Little over 100 years ago, no matter where you were on Earth you could step outside at night and look up see thousands of twinkling stars.
Today, bright electric lights in cities and towns block out most of the starlight, leaving just a few of the brightest stars visible. And with more than half of the world’s population now living in cities, 3 out of every 4 people have never experienced the magic of a really dark sky.
If you visit a deserted park on a clear night, you will be lucky enough to see the awesome glowing band of the Milky Way stretching across the sky. This is the view we get of our home galaxy as we look out through its disc.
Because our Solar System lies in the outer edge of the Milky Way, we can look towards the centre of the Galaxy and see most of its stars (along with many clouds of cosmic gas and dust).
Just using your eyes it’s difficult to pick out individual stars in the most crowded parts of the Milky Way but telescopes can.
Using a large telescope (with a 2.5-metre mirror), astronomers have put together this extraordinarily detailed map of the northern half of our Galaxy. The map charts the position of 219 million individual stars!
The northern half of our Galaxy actually contains more than 219 million stars. But the new map doesn’t include stars that are more than 1 million times fainter than the naked eye can see.