More from The National:
Saturday's best photos: from Iraqi ballet dancers to Beijing window cleaners
Friday's best photos: from Sri Lankan unrest to the Walla Walla aurora - in pictures
Thursday's best photos: from the Las Vegas Grand Prix to pet portraits
Wednesday's best photos: form a rocket launch to a skateboard jump
Tuesday's best photos: from an orange tank to pink campaigners
Monday's best photos: from bees to blossom
WHAT IS A BLACK HOLE?
1. Black holes are objects whose gravity is so strong not even light can escape their pull
2. They can be created when massive stars collapse under their own weight
3. Large black holes can also be formed when smaller ones collide and merge
4. The biggest black holes lurk at the centre of many galaxies, including our own
5. Astronomers believe that when the universe was very young, black holes affected how galaxies formed