Alien Earthlike worlds 'like grains of sand', say 'wobble' boffins
Five year NASA skyscan reveals planet cornucopia
In a boon for those anticipating future discovery of alien life and/or human colonisation of other worlds, NASA boffins say that their latest analysis indicates that almost one in four stars may be orbited by planets as small as Earth.
"We studied planets of many masses - like counting boulders, rocks and pebbles in a canyon - and found more rocks than boulders, and more pebbles than rocks. Our ground-based technology can't see the grains of sand, the Earth-size planets, but we can estimate their numbers," says Andrew Howard, boss scientist of the team conducting the study.
"Earth-size planets in our galaxy are like grains of sand sprinkled on a beach - they are everywhere," says Howard.
The astronomer and his colleagues used the Keck telescope in Hawaii for a five-year sky census involving 166 sun-like stars in the general vicinity of our solar system. A NASA statement released yesterday specifies that they employed the "the radial velocity, or 'wobble' technique" to assay just how many planets of various sizes each sun possessed.
According to NASA:
A distinct trend jumped out of the data: smaller planets outnumber larger ones. Only 1.6 percent of stars were found to host giant planets orbiting close in. That includes the three highest-mass planet groups in the study, or planets comparable to Saturn and Jupiter. About 6.5 percent of stars were found to have intermediate-mass planets, with 10 to 30 times the mass of Earth – planets the size of Neptune and Uranus. And 11.8 per cent had the so-called "super-Earths," weighing in at only three to 10 times the mass of Earth.
"The data tell us that our galaxy, with its roughly 200 billion stars, has at least 46 billion Earth-size planets, and that's not counting Earth-size planets that orbit farther away from their stars in the habitable zone," says top planet-hunter boffin Geoff Marcy, part of the Keck team.
Some models of planetary formation suggest that there would be a "desert" of planets in the hot zones close to stars, implying that Earth-size worlds would normally be found in the cooler outer regions.
Though the new study refers only to Earth-sized worlds orbiting close in to their parent stars - ones which would be too hot for liquid water to exist, and thus unable to develop or sustain life along Earthly lines - it means that there are in fact many, many such planets to be found orbiting nearby suns. This should also mean that there are a decent number within their stars' habitable zones, perhaps home to alien life now or the colonists of humanity one day in the far future once we've cracked the problems of star travel.
The planet-sniffing study is published here by major boffinry mag Science (subscription required for full article). ®
No one would have believed
in the first years of the 21st century...
Alas, there's not much we can do about it...
... until someone discovers an as yet unknown law of nature that enables faster than light travel.
The reality is, even getting to the edge of our solar system - the Oort cloud - is about a light year distant.
With the fastest spacecraft travelling away from the earth at around 38,000mph (Voyager 1), it would take thirty thousand years to reach the outer boundaries of our solar system.
Getting to Proxima Centauri would take 81,000 years.
"Space is big. You just won't believe how vastly, hugely, mind- bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space."
In the first years of the 21st century...
...the very first endosymbiosis of a prokaryote occurred on Alpha Centauri B II. The symbiont rapidly divested itself of excess genetic complexes and became totally dependant on the host cell. Fortunately, the symbiont provides the host cell with a method of producing energy it had heretofore previously not had. Soon, the cell divides; it’s new companion along for the ride. Another division, and another. Alien microbes have developed the mitochondria!
Evolution occurs at a furious pace; the alien eukaryotes develop into multi-cellular organisms of increasing complexity. They prey upon the hapless prokaryotes that surround them becoming more and more fit; more capable of adapting to new and different environments. This new life is on the verge of bursting forth from its ecological niche and unleashing a torrent of advanced life on it’s planet.
Suddenly, a shadow falls upon the small pool where these prokaryotes have evolved. Sunlight glints off of a foreign metallic tower. It must stretch a meter into the air…what could it be? An arm lowers itself into and with a small container scoops up both the tiny pond and much of the surrounding soil. Up through the air the entire mass is lifted, until it is deposited into a bin on the back of mysterious metallic device.
The temperature rises. The water starts to boil. The prokaryotes cannot adapt quickly enough to their new environment and they quickly perish. The newly evolved eukaryotes survive for a minute longer…maybe two. The probe finishes analysing the results of it’s findings and transmits the information back to Earth. Fiver years later the news electrifies the world:
…on a planet not to far from home, we have found life! Liquid water and the chemical signatures that indicate our faithful rover has boiled itself some bacteria! Disinterested with the news – Earth was really hoping for something more advanced than bacteria – the Rover is left to continue its journey until it fails. Ultimately, it is abandoned: the lone ambassador of a planet that won’t be returning to reclaim it. It’s sensors left to gaze upon the planet whose future it had accidentally destroyed.
Moral of the story: don’t boil your neighbours, mmmmkay?