Unit 1 - The Universe - The galaxies and our galaxy: the Milky Way
Hello space explorers!
Galaxies are systems composed by stars, gases and dust. Examples of galaxies range from dwarfs gallaxies, with as few as ten million stars (10^7) to giants galaxies, with a hundred trillion stars (10^14).
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| NGC 4414, a typical spiral galaxy |
They are normally spiral, eliptical or irregular. The only difference between the three is what shape they are.
The Local Group
There are billions of galaxies in our Universe. Most of these are clumped together in small groups. Our own galaxy which is called The Milky Way Galaxy lies within a group of galaxies that we call The Local Group.
There are billions of galaxies in our Universe. Most of these are clumped together in small groups. Our own galaxy which is called The Milky Way Galaxy lies within a group of galaxies that we call The Local Group.
The Local Group consists of about 30 galaxies. The three largest are The Andromeda Galaxy, The Milky Way Galaxy, and Triangulum.
THE MILKY WAY:
Our galaxy, the Milky Way:
- Diameter: 100 000 light years
- Thickness: 1 light-yea
- Number of stars: 400 billion.
CHECK THIS AMAZING VIDEO!
Time-lapse captured in Dakota (USA). Ten seconds of the video is about 2 hours 20 minutes in real time.
One question: if Milky Way is spiral, why do we see it lineal?
