When Albert Einstein published his papers on General Relativity in 1915, Karl Schwartzchild was serving as a very brilliant artillery officer on the Russian Front (probably aiming at my poor Latvian grand dad, who served with the Russians in WW1). Somehow, copies of Einstein’s 1915 articles on General Relativity, reached Schwartzchild and between bombarding sessions, he solved one of Einstein’s equations. The result of this solution was the essence of a Black Hole, an enormous, in the case of Schwartzchild, stationary mass with gravity so strong it even sucks in light (thus appearing black) and in some cases, the envelopes of enormous stars. He sent his solution to Einstein in a couple of papers. Einstein, who was very impressed, dutifully read them to the Prussian Academy of Sciences and had them published. Einstein recognized that the math was elegant and obviously correct but he could never stomach the idea of the Black Hole and never in his lifetime believed they existed.
What happened to Karl Schwartzchild? Well, he developed one of the most painful and horrible autoimmune diseases (a disease in which your own body attacks your tissue, in this case, the skin) and, of course, in 1916, there was nothing to ease the searing pain, which eventually led to death in most cases. Today only about 10% of sufferers actually die. Our hero and brilliant mathematician, died of pemphigus in May of 1916.
Except for a few researchers in the 1920’s, most of whom were not in the top ranks, no eminent researchers were convinced about the existence of Black Holes. That is until the resurgence of interest in General Relativity in the 1960’s. For some unknown reason, the oil men of Texas decided to fund a program of research on Einstein’s General Relativity, including a series of huge conferences that invited as many young physicist brilliants as they could find, including the likes of the young Steven Hawking and his friend Roger Penrose (very old men today). I honestly believe these guys thought in mathematical symbols.
Apparently, they managed to convinced the oil men to support research in Einstein’s General Relativity, which had been neglected for nearly half a century. It was so neglected that some physics research journals refused to even consider articles related to General Relativity. Well the oilmen of Texas refueled the engine of General Relativity and oiled it with gobs of money. If you consider General Relativity, you soon have to deal with Swartzchild and his black holes. Fairly quickly, the Physics Journals were full of articles on General Relativity (If he was alive, Einstein would have been beyond delighted!) A growing number of articles began to appear on Black Holes, including some by Steven Hawking and his colleague Roger Penrose, both obviously in the genius class.
We have by now come to the point in time where we have seen Black Holes, or the black disk that indicates their presence. We even have a good idea about how they come to be. They are end products of ‘burned out’ stars. Except it has nothing to do with burning per-se (burning is the result of the combination of oxygen with other materials above the kindling point – other substances than oxygen, such as chlorine can combine to produce a flame). Stars are fuelled by helium nuclear fusion releasing incredible amounts of energy in the forms of heat light and movement. Our sun is fueled this way and like all other stars, our sun will eventually run out of helium. When it does, it begins to collapse by the force of its own gravity, eventually forming a rather dull object, known as a neutron star. In the process of collapsing, it implodes spectacularly, releasing an enormous amount of energy, so much that the light radiating from it in the few seconds of its collapse is approaching the level of all the light radiating from all the stars and galaxies in the heavens. (At least so one knowledgeable physicist author has assured us! Let us just say it is a very very bright light!) It is a Supernova! The remaining material from the mother star is there. It still has some fuel, otherwise we wouldn’t notice these dull ornaments of the galaxies. Neutron stars, however, are very compact and have very strong gravitational properties placing enormous forces on the structure of these rather dull relics of once mighty stars. Those forces eventually cause it to collapse into itself.
When a neutron star collapses into its own gravitational pull it becomes incredibly compact, and its gravitational attraction becomes so powerful that it even sucks in light and then an envelope of strongly curved spacetime surrounds that very compact matter in the gravitational blockbuster of a Black Hole. Such is the gravitational pull of a black hole that it can eventually rip apart or strip off the outer mantle or more off a passing star and compact it into an unbelievably small volume. Unlike Schwartzchild’s Black Holes, which were static, our modern view of a Black Hole is constantly swirling around.
Steven Hawking considered what would happen to a Black Hole once it is formed. Does it go on there forever? He has proposed that they would simply evaporate away into spacetime leaving a glow of radiation for a million years or so.
When you think about the compacting power of a Black Hole it is important to remember that atoms are almost entirely empty space. When you think that a particle called a neutrino can pass 8,000 miles through the earth without hitting a single piece of matter, a proton, neutron or electron, you have to realize there is almost nothing there. When you look at your arm, it seems solid enough, but it isn’t, it is mostly empty space and particles are zinging through it 24 hours a day, hardly ever hitting anything that is you.
Black Holes have almost unbelievably strong gravitational attraction. That is why whatever is sucked into it is forced by the enormous gravitational forces into a very small volume, as mentioned above, the entire earth down to the size of a soccer ball and you to much less than a speck.
Oh yes, you shouldn’t worry about our sun running out of fuel, it has lots to keep you and your grandchildren and their grandchildren and their grandchildren and their grandchildren etc. nice and warm and cozy for many many thousands of years to come. Mind you, all good things come to an end …. or maybe a Black Hole.