Sunday, July 22, 2007

The Doppler Effect - Episode 27

When cars go screeching by your ear, their pitch changes due to the Doppler Effect. See and hear the Doppler Effect explained before your very eyes! Learn how the Doppler Effect even helps astronomers look at stars.

Science Theater Episode 27:Doppler Effect

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Muard said...

the spectral analysis is an extremely effective tool. Starting from a simple luminous ray, one can go up with an impressive number of information on the physical conditions reigning in a heavenly object and phenomena which occur there. It is thanks to this fantastic tool that astronomy as it was known a little more century ago, i.e. the simple study of the position and of the movement of planets, became astrophysics, the study of the physical nature of the celestial bodies and the processes which affect them.

markholden said...

Please Dr Carlson - It's GALAXIES that are (nearly) all moving away from us not stars.
The large scale expansion of the Universe is not detected on a scale as small as our galaxy.

Dr. Matt J. Carlson said...

Another excellent point.

I'm of the understanding (but may be wrong on this) that space itself is expanding, so that everything is getting farther away from everything else.

Now, local movement of stars (ie. within our own galaxy) and some galaxy clusters may be moving in such a way as to overcome such expansion and thus be moving toward us. I will try to look into that as best I can and get back to you.

Perhaps to be safest, I could claim all pulsars are moving away from us (as I can't believe any are moving abnormally enough to counteract their default "away" movement due to the creation of the universe.)