Earlier this month, scientists from NASA’s Kepler mission discovered 54 planets in so-called “habitable zones” in the Milky Way. The SETI Institute turned its telescopes toward those planets to listen.
It’s naive to think that our temperate rocky planet is unique in our vast universe—and in 1995, we found evidence the first evidence that the majority of other stars have orbiting planets too. Since then, we’ve detected thousands of “exoplanets” or “extra solar planets”, and currently have evidence for significant numbers of three types—gas giants, hot-super-Earths, and ice giants. In 2009, NASA’s Kepler Mission was launched specifically to search for terrestrial Earth-like planets, especially those orbiting within the “Goldilocks zone” of their stars where liquid water (and therefore life a we know it) might exist. The Kepler Mission seeks out exoplanets in the Milky Way by using the transit method: when a planet crosses in front of its star, i.e. “transits”, it causes the star’s brightness to dim by a tiny amount. Kepler continually and simultaneously monitors these transits, and since a planet’s transit will always last the same time and will always cause the same change in brightness, it’s a reliable method for confirming exoplanets. The planet’s orbital size can then be calculated, and so can its size and its temperature—which is key to determining habitability. Kepler has announced over 2,300 exoplanet candidates to date, and thanks to constantly improving technology, we’re discovering new exoplanets daily at an exponential rate.
NASA’s Kepler Mission Discovers Bigger, Older Cousin to Earth
NASA - Kepler Space Telescope patch.
July 23, 2015
NASA’s Kepler Mission Discovers Bigger, Older Cousin to Earth NASA’s Kepler mission has confirmed the first near-Earth-size planet in the “habitable zone” around a sun-like star. This discovery and the introduction of 11 other new small habitable zone candidate planets mark another milestone in the journey to finding another “Earth.”
The newly discovered Kepler-452b is the smallest planet to date discovered orbiting in the habitable zone – the area around a star where liquid water could pool on the surface of an orbiting planet – of a G2-type star, like our sun. The confirmation of Kepler-452b brings the total number of confirmed planets to 1,030.
Image above: This artist’s concept compares Earth (left) to the new planet, called Kepler-452b, which is about 60 percent larger in diameter. Images Credits: NASA/JPL-Caltech/T. Pyle.
“On the 20th anniversary year of the discovery that proved other suns host planets, the Kepler exoplanet explorer has discovered a planet and star which most closely resemble the Earth and our Sun,” said John Grunsfeld, associate administrator of NASA’s Science Mission Directorate at the agency’s headquarters in Washington. “This exciting result brings us one step closer to finding an Earth 2.0.“
Kepler-452b is 60 percent larger in diameter than Earth and is considered a super-Earth-size planet. While its mass and composition are not yet determined, previous research suggests that planets the size of Kepler-452b have a good chance of being rocky.
Image above: This size and scale of the Kepler-452 system compared alongside the Kepler-186 system and the solar system. Kepler-186 is a miniature solar system that would fit entirely inside the orbit of Mercury. Image Credits: NASA/JPL-CalTech/R. Hurt.
While Kepler-452b is larger than Earth, its 385-day orbit is only 5 percent longer. The planet is 5 percent farther from its parent star Kepler-452 than Earth is from the Sun. Kepler-452 is 6 billion years old, 1.5 billion years older than our sun, has the same temperature, and is 20 percent brighter and has a diameter 10 percent larger.
“We can think of Kepler-452b as an older, bigger cousin to Earth, providing an opportunity to understand and reflect upon Earth’s evolving environment,” said Jon Jenkins, Kepler data analysis lead at NASA’s Ames Research Center in Moffett Field, California, who led the team that discovered Kepler-452b. “It’s awe-inspiring to consider that this planet has spent 6 billion years in the habitable zone of its star; longer than Earth. That’s substantial opportunity for life to arise, should all the necessary ingredients and conditions for life exist on this planet.”
Image above: There are 4,696 planet candidates now known with the release of the seventh Kepler planet candidate catalog - an increase of 521 since the release of the previous catalog in January 2015. Image Credits: NASA/W. Stenzel.
To help confirm the finding and better determine the properties of the Kepler-452 system, the team conducted ground-based observations at the University of Texas at Austin’s McDonald Observatory, the Fred Lawrence Whipple Observatory on Mt. Hopkins, Arizona, and the W. M. Keck Observatory atop Mauna Kea in Hawaii. These measurements were 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.
The Kepler-452 system is located 1,400 light-years away in the constellation Cygnus. The research paper reporting this finding has been accepted for publication in The Astronomical Journal.
Image above: Since Kepler launched in 2009, twelve planets less than twice the size of Earth have been discovered in the habitable zones of their stars. Image Credits: NASA/N. Batalha and W. Stenzel.
