Friday, April 18, 2014

EXTRATERRESTRIAL MEMES: Monumental Discovery - NASA's Kepler Space Telescope Finds Earth-Sized Planet In The HABITABLE ZONE Of Another Star!

April 18, 2014 - SPACE -  Using NASA's Kepler Space Telescope, astronomers have discovered the first Earth-size planet orbiting in the "habitable zone" of another star. The planet, named "Kepler-186f" orbits an M dwarf, or red dwarf, a class of stars that makes up 70 percent of the stars in the Milky Way galaxy. The discovery of Kepler-186f confirms that planets the size of Earth exist in the habitable zone of stars other than our sun.


NASA's Kepler Space Telescope Finds Earth-Sized Planet In The HABITABLE ZONE Of Another Star
The artist's concept depicts Kepler-186f , the first validated Earth-size planet to orbit a distant star in the habitable
zone—a range of distance from a star where liquid water might pool on the planet's surface. The discovery of
Kepler-186f confirms that Earth-size planets exist in the habitable zones of other stars and
signals a significant step closer to finding a world similar to Earth.

The "habitable zone" is defined as the range of distances from a star where liquid water might pool on the surface of an orbiting planet. While planets have previously been found in the habitable zone, the previous finds are all at least 40 percent larger in size than Earth and understanding their makeup is challenging. Kepler-186f is more reminiscent of Earth.

Kepler-186f orbits its parent M dwarf star once every 130-days and receives one-third the energy that Earth gets from the sun, placing it nearer the outer edge of the habitable zone. On the surface of Kepler-186f, the brightness of its star at high noon is only as bright as our sun appears to us about an hour before sunset.

"M dwarfs are the most numerous stars," said Elisa Quintana, research scientist at the SETI Institute at NASA's Ames Research Center in Moffett Field, Calif., and lead author of the paper published today in the journal Science. "The first signs of other life in the galaxy may well come from planets orbiting an M dwarf."

However, "being in the habitable zone does not mean we know this planet is habitable," cautions Thomas Barclay, a research scientist at the Bay Area Environmental Research Institute at Ames, and co-author of the paper. "The temperature on the planet is strongly dependent on what kind of atmosphere the planet has. Kepler-186f can be thought of as an Earth-cousin rather than an Earth-twin. It has many properties that resemble Earth."

Kepler-186f resides in the Kepler-186 system, about 500 light-years from Earth in the constellation Cygnus. The system is also home to four companion planets: Kepler-186b, Kepler-186c, Kepler-186d, and Kepler-186e, whiz around their sun every four, seven, 13, and 22 days, respectively, making them too hot for life as we know it. These four inner planets all measure less than 1.5 times the size of Earth.


NASA's Kepler Space Telescope Finds Earth-Sized Planet In The HABITABLE ZONE Of Another Star
The diagram compares the planets of our inner solar system to Kepler-186, a five-planet star system about 500
light-years from Earth in the constellation Cygnus. The five planets of Kepler-186 orbit an M dwarf,
a star that is is half the size and mass of the sun.

Although the size of Kepler-186f is known, its mass and composition are not. Previous research, however, suggests that a planet the size of Kepler-186f is likely to be rocky.

"The discovery of Kepler-186f is a significant step toward finding worlds like our planet Earth," said Paul Hertz, NASA's Astrophysics Division director at the agency's headquarters in Washington.

The next steps in the search for distant life include looking for true Earth-twins -- Earth-size planets orbiting within the habitable zone of a sun-like star -- and measuring the their chemical compositions. The Kepler Space Telescope, which simultaneously and continuously measured the brightness of more than 150,000 stars, is NASA's first mission capable of detecting Earth-size planets around stars like our sun.

Looking ahead, Hertz said, "future NASA missions, like the Transiting Exoplanet Survey Satellite and the James Webb Space Telescope, will discover the nearest rocky exoplanets and determine their composition and atmospheric conditions, continuing humankind's quest to find truly Earth-like worlds."


More information:
Ames is responsible for Kepler's ground system development, mission operations, and science data analysis. NASA's Jet Propulsion Laboratory in Pasadena, Calif., managed Kepler mission development. Ball Aerospace & Technologies Corp. in Boulder, Colo., developed the Kepler flight system and supports mission operations with the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder. The Space Telescope Science Institute in Baltimore archives, hosts and distributes Kepler science data. Kepler is NASA's 10th Discovery Mission and was funded by the agency's Science Mission Directorate.

The SETI Institute is a private, nonprofit organization dedicated to scientific research, education and public outreach.  The mission of the SETI Institute is to explore, understand and explain the origin, nature and prevalence of life in the universe.

