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Tag Archives: Sun

One Ring to Bring Them All: Eclipse Enchants

Ever see ringlets of sunlight playing in the shadows of a tree or a fiery ring of light in the sky? These incredible effects are the results of an annular solar eclipse like the one that occurred when the moon passed directly between the sun and Earth on Sunday, May 20, 2012. The event was viewable from Japan all the way across the Pacific Ocean to midway through the United States.

Because the moon travels on a slightly tilted orbit compared to the plane of Earth’s orbit around the sun, eclipses do not occur every time the moon comes between the sun and Earth. However, there are two points or “nodes” when the moon does pass through this plane. If either of these nodes coincides with a new moon (when the sun is illuminating only its far side), a solar eclipse will occur. If a node is reached during a full moon, Earth will block the sun’s light, casting a shadow onto the moon causing a lunar eclipse.

An annular eclipse occurs when the moon is too far away from us to completely cover the disk of the sun. This results in an annularity: the ring-shaped outline of the sun that can be seen surrounding the dark new moon. Because of the surreal look of the “ring of fire,” annular eclipses are some of the most impressive celestial events visible from Earth.

This eclipse passed over some of the U.S.’s most famous national parks with the full annularity visible from 33 parks, while an additional 125 parks witnessed a partial eclipse. The NASA Lunar Science Institute (NLSI) at NASA’s Ames Research Center, Moffett Field, Calif., and the National Parks Service took advantage of this rare event and joined forces to facilitate safe viewings for as many people as possible.

Several NLSI scientists traveled to the Grand Canyon National Park and used the superimposition of our two most prominent celestial objects as an opportunity to explain to several thousand visitors about some of NASA’s past, current and future projects relating to the sun and moon. These include the Lunar Atmosphere and Dust Environment Explorer (LADEE), which will orbit the moon in order to characterize its atmosphere and the lunar dust environment, and the Interface Region Imaging Spectrograph, (IRIS) ,which will make detailed measurements of the flow of energy and plasma through the sun’s atmosphere and heliosphere.

The NLSI team gave presentations to three full-house audiences in the park’s theater and hosted an exhibit in its main visitor center. Samples of moon and Mars rocks and meteorites that people could handle were on display, as well as a model of a LADEE.

“Multiple missions to the moon in the past five years have revealed our nearest celestial neighbor is a fascinating place,” said NLSI director Yvonne Pendleton, who spoke at the event “The Apollo-era views, rich in geological insights from samples that continue to be studied today, have been enlarged to reveal detailed topography, composition and a bombardment history that will fascinate researchers for many years to come.”

More than 2,000 people viewed the eclipse at the event. Safe viewing equipment was also sent to other national parks and another public viewing was held by one of the NLSI teams at the University of Colorado football stadium in Boulder, where 10,000 people viewed the partial eclipse.

“Nature has provided us with a unique opportunity to capitalize on the huge public interest in the sun and moon,” said NLSI Director of Education and Public Outreach Brian Day. “It is an excellent opportunity to engage with the public and explain what we are doing at Ames.”

Although there have been a number of partial eclipses in recent years, May 20, 2012 was the first time in 18 years that we have been able to see the moon pass directly across the center of the sun from the U.S. James Schalkwyk
Ames Research Center, Moffett Field, Calif.

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Posted by on June 12, 2012 in Earth Changes, NASA, Science, Space

 

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Large X-class Flare Erupts on the Sun

Good thing it wasn’t aimed at Us! If it was we’d be gone, gone, gone! Just image a blast of plasma hitting earth at temperatures greater than 100,000 degrees!

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

 
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Posted by on February 7, 2012 in Earth Changes, Global Warming, NASA, Photo, Science, Space

 

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Space Storms to Pose Greater Risk to Flyers and Astronauts

If you thought the outlook for Earth’s climate looked bleak, don’t look up. A new study suggests that space weather—the hail of energetic particles above our atmosphere—is set to worsen in coming decades. The grim forecast suggests that astronauts and frequent flyers will face greater radiation hazards and could rule out a crewed mission to Mars before 2050.

Space weather is a general term for the environmental conditions above Earth’s atmosphere. When space weather is bad, dangerous particles abound. These include protons and ions, known as galactic cosmic rays (GRCs), raining down at near-light speed from space, and similar particles coming in bursts from the sun, called solar energetic particles (SEPs).

The sun has the biggest impact on space weather. The radiation it emits fluctuates both over the short term and across centuries. When the sun is emitting more radiation, it generates a strong external magnetic field, which swaddles the solar system in the “heliosphere”—a shield against GRCs. On the downside, a more active sun is thought to emit SEPs more consistently. Currently, the sun’s activity seems to be fading from a “grand maximum” that has been with us since the 1920s, suggesting a new minimum is upon us.

