Pondering Astronomy in 2009

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Science  16 Jan 2009:
Vol. 323, Issue 5912, pp. 309
DOI: 10.1126/science.1170104

This week in Paris, An opening ceremony held by the United Nations Educational, Scientific and Cultural Organization and the International Astronomical Union proclaims 2009 as the International Year of Astronomy. The year marks the 400th anniversary of Galileo's first observations with his telescope, when he detected the moons of Jupiter; and of Kepler's great book Astronomia Nova, which showed that the planets move in elliptical orbits.

People in all eras and cultures have gazed at the night sky, though it has been interpreted in many different ways. Astronomy is the oldest science, except for medicine. Through its role in timekeeping and navigation, it's perhaps the first to have done more good than harm. But its scope has expanded hugely in recent decades. The cosmos is now being explored at the cutting edge of technology, on the ground and in space. Often, it is through cooperative international ventures, such as the European Southern Observatory's giant array of telescopes in Chile and the Atacama Large Millimeter Array in Chile, a collaboration involving Europe, Japan, and the United States. Powerful instruments have revealed a vaster and more intricate universe than our forbears envisaged. But the subject remains accessible to a wide public.

Black holes, dark matter, and the Big Bang have entered the common vocabulary. Millions have followed the progress of probes to Mars, Jupiter, and Saturn and admired images from the Hubble Telescope. The Internet allows scientists worldwide to access and analyze huge digitized data sets. Sophisticated amateurs can pursue projects that were once the province of professionals with large telescopes.

During 2009, astronomers will step up their campaign against the ever more pervasive light pollution that degrades their observations. But the campaign to preserve dark skies deserves support from a wide public. Everyone's environment is diminished if they can't see a starry sky. It's not just astronomers who care about this, just as it's not only keen ornithologists who would feel deprived if songbirds disappeared from our gardens. 2009 also marks 200 years since Charles Darwin's birth and 150 years since the publication of his great book On the Origin of Species. So it's an appropriate time to highlight a fascinating question of where astronomy and biology overlap: Does life exist elsewhere?


Within the past decade, we've realized that most stars are orbited by retinues of planets. The planets so far discovered are mainly large, comparable to Jupiter and Saturn, the giants of our solar system. But an astronomical highlight of 2009 will be the launch, by the U.S. National Aeronautics and Space Administration, of the Kepler spacecraft, which should reveal planets no bigger than Earth by detecting the slight dimming of a star when a planet transits in front of it.

There are many steps between detecting an Earthlike planet and reliably assessing whether it has a biosphere. Life's origin on Earth is still a mystery, so we cannot lay firm odds on its likelihood elsewhere. But we may learn, in the coming decades, whether biological evolution is unique to the pale blue dot in the cosmos that is our home, or whether Darwin's writ also runs in the wider universe.

Darwin closes On the Origin of Species with these famous words: “whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning, forms most beautiful and most wonderful have been, and are being, evolved.” This “simple” beginning—the young Earth, orbiting a rather ordinary star—is itself very complicated, geologically and chemically. Astronomers aim to probe further back and set our entire solar system in a broader expanse of space and time.

Science is the one truly global culture, and it is surely a cultural deprivation to be unaware of the chain of events through which some mysterious genesis nearly 14 billion years ago triggered the emergence of atoms, galaxies, stars, and planets, and whereby, on at least one planet, Darwinian selection led to the emergence of creatures able to ponder their origins. The details are sharpening up faster than ever. The International Year of Astronomy is our opportunity to proclaim this immense story worldwide.

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