For more information about the Kepler mission, visit: http://www.nasa.gov/kepler. - NASA.




Wednesday, April 16, 2014

EXTRATERRESTRIAL MEMES: "Getting Closer And Closer" To Finding Another Earth - NASA Finds That The "Number of Potentially Habitable Planets In The Milky Way May Be Double"!

April 16, 2014 - SPACE -  New findings may have the effect of expanding that perceived habitable zone by 10 to 20 percent, almost doubling the number of potentially habitable planets in our galaxy.




A fluctuating tilt in a planet’s orbit does not preclude the possibility of life, according to astronomers at the University of Washington, Utah’s Weber State University and NASA. In fact, sometimes it helps. These " tilt-a-worlds,” as astronomers sometimes call them — turned from their orbital plane by the influence of companion planets — are less likely than fixed-spin planets to freeze over, as heat from their host star is more evenly distributed. This happens only at the outer edge of a star’s habitable zone, the swath of space around it where rocky worlds could maintain liquid water at their surface, a necessary condition for life.

Further out, a “snowball state” of global ice becomes inevitable, and life impossible. Such a tilt-a-world becomes potentially habitable because its spin would cause poles to occasionally point toward the host star, causing ice caps to quickly melt. The image at the top of the page shows the circumstellar habitable zone, what we colloquially call the Goldilocks zone.


“Without this sort of ‘home base’ for ice, global glaciation is more difficult,” said UW astronomer Rory Barnes. “So the rapid tilting of an exoplanet actually increases the likelihood that there might be liquid water on a planet’s surface.”

Earth and its neighbor planets occupy roughly the same plane in space. But there is evidence, Barnes said, of systems whose planets ride along at angles to each other. As such, “they can tug on each other from above or below, changing their poles’ direction compared to the host star.”

The team used computer simulations to reproduce such off-kilter planetary alignments, wondering, he said, “what an Earthlike planet might do if it had similar neighbors.”

Their findings also argue against the long-held view among astronomers and astrobiologists that a planet needs the stabilizing influence of a large moon — as Earth has — to have a chance at hosting life. “We’re finding that planets don’t have to have a stable tilt to be habitable,” Barnes said. Minus the moon, he said, Earth’s tilt, now at a fairly stable 23.5 degrees, might increase by 10 degrees or so. Climates might fluctuate, but life would still be possible.

“This study suggests the presence of a large moon might inhibit life, at least at the edge of the habitable zone.”

The work was done through the UW’s Virtual Planetary Laboratory, an interdisciplinary research group that studies how to determine if exoplanets — those outside the solar system — might have the potential for life.

“The research involved orbital dynamics, planetary dynamics and climate studies. It’s bigger than any of those disciplines on their own,” Barnes said.

Applying the research and its expanded habitable zone to our own celestial neighborhood for context, he said, “It would give the ability to put Earth, say, past the orbit of Mars and still be habitable at least some of the time — and that’s a lot of real estate.”

Barnes’ UW co-authors are Victoria Meadows, Thomas Quinn and Jonathan Breiner. Shawn Domagal-Goldman of NASA’s Goddard Space Flight Center is also a co-author. The research was funded by a grant from the NASA Astrobiology Institute. - Daily Galaxy.




Tuesday, April 15, 2014

EXTRATERRESTRIAL MEMES: "Getting Closer And Closer" To Finding Another Earth - NASA To Livestream New Kepler Mission Discovery Tomorrow, Is It A Twin Earth?!

April 15, 2014 - SPACE - NASA will host a news teleconference at 11 a.m. PDT (2 p.m. EDT) Thursday, April 17, to announce a new discovery made by its planet-hunting mission, the Kepler Space Telescope. The journal Science has embargoed the findings until the time of the news conference.


Image credit: Photo: SETI/P and NASA


The briefing participants are:
-- Douglas Hudgins, exoplanet exploration program scientist, NASA's Astrophysics Division in Washington
-- Elisa Quintana, research scientist, SETI Institute at NASA's Ames Research Center in Moffett Field, Calif.
-- Tom Barclay, research scientist, Bay Area Environmental Research Institute at Ames
-- Victoria Meadows, professor of astronomy at the University of Washington, Seattle, and principal investigator for the Virtual Planetary Laboratory, a team in the NASA Astrobiology Institute at Ames

Launched in March 2009, Kepler is the first NASA mission capable of finding Earth-size planets in or near the habitable zone -- the range of distance from a star in which the surface temperature of an orbiting planet might sustain liquid water. The telescope has since detected planets and planet candidates spanning a wide range of sizes and orbital distances, including those in the habitable zone. These findings have led to a better understanding of our place in the galaxy.

