Images: NASA hunts for a new Earth

TV can have a sweeps period so why can't the Hubble Space Telescope? In this SWEEPS survey, the Hubble studied 180,000 stars in the crowded central bulge of the Milky Way galaxy 26,000 light-years away from Earth.

The top image, which shows half of the surveyed area, displays nine different stars, circled in green, that contain planets. The planets were discovered as they blocked light when crossing in front of their sun.

The bottom image shows where astronomers were able to locate a planet due to the star's back and forth wobble caused by the planet's gravity.

NASA, ESA, K. Sahu (STScI) and the SWEEPS Science Team

This image shows a Jupiter-sized planet in transit across its home star. Telescopes on Earth can detect the planet by the amount of light it blocks from the star.

NASA, ESA, and G. Bacon (STScI)

Last month, a new NASA "Sleuth" telescope, equipped with a 4-inch camera lens and a digital camera, discovered a planet 500 light years away from Earth. The planet will provide a target for further study by a Sleuth telescope as part of NASA's Kepler mission which is scheduled to launch in 2008. The mission is to study a single patch of sky for four years to detect planets and gain more information about them.

Jeffrey Hall, Lowell Observatory.

NASA's Sim PlanetQuest is slated to identify nearby Earth-like planets that will be further examined by Terrestrial Planet Finder observatories to determine whether a planet is inhabitable or not. It is scheduled to launch within the next decade.

NASA

The Terrestrial Planet Finder Coronagraph and the Terrestrial Planet Finder Interferometer will check the data from Sim PlantQuest and also try to find more new planets. Their instruments will determine whether light from a planet outside our solar system is similar to the light from Earth.

NASA

NASA is also beginning to find out details about known planets outside our solar system. The Spitzer Space Telescope used heat-sensitive infrared technology to study the planet Upsilon Andromedae b--one of three known planets that orbit Upsilon Andromedae 40 light-years away. The measurements showed that one side of the planet, which orbits its sun at one-sixth the distance from Mercury to our sun, is 2,550 degrees Fahrenheit hotter than the other.

Left is an artist's conception of the Jupiter-like planet, Upsilon Andromedae b.

NASA/JPL-Caltech

How to detect a transiting planet.

NASA, ESA, and A. Feild (STScI)

Today, there are many planet-finding projects around the world as shown on the map (left).

Here's a code to the colors which indicate the methods employed in each planet search:

Orange: Radial velocity (10)
Green: Planetary transit surveys (30)
Blue: Micro-licensing surveys (15)
Red: Imaging (6)
Yellow: Astronomy (18)

NASA