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NASA STEREO Observes One Of The Fastest CMEs On Record


Credit: NASA/STEREO

Credit: NASA/STEREO

On July 23, 2012, a massive cloud of solar material erupted off the sun’s right side, zooming out into space, passing one of NASA’s Solar TErrestrial RElations Observatory (STEREO) spacecraft along the way. Using the STEREO data, scientists at NASA’s Goddard Space Flight Center in Greenbelt, Md. clocked this giant cloud, known as a coronal mass ejection, or CME, as traveling between 1,800 and 2,200 miles per second as it left the sun.

Conversations began to buzz and the emails to fly: this was the fastest CME ever observed by STEREO, which since its launch in 2006 has helped make CME speed measurements much more precise. Such an unusually strong bout of space weather gives scientists an opportunity to observe how these events affect the space around the sun, as well as to improve their understanding of what causes them.

“Between 1,800 and 2,200 miles per second puts it without question as one of the top five CMEs ever measured by any spacecraft,” says solar scientist Alex Young at Goddard. “And if it’s at the top of that velocity range it’s probably the fastest.”

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Astronomers Find Solar Storms Behave Like Supernovae

February 24, 2014 Leave a comment

Photo credit: NASA/SDO

Photo credit: NASA/SDO

Researchers at UCL have studied the behaviour of the Sun’s coronal mass ejections, explaining for the first time the details of how these huge eruptions behave as they fall back onto the Sun’s surface. In the process, they have discovered that coronal mass ejections have a surprising twin in the depths of space: the tendrils of gas in the Crab Nebula, which lie 6500 light-years away and are millions of times larger.

On 7 June 2011, the biggest ejection of material ever observed erupted from the surface of the Sun. Over the days that followed, the plasma belched out by the Sun made its way out into space. But most of the material propelled up from the Sun’s surface quickly fell back towards our star’s surface.

For the solar physicists at UCL’s Mullard Space Science Laboratory, watching these solar fireworks was a unique opportunity to study how solar plasma behaves.

“We’ve known for a long time that the Sun has a magnetic field, like the Earth does. But in places it’s far too weak for us to measure, unless we have something falling through it. The blobs of plasma that rained down from this beautiful explosion were the gift we’d been waiting for”, says David Williams, one of the study’s authors.

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Stanford Physicists Monitoring Huge Solar Event

November 13, 2013 Leave a comment

Every 11 years, the sun undergoes a complete makeover when the polarity of its magnetic field – its magnetic north and south – flips. The effects of this large-scale event ripple throughout the solar system.

Although the exact internal mechanism that drives the shift is not entirely understood, researchers at Stanford’s Wilcox Solar Observatory have monitored the sun’s magnetic field on a daily basis since 1975 and can identify the process as it occurs on the sun’s surface. This will be the fourth shift the observatory has monitored.

New polarity builds up throughout the 11-year solar cycle as sunspots – areas of intense magnetic activity – appear as dark blotches near the equator of the sun’s surface. Over the course of a month, a sunspot spreads out, and gradually that magnetic field migrates from the equator to one of the sun’s poles.

As the polarity moves toward the pole, it erodes the existing, opposite polarity, said Todd Hoeksema, a solar physicist at Stanford since 1978 and director of the Wilcox Solar Observatory. The magnetic field gradually reduces toward zero, and then rebounds with the opposite polarity.

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Sun Emits Third Solar Flare In 2 Days

October 31, 2013 Leave a comment

Image Credit: NASA/SDO/GSFC

Image Credit: NASA/SDO/GSFC

The sun emitted a significant solar flare, peaking at 4:01 a.m. EDT on Oct. 25, 2013. Solar flares are powerful bursts of radiation. Harmful radiation from a flare cannot pass through Earth’s atmosphere to physically affect humans on the ground, however — when intense enough — they can disturb the atmosphere in the layer where GPS and communications signals travel. This disrupts the radio signals for as long as the flare is ongoing, anywhere from minutes to hours.

This flare is classified as an X1.7 class flare. “X-class” denotes the most intense flares, while the number provides more information about its strength. An X2 is twice as intense as an X1, an X3 is three times as intense, etc. In the past, X-class flares of this intensity have caused degradation or blackouts of radio communications for about an hour.

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Eastern U.S. To See Partial Solar Eclipse Nov. 3

October 31, 2013 1 comment

For people in the eastern United States, the sun will rise half covered by the moon on Sunday morning, November 3, and the partial eclipse will last about 3/4 of an hour. Jay Pasachoff, Field Memorial Professor of Astronomy at Williams College and chair of the International Astronomical Union’s Working Group on Eclipses, advises that people able to see very low on the eastern horizon and having suitable filters in hand would enjoy the event.

A total solar eclipse will sweep across Africa about two hours later on that Sunday, when it will be afternoon, six hours later, in west Africa. After starting in the Atlantic, the shadow of the moon will reach Gabon, where Pasachoff and colleagues will observe totality, with the support of a research grant from the Committee for Research and Exploration of the National Geographic Society.

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Changes in Comet Rotation May Be Predicted With Greater Accuracy

September 6, 2013 Leave a comment

Credit: NASA / JPL-Calthech / UMD

Credit: NASA / JPL-Calthech / UMD

Planetary Science Institute researchers have discovered a way to predict the changes in the rotational states of comets that could help scientists learn more about the approaching Comet C/2012 S1 (ISON), which will pass by the Sun on Thanksgiving Day and has attracted worldwide interest because it may become sufficiently bright to be seen by the naked eye.

PSI Senior Scientists Nalin H. Samarasinha and Beatrice E.A. Mueller have determined such changes are a function of a comet’s size, period and solar energy it receives, but surprisingly not a function of the fraction of a comet’s surface that is active according to a paper published in the Astrophysical Journal Letters.

“You get more change if there is more solar energy and less change if it is spinning more rapidly to begin with or if it is a larger comet. Larger, rapidly rotating comets are not going to change their spin status very much,” Samarasinha said. “We expected that the fraction of the surface of the comet that is active would also be a controlling factor, but that proved not to be the case.”

Full Story: http://www.psi.edu/news/cometrotation.html

A&A Press Release – No Evidence Of Planetary Influence On Solar Activity

September 6, 2013 Leave a comment

Image Credit: Swedish Solar Telescope at the Roque de los Muchachos Observatory

Image Credit: Swedish Solar Telescope at the Roque de los Muchachos Observatory

In 2012, Astronomy & Astrophysics published a statistical study of the isotopic records of solar activity, in which Abreu et al. claimed that there is evidence of planetary influence on solar activity. A&A is publishing a new analysis of these isotopic data by Cameron and Schüssler. It corrects technical errors in the statistical tests performed by Abreu et al. They find no evidence of any planetary effect on solar activity.

The Sun is a magnetically active star. Its activity manifests itself as dark sunspots and bright faculae on its visible surface, as well as violent mass ejections and the acceleration of high-energy particles resulting from the release of magnetic energy in its outer atmosphere. The frequency with which these phenomena occur varies in a somewhat irregular activity cycle of about 11 years, during which the global magnetic field of the Sun reverses. The solar magnetic field and the activity cycle originate in a self-excited dynamo mechanism based upon convective flows and rotation in the outer third of the solar radius.

Systematic observations of sunspots since the beginning of the 17th century indicate that solar activity also varies on longer timescales, including periods of very low activity, such as the so-called Maunder minimum between 1640 and 1700.

Full Story: http://www.aanda.org/index.php?option=com_content&task=view&id=966&Itemid=277