Posted on 06/16/2008 10:57:17 AM PDT by NormsRevenge
NANTES, France (AFP) - European scientists on Monday said they had located five 'super-Earths', each of them between four and 30 times bigger than our planet, in a trio of distant solar systems.
The discovery suggests that at least one third of stars similar to our own Sun host these difficult-to-detect celestial bodies, multiplying previous estimates by five.
It also brings astronomers closer to finding planets outside our solar system, called exoplanets, that could potentially duplicate the conditions that gave rise to life on Earth.
"In a year or two, it is likely that we will find habitable planets circling small stars" such as the Sun, said Setphane Udry, a researcher at Switzerland's Geneva Observatory and a member of the team that made the discovery.
Three of the five 'super-Earths' -- so-called because they are several times the mass of our own planet -- orbit a star known as HD 40307 some 42 lights away, the scientists reported.
One light-year is roughly equivalent to 9.5 trillion kilometres (6 trillion miles).
They have 4.2, 6.7, and 9.4 times the mass of the Earth, and orbit their sun in periods of 4.3, 9.6, and 20.4 days, respectively.
The rapid orbits make the super-Earths easier to detect -- but it also means that they are probably gaseous balls of fire inhospitable to life as we know it.
The first exoplanet was detected in 1995, and less than 280 had been catalogued before today's findings, unveiled at an astronomy conference in Nantes, France.
But a new generation of powerful instruments is almost certain to expand the list rapidly, say scientists.
The recent batch of exoplanets were all spotted with the High-Accuracy Radial-Velocity Planet Searcher (HARPS), a 3.6-metre telescope and spectograph perched atop La Scilla mountain at the southern edge of Chile's Atacama Desert.
HARPS, sometimes called the "planet hunter", has uncovered 45 super-Earths since it began operation in 2004.
"Clearly these planets are only the tip of the iceberg," says Mayor. "The analysis of all the stars studied with HARPS shows that about one third of solar-like stars have either super-Earth or Neptune-like planets with orbital periods shorter than 50 days."
Earth orbits the Sun once every 365 days.
Distant planets, even big ones, are too small to be directly observed, and can only be detected by measuring their impact on the movement of the stars they orbit.
"The mass of the smallest planets is 100,000 times smaller than that of the star, and only the high sensitivity of HARPS made it possible to detect them," says co-author Francois Bouchy, from the Astrophysics Institute of Paris.
All of the exoplanets unveiled Monday have masses four to 30 times greater than Earth's, and orbits at least seven times shorter. The further from the star, the harder they are to observe.
At the same conference, astronomers announced the discovery of two other planetary systems, also with the HARPS spectrograph.
In one, a super-Earth orbits the star HD 181433 every 9.5 days. The same star also hosts a huge, Jupiter-like planet that circles every three years.
The second system contains a fiery planet 22 times the size of Earth that circumnavigates its sun every four days, and a Saturn-like sphere with a three-year orbit.
"It is probable that there are many other planets present -- not only super-Earths, but Earth like-planets that we cannot yet detect," said Stephane Udry, also a researcher at the Geneva Observatory.
Planets are formed from a disc of gas and dusty debris left over from the creation of a star. Just how long this process takes is still a matter of debate.
Earth is believed to be about 4.5 billion years old, and the Sun about 100 million years older.
NASA image from the Spitzer Space Telescope shows a fledgling solar system. European astronomers say they have located dozens of giant planets in three distant solar systems. European astronomers say they have located dozens of giant planets in three distant solar systems. (AFP/NASA/File/Ho)
Since we have no idea what the conditions that give rise to life are, how will we identify planets with similar ones?
Given the findings of the past few years, I would hate to bet the rent money that there is no life out there.
Ping
They’re grasping at straws.
Life on Earth happened because God created it to support life, and he then acted supernaturally to create life.
If any othe planet ever has life, it will be for the same reason.
I would find it extreamely dissapointing and a major let down that in this amazing incredible universe, we’re all alone.
There’s life out there. Similar, different, in forms beyond our narrow imagination.
They’re trying to find my home.
:p
Of course we have an idea of conditions required to sustain life, as we know it anyway.
The recent batch of exoplanets were all spotted with the High-Accuracy Radial-Velocity Planet Searcher (HARPS), a 3.6-metre telescope and spectograph
A spectroscope or spectograph aids in analyzing light to determine elements, gas and material present.
Agree. I can only hope a life form is discovered outside of this planet...Micro organisms or whatever, while I am still around.
What a show that would create on this planet!
Hmm. You never know what sort of useful information these science reporters are going to come up with...
Some years ago I read a cheesy sci fi novel about settlers on a planet populated by dinosaur type creatures. The struggle against the dinosaurs was a problem but the real problems came from protesters on earth.
errr.. yeah.. except in leap years. ;-)
I can see why these are referred to as "super-earths"...why they're so similiar to earth that it's astounding. /s
Actually, our orbit is not 365 days. It's slightly longer than that if I'm not mistaken.
They are called super-Earths based on their mass. They aren’t big, gas giants, but in the mass realm where they could be general structure of the earth - rocky planets and not big gas balls. But they fit a size range not found in our solar ssytem - between Earth and the gas giants. That’s about the depth of the similarity.
God is so awesome!!!!
I’ll give them a bit of a break - there’s no way they could detect an earth sized planet around a distant star, given the way they detect them - the wobble factor.
But it’s really begging the question to refer to these planets as anything similar to earth.
The requirements for life on earth as we know it make the odds incredibly against finding another that is even somewhat similar in our galaxy.
The moon and its formation, the gas giants, the type of star that we have, the distance from that star, the location of that star in the galaxy, the type of galaxy, many more factors - all are important, and rare.
Al Gore immediately booked a trip to visit each of them, stating "It's important that we prevent global warming from occurring on these earth-like worlds"
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