The public is invited to listen to the teleconference live on UStream at: http://www.ustream.tv/channel/nasa-arc and http://www.ustream.tv/nasajpl2

Audio of the teleconference also will be streamed live at: http://www.nasa.gov/newsaudio

Questions can be submitted on Twitter using the hashtag #AskNASA.

A link to relevant graphics will be posted at the start of the teleconference on NASA's Kepler site: http://www.nasa.gov/kepler




Five years ago today, on March 6, 2009, NASA's Kepler Space Telescope rocketed into the night skies to find planets around other stars within a field of view 1/400th the size of the Milky Way in search of potentially habitable worlds. Since then, Kepler has unveiled a whole new side of our galaxy -- one that is teeming with planets. Because of Kepler we now know that most stars have planets, Earth-sized planets are common, and planets quite unlike those in our solar system exist.
"This is the biggest haul ever,” says Jason Rowe of the nasa Ames Research Center, who co-led the research. The scientists studied more than 1,200 planetary systems and validated 715 planets. All the new worlds are members of multiplanet systems—stars with more than one orbiting satellite.

The top image in this article is an artist's impression of the Kepler-62 star system as seen from the Earth-like planet "f", which scientists believe could support life. Kepler-62 is a star smaller and dimmer than the Sun about 1,000 light years away in the constellation Lyra. A pair of so-called "super-Earths" have been detected within the "habitable zone" of the star, which is around two billion years older than the Sun, raising the possibility of intelligent life more advanced than it is on Earth.

Although no-one knows what the planets are made of, they are believed to be rocky. One, Kepler-62f, is thought to have a radius about 1.4 times greater than the Earth's. The other, Kepler-62e, is estimated to be 1.6 times larger.

This past December 2013, a team of European astrophysicists discovered the most extensive planetary system to date, orbiting star KOI-351. The star system has seven planets, more than in other known planetary systems arranged in a similar fashion to the eight planets in the Solar System, with small rocky planets close to the parent star and gas giant planets at greater distances.

Although the planetary system around KOI-351 is packed together more tightly, “We cannot stress just how important this discovery is. It is a big step in the search for a ‘twin’ to the Solar System, and thus also in finding a second Earth,” said Juan Cabrera, an astrophysicist at the DLR Institute of Planetary Research in Berlin-Adlershof.

KOI is the abbreviation for ‘Kepler Object of Interest’, which means the star was observed by NASA’s Kepler space telescope, between 2008 and 2013, and classified as a candidate for the existence of exoplanets. At present, KOI-351 is the star with the most extrasolar planets, or exoplanets for short. The star is 2500 light years away from Earth.

Astrophysicists around the world have been searching for a star system similar to our own for a long time. Now, the team led by Cabrera has taken a major step in this direction. Three of the seven planets in orbit around the star KOI-351 were discovered in recent years, and have periods of 331, 211 and 60 days, similar to those of Earth, Venus and Mercury.

The planets discovered by Cabrera and his team are even closer to the star and have orbital periods of 7, 9, 92 and 125 days. The outermost planet orbits the star at a distance of about 150 million kilometres, or roughly one Astronomical Unit (AU), so the entire planetary system is compressed into a space corresponding to the distance between Earth and the Sun.

“No other planetary system shows such a similar ‘architecture’ to that of our cosmic home as does the planetary system around KOI-351,” says Cabrera. “Just as in the Solar System, rocky planets with roughly the size of Earth are found close to the star, while, ‘gas giants’ similar to Jupiter and Saturn are found as you move away from the star.”

The development of a special computer algorithm enabled Cabrera and his team to detect the four new planets around KOI-351 by filtering out the light curves that reveal the ‘transit’ of a planet across its parent star from the Kepler measurements. The discovery was confirmed shortly afterwards by a US group led by Joseph R. Schmitt of Yale University, by visual inspection of the light curves recorded by Kepler.

“The resonances of the planetary orbits are another interesting feature of this system,” explains Szilárd Csizmadia, a member of the team. Resonance occurs when two or more orbiting bodies exert a regular, periodic gravitational influence on one another. “Resonances also play an important role in the Solar System; for example, the moons of Jupiter. So KOI-351 is a gold mine for all researchers investigating planetary formation and the stability of multi-body systems.”

The resonances in the planetary system of KOI-351, however, greatly complicated the search for the planets. Due to the strong interaction between the planets, the signals sought in the Kepler data were not strictly periodic, but showed strong variations in the orbital periods.

