In most situations, light helps us to see. But when it comes to looking at the night sky, light actually blocks our vision. Street lights and car headlights ruin our view of stars, planets and even the Milky Way, our home Galaxy. You should be able to see around 2,500 stars with your naked eyes, but if you live in a big city or town, you probably see less than 10 stars on a normal night!
This amazing space picture shows the shining star clusters and swirls of colourful gases of the Carina Nebula: an enormous expanse of gas, dust and stars lying deep in the heart of the Milky Way. If you live in the southern half of the world, you should be able to see this enormous object in the night sky even without the help of a telescope. But like many other wonders of the cosmos, the Carina Nebula has become all but invisible in cities and towns, due to light pollution.
Luckily for us, astronomers have built big, powerful telescopes to zoom in across billions and billions of kilometres and take pictures like this one. This image was taken from a large telescope in the middle of a vast desert in Chile, far from the slightest hint of a street light light. It captures the beauty and details of the Carina Nebula, the dark pillars of dust splitting up clouds of glowing gases and clusters of shining young stars.
In 2012, thousands of cities from all over the world turned off all their lights for one hour to celebrate and protect our planet. Even the astronauts at the International Space Station took part! If you want to keep our night skies dark and the stars bright, visit the 'Dark Skies Awareness' website and see how you can help!