The space-based observatory’s infrared eyes spotted 7 Earth-size worlds orbiting another star, a new ring around Saturn and many more cosmic wonders.
On Thursday, NASA’s Spitzer space telescope will sign off and go silent. But even during its final week of operation, the spacecraft was making one-of-a-kind observations.
The telescope, the size of a family sedan, follows Earth in its orbit around the sun, but trails 158 million miles behind. Lately, it has gazed out with its infrared eyes, taking sensitive measurements of fine cosmic dust that pervades the space between planets in the solar system. The resulting imagery will enable researchers to better understand our local celestial neighborhood, while informing models of worlds circling other stars and giving insight into the early universe.
Since it launched on Aug. 25, 2003, Spitzer has provided unique contributions to science. It gave us new views of distant galaxies, newborn stars and nearby exoplanets, as well as of asteroids, comets and other objects in our solar system. Its infrared cameras have observed the universe in a light imperceptible to human senses, providing otherwise unattainable visions of the sky.
“There is no field of investigation that has not been touched by Spitzer,” said Daniela Calzetti, an astronomer at the University of Massachusetts, Amherst, who has used the telescope to study galactic evolution.
Among the highlights of Spitzer’s 16-plus years of discovery:
- A never-before-seen ring around Saturn;
- Determining the point in cosmic history — 10 billion years ago — when star formation peaked;
- And, as part of its most famous finding, discovering four of the seven Earth-size planets spinning close around the star known as Trappist-1.
“It’s really the end of an era, particularly for me,” said Heather Knutson, an astrophysicist at the California Institute of Technology who, as a graduate student, used the telescope to map high-speed winds on a hot Jupiter-size exoplanet. “Spitzer has been around for as long as I’ve been doing science. I don’t remember a time without it.”