The Most Distant Sun
9.07.2007

When is the Sun most distant from Earth? It happened again just this past weekend. A common misconception is that the Sun is most distant during the winter, when it's the coldest. In truth, however, the seasonal temperatures are more greatly influenced by the number of daylight hours and how high the Sun rises.

An X Class Flare Region on the Sun
6.11.2007

Why does the Sun flare? Unpredictably, our Sun unleashes tremendous flares expelling hot gas into the Solar System that can affect satellites, astronauts, and power grids on Earth. This close up of an active region on the Sun that produced a powerful X-class flare was captured by the orbiting TRACE satellite.

Large Eruptive Prominence Imaged by SDO
10.05.2010

Sometimes part of the Sun can just explode into space. These explosions might occur as powerful solar flares, coronal mass ejections, or comparatively tame eruptive solar prominences. Pictured above is one of the largest solar prominence eruptions yet observed, one associated with a subsequent coronal mass ejection.

Sun Halo at Winter Solstice
14.01.2002

Sometimes it looks like the Sun is being viewed through a large lens. In the above case, however, there are actually millions of lenses: ice crystals. As water freezes in the upper atmosphere, small, flat, six-sided, ice crystals might be formed.

X Class Flare
17.02.2011

On Valentine's Day (ET) the Sun unleased one of its most powerful explosions, an X-class flare. The blast was the largest so far in the new solar cycle. Erupting from active region AR1158...

Sunspot Loops in Ultraviolet
10.04.2011

It was a quiet day on the Sun. The above image shows, however, that even during off days the Sun's surface is a busy place. Shown in ultraviolet light, the relatively cool dark regions have temperatures of thousands of degrees Celsius.

Double Eruptive Prominences
18.04.2003

Lofted over the Sun on looping magnetic fields, large solar prominences are composed of relatively cool, dense plasma. When seen against the brilliant solar disk they appear as dark filaments, but these enormous magnetic...

A Solar Prominence Erupts in STEREO
20.10.2009

What does a solar prominence look like in three dimensions? To help find out, NASA launched the STEREO satellites to keep a steady eye on the Sun from two different vantage points. The STEREO...

AR9077: Solar Magnetic Arcade
20.07.2000

On July 14th, solar active region 9077 (AR9077) produced a massive flare. The event also blasted an enormous cloud of energetic charged particles toward planet Earth, triggering magnetic storms and dramatic auroral displays. This striking close-up of AR9077 was made by the orbiting TRACE satellite shortly after the flare erupted.

Dark Sun Sizzling
10.07.2006

Is this our Sun? Yes. Even on a normal day, our Sun is sizzling ball of seething hot gas. Unpredictably, regions of strong and tangled magnetic fields arise, causing sunspots and bright active regions. The Sun's surface bubbles as hot hydrogen gas streams along looping magnetic fields.