This artist's concept shows two scientists examining rock formations on the Red Planet. Many scientists say sedimentary deposits evident in Mars Global Surveyor images could contain fossils visible under ordinary magnification -- all the more reason to send exobiologists and geologists there.
The Hubble telescope found a long-sought population of stars that were tossed into the dark emptiness of space from their home galaxies. It's the first time stars have been discovered more than 300,000 light-years from the nearest big galaxy. Above is an illustration of the view of the nighttime sky from a hypothetical planet orbiting an 'outcast' star in the Virgo cluster of galaxies.
This artist's concept depicts the pulsar planet system discovered by Aleksander Wolszczan in 1992. Wolszczan used the Arecibo radio telescope in Puerto Rico to find three planets -- the first of any kind ever found outside our solar system -- circling a pulsar named PSR B1257+12.
The giant planet HR 8799b was first discovered in 2007 at the Gemini North observatory. The planet is young and hot, with a temperature of 1,500 degrees Fahrenheit. It's slightly larger than Jupiter and may be 10 times more massive.
This artist's concept shows an imminent planetary collision around a pair of double stars. NASA's Spitzer Space Telescope found evidence that such collisions could be common around a certain type of tight double, or binary, star system.
HD 98800 is a multiple star system about 150 light years from Earth -- right in our section of the Milky Way galaxy. For years it has been known that HD 98800 consists of two pairs of double stars, with one pair surrounded by a disk of dust.
This is an artist's concept of a red dwarf star undergoing a powerful eruption, called a stellar flare. A hypothetical planet is in the foreground.
This artist's impression shows an infrared view of a gas-giant exoplanet passing by the face of its star. The planet, HD 189733b, lies 63 light-years away in the constellation Vulpecula, and was discovered in 2005 as it transited its parent star, dimming the star's light by some three percent.
In this artist's conception, a possible newfound planet spins in a nearby star's dusty, planet-forming disc. The possible planet, detected around the star CoKu Tau 4 by the Spitzer Space Telescope, is theorized to be at least as massive as Jupiter, and may have a similar appearance to what the giant planets in our own solar system looked like billions of years ago.
New observations from NASA's Spitzer Space Telescope have revealed that mature planetary systems -- dusty disks of asteroids, comets, and possibly planets -- are more frequent around close-knit twin, or binary, stars than single ones like our own. That means sunsets like the one portrayed in this artist's photo concept might be quite commonplace in the universe.
When NASA's illustrators stretch their imaginations -- giving shape and color to what, say, a sunrise on another world -- their work offers brilliant notions of what vistas beyond our tiny corner of space might look like. See the full slideshow at LIFE.com.