January 29, 1998. Copyright 1998, Graphic News. All rights reserved

Cambridge telescope unveils hidden detail
by Steve Farrar, Science Reporter

CAMBRIDGE, January 29, Graphic News- Scientists have for the first time watched a preview of our own sunÕs death throes. The revolutionary COAST telescope Ð which can pick out finer details than the Hubble Space Telescope Ð was used by the Cavendish Laboratory team who built it to observe a distant star swelling and shrinking as it reaches the end of its life
These undignified convulsions will be the ultimate fate of our our sun but there is no need to panic Ð this is not due to happen for around five billion years.
The ancients were so astonished by the behaviour of the brightest of this kind of dying star they called it Mira, Latin for wonderful. All similar ones, including that being studied by the scientists, now bear that name.
Professor John Baldwin, Professor of Radio Astronomy at the Mullard Radio Astronomy Observatory, said:
"Some of these Miras are stars you can easily see when theyÕre at their brightest but they appear totally invisible at other times. TheyÕre getting near the end of their life and when our Sun is very old, it too will start pulsating like a Mira."
 The scientists believe that by that stage the Sun will have swallowed the Earth as it swells to beyond the orbit of Mars. The pulsations will repeat themselves every year or so for tens of thousands of years until eventually all thatÕs left is a tiny, slowly-cooling cinder of a star, known as a white dwarf, dimly twinkling from inside a shell of glowing gas and dust called a nebula.
Dr Chris Haniff, a leading member of the COAST team, said theoreticians thought a star would start to act like this as its fuel began to run out. Its core would heat up so rapidly that the only way to release its energy was to swell up like a balloon. However once enough heat has escaped, gravity makes the star shrink back down. The process then starts again.
Dr Haniff said: " Roughly speaking, our results agree with what the theoretical models say. No-one has witnessed these pulsations directly before which makes it much more exciting."
The astronomers hope to learn more about Miras by using COAST to study features on their surface as well as the dust clouds that surround them.
COAST Ð the Cambridge Optical Aperture Synthesis Telescope Ð is the first fundamentally new type of telescope since GalileoÕs day, almost four centuries ago. The telescope is made up of four curved mirrors mounted on steel frames. Linked together by cunning new technology, each acts as though it were a fragment of a far larger mirror, creating a telescope far larger than any conventional one.
When COAST was first tested it could pick out five times as much detail as the Hubble Space telescope, yet it cost just over £1 million to develop Ð the bill for Hubble has topped £2 billion. COAST will soon get even better results as the distance between each mirror has been increased making it the equivalent of a 20-metre telescope.
COAST has already produced the first image of the two separate twinned stars that make up Capella, and has gazed upon the surface of the red giant Betelgeuse, producing the most detailed image of a star ever made. However, only the brightest objects are visible to COAST and it cannot produce the kind of spectacular pictures of very distant stars and galaxies that have made Hubble so famous. But the scientists predict that COASTÕs technology will one day create images 10,000 times better than anything produced by an earth-based telescope and may be able to pick out planets orbiting distant stars.

Sources: Cambridge Evening News, Mullard Radio Astronomy Observatory