Rocky planets, possibly with conditions suitable for life, may be more common than previously thought in our galaxy, a study has found. New evidence suggests more than half the Sun-like stars in the Milky Way could have similar planetary systems. There may also be hundreds of undiscovered worlds in outer parts of our Solar System, astronomers believe. Future studies of such worlds will radically alter our understanding of how planets are formed, they say. New findings about planets were presented at the American Association for the Advancement of Science (AAAS) in Boston.
NASA telescope
Michael Meyer, an astronomer from the University of Arizona, said he believed Earth-like planets were probably very common around Sun-like stars. “Our observations suggest that between 20% and 60% of Sun-like stars have evidence for the formation of rocky planets not unlike the processes we think led to planet Earth,” he said. “That is very exciting.” Mr Meyer’s team used the US space agency’s Spitzer space telescope to look at groups of stars with masses similar to the Sun. They detected discs of cosmic dust around stars in some of the youngest groups surveyed. The dust is believed to be a by-product of rocky debris colliding and merging to form planets. Nasa’s Kepler mission to search for Earth-sized and smaller planets, due to be launched next year, is expected to reveal more clues about these distant undiscovered worlds.
Frozen worlds
Some astronomers believe there may be hundreds of small rocky bodies in the outer edges of our own Solar System, and perhaps even a handful of frozen Earth-sized worlds. Speaking at the AAAS meeting, Nasa’s Alan Stern said he thought only the tip of the iceberg had been found in terms of planets within our own Solar System. More than a thousand objects had already been discovered in the Kuiper belt alone, he said, many rivalling the planet Pluto in size. “Our old view, that the Solar System had nine planets will be supplanted by a view that there are hundreds if not thousands of planets in our Solar System.” He said many of these planets would be icy, some would be rocky, and there might even be objects with the same mass as Earth. “It could be that there are objects of Earth-mass in the Oort cloud (a band of debris surrounding our planetary system) but they would be frozen at these distances,” Dr Stern added. “They would look like a frozen Earth.”
Goldilocks zone
Excitement about finding other Earth-like planets is driven by the idea that some might contain life or perhaps, centuries from now, allow human colonies to be set up on them. The key to this search, said Debra Fischer of San Francisco State University, California, was the “Goldilocks zone”. This refers to an area of space in which a planet is “just the right distance” from its parent star so that its surface is not-too-hot or not-too-cold to support liquid water. “To my mind there are two things we have to go after: we have to find the right mass planet and it has to be at the right distance from the star,” she said.
www.news.bbc.co.uk, 18-02-08
Hello!
While it certainly is possible to computer-project the radiated light from our sun as it expands and finally engulfs the earth and predict the total incidence of light and future rotation on what may be now a frozen world, a minor issue has been overlooked.
We have evolved and can only live on this planet because a special symbiosis exists between humans and micro-organisms which is the product of millions of years of joint symbiotic evolution.
It is highly likely that, when the rivers,streams,lightening bolts and volcanoes start flowing as a result either of solar warming or our induced terraforming,then organisms unique to this hypothetical planet will also start to evolve.
Unless we plan to send ’seed genetic capsules’ as part of a terraforming project together with a mastered genetic pre-programming
of highly specific coded genes (currently beyond our scientific capability) and hope for the best through a probability course of
attempted pre-programmed evolution or, indeed, unless we can develop ‘human’ mutant hybrids with a capability of synthetically altering their organic structure to compensate for local (alien) bacteria/micro-organisms (again at present way beyond our capability) against which we have no immunological defense whatsoever, then the chances of the human species as we know it ‘living’ on one of these planets in a similar manner to that which we live on earth is highly fanciful.
One could, of course, plan a project to ‘eliminate’ all micro-organic
life on this planet (in much the same way as colonists attempted to do with Native peoples when they arrived on lands hundreds of years ago.) The problem here is that we will be fighting against bacteria and organisms which have evolved over millions of years and unless we can decode their very DNA structure (that is to say, decode the basis of an alien life-form) the tasks of living a normal outdoor life as we know it on earth for existing homo sapiens on such a hypothetical planet are indeed highly formidable.
The article may however boost the imagination of people as a whole to popularly support the case to fund further astronomical and deep-space projects beyond our own solar system.