A Cosmological Journey - How modern scientific data is taking us back to the wisdom of the ancients (cont.) By Dr. Manjir Samanta-Laughton MBBS (MD in USA), Dip Bio-Energy
At the Heart of Every Galaxy
It was the autumn of 2003 and I had become captivated by the field of cosmology which had been in turmoil since around the turn of the century with many long held beliefs becoming obsolete as data came pouring in from telescopes. Cosmologists had just faced one of their biggest challenges for years — the unwelcome arrival of dark energy: a mysterious force that seemed to be blowing the universe apart and accelerating its expansion.
Images from Hubble and other telescopes were throwing open some of our long cherished beliefs and making us question our theories and expectations about the universe. I became particularly fascinated by black holes. The concept of black holes started life as a conclusion of Einstein's theory of relativity — that if space and time curved beyond a certain point they would create a point of infinite gravity. Initially it was thought that certain stars collapse at the end of their lives and produce these points of infinite density and gravity, with a pull so powerful that not even light can escape — hence a ‘black' hole.
For decades these objects remained a theoretical concept and although they sparked the imaginations of science fiction writers, it was not known if black holes really existed. It was not until the dawning of the 21st century when our telescopes were picking up black holes everywhere that we realised that not only did back holes exist, but they were actually quite common. How is a black hole detected if no light can escape it? One of the ways is to look at the material around them, called an accretion disc which spins very fast around it, so fast that only the gravity of a black hole could be creating it.
The amazing thing was, when we turned our telescopes on neighbouring galaxies, we found a supermassive black hole at the heart of each one. We even found a black hole at the centre of our own galaxy! So instead of being rare exotic creatures, it turned out that black holes are actually quite common, appearing not only in the heart of every galaxy, but smaller black holes appear all over our galaxy too. Sometimes, they are associated with objects such as quasars which give out bright radiation.
Hold on a minute — why would a quasar which has a black hole associated with it give out such bright radiation? Surely the black hole would suck up all the light so that we can't see it? Indeed! In fact the more we looked, the more the data showed up surprises that contradicted our current theories.
Minkel JR. Bye Bye black hole. New Scientist. 22 January 2005; 29-33.[back to text]