Monday, May 25, 2009
A golden time for gazing toward the stars
John Goss
John Goss is chairman of the Mid-East Region of the Astronomical League and a former president of the Roanoke Valley Astronomical Society.
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Blog
The Hubble, Chandra, and Swift telescopes in space; large optical telescopes in Hawaii, Arizona, and Chile; and giant radio telescopes at Green Bank, W.Va., and near Socorro, N.M., are studying extrasolar planets, star formation, neutron stars, pulsars, black holes, quasars, dark matter and galaxy evolution. We have sent robotic craft either to fly by, orbit around, crash into, land on, or drive across the surfaces of all the major planets and moons of our solar system.
Not a week goes by when there are no astronomical discoveries announced nor spectacular space images released. It's been said that we live in the "Golden Age of Astronomy." How true.
Up until 100 years ago, astronomers focused on cataloguing and categorizing the various objects visible in the telescopes of the day. It was the time for "descriptive" astronomy, a sedate and stodgy pursuit. Today, the science of astronomy strives to understand the processes that drive the cosmos. Now, it is the time for discovering the fundamental physical reasons of why the universe acts and appears the way it does.
How do all the advancements made possible by state-of-the-art telescopes and reconnaissance spacecraft affect our understanding of what we see as we peer into the starry realm on a late spring evening in the Golden Age?
Instead of seeing only the steady light of Saturn shining in the west after sunset, we visualize a giant methane-engulfed world, commanding a large array of orbiting moons, each one being quite unlike the rest.
Instead of seeing scores of twinkling points of light, we observe moments in stellar lifetimes: yellow-red Arcturus, a bloated star past its prime; white Vega, a blazing furnace twice as hot as our sun and still in full vigor; and red Antares, a giant star that can hold 10 million suns and whose life will end soon, astronomically speaking.
Instead of just seeing the glowing band of the Milky Way rising in the east, we picture a 100,000-light-year-wide complex of billions of stars mixed with gigantic clouds of gas and dust. As we mentally speed up time, we visualize stars condensing from those clouds, living long lives, and then dying either after a quiet, dignified decline or, much more rarely, in a self-destructive flash of a supernova explosion. All of this takes place as everything orbits an enormous black hole -- a place where light cannot escape -- that resides at the galactic center.
Instead of seeing only darkness between the stars, we now glimpse into the hiding places for tens of billions of galaxies strewn along a murky path leading 13 billion years back in time. It's an unfathomable sight.
The Golden Age influences our early-morning view, as well. From our earthbound perspective, we see the three rocky planets that are our closest neighbors in space slowly change their positions in the eastern sky.
Venus, the closest planet and by far the brightest, is a hellish world with a crushing atmosphere laced with swirling sulfuric acid clouds. The dimmer Mars, whose cold surface is periodically concealed by planet-wide dust storms, moves past brilliant Venus, taking several weeks to do so. After June 15, heavily cratered Mercury pops above the eastern horizon before 5 a.m., only to disappear 10 mornings later.
Detailed depictions of the planets, stars, and galaxies are all due to advancements made in the Golden Age of Astronomy, an age that likely will continue for years to come. We are lucky to be part of it. Take in a June night and take in the universe.
