Explore Astronomy

This distant object could help fill in the gap between stars and gas giant planets. Credit: Canada-France-Brown-Dwarf-Survey 2008

Brown dwarfs are not quite stars and not quite planets. They are the missing links between the lowest mass stars and the highest mass planets possible. Scientists recently discovered the coolest brown dwarf known — an important discovery that may shed light on the development of planets beyond our solar system.

• News release from the Canada France Hawaii Telescope.

A distant, dim flash in the sky marks the location of the biggest explosion ever recorded, as astronomers monitor a gamma ray burst brighter than 10 million galaxies combined. And astronomers have found tiny, early galaxies so thick with stars that they might never experience night as we do.

• Hubble Pinpoints Record-Breaking Explosion
• Compact Galaxies in the Early Universe Pack a Big Punch

Rhea peeks from behind Saturn's partially shaded rings.

NASA’s Cassini spacecraft has found evidence of material orbiting Rhea, Saturn’s second largest moon, which means Rhea could have rings. This is the first time rings have potentially been found around any moon. Astronomers speculate that a collision in the moon’s distant past led to the rings’ formation.

• Cassini Mission Web page.
• Solar Views' information on Rhea.
• The Planetary Society on Rhea's rings.

Enceladus may have water below its surface.

The Cassini space probe was launched in 1997 and flew by Earth, Venus and Jupiter. It entered orbit around Saturn in 2004. One of Saturn’s moons, Enceladus, is believed to have liquid water below its crusty surface. A daring flyby of Cassini into geyser plume of Enceladus has bolstered the idea.

• Cassini Mission Enceladus images.
• NASA's Cassini Mission page.

Artist's conception of extrasolar planet HD 189733b.

Astronomers know that complex molecules are required building blocks for life, and can indicate that biological activity is present on distant worlds. Methane, which can come from volcanic eruptions, among other sources, is a key ingredient for the formation of life and also a by-product of microbial activity.

• Locator for HD 189733.
• HubbleSite news release about the discovery.
• Space.com story about the discovery.

A possible underground ocean could affect Titan's rotation.

Saturn’s moon, Titan, may have a deep, hidden ocean. The second largest moon in the solar system, Titan has long been thought to have an environment similar to that of early Earth, before life began putting oxygen into atmosphere. If the ocean prediction is true, Titan will join three other solar system moons suspected of hiding underground oceans.

• NASA's Cassini page.
• Solar Views images of Titan.
• National Geographic on Titan's potential ocean.
• Discovery.com on Titan's possible ocean.

For the first time, an organic molecule has been located in the atmosphere of a planet beyond our solar system. The planet itself can’t sustain life, but could the molecule’s presence is good news for life elsewhere.

Back on Earth, art and science merge as the Walter’s Art Museum in Baltimore, Md., displays Hubble images on its walls. The special exhibit is the brainchild of a group of curating students at Johns Hopkins University, who worked with astrophysicists to create the display.

• Hubble Finds First Organic Molecule on an Exoplanet
• The Aesthetics of Hubble Images Showcased at Walters Art Museum

View of rock layers in Mars' Victoria Crater.

Mars was too salty to sustain life for much of its history, new evidence from the Opportunity rover on the Martian surface indicates. Minerals deposited in sedimentary rocks suggest they formed in extremely salty water — even saltier than oceans on Earth. Such conditions would have made it inhospitable to even the toughest micro-organisms.

• The BBC reports on the rover finding.
• Bad Astronomy discusses the finding.