Here’s a selection of great photos this week!

Image : This is an artist’s concept of the magnetosphere’s boundary as seen from the moon in soft X-rays emitted by solar wind charge exchange (SWCX).

Credit: NASA / Rob Kilgore
The sun continually blows a thin gas of electrically charged particles (plasma) into space in all directions. This is called the solar wind.

Cravens knew that the solar wind contains atoms with a lot of positive electric charge (oxygen and iron ions). Since opposite electric charges attract, he reasoned that these positive solar wind ions would steal negatively charged electrons from electrically neutral atoms emitted by the comet as its surface vaporized.
The ion with the stolen electron would initially be highly energetic, but as it relaxed to a less energetic state, it would get rid of the extra energy by emitting a soft X-ray.

This phenomenon, dubbed Solar Wind Charge Exchange, or SWCX, was responsible for the mysterious X-ray glow around the comet.
Interaction between the solar wind and the boundary of the magnetosphere causes space weather effects that can disrupt satellites, radio communication, and power systems. “This boundary is not visible in the ordinary light seen by our eyes, so typically spacecraft have to travel through it to get measurements.
But this area is huge, extending past the moon’s orbit on Earth’s night side, and spacecraft exploring the magnetosphere only give us information about a single tiny point. However, by observing the soft X-rays emitted from near the magnetosphere by SWCX, we can see the big picture – a global view.

An observatory on the moon provides a terrific vantage point.”

Flying at an altitude of about 240 miles over the eastern North Atlantic, the Expedition 30 crew aboard the International Space Station photographed this nighttime scene. This view looks northeastward. Center point coordinates are 46.8 degrees north latitude and 14.3 degrees west longitude.

Exospheric solar wind charge exchange emission as viewed by XMM-Newton
Jenny Carter, Steve Sembay & Andy Read
University of Leicester
X-ray Universe 2011


And finally we have a great group of solar telescope photos from Randy Shivak, check out his amazing photos at