Keele

IAU Symposium 256
The Magellanic System: Stars, Gas, and Galaxies
28 July - 1 August 2008            Keele University (UK)

IAU
Outreach: Introduction
The Milky WayOur galaxy is called the Milky Way. It is a spiral galaxy about 100,000 light-years across. It contains at least 200 billion stars, possibly as many as 400 billion. From Earth, the Milky Way looks like a streak of stars across the sky. The Sun is in one of the The Local Groupspiral arms, about two-thirds of the way out from the centre of the galaxy.

The Milky Way is a member of the Local Group of at least 30 galaxies. It is over ten million light-years across. Of these galaxies, the largest is Andromeda, followed by the Milky Way. Both of these galaxies  have satellite galaxies orbiting them; the Milky Way has 14 satellites, including the Large and Small Magellanic Clouds.


The Magellanic System consists of the Large and Small Magellanic Clouds. These are two small irregular galaxies which orbit our galaxy, the Milky Way. They can be seen from the southern hemisphere at night. The Clouds are important to astronomers because they contain stars of all types and all ages, all found at about the same distance away from Earth. The Magellanic CloudsThis means that it is easier for astronomers to compare the stars.                                                 
                                                                                                                                                                                                                       

The Large Magellanic Cloud is the fourth largest member of our Local Group of 30 galaxies, after Andromeda, the Milky Way and Triangulum. It is 160,000 light-years away from the Milky Way and about fifteen thousand light-years across.

The S
mall Magellanic Cloud is 200,00 light-years away and contains a few hundred million stars. It is one of the furthest objects that can be seen with the naked eye.

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