SINCE time immemorial man has looked at the stars in awe and wonderment. No longer. The observatories where light is collected are now run by robots that neither dirty the instruments nor take night-time naps. Does it matter? Some of the astronomers at this year’s meeting of the International Astronomical Union (IAU), held in Rio de Janeiro from August 3rd to 14th, think it does. They discussed what could be done to halt their subject’s trend towards mining data gathered by computers rather than peering into telescopes.
The Rio meeting is the high point of what has been dubbed by the union as the International Year of Astronomy. The reason for picking 2009 to receive this honour is that it is exactly 400 years since Galileo Galilei turned his telescope on the heavens to study what the naked eye could not disclose, and also since Johannes Kepler revealed to the world that planetary orbits are ellipses, not circles. These two events can be seen, in retrospect, as the beginning of modern astronomy.
The pace of discovery has not slowed down. Indeed, more than one participant in the meeting described the present as a “golden age”. The rate of discoveries has been increasing, along with the means to keep up with the details. That has, in turn, led to bigger and more expensive telescopes, and the introduction of management techniques intended to ensure the smooth running of large projects. But it is that managerialism that is beginning to worry some of the more thoughtful members of the union. They fear that although it brings short-term benefits, it may, in the long run, crush individual flair.
Simon White of the Max Planck Institute for Astrophysics in Garching, Germany, is one such worrier. He observes that in the 19th century and for most of the 20th, too, scientific progress usually came from brilliant individuals formulating and testing hypotheses using data accumulated by relatively modest means.
Big science has its place, of course. For one thing, enormous amounts of data allow subtle effects to be detected statistically. But Dr White suggests astronomers should ensure small science can flourish alongside its larger counterpart by, for example, ensuring that telescopes designed to look for big fish can also be used for projects that might be considered as small fry.
Thinking space
Another way to encourage gifted individuals might be to reform the way time on telescopes is allocated. The IAU’s new president, Robert Williams of the Space Telescope Science Institute in Baltimore, Maryland, is a supporter of this idea. He reckons decisions about who gets what observing time should be made by the directors of observatories, answerable to a governing body, rather than by groups of the great and good, as tends to happen now.
“High-risk, high-reward projects require hard decisions that are best made by individuals, not committees,” he says. And he should know. As director of the Space Telescope Science Institute he was, in 1995, allocated ten days on Hubble (pictured above), America’s most famous eye in the sky. Instead of using that time on a project with a preordained objective, he asked, in what might be seen as an act of either modesty or bravura, that the telescope be pointed at a typical patch of sky and left there for the whole period, to see what it could see.
The result was the Hubble Deep Field, a fantastically detailed image of a small region in a constellation called Ursa Major. The field of view is so narrow that only about 20 stars from the Milky Way, the galaxy in which the Earth resides, lie within it. What it shows instead is almost 3,000 galaxies, some of which are the most distant (and hence the youngest) ever observed. The image demonstrates that the universe is, indeed, uniform over large scales and that the Earth occupies a typical region of it. It is unlikely that a committee would have had the guts to allocate so much time to what was a speculative punt.
Yet despite the professed desire of some to do so, astronomers cannot turn their backs on big science. In particular, to see faint, distant objects at the dawn of time, as Dr Williams did with Hubble, you need to collect a lot of light. That means your telescopes need big mirrors. And big mirrors do not come cheap.
Back on Earth, the biggest mirrors in prospect belong to three telescopic projects that will, by coincidence, all come to fruition in 2018, if their backers get their way. The Giant Magellan Telescope, a joint effort by America, Australia and South Korea that is to be built in the Atacama Desert in Chile, would have seven mirrors, each 8.4 metres across, giving an effective diameter of 25 metres. An even larger beast, dubbed the Thirty Metre Telescope, for obvious reasons, is a collaboration between American and Canadian universities. It has been on the drawing board since 1990. Last month its project board announced that, if funding were forthcoming, it would be built on Mauna Kea in Hawaii.
The third, the European Extremely Large Telescope, is the suggested replacement for the Overwhelmingly Large Telescope, a proposal rejected by the European Southern Observatory three years ago when it discovered that the bill would also be overwhelmingly large. Its mirror would be 42 metres across, and it would probably be built either on one of the Canary Islands or in Chile.
Besides these new conventional telescopes, completely novel ways of doing Big Astronomy are likely to emerge to tempt astronomers back into its clutches. Several projects are already under way to detect gravitational waves—ripples in the fabric of spacetime itself—although none has yet caught its quarry. Should they, or their successors, eventually do so, it would open up a new window on the universe, allowing astronomers to study massive objects such as colliding black holes in unprecedented detail.
Astrophysicists have also begun to be able to detect the directions from which streams of subatomic particles called neutrinos arrive, and progress is being made as well on interpreting cosmic rays. Once these are better understood, astronomers could use them to study the universe in the way they now use light and radio waves.
Yet astronomers are still right to want space for the small. The two most exciting recent findings—the discovery of “dark energy”, which pushes space itself apart, and of planets beyond the solar system—were made using modest equipment. It is the very success of the small that promotes the growth of the big.
Source of Information : The Economist August 15 2009
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