ad info




CNN.com
 MAIN PAGE
 WORLD
 ASIANOW
 U.S.
 LOCAL
 POLITICS
 WEATHER
 BUSINESS
 SPORTS
 TECHNOLOGY
   computing
   personal technology
   space
 NATURE
 ENTERTAINMENT
 BOOKS
 TRAVEL
 FOOD
 HEALTH
 STYLE
 IN-DEPTH

 Headline News brief
 daily almanac
 CNN networks
 CNN programs
 on-air transcripts
 news quiz

  CNN WEB SITES:
CNN Websites
 TIME INC. SITES:
 MORE SERVICES:
 video on demand
 video archive
 audio on demand
 news email services
 free email accounts
 desktop headlines
 pointcast
 pagenet

 DISCUSSION:
 message boards
 chat
 feedback

 SITE GUIDES:
 help
 contents
 search

 FASTER ACCESS:
 europe
 japan

 WEB SERVICES:
Space

Hubble sights distortions from gravitational 'lenses'

Hubble Images
previous

next

iconINTERACTIVE
Maneuver the Hubble Space Telescope (3-D VRML)

May 14, 1999
Web posted at: 4:25 p.m. EDT (2025 GMT)

(CNN) -- The idea that images could be highly magnified by gravity from massive objects was suggested by Albert Einstein more than six decades ago. Now, the Hubble Space Telescope has uncovered exotic patterns, rings, arcs and crosses that astronomers believe are optical mirages produced by such "lenses," nature's equivalent of having giant magnifying glasses in space.

A gravitational lens is created when the gravity of a massive foreground object, such as a galaxy or black hole, bends the light coming from a far more distant galaxy directly behind it, according to astronomers at the Space Telescope Science Institute. This focuses the light to give multiple or distorted images of the background object as seen by the observer.

A look at over 500 Hubble fields of sky has uncovered 10 interesting lens candidates in the deepest 100 fields, the STSI said. This is a significant increase in the number of known optical gravitational lenses. Hubble's sensitivity and high resolution allow it to see faint and distant lenses that cannot be detected with ground-based telescopes whose images are blurred by Earth's atmosphere.

An analysis of this "Top Ten" list of Hubble gravitational lenses is published by Kavan Ratnatunga and Richard Griffiths of Carnegie Mellon University in the May issue of the Astronomical Journal.

Hubble's ability to see so many of these lenses in a small fraction of the sky takes them from being a scientific curiosity to serving as a potentially powerful tool for probing the universe's evolution and expansion, astronomers said.

In 1936 Einstein computed the gravitational deflection of light by massive objects and showed that an image can be highly magnified if the observer, source and the lensing object are well aligned. However, the lensed image separations were predicted to be so small in angular size, Einstein knew they were beyond the capabilities of ground-based optical telescopes. This made him remark that "there is no great chance of observing this phenomenon."

It wasn't for another 40 years since Einstein's conclusion that the first gravitational lens was discovered in 1979. Several bright and nearby lenses have been discovered since then from ground-based observations.


RELATED STORIES:
Net tool key to Hubble project
April 21, 1999
Oh, Io! Hubble views volatile moon
April 20, 1999
The latest in star fashion: the curly-Q
April 8, 1999
Hubble views aging stars inside brilliant cluster
April 2, 1999

RELATED SITES:
Space Telescope Science Institute
The Astronomical Journal
Carnegie Mellon
Kavan U. Ratnatunga
Note: Pages will open in a new browser window
External sites are not endorsed by CNN Interactive.

 LATEST HEADLINES:
SEARCH CNN.com
Enter keyword(s)   go    help

Back to the top   © 2001 Cable News Network. All Rights Reserved.
Terms under which this service is provided to you.
Read our privacy guidelines.