The Night Sky Guy

Earth-sized Exoplanets Detected!

Size comparison of newly discovered exoplanets that now hold record as smallest yet detected. Credit: NASA

We have just gotten a whole lot closer to finding that Holy Grail in astronomy- that elusive sister Earth. NASA announced that its Kepler spacecraft has spied the telltale light signatures of two of the smallest planets ever found – Earth sized rocky planets around a sun-like star 950 light years from us in the summertime constellation Lyra.

NASA says that “Kepler-20e is slightly smaller than Venus, measuring 0.87 times the radius of Earth while Kepler-20f is slightly larger than Earth, measuring 1.03 times its radius.” Both planets call the five-planet system  Kepler-20 home. But before we begin dreaming of vacations on these worlds, astronomers believe both have scorching surface temps measuring probably well over 600 degrees Celsius, orbiting their parent star way too close. So this means that neither planet is within the Goldilocks or habitable zone – and probably means it’s not ideal place for looking for any life there.

But this discovery is VERY exciting because it does signal the beginning of a whole new era in exoplanet hunting because now it has been proved that we have the technology and methods needed to find Earth-like planets. And i think the best is yet to come from Kepler. We might just see Earth’s twin being found in 2012.

“In the cosmic game of hide and seek, finding planets with just the right size and just the right temperature seems only a matter of time,” said Natalie Batalha, Kepler deputy science team lead and professor of astronomy and physics at San Jose State University. “We are on the edge of our seats knowing that Kepler’s most anticipated discoveries are still to come.”

Here is a great little NASA video summary of today’s announcement…

-with quotes from NASA/JPL news release

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First Exoplanet in Habitable Zone Found

NASA made a big announcement this week that it has confirmed the first detection of the smallest planet yet found orbiting a sun-like star in the zone where liquid water may exist! The planet which sits 600 light years away, dubbed Kepler 22b, is about 2.4 times larger than Earth – so it probably has a rocky surface – and takes only 290 days to orbit its G type sun-like star, putting it in the magical Goldilocks zone.

The find was made thanks to NASA’s Kepler spacecraft which has orbited Earth for about 2 years and has found over 2326 candidate planet detections. NASA says, “Of these, 207 are approximately Earth-size, 680 are super Earth-size, 1,181 are Neptune-size, 203 are Jupiter-size and 55 are larger than Jupiter.” This is only the first of these habitable zone planet candidates to be confirmed…so stay tuned.

Comparison of our own solar system to Kepler-22; credit: NASA

So why all the hoopla? This world is in the right spot for liquid water to exist. Since we think H20  is key in recipe of life – this makes this alien world worth a closer look. Of course no one on the discovery team is saying this latest alien world discovery is an Earth-twin, but we are getting closer than ever – so it’s only a matter of time now that we track down a world nearly identical in size and orbit. Big question astronomers are asking now of Kepler 22b is if it has a gaseous or liquid covered surface… so…lots of work still to be done.  I wouldn’t be surprised that dozens more like Kepler-22b will be confirmed in the coming months and years , with the Holy Grail exoplanet – Earth’s twin- possibly being discovered within the next 5 years.

I think this is such an exciting time to be alive in human history… the first generation that will most  likely confirm the existence of an Earth-like world around a distant star.

Check out the video of the NASA press conference announcing this new Goldilocks planet…

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Possible Earth-sized Exoplanets Found

NASA’s Kepler mission has discovered its first Earth-size planet candidates and its first candidates in the habitable zone, a region where liquid water could exist on a planet’s surface. Five of the potential planets are near Earth-size and orbit in the habitable zone of smaller, cooler stars than our Sun.

Candidates require follow-up observations to verify they are actual planets. Kepler also found six confirmed planets orbiting a Sun-like star, Kepler-11. This is the largest group of transiting planets orbiting a single star yet discovered outside our solar system.

“In one generation we have gone from extraterrestrial planets being a mainstay of science fiction, to the present, where Kepler has helped turn science fiction into today’s reality,” said NASA Administrator Charles Bolden. “These discoveries underscore the importance of NASA’s science missions, which consistently increase understanding of our place in the cosmos.”

