The telescope that found thousands of distant worlds over the past decade has run out of fuel. Kepler‘s successor has already embarked on a mission to add to the telescope's tally of planets that could support life.
Image: picture-alliance/AP Photo/NASA
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NASA on Tuesday announced the demise of its elite planet-hunting telescope just a few months shy of its 10th anniversary.
The Kepler space telescope that found thousands of planets beyond our solar system and boosted the search for worlds that might support life has run out of fuel, NASA said.
The spacecraft, which is currently orbiting the sun 94 million miles (156 million kilometers) from Earth, will drift further from our planet when mission engineers turn off its radio transmitters, the US space agency said.
"While this may be a sad event, we are by no means unhappy with the performance of this marvelous machine. Kepler's nine-and-a-half year flight was more than twice the original target," Charlie Sobeck, project system engineer at NASA's Ames Research Center in California, told reporters on a conference call.
The $700 million mission led to the discovery of more than 2,600 of the roughly 3,800 exoplanets or planets outside our solar system that have been documented in the past two decades.
Kepler found over two-third of the roughly 3,800 exoplanets that have been documented in the past two decades.Image: picture alliance/dpa/epa/NASA/W. Stenzel
Several of them are rocky and Earth-sized in the so-called Goldilocks or habitable zone of a star — an orbit where temperatures are neither too cold nor too hot, but just right for the existence of water, which is considered a key ingredient for life.
"Basically, Kepler opened the gate for mankind's exploration of the cosmos," William Borucki, Kepler's now-retired chief investigator, told reporters.
Second life
The mission was almost over in 2013 when the telescope's positioning system broke down. But scientists found a way to keep it operational.
"It was like trying to detect a flea crawling across a car headlight when the car was 100 miles away," said Borucki said.
The resurrected mission became known as K2 and yielded 350 confirmed exoplanets.
Borucki said his favorite exoplanet spotted by the telescope was Kepler 22B, located more than 600 light years from Earth. It is a possible "water world" the size of Earth perhaps covered with oceans and with a water-based atmosphere.
The washing machine-sized telescope will scan almost the entire sky for two years in the search for more worlds circling stars beyond our solar system that could harbor life.
Tess's range of observation is 400 times larger than that of Kepler, and unlike its predecessor, Tess will not always be looking at the same section of the sky. It will divide the heavens into 26 sectors. The craft will monitor each of those sectors for 27 days.
Tess will mainly scout for planets in the Goldilocks zone of a star.
NASA's bigger, more powerful James Webb Space Telescope, due to launch in another few years, will then study the most promising candidates to find out whether they could support life.
Earth-like planets and other celestial discoveries
Astronomers have found a new Earth-like planet in our neighboring solar system, Proxima Centauri. We take a look at this and other discoveries from Earth- and space-based telescopes.
Image: L. Calçada/ESO
Another planet Earth?
The European Southern Observatory (ESO) has discovered a third Earth-like planet orbiting the star Proxima Centauri, the closest star to our sun at four light years away. A planet is considered Earth-like if scientists suspect it provides conditions that could make life theoretically conceivable, such as a certain temperature range, gravity, an atmosphere and the possibility of water.
Image: L. Calçada/ESO
Discovery via the Very Large Telescope
Astronomers discovered the planet through the Very Large Telescope (VLT) in Chile's Atacama Desert. Proxima d is the lightest of the three planets discovered around our closest star. ESO researchers also discovered the somewhat larger Proxima b, but with a different telescope supported by the planet-search instrument HARPS.
Image: ESO/G. Lombardi
Spaceship Kepler: On the hunt for planets
Many Earth-like planets haven't been discovered by telescopes situated on Earth but by ones in space. Spaceship Kepler has been searching for Earth-like planets since 2009. Besides meeting the physical conditions, they must also consist of rock or metal compounds and have a solid surface, in contrast to gas giants like Jupiter and Saturn.
Image: NASA Ames/JPL-Caltech/T Pyle
A longer distance away
Exoplanet Kepler-186f is located 500 light years away from us, orbiting red dwarf Kepler-186. That small sun has only about 4% of the energy of our sun. Kepler-186f orbits Kepler-186 at a perfectly calibrated distance: Water would neither freeze nor evaporate on the planet, which is a precondition for life. But the question of whether there is water on Kepler-186f at all remains unanswered.
There are no detailed pictures of exoplanets, just artistic representations like this one of Kepler-186f. But not even a drawing exists of another recently discovered exoplanet, Kepler-438b, which orbits a sun-like star about 470 light years away from Earth and is just slightly larger than our planet. NASA published the discovery on January 6, 2014.
Image: picture-alliance/dpa
Ocean-covered giants?
This artist's drawing of Kepler-62e shows a planet covered by ocean. Scientists agree that Earth-like exoplanets most likely have large oceans. Kepler-62e can be found in the constellation of Lyra, located 1,200 light years away from us. And its mother star, Kepler-62, has yet another Earth-like planet ...
Image: NASA Ames/JPL-Caltech
The Kepler-62 brothers
... Kepler-62f, whose diameter is 1.4 times that of Earth. The Earth-like planet is located a bit further out in its solar system than its larger brother Kepler-62e, which is 1.61 times as big as Earth. Both may be suited for life. Researchers believe that the existence of rocks and water is plausible.
Image: NASA Ames/JPL-Caltech
Orbiting two suns
Even though Kepler-16b is located on the edge of an inhabitable zone, it probably doesn't host any life. This is a pity, because the planet orbits two suns — every morning and evening, its inhabitants would be able to observe two sunrises and sunsets! Too bad Kepler-16b is most likely a gas planet, composed of rock and ice — not good for beings needing to breathe fresh air.
Image: imago/UPI Photo
The Hubble Space Telescope offers many perspectives
The Pillars of Creation are located in the Eagle Nebula about 7,000 light years away. The joint ESA and NASA Hubble Space Telescope took new pictures of the formation through an infrared light spectrum. The pillars are home to numerous bright and young stars, including entire solar systems.
Image: NASA, ESA/Hubble and the Hubble Heritage Team
Lights on!
The same picture through visible light: more fog, but also more color. Dust and gas in the pillars are pierced by radiation originating from young stars. These new Hubble Telescope pictures enable researchers to monitor changes in the formation over a longer period of time.
Image: NASA, ESA/Hubble and the Hubble Heritage Team
A star is born
NGC 4102 is a LINER galaxy: a low-ionization nuclear emission-line region. This means it emits ionized radiation, like roughly one-third of all galaxies. At its center, there is a sun-burst region, where young stars seem to be born. It has a diameter of about 1,000 light years. Scientists don't understand the exact processes in the center yet.
Image: ESA/Hubble, NASA and S. Smartt (Queen's University Belfast)
A messier cluster
This cluster of stars, located in the northern part of the Hercules formation, is called Messier 92. On dark nights with clear skies, we can see it from Earth with bare eyes. The cloud includes roughly 330,000 stars, most of which consist of hydrogen and helium. Heavier elements like metals are rare.
Image: ESA/Hubble & NASA/Gilles Chapdelaine
The best view of Andromeda
The original version of this photo of the Andromeda Galaxy is 1.5 billion pixels in size — the most detailed picture ever taken of that galaxy. It includes 100 million stars and thousands of star clusters. To watch it in its entire beauty, one would need 600 HD-TV screens. The ends of the picture are 40,000 light years apart.
Image: NASA, ESA, J. Dalcanton (University of Washington, USA), B. F. Williams (University of Washington, USA), L. C. Johnson (University of Washington, USA), the PHAT team, and R. Gendler
