Beyond Galileo’s Universe

By Ron Cowen, Science News

Four hundred years ago, astronomy embraced all that was visible. For Galileo, looking through his primitive telescope, the vistas included jewel-like stars, mountains on the moon, moons orbiting Jupiter and the glow of comet tails.

Today astronomy is often about what cannot be seen. Astronomers have known for decades that stars and galaxies are mere baubles floating on a vast sea of dark matter. More recently, astronomy’s roster of Darth Vaders has expanded to include an even more mysterious force: dark energy, an entity that drives the universe to accelerate its expansion just when gravity’s tug ought to be slowing it down.

On the brighter side, astronomers are beginning to learn more about the complicated processes that formed stars and galaxies, giving the universe its light. The Planck mission (SN: 4/11/09, p. 16) will test the idea that the Big Bang was accompanied by a brief burst of rapid expansion called inflation, which is thought to have created the seeds of matter from which stars and galaxies arose.

On smaller scales, explorations within the solar system, along with the discovery of more than 345 extrasolar planets, pose questions about the possible existence of life beyond Earth. The Kepler mission, launched in March, will provide a head count of Earthlike planets in the nearest reaches of the galaxy. Other new telescopes will examine the composition of these orbs and their potential for life.

Galileo’s successors have pieced together an impressive outline of cosmic history, from the inflationary beginnings of spacetime to the arrival of planets and people. But many details remain to be filled in, and strange new features may be added as astronomers push the limits of current theory and knowledge. New forms of matter, new twists in spacetime and even entire extra universes may emerge from the ongoing efforts to explain and understand the workings of the heavens.

To read more of this article click here or to read other articles from the Science News special issue on the International Year of Astronomy, visit Atom & Cosmos at www.sciencenews.org.