Kepler-11 is a sun-like star around which six planets orbit. Image credit: NASA/Tim Pyle

The discoveries are part of several hundred new planet candidates identified in new Kepler mission science data, released on Tuesday, Feb. 1. The findings increase the number of planet candidates identified by Kepler to-date to 1,235. Of these, 68 are approximately Earth-size; 288 are super-Earth-size; 662 are Neptune-size; 165 are the size of Jupiter and 19 are larger than Jupiter.  Of the 54 new planet candidates found in the habitable zone, five are near Earth-sized. The remaining 49 habitable zone candidates range from super-Earth size — up to twice the size of Earth — to larger than Jupiter.

The findings are based on the results of observations conducted May 12 to Sept. 17, 2009, of more than 156,000 stars in Kepler’s field of view, which covers approximately 1/400 of the sky.

“The fact that we’ve found so many planet candidates in such a tiny fraction of the sky suggests there are countless planets orbiting Sun-like stars in our galaxy,” said William Borucki of NASA’s Ames Research Center in Moffett Field, Calif., the mission’s science principal investigator. “We went from zero to 68 Earth-sized planet candidates and zero to 54 candidates in the habitable zone, some of which could have moons with liquid water.”

Among the stars with planetary candidates, 170 show evidence of multiple planetary candidates. Kepler-11, located approximately 2,000 light years from Earth, is the most tightly packed planetary system yet discovered. All six of its confirmed planets have orbits smaller than Venus, and five of the six have orbits smaller than Mercury’s.

The only other star with more than one confirmed transiting planet is Kepler-9, which has three. The Kepler-11 findings will be published in the Feb. 3 issue of the journal Nature.

his artist’s conception shows the Kepler-11 planetary system and our solar system from a tilted perspective to demonstrate that the orbits of each lie on similar planes. Image credit: NASA/Tim Pyle

“Kepler-11 is a remarkable system whose architecture and dynamics provide clues about its formation,” said Jack Lissauer, a planetary scientist and Kepler science team member at Ames. “These six planets are mixtures of rock and gases, possibly including water. The rocky material accounts for most of the planets’ mass, while the gas takes up most of their volume. By measuring the sizes and masses of the five inner planets, we determined they are among the lowest mass confirmed planets beyond our solar system.”

All of the planets orbiting Kepler-11 are larger than Earth, with the largest ones being comparable in size to Uranus and Neptune. The innermost planet, Kepler-11b, is ten times closer to its star than Earth is to the Sun. Moving outward, the other planets are Kepler-11c, Kepler-11d, Kepler-11e, Kepler-11f, and the outermost planet, Kepler-11g, which is half as far from its star as Earth is from the Sun.

The planets Kepler-11d, Kepler-11e and Kepler-11f have a significant amount of light gas, which indicates that they formed within a few million years of the system’s formation.

“The historic milestones Kepler makes with each new discovery will determine the course of every exoplanet mission to follow,” said Douglas Hudgins, Kepler program scientist at NASA Headquarters in Washington.

Kepler, a space telescope, looks for planet signatures by measuring tiny decreases in the brightness of stars caused by planets crossing in front of them. This is known as a transit.

Since transits of planets in the habitable zone of Sun-like stars occur about once a year and require three transits for verification, it is expected to take three years to locate and verify Earth-size planets orbiting Sun-like stars.

The Kepler science team uses ground-based telescopes and the Spitzer Space Telescope to review observations on planetary candidates and other objects of interest the spacecraft finds.

The star field that Kepler observes in the constellations Cygnus and Lyra can only be seen from ground-based observatories in spring through early fall. The data from these other observations help determine which candidates can be validated as planets.

More information about the Kepler mission:

http://www.nasa.gov/kepler

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Space News This Week

This week in space news we talk about the hottest and smallest exoplanet discoveries to date and a unprecedented storm of comets has been seen to bombard the Sun. Check out my national news interview below…

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