Kepler's planet finding bonanza: Nasa's space telescope finds 715 new worlds - including four that could be habitable
- Newly developed technique to spot planets led to massive haul
- Four of the new planets are in habitable zones
- Nearly 95 percent of these planets are smaller than Neptune, which is almost four times the size of Earth
Our galaxy is suddenly looking far more crowded.
NASA has confirmed a record setting bonanza of 715 newly discovered planets outside our solar system.
Scientists using the planet-hunting Kepler telescope have nearly doubled the number of planets discovered in the galaxy to around 1,700.
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Nasa says many of the new finds are multiple-transiting planet systems, which are stars with more than one planet. The planets eclipse or transit their host star from the vantage point of the observer. This angle is called edge-on.
HUNTING FOR PLANETS
Nasa says its new technique for spotting planets can be likened to the behavior we know of lions and lionesses.
In our imaginary savannah, the lions are the Kepler stars and the lionesses are the planet candidates.
The lionesses would sometimes be observed grouped together whereas lions tend to roam on their own.
If you see two lions it could be a lion and a lioness or it could be two lions.
But if more than two large felines are gathered, then it is very likely to be a lion and his pride.
Thus, through multiplicity the lioness can be reliably identified in much the same way multiple planet candidates can be found around the same star.
Astronomers used a new confirmation technique to come up with the largest batch of planets announced at one time.
Twenty years ago, astronomers had not found any planets circling stars other than our sun.
All the new planets are in systems like ours where multiple planets circle a star.
Four of those new planets are in habitable zones where it is not too hot or not cold.
NASA's Kepler mission announced Wednesday the discovery of 715 new planets.
These newly-verified worlds orbit 305 stars, revealing multiple-planet systems much like our own solar system.
Nearly 95 percent of these planets are smaller than Neptune, which is almost four times the size of Earth.
This discovery marks a significant increase in the number of known small-sized planets more akin to Earth than previously identified exoplanets, which are planets outside our solar system.
'The Kepler team continues to amaze and excite us with their planet hunting results,' said John Grunsfeld, associate administrator for NASA's Science Mission Directorate in Washington.
'That these new planets and solar systems look somewhat like our own, portends a great future when we have the James Webb Space Telescope in space to characterize the new worlds.'
Since the discovery of the first planets outside our solar system roughly two decades ago, verification has been a laborious planet-by-planet process.
A record breaking day for Kepler: The histogram shows the number of planet discoveries by year for roughly the past two decades of the exoplanet search. The blue bar shows previous planet discoveries, the red bar shows previous Kepler planet discoveries, the gold bar displays the 715 new planets.
Now, scientists have a statistical technique that can be applied to many planets at once when they are found in systems that harbor more than one planet around the same star.
To verify this bounty of planets, a research team co-led by Jack Lissauer, planetary scientist at NASA's Ames Research Center in Moffett Field, Calif., analyzed stars with more than one potential planet, all of which were detected in the first two years of Kepler's observations -- May 2009 to March 2011.
WHAT IS KEPLER?
The Kepler space telescope orbits around the Sun, 40 million miles from Earth.
It is named after 17th Century astronomer Johannes Kepler.
It was launched in 2009 with the sole purpose of finding new stars and planets.
Kepler is a space observatory launched by Nasa to discover Earth-like planets orbiting other stars. Data from Kepler could help humans find alien life
Kepler's mission was supposed to be over by now, but last year NASA agreed to keep Kepler running through 2016 at a cost of about £13 million ($20 million) a year.
According to Nasa scientists, there is, what's dubbed, a 'Goldilocks Zone' in space where the temperature is not too hot, or too cold, for water to exist in liquid form.
Any planets found in this zone could have life on them.
If Kepler is retired, Nasa scientists believe the search for other lives on planets could be severely hindered.
The research team used a technique called verification by multiplicity, which relies in part on the logic of probability.
Kepler observes 150,000 stars, and has found a few thousand of those to have planet candidates.
If the candidates were randomly distributed among Kepler's stars, only a handful would have more than one planet candidate.
However, Kepler observed hundreds of stars that have multiple planet candidates.
Through a careful study of this sample, these 715 new planets were verified.
'Four years ago, Kepler began a string of announcements of first hundreds, then thousands, of planet candidates --but they were only candidate worlds," said Lissauer.
The blue bars on the histogram represents all the exoplanets known, by size, before today's Kepler Planet Bonanza announcement on Feb. 26, 2014. The gold bars on the histogram represent Kepler's newly-verified planets.
'We've now developed a process to verify multiple planet candidates in bulk to deliver planets wholesale, and have used it to unveil a veritable bonanza of new worlds.'
These multiple-planet systems are fertile grounds for studying individual planets and the configuration of planetary neighborhoods. This provides clues to planet formation.
Four of these new planets are less than 2.5 times the size of Earth and orbit in their sun's habitable zone, defined as the range of distance from a star where the surface temperature of an orbiting planet may be suitable for life-giving liquid water.
One of these new habitable zone planets, called Kepler-296f, orbits a star half the size and 5 percent as bright as our sun. Kepler-296f is twice the size of Earth, but scientists do not know whether the planet is a gaseous world, with a thick hydrogen-helium envelope, or it is a water world surrounded by a deep ocean.
Sizes of Verified Planets found by Kepler - boosted significantly by today's announcement
'From this study we learn planets in these multi-systems are small and their orbits are flat and circular -- resembling pancakes -- not your classical view of an atom,' said Jason Rowe, research scientist at the SETI Institute in Mountain View, Calif., and co-leader of the research.
'The more we explore the more we find familiar traces of ourselves amongst the stars that remind us of home.'
This latest discovery brings the confirmed count of planets outside our solar system to nearly 1,700.
Launched in March 2009, Kepler is the first NASA mission to find potentially habitable Earth-size planets.
Discoveries include more than 3,600 planet candidates, of which 961 have been verified as bona-fide worlds.
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