“The orbital period of planet KOI-351g varies by about a day between consecutive transits during the observations, said Rudolf Dvorak of the University of Vienna. "Disturbances of this kind have been noted previously, but so far only with maximum deviations of a few minutes.”

After the two successful space telescopes CoRoT and Kepler were decommissioned this year, planet hunters are now hopeful with regard to the pending decision on the PLATO mission. PLATO (Planetary Transits and Oscillations of Stars) will build on the experience of CoRoT and Kepler in the search for planetary systems around nearby bright stars, and thus allow for extensive follow-up observations. This could allow the determination of the radius (as in the system KOI-351) and the mass of the planets, as well as a first look at the composition of the planet.

Furthermore, it would even be possible to examine the atmosphere of the planets in such systems, which may give rise to indications of the activity of living organisms. This would be a major breakthrough in search for a ’second Earth’. The European Space Agency will make a decision on the PLATO mission in early 2014.

Until now, 771 stars with planets have been identified. However, most of the exoplanets discovered so far are ’solitary’. Only 170 stars are known to be orbited by more than one planet. Large planetary systems are the exception – not because they do not exist, but because they are particularly difficult to detect and characterise.

At present, only a handful of systems with at least five planets have been confirmed, including planets KOI-351b and 351c were confirmed. They are only 31 percent and 19 percent larger than the Earth. To detect such small planets, a special algorithm was developed by Cabrera. Besides the size of these planets, what is remarkable is the 5:4 orbital resonance. In the time it takes planet b to complete five orbits, planet c has completes exactly four orbits. Similar resonances are found among the inner moons of Jupiter.

Planet KOI- 351d was already known. It has an orbital period of 60 days. Its diameter is 2.9 times that of Earth’s. It is therefore likely a ’super-Earth’ or a ‘mini-Neptune’. Since the mass is not known, it is not yet possible to classify this planet.

The planet KOI-351e is also a new discovery and is roughly the same size as KOI- 351d (2.9 times the diameter of Earth). We know that neighbouring planets in planetary systems have similar sizes, as we see in the Solar System (Neptune and Uranus, or Venus and Earth). This has now been observed for the first time in exoplanets, and underlines the similarity of this system to our own.

The large gas giants KOI-351g and 351h (about 8 and 11 times the diameter of Earth) are outer planets and have long orbital periods (211 and 331 days). This is very reminiscent of the Solar System, where there also four rocky planets (Mercury, Venus, Earth, Mars) and two gas giants (Jupiter and Saturn ) with diameters 10 and 8 times that of Earth.

By analyzing Kepler data, scientists have identified more than 3,600 candidates believed to be planets, and verified that 961 of those candidates actually are planets, many as small as Earth. Discoveries made using Kepler now account for more than half of all the known exoplanets.

"During the last five years, Kepler has produced results needed to take the next big step forward in humankind's search for life in our galaxy— providing information needed for future missions that will ultimately determine the atmospheric composition of Earth-sized exoplanets to discover if they could be habitable," said William Borucki, Kepler principal investigator at NASA's Ames Research Center in Moffett Field, Calif.

The panel below features an image of Kepler's launch and artist concepts of milestone discoveries (l to r): Kepler-9b and c, Kepler-10b, Kepler-11, Kepler-16b, Kepler-22 and Kepler-64f. The final panel illustrates exoplanet discoveries: blue is previous; red is previous Kepler; gold is Kepler's on Feb. 26.


Image Credit: NASA Ames/W. Stenzel


Kepler's finds include planets that orbit in the habitable zone, the range of distances from a star where the surface temperature of an orbiting planet may be suitable for life-giving liquid water. One example of a habitable zone planet found by the mission is known as Kepler-22b. At 2.4 times the size of Earth, it is thought to be too big to be rocky and support life. Scientists believe other habitable zone planets found by the Kepler mission might be rocky, such as Kepler-62f, which is 40 percent larger in size than Earth.

A twin to Earth -- a planet with the same temperature and size as Earth -- has not yet been identified, but the analysis is far from over as scientists continue to search the Kepler data for the tiny signature of such a planet. Other Kepler discoveries include hundreds of star systems hosting multiple planets, and have established a new class of planetary system where planets orbit more than one sun.

In August of last year, the mission ended its science observations after a faulty reaction wheel affected the telescope's ability to point precisely. The mission may be able to operate in a different mode, and continue to do science. This next-generation mission proposal, called K2, will be considered for funding by NASA in the 2014 Astrophysics Senior Review of Operating Missions. - Daily Galaxy.



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