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The Milky Way Galaxy - Our Home

The Milky Way galaxy is a giant star-city. Our Sun is one star in the city, and there are many, many others, our neighbors. Our Galaxy looks like a pinwheel - it is a spiral galaxy. There are spiral arms and a bright central part. The Sun is far from the center of the Galaxy. The Sun is going around the center of the Galaxy, and it takes the Earth with it!

In our Galaxy, there are some old stars and some young ones. While the Sun is old compared to you, it is young compared to the Galaxy.

Look at where the Sun is in our Galaxy. There are many more stars in the center part than in the spiral arms where the Sun is. Can you imagine what the sky might look like if our Sun, and the Earth, lived near the center of the Galaxy, our star-city?



A galaxy like the Milky Way as viewed from the top, and the actual Milky Way as viewed in the infrared
Click on top image for diagram (276K JPEG)
Click on bottom image for diagram (204K JPEG)
European Southern Observatory & NASA COBE Project
Like other spiral galaxies, the Milky Way has a bulge, a disk, and a halo. Although all are parts of the same galaxy, each contains different objects. The halo and central bulge contain old stars and the disk is filled with gas, dust, and young stars. Our Sun is itself a fairly young star at only 5 billion years old. The Milky Way galaxy is at least 5 billion years older than that.

Questions and answers about the Milky Way

A Matter of Scale - interactive showing the sizes of things, from very tiny to huge - from NSF

Last modified January 11, 2006 by Travis Metcalfe.

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Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part by the National Science Foundation and NASA, our Founding Partners (the American Geophysical Union and American Geosciences Institute) as well as through Institutional, Contributing, and Affiliate Partners, individual memberships and generous donors. Thank you for your support! NASA AGU AGI NSF