Tranquil environment around Earth may be unusual
PARTICLE PHYSICS AND ASTRONOMY RESEARCH COUNCIL
Posted: July 5, 2004
UK astronomers studying the Tau Ceti system have discovered that it contains ten times as much material in the form of asteroids and comets as our own solar system. Their discovery, being published in Monthly Notices of the Royal Astronomical Society, suggests that even though Tau Ceti is the nearest Sun-like star, any planets that may orbit it would not support life as we know it due to the inevitable large number of devastating collisions. It also suggests that the tranquil space environment around the Earth may be more unusual than previously realised.
The discovery means that scientists are going to have to rethink where they look for civilisations outside our Solar System. Jane Greaves continues "We will have to look for stars which are even more like the Sun, in other words, ones which have only a small number of comets and asteroids. It may be that hostile systems like Tau Ceti are just as common as suitable ones like the Sun."
The reason for the larger number of comets orbiting Tau Ceti is not fully understood, explains Mark Wyatt, another member of the team: "It could be that our Sun passed relatively close to another star at some point in its history and that the close encounter stripped most of the comets and asteroids from around the Sun."
The new results are based on observations taken with the world's most sensitive submillimetre camera, SCUBA. The camera, built by the Royal Observatory, Edinburgh, is operated on the James Clerk Maxwell Telescope in Hawaii. The SCUBA image shows a disk of very cold dust (-210 BAC) in orbit around the star. The dust is produced by collisions between larger comets and asteroids that break them down into smaller and smaller pieces.
UK participation in the James Clerk Maxwell Telescope is provided by the Particle Physics and Astronomy Research Council (PPARC). Professor Ian Halliday, PPARC Chief Executive said "SCUBA continues to unveil the mysteries of planetary systems, in this case the "asteroid alley" that is Tau Ceti; - clearly a place you would not wish to be."
Publication of the result coincides with an exhibit "Hunting for Planets in Stardust" at the Royal Society Summer Exhibition by the same science team from the UK Astronomy Technology Centre in Edinburgh and the University of St Andrews.
Tau Ceti is in the constellation Cetus. Although it is visible without a telescope, at this time of year it rises in the South East at about 3am - just before the sun, so is very hard to spot.
The Particle Physics and Astronomy Research Council (PPARC) is the UK's strategic science investment agency. It funds research, education and public understanding in four broad areas of science - particle physics, astronomy, particle astrophysics and space science.
PPARC is government funded and provides research grants and studentships to scientists in British universities, gives researchers access to world-class facilities and funds the UK membership of international bodies such as the European Organisation for Nuclear Research, CERN, the European Southern Observatory and the European Space Agency. It also contributes money for the UK telescopes overseas on La Palma, Hawaii, Australia and in Chile, the UK Astronomy Technology Centre at the Royal Observatory, Edinburgh and the MERLIN/VLBI National Facility.