Astronomers using NASA’s Kepler Space Telescope announced they have confirmed the existence of 1284 newly discovered planets around distant stars, doubling the number of alien worlds detected by the agency’s planet-hunting probe.Nine of these newly verified worlds are potentially habitable, orbiting their stars in a zone warm enough for water to pool as a liquid, which is considered essential for life as we know it, the scientists said.
Nearly 550 of the newly verified worlds could be rocky planets like Earth. More than 100 of them are about the size of Earth or smaller.
“This is the most exoplanets that have ever been announced at one time,” said Princeton University astrophysicist Timothy Morton. “This more than doubles the number of known Kepler exoplanets.”
The new findings were announced at a media briefing by researchers from Princeton University, Columbia University, the California Institute of Technology and the National Aeronautics and Space Administration’s Ames Research Center at Moffett Field in California. A research paper supporting their conclusions was published in the Astrophysical Journal.
So far, however, these alien worlds verified by the Kepler scientists haven’t been confirmed by independent observations from ground-based telescopes. Until April 1994, there was no other known solar system, but in recent years astronomers have detected thousands of planets orbiting around different stars — so many, in fact, that some astronomers have calculated that each of the stars in the Milky Way is likely to have at least one planet in orbit around it. Many of them are likely to be suitable for life.
“You quickly realise that there are 10 billion such potentially habitable planets in our galaxy,” said Kepler mission scientist Natalie Batalha at the Ames Research Center.
Just last week, astronomers at the European Southern Observatory discovered three planets with sizes and temperatures similar to those of Venus and Earth, orbiting an ultracool dwarf star just 40 light years from Earth.
The announcement came barely a month after the Kepler spacecraft, orbiting more than 75 million miles from Earth, recovered from engineering problems that briefly threatened its continued operations. NASA launched the $US600 million Kepler mission in 2009 to search for potentially habitable Earth-size planets. For four years, Kepler monitored 150,000 stars in a single patch of sky near the constellation Cygni, measuring the tiny, telltale dip in the brightness of a star that can be produced by a transiting planet. In the latest study, astronomers analysed 4302 potential planets identified by the Kepler telescope.
For 1284 of those candidates, the probability of being a planet is greater than 99 per cent — the minimum required to earn the status of “planet” — the scientists said. “We now know that exoplanets are common,” said Paul Hertz, Astrophysics Division director at NASA headquarters in Washington, D.C. “Knowing this is the first step toward addressing the question: Are we alone in the universe?”
By Robert Lee Hotz
With many thanks to The Australian