Globular cluster Terzan 5 Credit: NRAO

Globular cluster Terzan 5, a densely packed group of stars in the Milky Way, is probably the remnants of a long-ago merger between the Milky Way and a dwarf galaxy. Galaxies are known to grow by colliding and merging, combining their stars. Terzan 5 has two different populations of stars, indicating an unusual origin — globular clusters ordinarily have uniform populations of stars that all formed at the same time from a single cloud of gas and dust.

• Space.com on Terzan 5.
• Astrobiology Magazine discusses the findings.
• Universe Today talks Terzan 5.

A solar tsunami erupts on the Sun. Credit: NASA

Incredibly powerful waves of plasma are rippling across the Sun’s surface. These “solar tsunamis” were once thought to be an optical illusion. The first witnessed wave, taller than the Earth and creating a rippling pattern millions of kilometers around, was so amazing researchers thought they might be seeing some kind of flaw or trick in the satellite’s vision instead of a real wave. The Solar Terrestrial Relations Observatory (STEREO) spacecraft were able to confirm the tsunamis existence.

• NASA news release on the solar tsunamis.
• Physorg.com discusses solar tsunamis.

Two young brown dwarfs, labeled A and B.

Brown dwarfs are objects that are bigger than planets but not massive enough to become stars, yet have nuclear reactions in their cores. How do they form? Are they more like planets, or more like stars? A team of astronomers using the Spitzer Space Telescope discovered two objects that appear to be brand-new brown dwarfs. Observatories across the globe are participating in the hunt for new information.

• Spitzer Space Telescope news release on the brown dwarfs.
• Space.com discusses the brown dwarfs.

Combined image of the Milky Way's center.

As the International Year of Astronomy draws to a close, a dramatic composite image of the center of our own Milky Way Galaxy was unveiled. The image was a combination of observations from NASA’s Great Observatories: Hubble, Spitzer and Chandra. In addition to the composite image, the public can view the individual images obtained by each observatory.

• HubbleSite news release.
• Astronomy Now on the image.

Artist's depiction of the Swift satellite with a gamma ray burst in the background. Credit: Spectrum and NASA E/PO, Sonoma State University, Aurore Simonnet

Astronomers observing the tremendous stellar explosions known as gamma ray bursts have gained new insights into the nature of the most distant objects ever observed in the universe. A huge explosion detected in April 2009 by NASA’s Swift satellite has been deemed to be more than 13 billion light years from Earth.

• National Radio Astronomy Observatory news release on the gamma ray burst.
• Science Daily reports on the gamma ray burst.
• Universe Today on the gamma ray burst.

Artist's impression of the system Gliese 667. Credit: ESO/L. Calçada

A survey of a carefully selected list of stars has turned up 32 new planets beyond our solar system. An instrument called the High Accuracy Radial Velocity Planet Searcher (HARPS) in La Silla, Chile, provided the information after a five-year effort. Several stars appear to have multiple planetary systems, and a number of super-Earths, planets a few times the mass of Earth, were located.

• European Space Agency news release on the discovery.

Hubble takes a picture of the Southern Pinwheel, a dazzling galaxy with three spiral arms. The images show the aftermath of star death and the rise of new stars. In commemoration of the 400th anniversary of Galileo turning a telescope on the skies,
Hubble teams up with the Chandra and Spitzer space telescopes to capture the heart of our Milky Way galaxy.

• Hubble Image Showcases Star Birth in M83, the Southern Pinwheel
• NASA's Great Observatories Celebrate International Year of Astronomy

The first IBEX data was released in October 2009.

Our Sun creates an insulating bubble, called the “heliosphere” around our solar system. This heliosphere shields us from a tenth of the galactic radiation pouring in from space. In 2008, NASA launched the Interstellar Boundary Explorer (IBEX) to study the particles in this region. The first IBEX maps are now available, and they reveal much more complexity than models predicted.

• The IBEX mission home page.