmosphere and Volatile Evolution (MAVEN) probe, and by the Mars Science Laboratory‘s  (MSL)Curiosity rover’s Radiation Assessment Detector (RAD).

MAVEN is operated by the University of Colorado at Boulder (CU Boulder) while MSL RAD is run by the Southwest Research Institute (SwRI) in Boulder, Colorado.

The solar storm occurred on September 11 and produced an aurora 25 times brighter than any ever seen by MAVEN, which has studied the interaction between Mars’ atmosphere and the solar wind for three years.

“When a solar storm hits the Martian atmosphere, it can trigger auroras that light up the whole planet in ultraviolet light,” stated MAVEN Imaging Ultraviolet Spectrograph team member Sonal Jain of CU Boulder’s Laboratory for Atmospheric and Space Physics.

Scientists were surprised by the solar activity, which occurred at a time in the 11-year solar cycle that is usually quiet, on approach to solar minimum.

Several storms have recently erupted on the Sun’s surface. The storm that produced the auroras on Mars was observed from Earth in spite of the fact that Earth and Mars are currently on opposite sides of the Sun.

On the Martian surface, NASA’s Curiosity rover’s RAD measured radiation levels twice as high as any detected since its 2012 landing.

“NASA’s distributed set of science missions is in the right place to detect activity on the Sun and examine the effects of such solar events at Mars as never possible before,” noted MAVEN Program Scientist Elsayed Talaat.

Radiation measurements by Curiosity’s RAD are assisting scientists in assessing the planet’s habitability as well as planning for the safety of future astronauts.

Strong solar storms like those in September significantly increase the level of radiation that comes through the Martian atmosphere to its surface. Interactions between this radiation and the atmosphere produce secondary particles from which astronauts will need shielding.

“If you were outdoors on a Mars walk and learned that an event like this was imminent, you would definitely want to take shelter, just as you would if you were on a space walk outside the International Space Station (ISS). To protect our astronauts on Mars in the future, we need to continue to provide this type of space weather monitoring there,” said RAD Principal Investigator Don Hassler, also of SwRI Boulder.

Because Mars has no magnetic field, auroras produced by solar storms can cover the entire planet. On Earth, such auroras are usually confined to the polar regions.

Solar storms may also be responsible for the loss of Mars’ atmosphere in the solar system’s early years. Atmospheric loss is believed to be one of the reasons the planet changed from wet to dry.

The aurora was also detected by instruments on NASA’s Mars Odyssey orbiter and Mars Reconnaissance Orbiter and by the European Space Agency’s (ESA) Mars Express orbiter.

Record numbers of people viewed August 21 solar eclipse

Public outreach by science organizations and free webcasts drove high level of participation.

The August 21 “Great American Eclipse” was watched by record numbers of people, according to a joint study conducted by the University of Michigan and NASA.

A total of 154 million people observed the eclipse directly, using safety devices such as pinhole boxes or eclipse glasses, while another 61 million viewed it digitally through television and online broadcasts.

A record 88 percent of the US population, about 215 million adults, watched at least part of the eclipse. In contrast, 111 million people in the country watched the Superbowl on February 5, 2017.

The study included both those who watched the total eclipse, visible in a narrow 70-mile (113-km) band that swept from the northwest to southeast, and those who watched the partial eclipse in areas outside the path of totality.

Jon Miller, director of the International Center for the Advancement of Scientific Literacy at the University of Michigan’s Institute for Social Research, reported more than 2,000 adults took part in the survey, which involved one set of questions in early 2017 and a second shortly after the eclipse.

Participants will be surveyed once more, in either October or November, and a final report will be published in January 2018.

A majority of viewers experienced the eclipse as being both enjoyable and educational.

Extensive public outreach by individuals and organizations is likely responsible for the large percentage of people who watched the first total solar eclipse visible in the US mainland in 38 years.

As part of a nationwide project, public libraries distributed 2.1 million free pairs of eclipse glasses.

Groups such as NASA, the National Science Foundation (NSF), and the American Astronomical Society (AAS) spent significant time and effort educating people about the science of eclipses and how to safely view them, noted Paul Dusenbery, who heads the Space Science Institute’s National Center for Interactive Learning in Boulder, Colorado.

NASA played a significant role in making the event accessible, conducting numerous free webcasts on the the day of the eclipse. Its nasa.gov and eclipse2017.nasa.gov sites had a record of 90 million views on that day.

“This level of public interest and engagement with a science-oriented event is unparalleled,” Miller emphasized.

A free copy of the study is available at https//www.isr.umich.edu/cps/initialeclipseviewingreport.pdf.

