Determining the Galaxy's Size
Name: pieter de bruin
Date: 1993 - 1999
How is the size of our galaxy determined?
How is the motion and shape of our galaxy established?
I believe the best observations are made with radio waves, because
they can penetrate the gas and dust that obscures the visible light
from all the stars in the galaxy. In particular, the galaxy has
big clouds of hydrogen whose positions and speeds can be
determined from the radio observations, and this gives a rough
map of the galaxy. But your question is a good one: our
galaxy is a lot harder to figure out than some of the others
which are much further away, because from where we are
we don't have a very good perspective view of it!
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Update: June 2012