On Wednesday, April 10th, the headlines throughout the world screamed, “We have seen a black hole for the first time!”. The picture was in the newspapers and all over the news channels. For a day, it drowned out the steady stream of political drama, armed conflicts, and natural disasters. Why did this picture of a black hole capture the imagination of the world?
The picture itself was arresting. It showed the shadow of the black hole against a bright background of red, orange and yellow. The bright background came from hot gases being sucked into the black hole by its massive gravity. As they get backed up, the swirling gases get tremendously hot and their glow outlines the black hole.
A black hole is a massive amount of matter in an extremely small space – the densest thing imaginable. This density surrounds it with an incredibly strong gravitational field. In astronomical terms, black holes are infinitely deep wells of gravity that distort the landscape of space and time around them. The gravity associated with a black hole sucks everything nearby into it, and light itself cannot escape They are invisible unless outlined by the hot gases they are swallowing.
The dramatic picture was of a supermassive black hole in the center of a galaxy called M87, which is 55 million light years from earth. This “gargantuan” black hole has the mass of 6.5 billion of our suns, and it is the size of our entire solar system. The black hole also sends out a massive amount of energy. In the middle of M87, there is a jet of high energy matter more 1000 light years long which is thought to be powered by the black hole. This jet alone produces a trillion times more energy than our whole Milky Way galaxy.
As we ponder this now-famous picture, we are staring into one of the most incredible objects in the universe. As it stares back at us, it raises questions – both scientific and philosophic. How do massive black holes form? Why does every galaxy seem to need one at its center? What kind of an architect could conceive of such a thing? What kind of builder could construct such a thing? What kind of engineer could power such a thing for billions of years?
By next day the black hole was old news. The news cycle had moved on to other things. Why did it capture our imagination? Perhaps for one day it transported us away from ourselves and our world here. For one day it moved us to reflect on something much greater – the wonder and power of a black hole millions of light years away. And for one day it challenged us to ask, “What lies behind it?”
(Photo courtesy of Event Horizon Telescope collaboration et al.)