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The Milky Way. Sum up. Introduction : the Milky Way’s identity View from Earth: a few explications Size and mass Age Spiral arms Environment Velocity Some order of magnitude. Introduction.
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Sum up • Introduction: the Milky Way’s identity • View from Earth: a few explications • Size and mass • Age • Spiral arms • Environment • Velocity • Some order of magnitude
Introduction • The Milky Way galaxy is visible from Earth as a band of light in the night sky, and it is the appearance of this band of light which has inspired the name for our galaxy.
Size and mass • Mass: about 5.8×10^11 • Size: approximately 10×10^4 light years in diameter, and about 10×10^2 light years thick.
Age About 13.2×10^9 years
Spiral arms There are four major spiral arms in the Milky way.
Environment • The Milky Way and the Andromeda Galaxy are a binary system of giant spiral galaxies. Together with their companion galaxies they form the Local Group, a group of some 50 closely limited galaxies. Andromeda Galaxy
velocity • Many astronomers believe that the Milky Way is moving at approximately 600 km per second.
Some order of magnitude • 10^23 m: 10 million light years away from the Milky Way • 10^21 m: our galaxy, the Milky Way • 10^20 m: stars at the rim of the Milky Way galaxy • 10^19 m: stars in the Milky Way galaxy • 10^18 m: 100 light years from earth and nothing but stars • 10^13 m: our solar system • 10^9 m: the earth and the orbit of the moon
The end Our references: • Images: Google • Text: Wikipédia http://www.eso.org/public/outreach/press-rel/pr-2004/pr-20-04.html. Nwnw.gsfc.nasa.gov/-5k-