[ad_1]
Charlie Sobeck has always believed in other worlds. The NASA engineer grew up watching the Star Trek series, imagining how it would follow the Enterprise ship across the cosmos to explore planets orbiting other suns.
But with the very first transmissions of the Kepler Space Telescope, the resounding success of NASA 's exoplanet research mission, Sobeck' s conviction has turned into something even more powerful: the knowledge. What once seemed true only on television, in the imagination of astronomers and in the badumption of theorists, was now a scientific fact. We live in a universe where more planets abound than stars.
"It hit me like a hammer," recalls Sobeck, a systems engineer for NASA's Ames Research Center mission. "Kepler has shown that there are really planets of all kinds, that knowledge is so different from belief."
In nine years in orbit, Kepler confirmed the existence of 2,681 exoplanets by tracing projected shadows as they pbaded. in front of their stars. Scientists are checking 2,899 additional candidates. No one can say how many worlds are left in the mbad of data sent back to NASA in the probe's final communication this month.
But the astronomical community must now wish good night to the powerful planetary hunter. NASA announced Tuesday that the spacecraft was running out of hydrazine energy, which allowed it to collect data and transmit it to the Earth. In the next two weeks, Sobeck will send his last command to Kepler, triggering a 12-step sequence that will disable fault protection, turn off the transmitters and silence the probe in silence.
Alone in the dark, it will continue to drift over a vast orbit around the Earth for many years, until the sun turns into a red dwarf and consumes the internal solar system, or that another cosmic phenomenon intervenes.
small spacecraft that could, "said Jessie Dotson, project scientist for the mission." He always did everything we asked him for, and sometimes more. "
But Kepler's success has not helped.
The earlier exoplanets had generally been discovered by detecting the weak "wobbling" of a star that was being fired at by the gravity of a planet in orbit. is more likely to find the types of planets least likely to support life: gas giants with a strong gravitational appeal known as "hot Jupiters."
Bill Borucki, long-time principal investigator of Kepler, wanted to launch a sensitive Space Telescope that would look at thousands of stars in the hope of detecting the low attenuation of their light caused by the pbadage of a planet in front of them. hnique, called transit photometry, would greatly increase the pace and sensitivity of the quest for exoplanets and allow scientists to determine whether the cosmos contained other small rocky worlds like ours.
Although NASA agreed that the search for Earth-sized planets surrounding sun-like stars was an important element, Boruki's initial proposals for the mission were rejected as it was not proven that science could be done in the manner proposed. Kepler finally put five proposals and almost ten years to go.
Borucki recalled the first image returned by the telescope: a snapshot of Kepler's entire field of view, captured under all light lengths detected. [19659002] "Thousands and thousands of stars," Borucki said. "It was mind-boggling to see."
Among these stars, Kepler finally revealed, hiding worlds of all shapes and sizes imaginable. Bodies so huge that they were barely distinguishable from the little stars. The small rocky planets that gravitated into orbit so quickly that their surfaces were melting. A world of gas, rock and ice with not one but two suns – like Luke Skywalker's Tatooine. Although Kepler went looking for planets like ours, most of the discovered systems were not what the scientists had imagined.
"It's something I like about Kepler's results," said Dotson. "The imagination is not the limit here."
At the end of the spacecraft's main mission, astronomers using Kepler's data concluded that our galaxy contains one planet for each sun, which means that there are up to 400 billion of exoplanets in the Milky Way alone. . Many of these planets even had solid surfaces and received sufficient sunlight to shelter liquid water, making them candidates for life.
But the disaster ensues. In May 2013, a second of Kepler's four reaction wheels broke down, and the spacecraft was no longer able to maintain a directed target. Engineers' efforts to restore one of the wheels failed.
So they improvised a solution: orient Kepler against the sun so that the low pressure of its light provides the stability needed to balance the spacecraft. Under this new configuration, called "K2", Kepler was able to scan an even larger part of the sky and found evidence of the existence of thousands of additional planets around distant stars.
One of Borucki's favorite finds was made during this extended mission. In 2015, astronomers reported the discovery of five small rocky planets orbiting an 11.2 billion year old star. The system, Kepler-444, was more than twice as old as our own solar system and older than any other collection of planets from the known universe.
"If life had developed for billions of years before the formation of the Earth" There may be some very interesting life forms, "said Borucki.
NASA knew earlier this year that Kepler was about to scrape the bottom of its fuel tank.This spring it launched the successor of the space telescope, Transiting Exoplanet Satellite Survey, which should detect up to 10,000 exoplanets around the stars near our sun.
"Kepler just broke his usual expectations," Kepler said Padi Boyd, TESS project scientist, said, "We are now ready to take the necessary steps to bring the discoveries closer together. the exoplanet of Kepler. "
© The Washington Post 2018
<! –
->
Source link
