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Happy Anniversaries! 400 For The Telescope And 10 For Chandra


January 6, 2008 ::
In 2009 we celebrate the International Year of Astronomy (IYA), a worldwide education and public outreach effort to honor the 400th anniversary of the first use of an astronomical telescope by Galileo. A primary goal of IYA is to "expose as many people as possible to the wonders of astronomy."


Informing everyone about the nature of the universe was a goal that Galileo pursued at risk to his livelihood and his life. In his hands the telescope became the instrument of an intellectual revolution. His observations of the moon, his discovery of the moons of Jupiter, and the resolution of the Milky Way into "...a mass of innumerable stars ..." transformed people's view of their place in the grand scheme of things. Galileo proved that the Earth is not distinct from the universe, but part of it, and he showed that there is much more to the universe than we see with the naked eye.

In the 400 years since Galileo's discoveries, astronomers have continued to explore the heavens with increasingly powerful optical telescopes located on mountaintops and in space. We now know that, just as our sun is not unusual among stars, our Milky Way galaxy is not exceptional among galaxies. The size of the known universe is measured in billions of light years and contains a hundred billion or more galaxies, each of which contains hundreds of billions of stars.

Meanwhile, there has been another revolutionary discovery - that optical telescopes can reveal only a portion of the universe. New types of telescopes and detectors built especially for invisible wavelengths of light have detected microwave radiation from the Big Bang, infrared radiation from proto-planetary disks around stars, X-rays from superheated matter in the warped space near the event horizons of black holes, and intense gamma-ray bursts in galaxies billions of light years away.

The year 2009 is also a special anniversary for one of the most productive of these non-optical telescopes, NASA's Chandra X-ray Observatory. Ten years ago this July, Chandra began its exploration of the universe with a launch aboard the space shuttle Columbia.

Chandra's exceptional mirrors and detectors have enabled astrophysicists to make critical investigations of high-energy phenomena from comets to cosmology. These discoveries are accumulating at a rapid rate as Chandra observes hundreds of objects each year. Some examples displayed on this year's calendar are:

* A high-energy view of the drama of stellar evolution, from the flaring rates of young sun-like stars with implications for the formation of planets (RCW 108), the fast-paced, violent lives of massive stars (30 Doradus), and their eventual explosion (G1.9+0.3, SN 1006, N132 D), which disperse elements critical for life such as oxygen into space.

* An image of the Crab Nebula that shows the awesome ability of a rapidly rotating neutron star to produce beams of matter and antimatter, and influence space for light years in its vicinity.

* On a larger scale, the effect of a spinning supermassive black hole on an entire galaxy is revealed in the image of Centaurus A.

* The image of the galaxy cluster A1689 adds to the evidence that clusters of galaxies, the largest gravitationally bound structures in the universe, are assembled by mergers of smaller clusters.

* Combined optical and X-ray data from the galaxy cluster MACS J0025 provide strong evidence for the existence of dark matter by demonstrating the separation of dark matter and ordinary matter in a titanic collision.

Chandra observations have also probed the geometry of space-time around black holes, unveiled the role of active, supermassive black holes in influencing the evolution of the most massive galaxies, and provided independent confirmation for the existence of dark energy.

The growing body of evidence for the existence of dark matter and dark energy has been the result of a collaborative effort involving observations with optical telescopes and ones operating at wavelengths outside the optical range. Dark matter and dark energy amount to a "doubling-down" on Galileo's discovery that there is far more of the universe than can be seen with the naked eye.

The startling conclusion of 21st century astronomy is that there is much more to the universe than can be seen even with the most powerful telescopes of any kind built to date. Not just a little more, but TWENTY-FIVE TIMES MORE!

We know that Galileo would have been eager to explore and investigate this profoundly perplexing universe we inhabit, and to tell the world about it. As his scientific descendants carry on this exploration, we at the CXC and other participants in the IYA will be telling you what they find.

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