The long-running BBC educational program "The Sky at Night" presents a guide to the galaxies. This documentary takes us on a fascinating journey through our discovery of knowledge about these unimaginably enormous collections of stars.
It tells the story beginning from a time when we thought our galaxy, The Milky Way was the only one in the universe, to our current understandings. We now know that there are roughly 200 billion to 2 trillion galaxies in the observable universe, many of which containing a supermassive black hole at their centre.
Thanks to the study of galaxies we know our universe is way-way bigger than the human mind can even comprehend. To put this into perspective, there are 10 times more stars in the night sky than grains of sand in the world's deserts and beaches.