Artist's depiction of the Gliese 581 planetary system

Astronomers have searched diligently for a planet of the size of Earth. Researchers would love to find such a planet in the zone appropriate for liquid water – what they call “the habitable zone.” New observations from the European Southern Observatory indicate that the star Gliese 581 has a fourth planet in addition to the known 3. The other planets are large “super earths” and one Neptune-sized planet. But the new planet is about twice the mass of Earth, and could be close to the habitable zone as well.

• ESO news release on the discovery.

Hubble anniversary image of galaxy clusters 1E 0657-556.

Hubble is celebrating its 19th anniversary by releasing new, beautiful images. One image shows a complex interaction of four galaxies in a group called Arp 194. This group’s numerous star clusters formed recently as a result of the galaxies’ gravitational interaction. A second image of two clusters of colliding galaxies, called 1E 0657-556, was also released for the birthday. The galaxies passed through one another, leaving large amounts of gas behind, in the center of the collision.

• Hubble's 19th Anniversary images.

Artist's depiction of the Lunar Reconnaissance Orbiter.

A new NASA lunar satellite planned for a May launch will send back the highest-resolution photos ever taken of the Moon’s surface and provide virtual views close to the ones seen by the Apollo astronauts. The Lunar Reconnaissance Orbiter (LRO), passing 31 miles above the moon, will have cameras with resolution equal to roughly one foot of Moon surface for every pixel.

• NASA's Lunar Reconnaissance Orbiter page.
• Malin Space Systems Lunar Reconnaissance Orbiter page.
• NASA on LRO and the search for lunar water sources.
• NASA explains what LRO is and does.

A Delta II rocket carries the Kepler probe into space. Credit: NASA/Kim Shiflett

NASA’s Kepler Mission was launched on Marcy 7, 2009 to begin its quest for earth-like planets. As the spacecraft slowly drifts away from Earth, the first order of business is calibration of the detectors and discarding the dust cover that protects the telescope. Kepler will look for the tiny dimming of light that occurs as a planet passes between us and the star it orbits. Kepler will capture this dimming effect as it “stares” at one part of the sky for three and a half years.

• The Kepler Mission Web site.
• Hear a webcast about the mission.

An artist's depiction of the orbiting black holes. Credit: NOAO

Astronomers recently found what looks like two massive black holes orbiting each other in the center of a distant galaxy. It’s long been thought that twin black holes might exist, but a new, innovative search was needed to find this rare pair. The discovery may lead to a greater understanding of how massive black holes form and evolve at centers of galaxies.

• National Optical Astronomy Observatory news release on the discovery.
• Discover Magazine on the binary black holes.
• Astronomy.com discusses the discovery.

The newly discovered moonlet, positioned in a gap between Saturn's rings.

Saturn has a complex system of moons and rings. Scientists have thought that moons, or smaller bodies called “moonlets,” have something to do with the formation of Saturn’s rings. Recent images from NASA’s Cassini spacecraft turned up a small moonlet in the G-ring of Saturn’s system. The G-ring is a diffuse ring, nearly the last ring in the system. It contains a curious arc that is probably due to material crashing into the little moonlet embedded in it.

• Cassini Mission news release on the moonlet.
• NASA's Cassini Mission page discusses the news.

The Ares V rocket.

Getting crisp, clear images of objects billions of light years away requires big space telescopes. But the size of telescopes sent into orbit is constrained by the size of the rockets that carry them.

NASA’s new Ares V rocket may completely change rules of the game. The Ares V, which will carry the next lunar lander to the Moon, is big enough to hold eight school buses. It can haul six times more mass and three times the volume the Space Shuttle can.

• Science@NASA on the Ares V.
• Space.com talks about the Ares V.

Artist's rendition of the Dawn mission examining Vesta.

NASA’s Dawn mission is on its way to the asteroid belt. Once there, the spacecraft will orbit two asteroids, Ceres and Vesta, gathering information with its two cameras. The asteroids are pieces left over from the formation of the solar system, so scientists hope the mission will help us understand how the solar system evolved.

• The Dawn Mission Web site.