Share

Large Coronal Hole Found Near Sun's North Pole

Karen C. Fox
Published: July 22, 2013

The European Space Agency/NASA Solar and Heliospheric Observatory, or SOHO, captured this image of a gigantic coronal hole hovering over the sun’s north pole last week. (ESA/NASA/SOHO)

The European Space Agency/NASA Solar and Heliospheric Observatory, or SOHO, captured this image of a gigantic coronal hole hovering over the sun’s north pole on July 18, 2013, at 9:06 a.m. EDT. Coronal holes are dark, low density regions of the sun’s outermost atmosphere, the corona. They contain little solar material, have lower temperatures, and therefore, appear much darker than their surroundings.

Coronal holes are a typical feature on the sun, though they appear at different places and with more frequency at different times of the sun’s activity cycle. The activity cycle is currently ramping up toward what is known as solar maximum, currently predicted for late 2013. During this portion of the cycle, the number of coronal holes decreases.

During solar max, the magnetic fields on the sun reverse and new coronal holes appear near the poles with the opposite magnetic alignment. The coronal holes then increase in size and number, extending further from the poles as the sun moves toward solar minimum again.  At such times, coronal holes have appeared that are even larger than this one.

(MORE: How Do Stars Get Their Colors?)

The holes are important to our understanding of space weather, as they are the source of a high-speed wind of solar particles that streams off the sun some three times faster than the slower wind elsewhere. While it’s unclear what causes coronal holes, they correlate to areas on the sun where magnetic fields soar up and away, failing to loop back down to the surface, as they do elsewhere.

MORE: Seeing Red in Space

The Sun's Innermost Atmosphere

The Sun's Innermost Atmosphere

This picture is made of images taken far away as well as close to the sun, which allows scientists to compare what happens at both locations. Here you see a coronal mass ejection moving away from the sun in the upper right corner. (Image: ESA/NASA)

  • The Sun's Innermost Atmosphere
  • Cone Nebula
  • It Takes Two
  • A Valentine from the Heavens
  • Saturn's String of Pearls
  • White Hot Cigar Galaxy
  • Studying the Birth of Stars
  • New Year's Eve Eruption
  • Jellyfish Nebula
  • Dusty Clouds
  • Hotbed of Star Birth
  • The Powerful Sun

Featured Blogs

June 2014: Earth's 3rd Consecutive Warmest Month on Record

By Dr. Jeff Masters
July 24, 2014

June 2014 was Earth's warmest June since records began in 1880, said NOAA's National Climatic Data Center (NCDC). NASA rated June 2014 a bit cooler: the 3rd warmest. According to NOAA, the planet has now had three back-to-back warmest months on record--April, May and June of 2014. Global ocean temperatures during June 2014 had the greatest departure from average of any month in recorded history.

Warmest Days of the Year for the U.S.

By Christopher C. Burt
July 9, 2014

NOAA recently produced an interesting map showing when the hottest day of the year is likely to occur in the contiguous U.S. Complimenting this map is one produced by Brian Brettschneider of Borealis Scientific, LLC, which illustrates the date of summer’s midpoint (peak of summer average temperatures) which was reproduced in my blog posted last August. Brian has also produced maps of such for the Fall, Winter and Spring seasons. There is also some other great material from Brian herein.

Live Blog: Tracking Hurricane Arthur as it Approaches North Carolina Coast

By Shaun Tanner
July 3, 2014

This is a live blog set up to provide the latest coverage on Hurricane Arthur as it threatens the North Carolina Coast. Check back often to see what the latest is with Arthur. The most recent updates are at the top.

Tropical Terminology

By Stu Ostro
June 30, 2014

Here is some basic, fundamental terminology related to tropical cyclones. Rather than a comprehensive and/or technical glossary, this represents the essence of the meaning & importance of some key, frequently used terms.

2013-14 - An Interesting Winter From A to Z

By Tom Niziol
May 15, 2014

It was a very interesting winter across a good part of the nation from the Rockies through the Plains to the Northeast. Let's break down the most significant winter storms on a month by month basis.

What the 5th IPCC Assessment Doesn't Include

By Angela Fritz
September 27, 2013

Melting permafrost has the potential to release an additional 1.5 trillion tons of carbon into the atmosphere, and could increase our global average temperature by 1.5°F in addition to our day-to-day human emissions. However, this effect is not included in the IPCC report issued Friday morning, which means the estimates of how Earth's climate will change are likely on the conservative side.