Our galaxy the Milky Way, along with Earth, are travelling through space at approximately 530 km’s per second. This means that according to the geography of the Universe, one minute ago we were located around 19,000 km’s from here now.
Andromeda Galaxy
The Andromeda galaxy, otherwise known as M31, is the closest major galaxy to our own galaxy the Milky Way. It lies 2.9 million light-years from our own galaxy and it has a diameter of 250,000 light years. It has a magnitude of 3.4 when viewed in the night sky. It is approximately twice the width of our galaxy and it has been studied longer than any other galaxy because of its proximity, size and brightness. However, it is not as big as our own galaxy.
It is estimated that the black hole in the centre of the Andromeda galaxy is the size of 30 million Suns. The Andromeda galaxy and the Milky Way are moving towards each other and it is estimated that they will collide and coalesce in around 5 billion years. It was difficult to calculate where exactly the M31 galaxy lay in relation to our own, as both were so close to each other, but in 1923 Edwin Hubble calculated and proved that the Andromeda galaxy lay outside our own galaxy by measuring the luminosities of its Cepheid stars against their true apparent magnitude. Other similar spiral galaxies to be found in the Universe are Bode’s, Pinwheel, Spindle and Black Eye galaxies.