 

 

Powerful solar storms erupt from the Sun

Numbers assigned within the X-class are based on the flares’ intensity. X2s have twice the energy of X1s; X3s have three times the energy of X1s, and so on.

The Sun emitted two powerful flares on Wednesday, September 6, followed by a coronal mass ejection (CME) that could damage Earth-orbiting satellites and shut down electronic communication and power grids while also producing beautiful auroras.

An X-class flare, the most powerful of solar storms, erupted from at 5:10 AM EDT (0910 GMT) from a huge sunspot. Less than three hours later, at 8:02 AM EDT, a second, much more powerful X-class flare followed it.

Numbers assigned within the X-class are based on the flares’ intensity. X2s have twice the energy of X1s; X3s have three times the energy of X1s, and so on.

While the first flare, measured at X2.2, was the most powerful emitted by the Sun since 2015, the second one, an X9.3, was the strongest solar storm in 11 years.

Solar flares are eruptions of powerful radiation that cannot reach Earth’s surface but can cause harm to GPS and communications satellites in orbit around the planet.

Both flares came from AR 2673, an active area on the solar surface that generated a medium-strength M-class flare just two days earlier.

NASA’s Solar Dynamics Observatory (SDO), a satellite that has continuously studied the Sun since 2010, captured images of both flares, which appear as bright flashes of light coming from the solar surface.

The National Oceanic and Atmospheric Administration’s (NOAA) Space Weather Prediction Center (SWPC) reported high-frequency radio blackouts and disruptions in the low-frequency communication used for navigation as a result of the flares.

A coronal mass ejection, or cloud of powerful plasma from the Sun’s corona, and carried by the solar wind, was later detected by the Solar and Heliospheric Observatory, a joint NASA-European Space Agency (ESA) spacecraft that studies the Sun’s internal structure.

NOAA scientists are monitoring the CME to determine whether it is headed in Earth’s direction.

A CME generated by Monday’s solar flare is expected to produce brilliant, colorful auroras in high-latitude northern skies over the next few days.

 

 

Millions view solar eclipse in person and online

The great American eclipse puts on a show seen by tens of millions.

The “Great American Eclipse” of August 21, the first with a path of totality from one US coast to another in 99 years, may have been the most observed and photographed solar eclipse in history.

Approximately 12 million people live in the 70-mile wide path of totality that ran through 14 states while several million more traveled from all over the country and the world to locations on the path to view the phenomenon.

A partial eclipse was visible in all US states, Canada, Central America, northern South America, northwestern Europe and Africa, and the eastern Chukchi Peninsula in Asia.

More than 40 million people watched NASA’s live online broadcast of the event, making it the agency’s most watched live broadcast, seen by more people than the highly popular broadcasts of the 2012 Mars Curiosity rover landing and the 2015 New Horizons Pluto flyby.

“We’ll admit it–even we were blown away by the sheer magnitude of response to the total solar eclipse of August 21, 2017,” the space agency said in a public statement.

According to YouTube, more than 100 million people watched livestreams and videos of the eclipse.

Many students took part in citizen science projects that involved photographing the event.

The Eclipse MegaMovie Project is assembling photos and videos taken by more than 1,000 photographers and amateur astronomers across the country to create a continuous view of the eclipse as it traversed the continent.

Images taken along the path of totality will provide scientists with unprecedented insight into the solar corona and changes it undergoes over time.

Because the project will be repeated during the next solar eclipse in the US on April 8, 2024, it will illustrate changes in the Sun’s outer atmosphere over a period of seven years.

In Lake Barkley State Resort Park, just outside of Hopkinsville, Kentucky, as in numerous locations along the path of totality, hundreds of people observed the eclipse after traveling many hours from other states and even from Prince Edward Island in Canada.

Like many parents, Kale Dowdy and his wife, residents of Evansville, Indiana, took their children out of school to view the eclipse as a family event.

Mark Grove of South Bend, Indiana, viewed solar flares coming from the Sun’s surface through a ten-inch telescope with a 25-millimeter eyepiece.

Temperatures at the Cadiz, Kentucky State Resort Park were in the 90s when the eclipse started, with a heat-humidity index ranging from 100-105 degrees Fahrenheit.

As more and more of the Moon proceeded to obscure the Sun, a slight wind picked up; lighting became muted, and weather conditions went from brutal to comfortable.

At totality, the sky suddenly darkened to twilight. Venus became visible, and strange clouds appeared on the western horizon while observers marveled at the corona.

Following totality, the heat and humidity returned as the Moon moved away from the Sun.