Mysteries of the Sun . . . Explained in Video

Anatomy of the Sun -- one of the illustrations from the Mysteries of the Sun book. Credit: NASA/Jenny Mottar

NASA has just released five new videos called “Mysteries of the Sun”. The videos describe the science of the sun and its effects on the solar system and Earth. Scientists study the sun not only to better understand the orb that influences life, but also to study how it sends solar material out into space, filling up the bubble that defines the farthest reaches of the solar system. The sun can also impact Earth’s technology: solar storms can affect our communications satellites and cause surges in power lines. These movies cover the breadth of solar, heliospheric, and geospace science, a field known as heliophysics.

With beautiful graphics and well-explained narration, the series has won awards even before its public release, including the 2011 Platinum 3rd Annual Pixie Award in the category of Motion Graphics, receiving compliments from the judges such as “breath-taking animation” and “Some of the best in the competition.”

“NASA constantly creates science products to reach out to the public,” said Ruth Netting, Manager, Communications and Public Engagement for NASA’s Science Mission Directorate, Washington. “Informing the public is not the only reason — we also want to get people involved in science.”

The five movies, available online at and on DVD, cover five areas of heliophysics: Space Weather, Solar Variability, the Heliosphere, Earth’s magnetosphere, and Earth’s upper atmosphere.

The five videos are:

 1. Space Weather
This video describes the direct and dramatic effects that eruptions on the sun can cause at Earth. Earth’s magnetic fields change shape and strength in response to an eruption on the sun, and these changes in turn can damage space born technology and disrupt communications traveling through space. They also cause aurora.

2. Solar Variability
Rotations of the material deep inside the sun cause constantly shifting magnetic field lines. This variability drives the solar cycle, during which the north and south magnetic poles reverse position approximately every 11 years.

3. The Heliosphere
The solar wind streams out from the sun until it collides with material from the rest of space. This entire bubble defined by the solar wind is called the heliosphere and scientists study the very boundaries to better understand our place in space.

4. Earth’s Magnetosphere
Earth is enveloped in a protective magnetic envelope called the magnetosphere. This can change shape in response to the sun’s effects, causing various types of space weather at Earth.

5. Earth’s Upper Atmosphere
Certain layers, high up in the atmosphere also respond to incoming energy from the sun. These layers contain charged particles and so naturally respond to an influx of magnetic energy. Understanding such variability is crucial since it can, in turn, degrade radio communication as well as satellite orbits.

Plasma Indirection

Spectacular rotation of material from solar prominences and the coronal cavities on September 25, 2011. Credit: NASA/Dr. Xing Li, Dr. Huw Morgan and Mr. Drew Leonard.

The Solar Dynamics Observatory captured a spectacular rotation of material in a solar prominence, which created a massive tornado-like feature on the Sun, five times bigger than the Earth. “This is perhaps the first time that such a huge solar tornado is filmed by an imager,” said Dr. Xing Li of Aberystwyth University, presenting his team’s work at the National Astronomy Meeting this week in the UK. “The superb spatial and temporal resolution of SDO allows us to observe the solar atmosphere in great detail.”

The solar tornado was discovered using the Atmospheric Imaging Assembly (AIA) telescope on board SDO. On September 25, 2011, the AIA saw superheated gases as hot as 50,000 – 2,000,000 Kelvin sucked from the origin of a solar prominence, and spiral up into the high atmosphere. It traveled about 200,000 kilometers along the Sun for a period of at least three hours.
The hot gases in the tornadoes have speeds as high as 300,000 km per hour, as opposed to terrestrial tornadoes, which can reach 150km per hour.
Li and his team said that these tornadoes often occur at the root of huge coronal mass ejections. The solar tornadoes drag winding magnetic field and electric currents into the high atmosphere. It is possible that the magnetic field and currents play a key role in driving the coronal mass ejections.
A smaller solar tornado was captured in February of 2012:

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Solar Storm Dumps Gigawatts into Earth’s Upper Atmosphere

Earth’s atmosphere lights up at infrared wavelengths during the solar storms of March 8-10, 2012. This ScienceCast video explains the physics of this phenomenon.
A recent flurry of eruptions on the sun did more than spark pretty auroras around the poles. NASA-funded researchers say the solar storms of March 8th through 10th dumped enough energy in Earth’s upper atmosphere to power every residence in New York City for two years.

