Get out to the country on a clear night and look up and you will be treated to many hundreds and possibly thousands of stars twinkling and shimmering. Our eyes are capable of seeing 6000 stars without optical aid. That’s about 3000 in the northern hemisphere and depending on the amount of light pollution and haze, and the condition of our eyes typically a few hundred to a few thousand stars are visible. Each star is a sun and most have planets around them. Whether they are suitable for life or not is another question.
Each star that you see is part of our home galaxy, the Milky Way, a vast cloud of over 100 thousand, million stars (100 billion). The Milky Way is so vast that light travelling at 300,000 kilometres a second will take over 100,000 years to pass from one side of the galaxy to the other!!!
The Milky way is just one of many billions of galaxies in our universe and the good news is that our nearest galactic neighbour, the Andromeda galaxy can be glimpsed with our naked eye from a dark site. To spot it, we need to perform a few star jumps. Firstly find the constellation the Plough, then draw an imaginary line from the second star in the “handle” through the north star and on for the same distance again. That should bring you to the constellation Cassiopeia, a distinct W or M shape. Next go back to the north star and draw line through the middle star of the W and continue on for almost the same distance again. You should come across a faint fuzzy patch of sky.
This is the Andromeda galaxy home to a trillion stars and over 2.5 million light years away. Imagine, the light from the galaxy that is hitting your eyeball is 2.5 million years old and has been travelling since before modern humans had evolved and left before our ancestors lit their first fire.