Explore Astronomy

An artist's concept of an Earth-like planet circling a distant star.

We’ve found planets beyond our solar system, but nothing Earth sized. Still, astronomers are considering what such a world might look like.

Computer models provide ideas of 14 different theoretical planet types, to help planet hunters spot telltale indicators. Researchers hope that the models will provide information about planet composition and similar characteristics when astronomers begin finding Earth-sized planets.

• NASA news release about the project.

The Moon rises over Earth. Credit: NASA

Want to win a quick $30M? Just finance and successfully land a robotic mission on the moon! The X Prize Foundation and Google have combined to offer a prize for a lunar lander to rove around, take pictures and video and send data back to us on Earth.

The foundation and Google expect private companies from around the world to compete for the prize and the achievement. About 347 inquiries have already been made!

• The Planetary Society article on the competition.
• The X Prize Foundation Web site.

Credit: Nicolas Martin & Rodrigo Ibata, Observatoire de Strasbourg

A tiny galactic neighbor to the Milky Way, Canis Major Dwarf, was discovered in 2003. The galaxy, 25,000 light years away from our solar system, is being torn apart by the gravity of the Milky Way as it orbits our galaxy. It was detected because it has a large number of red giant stars, detectable by the Two Micron All Sky Survey, which views the sky in infrared.

• Two Micron All Sky Survey
• Students for the Exploration and Development of Space on Canis Major Dwarf

A star similar to the Sun is located in the constellation Draco. Credit: Tim Jones/McDonald Obs./UT-Austin

Astronomers search for stars similar to the Sun in order to understand how the Sun formed and if it is unique. So far, the stars we’ve found that are like the Sun have had notable differences. The closest candidate was analyzed recently and found to have a composition that strongly resembles our Sun. The research gives us ideas about the nuclear fusion processes that take place in the cores of Sun-like stars and clues about the formation of planetary systems.

• Space.com discuses the new research.
• McDonald Observatory release on the discovery of a Sun-like star.

Could cosmic rays cause extinctions on Earth? Credit: NASA

Every 62 million years or so, a mass extinction occurs on Earth. A new theory about the motion of the solar system around the Milky Way says cosmic rays may be involved. Charged particles caused by the motion could expose the Earth to high-energy radiation, damaging the biosphere and affecting the environment.

• University of Kansas Cosmology Group article on the theory.
• Physics Today on the theory.
• The Centauri Dreams forum discuses the theory.

Astronomers are using Hubble to look at Comet Holmes, a strange comet that brightened this October to nearly a million times in less than 24 hours. Comet Holmes is the only comet ever seen to brighten so strangely and dramatically. The brightening was first witnessed 115 years ago – astronomers will be able to get a better look now that the comet is performing under Hubble’s gaze.

An elliptical galaxy with a supermassive black hole in its center looks like it underwent a collision in the distant past. The collision is fueling the black hole, feeding it meals of stars, gas and dust.

• Hubble Spies Shells of Sparkling Stars Around Quasar

Comet Holmes flared to a million times its normal brightness in 24 hours. Credit: NASA, ESA, and A. Dyer

A bright new comet flared into naked eye visibility a few weeks back and continues to be bright enough to see, perhaps for another few weeks. Comet Holmes went through a similar outburst that led to its discovery 115 years ago. It’s acting strangely, so go outside and check out this celestial wonder.

• HubbleSite news release on Comet Holmes.
• Sky and Telescope is providing continuous Comet Holmes updates.
• Space.com on Comet Holmes and how to find it.
• Cometography provides Comet Holmes pictures.
• See Comet Holmes through Google Earth.

Artist's illustration of water dousing a young star system. Credit: NASA/JPL-Caltech/R. Hurt (SSC)

Water vapor is raining down on a young star system, pouring from the cloud of gas and dust around the star onto the dusty disk where planets may form.

In the system known as NGC 1333-IRAS 4B, the icy material found in the cloud is dropping towards the star and vaporizing as it reaches the disk. The process could show how water first shows up on planets like our own.

• The Spitzer Space Telescope Web site announces the discovery.