Choose your language:

Macro and microlensing

Loading player...

This animation shows the principle of macro- and microlensing. In "macrolensing", a galaxy plays the role of a cosmic magnifying glass or a natural telescope, an effect that was predicted by Albert Einstein as a consequence of his theory of general relativity. The light from a distant quasar is bent in its path and magnified by the gravitational field of the lensing galaxy. This proves very useful in astronomy as it allows us to observe distant objects that would otherwise be too faint to explore using currently available telescopes. In addition to macrolensing by the galaxy, stars in the lensing galaxy act as secondary lenses to produce an additional magnification. This secondary magnification is based on the same principle as macrolensing, but on a smaller scale, and since stars are much smaller than galaxies, is known as "microlensing". As the stars are moving in the lensing galaxy, the microlensing magnification also changes with time. From Earth, the brightness of the quasar images (four in the case of the Einstein Cross) flickers around a mean value, due to microlensing.

Credit:

ESO

Bookmark and Share

About the Video

Id:eso0847b
Release date:12 December 2008
Related releases:eso0847
Duration:49s

About the Object

Name:Gravitational Microlensing
Type:• Unspecified : Cosmology : Phenomenon : Lensing
• X - Cosmology

HD

HD & Apple TV
24.6 MB

Large

Large QT
11.2 MB

Medium

Video Podcast
8.4 MB
Medium MPEG-1
4.6 MB
Medium Flash
9.3 MB

Small

Small Flash
4.2 MB
Small QT
2.7 MB

For Broadcasters

Broadcast SD
249.9 MB

Also see our