In addition to confirming Kepler-452b, the Kepler team has increased the number of new exoplanet candidates by 521 from their analysis of observations conducted from May 2009 to May 2013, raising the number of planet candidates detected by the Kepler mission to 4,696. Candidates require follow-up observations and analysis to verify they are actual planets.
Twelve of the new planet candidates have diameters between one to two times that of Earth, and orbit in their star’s habitable zone. Of these, nine orbit stars that are similar to our sun in size and temperature.
“We’ve been able to fully automate our process of identifying planet candidates, which means we can finally assess every transit signal in the entire Kepler dataset quickly and uniformly,” said Jeff Coughlin, Kepler scientist at the SETI Institute in Mountain View, California, who led the analysis of a new candidate catalog. “This gives astronomers a statistically sound population of planet candidates to accurately determine the number of small, possibly rocky planets like Earth in our Milky Way galaxy.”
Image above: This artist’s concept depicts one possible appearance of the planet Kepler-452b, the first near-Earth-size world to be found in the habitable zone of star that is similar to our sun. Image Credits: NASA/JPL-Caltech/T. Pyle.
These findings, presented in the seventh Kepler Candidate Catalog, will be submitted for publication in the Astrophysical Journal. These findings are derived from data publicly available on the NASA Exoplanet Archive.
Scientists now are producing the last catalog based on the original Kepler mission’s four-year data set. The final analysis will be conducted using sophisticated software that is increasingly sensitive to the tiny telltale signatures of Earth-size planets.
Ames manages the Kepler and K2 missions for NASA’s Science Mission Directorate. NASA’s Jet Propulsion Laboratory in Pasadena, California, managed Kepler mission development. Ball Aerospace & Technologies Corporation operates the flight system with support from the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder.
BREAKING: Kepler Telescope Discovers a System of Six Small Exoplanets
Nature Magazine reports a NASA-Kepler discovery of a system that has six low-mass, low-density exoplanets that transit their star. The system is being designated Kepler-11. These planets are rather unusual for their combination of low mass and low density, and are surrounded at least with gaseous envelopes, or are likely to be icy.
It seems as if there are more questions than answers about this at the moment, but we thought it would be worth sharing.
Since 2009, NASA’s Kepler Mission has been scanning the depths of the universe for distant planets. Exo is a hypnotic visualization tool for exploring the nearly 2,300 exoplanet candidates that have been identified so far.
Kepler Mission - уникальная миссия NASA с целью найти планеты, максимально похожие на Землю. B видео они так и называются - “Earths” (дословно - “Земли”). Это даст нам ключ к вопросу - возможна ли жизнь на других планетах? откуда? как? где?
Вот познавательное видео об этой миссии. Заметим, что само имя “Kepler” - название телескопа, поэтому, где-то с середины начинаются объяснения, как он работает. Они немного технические, но я считаю, что вы обязательно с ними можете справиться, т.к. "разжеваны" они максимально просто и понятно.
Words/Expressions you might not know:
innate curiosity: врожденное любопытство.
habitable: годный для жизни. Обратим внимание, что в видео используют жаргон “Goldilock zone”, означающий тоже самое - зона, пригодная для жизни.
capable (of finding): способный (найти что-то)
just right for (…): правильный, нужный, имеющий именно те условия, которые нужны (для чего-либо)
to detect: обнаружить (о технике)
field of view: поле зрения
Kepler takes very fuzzy pictures fuzzy: нечеткие
Earth-like: Sun-like: похожий на Землю (Солнце) - поясним, что для выражения “похожий на что-то”, вполне уместно употреблять суффикс -like. Часто употребляемые слова: Godlike, cartoonlike, childlike, dreamlike. Эти слова - прилагательные, сможете ли вы догадаться, что они означают? :)
NASA’s Kepler mission has found a new solar system where a Saturn-like planet spins around twin stars 200 light-years away from us. It’s the first direct observation of such an arrangement, and astronomers say they’re not sure why the planet is there. […]
NASA’s Kepler mission has confirmed the first near-Earth-size planet in the “habitable zone” around a sun-like star. The newly discovered Kepler-452b is the smallest planet to date discovered orbiting in the habitable zone – the area around a star where liquid water could pool on the surface of an orbiting planet – of a G2-type star, like our sun. The confirmation of Kepler-452b brings the total number of confirmed planets to 1,030.
Chalk another one up to NASA’s Kepler Mission. The Agency’s team of planet-hunters announced yesterday the discovery of 11 new planetary systems, which together harbor 26 brand spanking new planets.
For those you keeping score at home, that brings the total number of Kepler-confirmed extrasolar planets from 35 to 61, and almost triples the number of verified, multi-planet star systems, raising that number from 6 to 17.
