Astronomy's Scientific Power to Grow During Next 400 Years

The scoop: About 400 years ago, Hans Lippershay of the Netherlands invented the telescope -- and an Italian scientist known as Galileo Galilei was smart enough to point it at the night sky.

How far has modern astronomy come along since Galileo discerned mountains on the moon, Jupiter's satellites and the Milky Way's stars?

Ever since Galileo aimed his telescope skyward, our knowledge of the universe has profoundly increased and become an integral part of the experience that we call science.

In Galileo's time, the distance to the moon was the one distance we had actually measured, but every other distance was an ill-educated guess. We had no idea how much matter comprised the Earth, let alone any other object. On the origins and development of any astronomical object -- not even the Earth, sun or moon -- humankind was clueless.

Science has come a long way since then.

Today we know that the distance to the moon is 239,000 miles on average, and the gravitational "drain" of Earth's oceanic tides is causing our lunar companion to drift away at about 1.5 inches per year. We can accurately estimate the amount of matter in objects both near and far, even vast amounts of stuff we can't see (so-called dark matter) hanging out with galaxies. The life history of stars, planets, moons, comets, asteroids and most other objects no longer eludes us; we know that all matter appeared on the cosmic scene 13.7 billion years ago, which is about 9.5 billion years before the solar system was born.

In spite of all we now know, however, we have merely scratched the surface of astronomical knowledge.

Only in the past 15 years have scientists discovered planet-like objects beyond the solar system's boundaries. Now we are just beginning to understand these distant star systems and look for signs of life in them. And yet we can't even agree on what, exactly, defines a living thing. Molecular biology is a young 56 years old.

So, life elsewhere in the universe is both a search and an understanding waiting in our future. A return to looking for objects resembling our home planet as well as complex systems that behave like life is a necessary step in human scientific progress.

In Galileo's time, the world population was about 600 million people. Today there are 11 times as many of us, because the noble things we have done to alleviate famine and disease have, in a sense, backfired. Ironically, this global population crisis comes just as we've reached the verge of understanding how complex civilizations arise, develop and survive.

Astronomy holds many keys to our survival.

If we can learn what is happening to our home planet and understand the implications, then it's no stretch of the imagination that we can take action to limit those runaway processes. One runaway has been the burning of fossil fuels, so much and so quickly that Earth's climate is in part changing as a result (the carbon dioxide-choked atmosphere of Venus need only serve as a hot reminder). We hope to replace that energy source with light from our closest star, the sun.

Practicing astronomy will only grow in importance as the years pile up, especially when it comes to avoiding the fate of the dinosaurs. In the future, astronomy will shrink in distance from the main body of science, becoming highly integrated in the minds of both scientists and non-scientists.

Four hundred years ago, astronomy led the way. Perhaps, as the 16th-century English poet John Donne eluded to mankind, it will soon be "a part of the continent, a piece of the main."

Nick Woolf is an emeritus professor of astronomy at the University of Arizona and led a team of the NASA Astrobiology Institute from 2003-2008. The views expressed are the author's alone and do not represent the official position of the Discovery Channel.

Article posted March 30, 2009.

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