Are we alone in the universe?

By Sapana Singh

Life may not necessarily exist on either of a new world, but even if they are sterile, their very existence is a powerful piece of astronomical news. If our solar system is any indication, giant, unpleasant, planets are likely to be accompanied by small friendly ones, or the giant planets might be attended by large moons that could be hospitable to life.

It’s hard to imagine two more undesirable places. The first a planet orbiting the star 47 Ursae Majoris, 320 trillion kilometres (34 light-years) from Earth in the Big Dipper, is at least 2.5 times the mass of Jupiter. Like our own largest planet, it probably consists mostly of noxious gas that sometimes spiral into hurricanes big enough to swallow Earth.

The second is a planet (though some scientist consider it a brown dwarf star) that circles the star 70 virgin is in the constellation Virgo, also some 320 trillion kilometers away. It has more than six times the mass of Jupiter, and weather conditions there might even be more extreme. Yet inhospitable as both these worlds seem, their discovery.

According to the astronomers Geoffrey Marcy and Paul Butler of San Francisco state University says that first concrete evidence that our planet and its life forms might not be unique in the cosmos not only do these discoveries triple the number of known worlds out side our solar system but both are temperate enough to allow water to exist in liquid form. This, say biologist, is a prerequisite for life as we know it.

Life may not necessarily exist on either of a new worlds, but even if they are sterile, their very existence is a powerful piece of astronomical news.

If our solar system is any indication, giant, unpleasant planets are likely to be accompanied by small friendly ones, or the giant planets might be attended by large moons that could be hospitable to life. Perhaps most important the discovery of planets around relatively nearby sunlike stars implies that our galaxy, the milky way, 100 billion stars strong, must be bursting with other worlds and that there is life out there somewhere if so, it may not be long before we find out.

Scientists are eagerly awaiting the results from the Infrared space observatory (ISO), a newly orbiting European Satellite that can detect the taint heat from distant planets. In 1997 installation of new infrared camera on the Hubbell Space Telescope, was made and it took the picture of newly discovered worlds. Most promising of all, they’re buoyed by a newly unveiled NASA initiative, known as the origin programme, which as a goal understanding the origin of planets. Origin’s planners hope to build a generation of space telescope to search for a new worlds.

Picking out a planet against the glare of a star is like trying to spot a 100-watt light bulb next to a 100-billion watt search light. Astronomers find it much easier to look for the subtle influence a planet might have on its parent stars orbit. As a star is being pulled first forwards and then away from Earth by its planet its light waves are squeezed together, then stretched apart-producing subtle colour changes from blue to red.

These changes examples of what is known as the Doppler shift, are measured with device called a spectrometer. The telescope Marcy and Butler use at lick observatory in the mountains above California’s silicon valley has one of the world’s finest spectrometer. Marcy and Butler verified the Swiss teams claim with their own telescope, then went into high gear, determined to be at least, to find planets around a Sunlike star.

While finding new planets of any sort is exciting says Alan Boss, an astrophysicist at the Carnegie Institution of Washington "The Holy Grail is to Find an Extra solar Planet That is Capable of Supporting Life". The best way to find these distant taint objects, astronomers agree, would be to use a space telescope with a mirror as wide as a football field is long.

By about 2010, NASA hopes to launch a "Planet Finder" a telescope with one to two metre mirrors spread over 100 meters, orbiting out by Jupiter, where the solar system dust begins to thin out. This telescope should allow scientists to identify the earth like planets showing up as pale buledots in the images beamed back to ground controllers.

They can then analyze the planet’s atmosphere for prerequisites of life, such as Ozone, Oxygen or Carbon Dioxide. If other solar system do contain Earth-like worlds, says NASA biologist Michael Meyer, at least some should. Tall into the "Habitable zone" -the region governed by a planet’s distance from its star, where water is liquid rather than solid or gaseous. "The good news," he says is that if our solar system is typical, there’s a 50 percent chance that a planet will be in the right zone.

Alien life of any sort would make biologists ecstatic, but it is the prospect of intelligent life that fires most people’s imagination. The final step from life to intelligent life is probably the longest shot of all, observes Des Marais. Even so, a small band of astronomers around the world have been devoting themselves since 1960 to the search for extraterrestrial intelligence (knowasseti). And they are hopeful. Their quest has always rested on the assumption that planets exist outside the solar system and that there may be life out there intelligent enough to transmit radio signals across vast stretches of space. Since they’ve been proved right about the planets, their search for some sounds of life seems quixotic.

ET is out there trying to get in touch with us, his message may well be received first in quiet rural setting 48 kilometers north-west of Boston. There, a dish-shaped antenna, nearly 28 meters across, faces sky worlds, attuned to the murmurings of the cosmos. This Harvard-Smith sonian radio telescope is the latest and most ambitious SETI effort yet.

Each day as Earth turns, the BETA telescope (for Billion-channel Extra-Terrestrial Assay) sweeps a circular swathe through the heavens, elevated different fixed angle from the horizon with each successive turn. Incoming radio waves are read into a supercomputer that sorts through the input and discards cosmic radio "noise".

Should BETA spot a signal that meet the programmed criteria for artificiality, the radio telescope would abandon its fixed position and automatically leapfrog further west so that the same sector of sky would pass before it again: "I have no doubts" says BETA director and Harvard Physicist Paul Horowitz "Intelligent life in the Universe? So overwhelmingly likely that I’d give you almost any odds".

Still Horowitz is realistic. "The hard part is intelligent life in the galaxy transmitting radio waves to us at a wavelength that we’re expecting and at a such a power level that we can detect them". That he concedes "is a lot of its". There is however a contrary view that is gaining strength complexity can emerge spontaneously through a process of self organization. Meanwhile, the astronomers who are looking for planets are sounding downright cocky, says Paul Butler "very shortly there could be more planets known outside the solar system that inside. If so, the human race may move closer to answering the must enduring question about its true place in the cosmos.

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