Artist's illustration of the carbon-rich planet.

Astronomers are interested in finding out about the composition of the distant worlds now being discovered. A new observation from the Spitzer Space Telescope, combined with ground-based observations from the Canada-France-Hawaii telescope, reveals a planet that has an unusual amount of carbon in it. Its discovery highlights suggests that smaller, rocky planets made of carbon could exist. If so, they would contain graphite, diamond and tar.

• NASA on the discovery.
• Spitzer Space Telescope news release on the discovery.

Artist's impression of a nova.

An Air Force satellite carrying instruments to measure wind velocity on Earth and another to measure disturbances in the solar wind also detected explosive stars, or “novae.” These novae are stellar flare-ups that are not as catastrophic or bright as supernovae. The observations were of confirmed novae, but some of the data captured the explosion before it achieved peak brightness. This has not been done before from the ground or space. Such observations can be used to study the phenomena that create such repeated stellar explosions in greater detail.

• Wikipedia on the Coriolis Satellite.

A close-up view of the Iapetus ridge.

A huge, mountainous ridge circling the equator of Saturn’s moon Iapetus was discovered in 2004 by the Cassini spacecraft. The ridge reaches 12 miles high and runs 1,000 miles (1,600 km) from end to end. Astronomers now propose a new idea for its formation.

• Science Daily on how Iapetus got its ridge.
• Cassini’s Iapetus flyby.

An artist's illustration of the giant gamma-ray bubbles.

A NASA telescope has detected a previously unseen structure centered in our Milky Way galaxy. It’s pair of gamma-ray emitting bubbles, 50,000 light years across, that could be a remnant of an eruption from the black hole at the galaxy’s center.

• NASA feature on the discovery.
• The Fermi Gamma Ray Space Telescope

Jets stream from Comet Hartley 2 as it travels through space.

The EPOXI Deep Impact comet investigation team, known for its flyby of Comet Tempel 1, was able to re-use its spacecraft to fly near a second comet, Hartley 2. The second flyby was executed in November 2010. The close approach of the spacecraft showed the comet’s unusual shape, and jets emerging from various lumps. The images are now being analyzed to glean clues to the formation of Hartley 2.

• NASA's EPOXI page.
• The EPOXI website.

Elliptical Galaxy NGC 4150

Elliptical galaxies are traditionally thought of as old objects where most star formation happened long ago and then evened out. They appear smooth and more or less featureless. However, Hubble observations reveal that elliptical galaxies may not be so undisturbed. These objects, judging by a galaxy called NGC 4150, may actually cannibalize smaller galaxies. In doing so, they become the sites of localized star formation, though less than in spiral galaxies.

• HubbleSite news release on this topic.

The Earth's shadow dyes the Moon red in this image of the December 2010 eclipse. Credit: Thxguy, Wikimedia Commons

A total eclipse of the Moon took place in the morning hours of December 21. Eclipses of the Moon only happen when the Moon is full, and it passes through the shadow cast by our planet. This eclipse was visible for all of North America.

• Wikipedia on the December 2010 lunar eclipse.
• Lunar eclipses for beginners.
• A time-lapse video of the eclipse.

Asteroid Ida is one of the members of the asteroid belt.

Scientists recently discovered water ice on an asteroid for the second time in a few months. This new finding suggests that water is more common on asteroids than previously thought. Perhaps asteroids delivered much of the water present on the early Earth.

• Space.com on the topic.
• Science Codex on the discovery.