“This was the biggest dose of heat we’ve received from a solar storm since 2005,” says Martin Mlynczak of NASA Langley Research Center. “It was a big event, and shows how solar activity can directly affect our planet.”

Mlynczak is the associate principal investigator for the SABER instrument onboard NASA’s TIMED satellite. SABER monitors infrared emissions from Earth’s upper atmosphere, in particular from carbon dioxide (CO2) and nitric oxide (NO), two substances that play a key role in the energy balance of air hundreds of km above our planet’s surface.

“Carbon dioxide and nitric oxide are natural thermostats,” explains James Russell of Hampton University, SABER’s principal investigator. “When the upper atmosphere (or ‘thermosphere’) heats up, these molecules try as hard as they can to shed that heat back into space.”

That’s what happened on March 8th when a coronal mass ejection (CME) propelled in our direction by an X5-class solar flare hit Earth’s magnetic field. (On the “Richter Scale of Solar Flares,” X-class flares are the most powerful kind.) Energetic particles rained down on the upper atmosphere, depositing their energy where they hit. The action produced spectacular auroras around the poles and significant1 upper atmospheric heating all around the globe.

“The thermosphere lit up like a Christmas tree,” says Russell. “It began to glow intensely at infrared wavelengths as the thermostat effect kicked in.”

For the three day period, March 8th through 10th, the thermosphere absorbed 26 billion kWh of energy. Infrared radiation from CO2 and NO, the two most efficient coolants in the thermosphere, re-radiated 95% of that total back into space.

A surge of infrared radiation from nitric oxide molecules on March 8-10, 2012, signals the biggest upper-atmospheric heating event in seven years. Credit: SABER/TIMED.

In human terms, this is a lot of energy. According to the New York City mayor’s office, an average NY household consumes just under 4700 kWh annually. This means the geomagnetic storm dumped enough energy into the atmosphere to power every home in the Big Apple for two years.

“Unfortunately, there’s no practical way to harness this kind of energy,” says Mlynczak. “It’s so diffuse and out of reach high above Earth’s surface. Plus, the majority of it has been sent back into space by the action of CO2 and NO.”

During the heating impulse, the thermosphere puffed up like a marshmallow held over a campfire, temporarily increasing the drag on low-orbiting satellites. This is both good and bad. On the one hand, extra drag helps clear space junk out of Earth orbit. On the other hand, it decreases the lifetime of useful satellites by bringing them closer to the day of re-entry.

The storm is over now, but Russell and Mlynczak expect more to come.

“We’re just emerging from a deep solar minimum,” says Russell. “The solar cycle is gaining strength with a maximum expected in 2013.”

More sunspots flinging more CMEs toward Earth adds up to more opportunities for SABER to study the heating effect of solar storms.

“This is a new frontier in the sun-Earth connection,” says Mlynczak, and the data we’re collecting are unprecedented.”
Dr. Tony Phillips
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Sunspots and Solar Flares

NASA’s Solar Dynamics Observatory (SDO) captured this image of an M7.9 class flare on March 13, 2012 at 1:29 p.m. EDT. It is shown here in the 131 Angstrom wavelength, a wavelength particularly good for seeing solar flares and a wavelength that is typically colorized in teal. The flare peaked at 1:41 p.m. EDT. It was from the same active region, No. 1429, that produced flares and coronal mass ejections the entire week. The region has been moving across the face of the sun since March 2, and will soon rotate out of Earth view.

A solar flare is an intense burst of radiation coming from the release of magnetic energy associated with sunspots. Flares are our solar system’s largest explosive events. They are seen as bright areas on the sun and last from mere minutes to several hours.

