European Association for Astronomy Education

Source:  arXiv

On November 4, 2010, NASA's EPOXI spacecraft went within 450 miles of Comet Hartley 2.  Designated officially as 103P/Hartley 2, the comet thus became the fifth comet with close-up images.

Hartley 2 is a short period comet that about six and a half years to orbit the Sun and is also a small comet with about 1.5 km in diameter.

But the Solar and Heliospheric Observer (SOHO), better known for its observations of the sun, also observed comet Hartley 2. Together, the two returned data about what appears to be an irregular comet, ejecting  chunks of ice and losing water at a very fast pace.

These findings were described in an article of the June 10, 2011 issue of the Astrophysical Journal Letters.

Source: NASA/SDO

Jets, known as spicules, captured in an SDO image on April 25, 2010.
Image credits: NASA/SDO/AIA

Like giant strands of seaweed some 32,000 miles high, material shooting up from the sun sways back and forth with the atmosphere. In the ocean, it's moving water that pulls the seaweed along for a ride; in the sun's corona, magnetic field ripples called Alfvén waves cause the swaying.

For years these waves were too difficult to detect directly, but NASA's Solar Dynamics Observatory (SDO) is now able to track the movements of this solar "seaweed" and measure how much energy is carried by the Alfvén waves. The research shows that the waves carry more energy than previously thought, and possibly enough to drive two solar phenomena whose causes remain points of debate: the intense heating of the corona to some 20 times hotter than the sun's surface and solar winds that blast up to 1.5 million miles per hour.(read more)

Getting ready for ALMA’s first scientific observations
Source: ESO Organisation Release eso1127

Image credits: ESO/S. Rossi

The first European antenna for the Atacama Large Millimeter/submillimeter Array (ALMA) has reached new heights, having been transported to the observatory’s Array Operations Site (AOS) on 27 July 2011. The 12-metre diameter antenna has arrived at the Chajnantor plateau, 5000 metres above sea level. Here, it joins antennas from the other international ALMA partners, bringing the total number at the AOS to 16.(read more)