Thursday, October 14 2004 @ 07:17 am EDT
Contributed by: bobmoody
October 8, 2004
-- The technological magicians at NASA's Jet Propulsion Laboratory and the W.M. Keck Observatory are a step closer to performing a vanishing act on a cosmic scale.What's left when you remove a star?
This demo illustrates how the bright light of a star obscures the faint surrounding material. NOTICE
To view this demo, go to: http://planetquest.jpl.nasa.gov/
to the PlanetQuest page where this article originated. Once there, click on the art in the upper corner, then use the slider provided to "dim" the light and reveal a dust disk.Interferometry: A new window on the Universe
With an instrument recently installed as part of the Keck Interferometer, they can make stars disappear almost completely from a telescope's view and reveal the close-in regions where planets may have formed. This fall, astronomers will continue integration and test of the instrument, called the "Nuller,"
which will contribute to NASA's search for planets around other stars.
"We have successfully combined infrared light from both 10-meter (33-foot) Keck telescopes using the new Nuller instrument," said Dr. Jim Fanson, Keck Interferometer project manager at JPL. "This permits a so-called 'visibility' measurement, where we can measure the size of objects with exquisite precision.
"Later this year, when we complete our functional tests of the Nuller, we'll be ready to attempt our first null measurement," Fanson said.
The Keck Interferometer is a NASA project that combines light from the world's largest optical telescopes to create a new type of telescope with unprecedented power. An interferometer is a device that gathers light waves from multiple telescopes, and then combines the waves in such a way that they interact, or "interfere" with each other. Depending on how the light waves are combined, they can combine constructively, creating higher intensity, or they can combine destructively, creating lower intensity The resulting light pattern, called an "interference fringe," can be decoded by astronomers to make high precision measurements, such as a star's diameter or the size of an accretion disk around a black hole.