Scene

Module Menu

Module: Astrophysik: Gravitationslinsen

Sequence: Start

Slide:

Slide: A Galaxy Produces a Multi-image of a Quasar

Branching Point: The visible sky is nothing but an optical fraud

Sequence: (1) Prinzip

Slide: Why does a mass act like a lens ?

Slide: Mass distributions acting as lenses

Slide: Glas lens visualizing the effect of a gravitational lens

Slide: Extreme Deflections

Slide: Strange Optics

Slide: Cosmic Distortions

Slide: The image of the sky is permanently changing

Slide: Encounter of third degree

Sequence: (2) History

Slide: Early speculations

Slide: Einsteins triumph

Slide: Einstein remains sceptical

Slide: ... an odd publication

Slide: Galaxies as gravitational lenses

Sequence: (3) Astrophysics

Branching Point: Gravitational Lenses as Tools in Astrophysics

Sequence: (3.1) galaxies

Slide: How Massive is a Galaxy ?

Slide: How Massive is a Galaxy Cluster ?

Sequence: (3.3) Hubble

Slide: How Does the Universe Expand ?

Sequence: (3.4) planets

Slide: Double Quasar Q0957+561

Slide: Planets in Foreign Solar Systems

Forward

How Massive is a Galaxy ?

Measuring the mass of stellar and galactic objects usually is a tough problem in astrophysics.

Thus it is highly welcome that gravitational lenses allow to directly determine the mass of a galaxy.

For instance one can use the fact, that for an Einstein ring the mass of the lense is directly proportional to the square of the diameter of the ring.

[ Sitemap ] [ info ] This website was created by the MPI for the History of Science.