Thursday, April 02, 2009

Not your father's galaxy

Checking up on how many stars are in our galaxy, I find that my pre-teen education in astronomy has misled me once again: the galaxy does not look like I thought it did.
The Galaxy consists of a bar-shaped core region surrounded by a disk of gas, dust and stars forming four distinct arm structures spiralling outward in a logarithmic spiral shape. The mass distribution within the Galaxy closely resembles the Sbc Hubble classification, which is a spiral galaxy with relatively loosely-wound arms. Astronomers first began to suspect that the Milky Way is a barred spiral galaxy in the 1990s rather than an ordinary spiral galaxy. Their suspicions were confirmed by the Spitzer Space Telescope observations in 2005 which showed the Galaxy's central bar to be larger than previously suspected.
Here is a picture of Messier 109, which may resemble our own galaxy:

If I had known this sooner, surely "it would have prevented some mistakes."
... the same sun which ripens my beans illumines at once a system of earths like ours. If I had remembered this it would have prevented some mistakes. This was not the light in which I hoed them.

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