The giant telescope took seven years to build.

Tests have begun on one of world’s largest optical telescopes, located on a mountaintop on the Canary Islands. Situated 7,900 feet above sea level, the huge Gran Telescopio Canarias (GTC) consists of a mirror measuring 34 feet across and is made up of 36 separate hexagonal mirror segments. This Spanish-led telescope will be able to spot some of faintest, most distant objects in universe.

• GTC Web site
• BBC story on the GTC
• Guardian story on the GTC

Location of the Orion Nebula from the Sky in Google Earth.

Google Earth let users explore the planet through satellite imagery. Now it’s letting those users turn their attention to the heavens.

Google Earth, working with the Space Telescope Science Institute, now offers a feature that explores the night sky. Users can browse the cosmos and zoom in to get Hubble images, background information and links.

And speaking of satellites, 2007 is the 50th anniversary of the International Geophysical Year, declared in 1957. Sixty-seven countries participated in the coordinated attempt to observe the globe and atmosphere. Americans and the Soviet Union successfully launched satellites as part of the program. The National Academy of Sciences is celebrating the anniversary with events around the United States.

• HubbleSite's gSky page.
• HubbleSite news release.
• Google Earth explains its new feature.
• The National Academy of Sciences on the International Geophysical Year.

A strangely shaped cloud of dust around a newborn star has astronomers scratching their heads. The lopsided disk may have been caused by the gravity of planets sweeping up debris in the disk, or by the gravity of a nearby star.

And Uranus’ rings are about to go missing. Every 42 years, Uranus’ orbit brings its thin rings in line with Earth, making them vanish like a sheet of paper held up on its edge at eye level. Astronomers use the opportunity to search for moons that might otherwise be hidden by the rings.

• Astronomers Find Highly Elliptical Disk Around Young Star
• Going, Going, Gone: Hubble Captures Uranus's Rings on Edge

The Moon takes on a reddish hue during an eclipse. Credit: Fred Espenak

Two to four times a year, the Moon passes through a portion of the Earth’s shadow, causing an eclipse. On August 28, skywatchers will be treated to a total lunar eclipse starting at 4:30 a.m. EST. All of North America will be able to see some portion of the eclipse. From the eastern USA, the Great Lakes region and Ontario, the Moon will sets while total eclipse. Only observers to the west of the Rockies (including Alaska) will be treated to the entire event.

• NASA's Eclipse Home Page.

Researchers are looking into the effects of a trip to the red planet.

The European Space Agency (ESA) is seeking volunteers for a simulated trip to Mars. Six crew members will spend 17 months in an isolation tank, simulating a round trip to the Red Planet. The crew will live and work in series of interlocked modules at a research institute in Moscow. Once the hatches close, their only contact with outside world will be through a radio link to “Earth.”

• ESA's call for volunteers.

Saturn's moon, Hyperion, is riddled with deep pits. Credit: NASA

One of the solar system’s strangest looking moons is Hyperion, which orbits the ringed planet Saturn. The Cassini spacecraft, now orbiting Saturn, photographed Hyperion a few years ago and revealed a moon that looks more like a sponge or coral than rock or ice. Now scientists think they know what causes the strange appearance.

• The Cassini mission's Hyperion page.

Scientists warn that life elsewhere may not mirror that on our own planet. Credit: National Research Council

When we are planning research to look for biological activity elsewhere, are we — to borrow a lyric — “looking for life in all the wrong places?”

A recent report from the National Academy of Science (NAS) points out that researchers are concerned that the assumption that life is water-based and uses DNA to encode important life information will limit our ability to recognize life elsewhere. The report advises NASA and other research agencies to expand research beyond conventional views.

• Space.com discusses the report.
• The NAS Report

Pluto-like object Eris is circled by its own moon, Dysnomia. The discovery of Eris helped provoke debate about Pluto's planetary status.

New details about some of the interesting smaller objects in the solar system are shedding some light on the “planet controversy.” Astronomers have been trying to establish what constitutes a planet, taking size, orbit and other factors into consideration.

One of the important objects astronomers have been studying is Eris, discovered in 2005. Astronomers suspected Eris was bigger than Pluto, but now they know for sure that Eris has 1.27 times more mass that Pluto. Eris appears to have a density similar to Pluto’s, and probably contains rocky material as well as ice.

Another object of interest is the asteroid Ceres. Astronomers have imaged Ceres with the Hubble Space Telescope in preparation for the launch of the DAWN mission in 2007. DAWN will travel to and orbit Ceres as well as another large body in the asteroid belt between Mars and Jupiter – Vesta.

• Astronomers Measure Mass of Largest Dwarf Planet
• Hubble Images of Asteroids Help Astronomers Prepare for Spacecraft