Astro Image in the News:
A Spectacular Light Echo

By: Alan MacRobert July 23, 2003 0

Click image for a 125-kilobyte animated GIF.

Courtesy NASA, ESA, and H. E. Bond (STScI).

A wave of light sweeps outward from an erupting star to illuminate surrounding gas and dust in this eight-month-long sequence of images. A team of astronomers led by Howard E. Bond (Space Telescope Science Institute) used the Hubble Space Telescope’s newest and best camera, the Advanced Camera for Surveys (ACS), to take this extraordinary time-lapse series. The four frames were captured on May 20, September 2, October 28, and December 17, 2002.

Each frame is about 8 light-years wide at the nebula's distance of some 20,000 light-years. Nothing is actually moving; the apparent faster-than-light expansion stems merely from the geometry of the light echo. The group’s analysis of the images appears in the March 27th Nature.

For more information see our January article about these pictures. Full-resolution images and animations are available from the Space Telescope Science Institute, which operates Hubble.

About Alan MacRobert

Alan M. MacRobert became an avid Sky & Telescope subscriber in 1966 at age 14, joined the editorial staff in 1982, and is now a senior contributing editor, semi-retired. He played a role in practically every part of the magazine and the company's other products for more than a generation, both on the amateur-observing side and the science-reporting side. In 1994 a book collection of his observing how-tos and telescopic sky tours was published as Star Hopping for Backyard Astronomers. He has produced This Week's Sky at a Glance online every week since 1989.