NASA’s blockbuster discovery of an Earth-like planet 1,400 light-years away was made possible in part by data from the W.M. Keck Observatory atop Mauna Kea, the space agency announced Thursday.

While the Kepler Space Telescope was responsible for primary data behind the breakthrough, the Keck Observatory was one of three ground-based sites whose observations detailed critical aspects of the planet, now referred to as Kepler-452b.

NASA called observations from Keck and the other ground partners (the University of Texas at Austin’s McDonald Observatory and the Fred Lawrence Whipple Observatory on Mount Hopkins, Arizona) “key for the researchers to confirm the planetary nature of Kepler-452b, to refine the size and brightness of its host star and to better pin down the size of the planet and its orbit.”

452-b-vs-earth

This artist’s rendering compares Earth (left) to the newly discovered planet, Kepler-452b. The illustration represents one possible appearance for Kepler-452b — scientists don’t yet know whether it has oceans and continents like Earth.

NASA/Ames/JPL-Caltech/T. Pyle

“Sometimes research can be a slow process, and you learn things bit by bit. But when the pieces come together and you realize you’re looking at something like this, it’s the day you look forward to,” said Howard Isaacson, a research astronomer at the University of California, Berkeley, who collaborated with colleagues at Berkeley and the University of Hawaii on the Keck observations.

Keck Communications Officer Steve Jefferson said the Mauna Kea observatory’s participation in the discovery is “an excellent example of the role we typically play in astronomy.”

“Typically what happens is Kepler will find these objects, but it doesn’t have the instrumentation to allow it to confirm or define characteristics. That’s where we come in,” said Jefferson of the various scientific teams that use the Keck telescope.

Kepler looks for the dimming of the light from a star in a regular pattern that suggests something is orbiting the star. Once they have a “planet candidate,” scientists apply for time at Keck to use instrumentation that can determine if the star is wobbling side to side from gravitational tugs exerted by a planet. If the tugs and dimming fall in the same pattern, that confirms a planet is orbiting.

Scientists at Keck can also determine the planet’s mass by the size of the tug it exerts and compare that with dimming data to describe the planet’s size. Together, the data would characterize the composition of the planet. It could be big and light, which would point to a gaseous planet, or small and massive, denoting a rocky planet.

“Sometimes research can be a slow process, and you learn things bit by bit. But when the pieces come together and you realize you’re looking at something like this, it’s the day you look forward to.” — Howard Isaacson, research astronomer

News of the planet’s discovery and its close similarities to Earth electrified the scientific community and grabbed global attention Thursday as the story broke around the world.

While Kepler-452b is larger and older than Earth, it orbits its parent star in the so-called Goldilocks zone — where it’s not too hot nor too cold and liquid water can pool on its surface. Its sun, in fact, has the same temperature as ours, though it’s brighter and slightly larger.

Though the Kepler telescope’s work has increased the number of known, confirmed planets to 1,030, Kepler-452b is one of only 11 found so far in the habitable zone of a solar system, likely with a rocky surface. NASA called the planet’s discovery a “milestone in the journey to finding another ‘Earth.’ “But confirming that the planet is indeed rocky rather than gaseous is a critical element. “You need some form of land for life to live on — intelligent life, at least,” said Isaacson.

Keck crew

The Keck summit crew showing off the mirror of the Keck telescope on the summit of Mauna Kea.

Courtesy of Rick Peterson

Isaacson said there isn’t much more that can be learned about Kepler-452b with current technology. Space-based telescopes such as Kepler will be key to gleaning further information, but the most likely candidate to be able to deliver significant new data would be the James Webb Space Telescope, currently under construction and likely to launch in 2018.

This is only the latest significant discovery in which Keck has played a critical role. Last month, it was part of a similar collaboration that discovered evidence of “monster stars” in a far-off galaxy thought to have brought light into the universe following the Big Bang and then helped to create the elements that make life possible before disappearing. In that work on the galaxy CR7, scientists at Keck teamed with colleagues in Portugal, Chile and the Netherlands.

The lead scientist on that work described Keck’s contributions as “tremendously important in spectroscopically confirming what are now the most luminous of these distant sources …”

This is only the latest significant discovery in which Keck has played a critical role.

“Impressively, the Keck II telescope … spectroscopically confirmed CR7 in 15 minutes, even though the galaxy is 13 billion light years away,” principal investigator David Sobral of the University of Lisbon in Portugal told the New York Times News Service.

The site of the Keck Observatory, Mauna Kea has been under siege for more than four months over the controversial construction of the Thirty Meter Telescope, which is expected to be the most powerful telescope in the world. Native Hawaiian activists oppose the construction and have blocked crews trying to access the site, calling it desecration of a sacred area.

Gov. David Ige has said the project is legally entitled to proceed and has pledged state assistance to make that happen.

Construction is halted for the moment, but expected to proceed soon.

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