In this short film Prof. Hugo van Woerden (Univ. of Groningen, the Netherlands) explains how the distance to a hydrogen gas cloud in our Milky Way is determined from measurements of the 21 cm radio-emission that such a clouds emits. The film is Dutch spoken and subtitled in English.

This is a preview of one of the six extra features available on the DVD 'Spiral Galaxy, the Milky Way unravelled'.

Spiral Galaxy Trailer:
Spiral Galaxy 5:30 minute preview:

For more background information on the film and on how to purchase the DVD, please visit

Production & Initiative:
Produced by Lightcurve Films and DKW Film © 2009

With thanks to:
Netherlands Research School for Astronomy
Media Junkies
Zcene Moving Media Company

Loading more stuff…

Hmm…it looks like things are taking a while to load. Try again?

Loading videos…