You may have heard before that looking towards the Heavens is like looking back in time. And that is indeed true, as light from distant stars and galaxies takes time to reach us. As such, when we see objects lit up in the sky, we see them as they were when that light left those objects, which could be as little as 8 minutes ago (for the Sun for example), all the way up to millions and even billions of years ago!

Of course, the further objects are, the dimmer they appear to us. This is exactly the same effect you might observe when seeing a boat or a car become smaller and smaller as it gets further away. This means that if we want to look back to the very earliest moments of the Universe, over 10 billion years ago, we need to use very sensitive telescopes that can detect very dim light! 

 

The Hubble Space Telescope surprised everyone when it spotted millions of galaxies in a patch of sky that appears dark to the naked eye and less powerful telescopes

 

Luckily, this is something that we are now able to do, and, combining observations with theoretical predictions, we thus have a very good understanding of the history of our Universe since its beginning 13.7 billion years ago. The study of this history, and in particular of how structures emerge over this time, is a field of astronomy known as Cosmology.