Although that might seem like good news, it’s actually not, according to space meteorologist Michael Lockwood of the University of Reading in the United Kingdom and colleagues. Lockwood’s group has analyzed how variations in GRCs and SEPs reaching Earth have correlated with the sun’s activity over hundreds of years. No one was recording the influx of GRCs or SEPs back then, so the researchers use proxy data taken from the composition of ancient ice cores dug up at the poles. Nitrates are produced as GRCs react with the atmosphere, so an ice sample containing more nitrates is likely to have been frozen at a time of abundant GRCs. Meanwhile, SEPs are thought to fill ice with rare isotopes of beryllium-10.

Lockwood’s group found that in times of low solar activity, there seem to have been more GRCs reaching Earth. This wasn’t too surprising: low activity means the solar system’s shield—the heliosphere—would have been weaker. The researchers also found that low solar activity seemed to bring fewer SEP events. But to their surprise, there was a caveat: Although fewer, the SEP events appeared to be far more intense. The worst time for SEPs appeared to be at times of “middling” solar activity—precisely the transition period we are thought to be entering. The results were published last month in Geophysical Research Letters.

How dangerous is this? One problem could arise for frequent flyers, because the thin air at high altitudes offers less protection from space weather. Currently, someone could take up to five long-haul flights every year that go near the poles—where GRCs and SEPs are channeled most—without exceeding the recommended limit on radiation exposure. But in coming decades, Lockwood explains, that safe number could drop to two. “I wouldn’t want to be on a plane when an SEP event went off,” he says.

Astronomer Sten Odenwald of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, thinks we should keep the risk in perspective. He says many people will face a greater risk of radiation from natural radon gas seeping into their basements. What’s more, Bob Rutledge, who monitors space weather at the Space Weather Prediction Center in Boulder, Colorado, adds that Lockwood and colleagues’ predictions haven’t yet been tested to see if they’ll hold up in the coming years. “Many of these theories come out, and some will prove to be right,” he says. Until time bears out a theory, Rutledge says he won’t “change the way I do business.”

Astronauts might face more problems, particularly those headed for the moon or beyond. Scientists currently predict that a roundtrip to Mars exposes a male astronaut to a lifetime’s worth of radiation; female astronauts experience double what’s considered a safe lifetime dose. But Lockwood believes that in our transition to minimum solar activity—which could last anywhere between 40 and 200 years—this dose could increase at least twofold.

Biophysicist Francis Cucinotta of NASA’s Space Radiation Program at the Lyndon B. Johnson Space Center in Houston, Texas, says it should be possible to shield astronauts against the SEP events. But GRCs would require an amount of shielding that is “not feasible” for spacecraft, he says. That means a crewed Mars mission, which NASA still has penciled in for the 2030s, would need another means of protecting astronauts.

Correction: The original version of this article attributed a quote addressing the hazard of natural radon gas to William Murtagh of the Space Weather Prediction Center in Boulder, Colorado. The article has now been corrected to attribute this quote, rightly, to Sten Odenwald of NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

by Jon Cartwright

 
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Posted by on September 28, 2011 in Science, Space

 

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International Space Station & Sun

The Brightness of the Sun

The bright sun, a portion of the International Space Station and Earth’s horizon are featured in this image photographed during the STS-134 mission’s fourth spacewalk in May 2011. The image was taken using a fish-eye lens attached to an electronic still camera.

Image Credit: NASA

 
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Posted by on September 22, 2011 in NASA, Photo

 

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Getting Ready for the Next Big Solar Storm

Modern power grids are vulnerable to solar storms. Credit: NASA/Martin Stojanovski

June 21, 2011: In Sept. 1859, on the eve of a below-average solar cycle, the sun unleashed one of the most powerful storms in centuries. The underlying flare was so unusual, researchers still aren’t sure how to categorize it. The blast peppered Earth with the most energetic protons in half-a-millennium, induced electrical currents that set telegraph offices on fire, and sparked Northern Lights over Cuba and Hawaii.

This week, officials have gathered at the National Press Club in Washington DC to ask themselves a simple question: What if it happens again?

“A similar storm today might knock us for a loop,” says Lika Guhathakurta, a solar physicist at NASA headquarters. “Modern society depends on high-tech systems such as smart power grids, GPS, and satellite communications–all of which are vulnerable to solar storms.”

She and more than a hundred others are attending the fifth annual Space Weather Enterprise Forum—”SWEF” for short. The purpose of SWEF is to raise awareness of space weather and its effects on society especially among policy makers and emergency responders. Attendees come from the US Congress, FEMA, power companies, the United Nations, NASA, NOAA and more.