And if you think that sounds impressive, remember: Kepler is just getting warmed up. With over 2,300 exoplanets in the wings still awaiting confirmed-planet status (and new candidate planets being discovered all the time), many astronomers believe it’s only a matter of time until Kepler achieves that which it was designed to do: discover Earth-like planets orbiting within the life-permitting “habitable zones” of other star systems (assuming, of course, that we haven’t already found one).
NASA is extending three missions affiliated with the Jet Propulsion Laboratory in Pasadena, Calif. – Kepler, the Spitzer Space Telescope and the U.S. portion of the European Space Agency’s Planck mission – as a result of the 2012 Senior Review of Astrophysics Missions.
“This means scientists can continue using the three spacecraft to study everything from the birth of the universe with Planck, and galaxies, stars, planets, comets and asteroids with Spitzer, while Kepler is determining what percentage of Sun-like stars host potentially habitable Earth-like planets,” said Michael Werner, the chief scientist for astronomy and physics at JPL.
Astronomers using data from NASA’s Kepler mission have discovered the three smallest planets yet detected orbiting a star beyond our sun. The planets orbit a single star, called KOI-961, and are 0.78, 0.73 and 0.57 times the radius of Earth. The smallest is about the size of Mars.
All three planets are thought to be rocky like Earth but orbit close to their star, making them too hot to be in the habitable zone, which is the region where liquid water could exist. Of the more than 700 planets confirmed to orbit other stars, called exoplanets, only a handful are known to be rocky.
“Astronomers are just beginning to confirm the thousands of planet candidates uncovered by Kepler so far,” said Doug Hudgins, Kepler program scientist at NASA Headquarters in Washington. “Finding one as small as Mars is amazing, and hints that there may be a bounty of rocky planets all around us.”
Kepler searches for planets by continuously monitoring more than 150,000 stars, looking for telltale dips in their brightness caused by crossing, or transiting, planets. At least three transits are required to verify a signal as a planet. Follow-up observations from ground-based telescopes also are needed to confirm the discoveries.
The latest discovery comes from a team led by astronomers at the California Institute of Technology in Pasadena. The team used data publicly released by the Kepler mission, along with follow-up observations from the Palomar Observatory, near San Diego, and the W.M. Keck Observatory atop Mauna Kea in Hawaii. Their measurements dramatically revised the sizes of the planets from what was originally estimated, revealing their small nature.
In a news conference today, Kepler mission scientists announced the first confirmed circumbinary planet ( a planet that orbits a binary star system). The planet in question, designated Kepler-16b has been compared to the planet Tatooine from the Star Wars saga.
Would it be possible for someone like Luke Skywalker to stand on the surface of Kepler-16b and see the famous “binary sunset” as depicted in Star Wars?
Despite the initial comparison between Kepler-16b and Tatooine, the planets really only have their orbit around a binary star system in common. Kepler-16b is estimated to weigh about a third the mass of Jupiter, with a radius of around three-quarters that of Jupiter.
Given the mass and radius estimates, this makes Kepler-16b closer to Saturn than the rocky, desert-like world of Tatooine. Kepler-16b’s orbit around its two parent stars takes about 229 days, which is similar to Venus’ 225-day orbit. At a distance of about 65 million miles from its parent stars, which are both cooler than our sun, temperatures on Kepler-16b are estimated in the range of around -100 C.
The team did mention that Kepler-16b is just outside of the habitable zone of the Kepler-16 system. Despite being just outside the habitable zone, the team did mention that it could be possible for Kepler-16b to have a habitable moon, if said moon had a thick, greenhouse gas atmosphere.
During the press conference John Knoll, visual effects supervisor at ILM, mentioned: “When I was a kid, I didn’t think it was going to be possible to make discoveries like this.” Knoll also added, “The science is stranger and cooler than fiction!”
The Kepler mission detects exoplanet candidates by using the transit method which detects the dimming of the light emitted from a star as a planet crosses in front of it. In the case of Kepler-16b, the detection was complicated by the two stars in the system eclipsing each other.
The system’s brightness showed variations even when the stars were not eclipsing each other, which hinted at a third body. What further complicated matters was that the variations in brightness appeared at irregular time intervals. The irregular time intervals hinted that the stars were in different positions in their orbit each time the third body passed. After studying the data, the team came to the conclusion that the third body was orbiting, not just one, but both stars.
“Much of what we know about the sizes of stars comes from such eclipsing binary systems, and most of what we know about the size of planets comes from transits,” added Kepler scientist Laurance Doyle of the SETI Institute. “Kepler-16 combines the best of both worlds, with stellar eclipses and planetary transits in one system.” Doyle’s findings will be published in the Sept. 15th issue of the journal Science.
The Kepler mission is NASA’s first mission capable of finding Earth-size planets in or near the habitable zone – the region around a star where liquid water can exist on the surface of an orbiting planet. A considerable number of planets and planet candidates have been detected by the mission so far. If you’d like to learn more about the Kepler mission, visit: http://kepler.nasa.gov/