Scientists classify solar flares according to their x-ray brightness. There are 3 categories: X-, M- and C-class. X-class flares are the largest of these events. M-class flares are medium-sized; they can cause brief radio blackouts that affect Earth’s polar regions. Compared to X- and M-class, C-class flares are small with few noticeable consequences on Earth.
Image Credit: NASA/SDO
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Active Region on the Sun Spits Out Three Flares

On March 2, 2012 a new active region on the sun, region 1429, rotated into view. It has let loose two M-class flares and one X-class so far. The M-class flares erupted on March 2 and on March 4. The third flare, rated an X1, peaked at 10:30 ET on March 4. A CME accompanied each flare, though due to the fact that this active region is still off to the side of the sun, they will likely have a weak effect on Earth’s magnetosphere.

The M class flare on March 4 flare also came with what’s called a Type IV radio burst that lasted for about 46 minutes. Sending out broadband radio waves, these bursts can occur towards the end of a solar flare and are believed to be created by moving electrons trapped in great, looping magnetic fields left over from the initial flare. The bursts can interfere with radio communications on Earth.

The Sun As Art

A new interactive NASA art exhibit opens February 9 at the Maryland Science Center in Baltimore that will showcase stunning images of the sun.

Called “Sun As Art,” the collection consists of 20 full-color, high-resolution images of the star with which we live. Some of the pieces stand alone, beautiful images that hold true to the original picture. Others have been modified: one looks like an Andy Warhol painting; another like an orange. Several pieces in the collection have an interactive component where visitors using smart phones can scan a QR code and watch the particular solar event that inspired the finished image.

The exhibit is the brainchild of Dr. Steele Hill, a media specialist at NASA’s Goddard Space Flight Center in Greenbelt, Md. Hill selected images from some of the agency’s solar missions to showcase incredible details of the sun in a unique way.

Sun Flower: There was something about the bright coronal mass ejection (cropped but un-retouched) in February 2002 that, when copied into a circular pattern, suggested the splash of color found in a flower petal. Add an extreme ultraviolet image of the Sun as the centerpiece and it seemed to suggest a recreation of oneness in the universe. The English poet William Blake expressed it as “all the world in a grain of sand.”

The exhibit will be on display for three months before traveling to other venues across the country. The Maryland Science Center is located at 601 Light Street, Baltimore, Md. The content is also available online at:

Large X-class Flare Erupts on the Sun

On Jan. 27, 2012, a large X-class flare erupted from an active region near the solar west limb. X-class flares are the most powerful of all solar events. Seen here is an image of the flare captured by the X-ray telescope on Hinode. This image shows an emission from plasma heated to greater than eight million degrees during the energy release process of the flare.

Image Credit: JAXA/Hinode –

Was The Sun Born In A Massive Cluster?

The log of the probability of a close encounter exciting each Jovian planet's eccentricity to greater than 0.1 as a function of cluster mass Mc and surface density Σc

Donald Dukes, Mark R. Krumholz
A number of authors have argued that the Sun must have been born in a cluster of no more than about 1000 stars, on the basis that, in a larger cluster, close encounters between the Sun and other stars would have truncated the outer Solar System or excited the outer planets into eccentric orbits. However, this dynamical limit is in tension with meteoritic evidence that the Solar System was exposed to a nearby supernova during or shortly after its formation; a 1000-star cluster is much too small for supernova contamination to be likely. In this paper we revisit the dynamical limit in the light of improved observations of the properties of young clusters. We use a series of scattering simulations to measure the velocity-dependent cross-section for disruption of the outer Solar System by stellar encounters, and use this cross-section to compute the probability of a disruptive encounter as a function of birth cluster properties. We find that, contrary to prior work, the probability of disruption is small regardless of the cluster mass, and that it actually decreases rather than increases with cluster mass. Our results differ from prior work for three main reasons: (1) unlike in most previous work, we compute a velocity-dependent cross section and properly integrate over the cluster mass-dependent velocity distribution of incoming stars; (2) we adopt realistically-short cluster lifetimes of a few crossing times, rather than assuming lifetimes of 10 to 100 Myr; and (3) following recent observations, we adopt a mass-independent surface density for embedded clusters, rather than a mass-independent radius as assumed many earlier papers. Our results remove the tension between the dynamical limit and the meteoritic evidence, and suggest that the Sun was born in a massive cluster….
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