Milky Way elliptical?
Date: Around 1999
A student wishes to know just how we know that the Milky Way is a
spiral galaxy. We have seen examples of elliptical, etc., and the model on
Laser disc about football-shaped galaxies. Help here, please.
Currently it is theorized that there are 3 main types of galaxies:
3) Irregular (means no shape at all).
Originally, optical means had shown a single arm during summer months,
but now with other technologies, other arms are now "visible". Radio
waves (longer wavelength than light) are emitted from the Milky Way.
Using telescopes monitoring these waves (Radio Telescopes) other arms
of the galaxy and a spherical center have been "observed".
Our sun is located 2/3 of the distances from the center to the
edge on one of the arms. The arm is called Orion.
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Update: June 2012