As 2011 unfolds, the sun is once again on the eve of a below-average solar cycle—at least that’s what forecasters are saying. The “Carrington event” of 1859 (named after astronomer Richard Carrington, who witnessed the instigating flare) reminds us that strong storms can occur even when the underlying cycle is nominally weak.

In 1859 the worst-case scenario was a day or two without telegraph messages and a lot of puzzled sky watchers on tropical islands.

In 2011 the situation would be more serious. An avalanche of blackouts carried across continents by long-distance power lines could last for weeks to months as engineers struggle to repair damaged transformers. Planes and ships couldn’t trust GPS units for navigation. Banking and financial networks might go offline, disrupting commerce in a way unique to the Information Age. According to a 2008 report from the National Academy of Sciences, a century-class solar storm could have the economic impact of 20 hurricane Katrinas.

As policy makers meet to learn about this menace, NASA researchers a few miles away are actually doing something about it:

“We can now track the progress of solar storms in 3 dimensions as the storms bear down on Earth,” says Michael Hesse, chief of the GSFC Space Weather Lab and a speaker at the forum. “This sets the stage for actionable space weather alerts that could preserve power grids and other high-tech assets during extreme periods of solar activity.”

They do it using data from a fleet of NASA spacecraft surrounding the sun. Analysts at the lab feed the information into a bank of supercomputers for processing. Within hours of a major eruption, the computers spit out a 3D movie showing where the storm will go, which planets and spacecraft it will hit, and predicting when the impacts will occur. This kind of “interplanetary forecast” is unprecedented in the short history of space weather forecasting.

“This is a really exciting time to work as a space weather forecaster,” says Antti Pulkkinen, a researcher at the Space Weather Lab. “The emergence of serious physics-based space weather models is putting us in a position to predict if something major will happen.”

Some of the computer models are so sophisticated, they can even predict electrical currents flowing in the soil of Earth when a solar storm strikes. These currents are what do the most damage to power transformers. An experimental project named “Solar Shield” led by Pulkkinen aims to pinpoint transformers in greatest danger of failure during any particular storm.

“Disconnecting a specific transformer for a few hours could forestall weeks of regional blackouts,” says Pulkkinen.

Astronauts like this one on the STS-103 mission are on the front line of stormy space weather. Credit: NASA/STS-103 crew

Another SWEF speaker, John Allen of NASA’s Space Operations Mission Directorate, pointed out that while people from all walks of life can be affected by space weather, no one is out on the front lines quite like astronauts.

“Astronauts are routinely exposed to four times as much radiation as industrial radiation workers on Earth,” he says. “It’s a serious occupational hazard.”

NASA keeps careful track of each astronaut’s accumulated dosage throughout their careers. Every launch, every space walk, every solar flare is carefully accounted for. If an astronaut gets too close to the limits … he or she might not be allowed out of the space station! Accurate space weather alerts can help keep these exposures under control by, e.g., postponing spacewalks when flares are likely.

Speaking at the forum, Allen called for a new kind of forecast: “We could use All Clear alerts. In addition to knowing when it’s dangerous to go outside, we’d also like to know when it’s safe. This is another frontier for forecasters–not only telling us when a sunspot will erupt, but also when it won’t.”

The educational mission of SWEF is key to storm preparedness. As Lika Guhathakurta and colleague Dan Baker of the University of Colorado asked in a June 17, 2011 New York Times op-ed: “What good are space weather alerts if people don’t understand them and won’t react to them?”

By spreading the word, SWEF will help.

 

Related Links:

 › SWEF 2011 home page

› Integrated Space Weather Analysis System

› Community Coordinated Modeling Center

› Solar Shield–Protecting the North American Power Grid

› How’s the Weather on the Sun? – New York Times op-ed

› 1859 Carrington Super Flare

 

Dr. Tony Phillips
NASA’s Goddard Space Flight Center

 
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Posted by on June 27, 2011 in News Article, Science

 

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NASA Captures a Monster Prominence – Video

NASA image captured Feb. 24, 2011

To see an image showing the size of the prominence in comparison to the size of earth.

NASA image posted March 2, 2011

When a rather large-sized (M 3.6 class) flare occurred near the edge of the Sun, it blew out a gorgeous, waving mass of erupting plasma that swirled and twisted over a 90-minute period (Feb. 24, 2011). This event was captured in extreme ultraviolet light by NASA’s Solar Dynamics Observatory spacecraft . Some of the material blew out into space and other portions fell back to the surface. Because SDO images are super-HD, we can zoom in on the action and still see exquisite details. And using a cadence of a frame taken every 24 seconds, the sense of motion is, by all appearances, seamless. Sit back and enjoy the jaw-dropping solar show.

Credit: NASA/GSFC/SDO

NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission.

 
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Posted by on April 20, 2011 in News Article, Photo, Video

 

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