Following on from my last post I decided to again revisit the material but under a different heading. That is to encapsulate the previous fruitful discussions kindly provided by Tom and expand upon the topic.
The recent sighting of a black hole, some 50 billion light years from the earth, brought back memories of first reading the late Stephen Hawking’s ‘A Brief History of Time ’. For Hawking, together with Roger Penrose, were the pioneers in proving the existence of black holes beyond doubt, by observations of the surrounding activity which validated what Einstein had first reluctantly concluded, as a corollary to his general theory of relativity.
At the time when I first read his best seller, I couldn’t understand many of the concepts, but on a second and third attempt some of it began to sink in as inevitably things do if you give the subject sufficient patient thought and/or research. Once I got the hang of his first publication I read the remaining books and hence have entertained an interest in our marvellous cosmos ever since. So that Hubbard’s pictures stretching back into the early universe we’re a fascination to me, just as were the pictures beamed back from Voyager. But what a thrill it would have been for Hawking, if he was alive today, to see these remarkable images of a black hole!
Amongst other things, what Hawking was able to do was to explain in graphic detail, just how dramatically Einstein’s general theory of relativity disproved the previous notion that the universe operated like a giant clockwise movement, more or less principally a product of Newtonian science. Rather, Einstein talked about curved Space -Time, an amalgam of 3 dimensions of space and time combined to make up a continuum.
The inevitable result is the formulation of singularities, the consequence of stars, over immense periods of time, becoming unimaginably heavier and dense, to emerge as white and brown dwarfs, to the heavier Neutron Stars. A Neutron star about 20 km in diameter would have the mass of about 1.4 times our Sun. This means that a neutron star is so dense that on Earth, one teaspoonful would weigh a billion tons!
Given sufficient initial stellar material, stars will eventually shrink to where their size is zero and their density is infinite, when you have a so called singularity.
At the heart of every black hole is a singularity where it is believed nothing can escape. That is what we see today with the event horizon as matter is drawn inward into the invisible centre. Einstein reluctantly concluded that nothing can escape from a black hole where the laws of science break down.
Big Bang theory.
This is accepted in cosmology despite the fact that it does not provide an authoritative answer, but remains a hypothesis, as to the origin of the universe. In a nutshell its logic flows from observations the universe has always been expanding, so that it must have arisen from a corresponding explosive finite beginning. We have the evidence in the left over cosmic radiation effects today in the form of cosmic microwaves. The clear inference for those who followed Einstein was the Universe had a definite beginning. This idea was first put forward by George Lemaitre in 1927, who called it ‘the hypothesis of the primeval atom’. As a catholic priest the idea of a definite beginning ideally allowed him to link science to theological implications. But interestingly enough Einstein saw this idea as an anathema to his general theory of relativity and his idea of a continuum. But the idea of Lemaitre grew in favour so that its name (big bang) was coined from a radio broadcast in 1949 when Hubble made reference to Lemaitre’s ideas and called it the BBT, so the name has remained ever since.
For Einstein was uneasy concerning the conclusions that arose from his work and invested the idea of a cosmological constant which has turned out to be almost correct but for the wrong reason. The discovery of the ubiquitous dark matter gravity waves made up the difference in lieu of his cosmological constant.
We have made tremendous strides in technology and engineering feats that has underpinned space exploration since those heady days. But in terms of Einstein’s contribution very little is new or was not previously predicted by him. The mystery remains.