NASA reported today that its Kepler spacecraft has begun to search for other Earth-like planets.
The spacecraft, which is carrying a telescope and a series of computers, was launched into space on March 6. Kepler is expected to spend the next three and a half years searching more than 100,000 stars for signs of Earth-like planets. According to the National Aeronautics and Space Administration, the Kepler mission is the first set up specifically to find planets like ours -- small, rocky habitable planets orbiting sun-like stars in the habitable zone.
The craft is expected to drift away from the Earth at a rate of 10 million miles per year.
Kepler still is within a two-month period of calibrations and testing. Early last week, NASA engineers successfully popped off a protective dust cover from Kepler's telescope. With the dust cover off, the spacecraft can begin gathering images and sending them back to Earth.
"The cover released and flew away exactly as we designed it to do," said Kepler project manager James Fanson, in a statement made last week. "This is a critical step toward answering a question that has come down to us across 100 generations of human history: Are there other planets like Earth, or are we alone in the galaxy?"
The first images that the spacecraft has sent back to NASA show a "vast starry field" in the Cygnus-Lyra region of the Milky Way galaxy, according to NASA's Jet Propulsion Laboratory. One image shows millions of stars in the craft's full field of view, while two other images zoom in specific sections of that region.
"Kepler's first glimpse of the sky is awe-inspiring," said Lia LaPiana, Kepler's program executive, in a statement. "To be able to see millions of stars in a single snapshot is simply breathtaking."
"It's thrilling to see this treasure trove of stars," said William Borucki, science principal investigator for Kepler. "We expect to find hundreds of planets circling those stars, and for the first time, we can look for Earth-size planets in the habitable zones around other stars like the sun," he added.
The telescope aboard Kepler eventually will measure the brightness of the stars every half hour, allowing scientists to detect any dimming in their brightness caused by orbiting planets passing in front of them.
Based on the dimming of a star's light, NASA scientists should be able to calculate the size of an orbiting planet, along with whether it has a solid surface and if there's the potential for it to have liquid water, which scientists say is crucial to the formation of life.