Zientzia (Fisika)
Professor Stephen Hawking 1942-2018
(http://www.cam.ac.uk/stephenhawking)
… An interest in singularities naturally led to an interest in black holes and his subsequent work in this area laid the foundations for the modern understanding of black holes. He proved that when black holes merge, the surface area of the final black hole must exceed the sum of the areas of the initial black holes, and he showed that this places limits on the amount of energy that can be carried away by gravitational waves in such a merger. He found that there were parallels to be drawn between the laws of thermodynamics and the behaviour of black holes. This eventually led, in 1974, to the revelation that black holes have a temperature and produce radiation, now known as Hawking radiation, a discovery which revolutionised theoretical physics.
He also realised that black holes must have an entropy – often described as a measure of how much disorder is present in a given system – equal to one quarter of the area of their event horizon: – the ‘point of no return’, where the gravitational pull of a black hole becomes so strong that escape is impossible. Some forty odd years later, the precise nature of this entropy is still a puzzle. However, these discoveries led to Hawking formulating the ‘information paradox’ which illustrates a fundamental conflict between quantum mechanics and our understanding of gravitational physics. This is probably the greatest mystery facing theoretical physicists today.
To understand black holes and cosmology requires one to develop a theory of quantum gravity. Quantum gravity is an unfinished project which is attempting to unify general relativity, the theory of gravitation and of space and time with the ideas of quantum mechanics. Hawking’s work on black holes started a new chapter in this quest and most of his subsequent achievements centred on these ideas. Hawking recognised that quantum mechanical effects in the very early universe might provide the primordial gravitational seeds around which galaxies and other large-scale structures could later form. This theory of inflationary fluctuations,developed along with others in the early 1980’s, is now supported by strong experimental evidence from the COBE, WMAP and Planck satellite observations of the cosmic microwave sky. Another influential idea was Hawking’s ‘no boundary’ proposal which resulted from the application of quantum mechanics to the entire universe. This idea allows one to explain the creation of the universe in a way that is compatible with laws of physics as we currently understand them.
Bideoa: Professor Stephen Hawking 1942 – 2018
(https://www.youtube.com/watch?v=ZrVVvXOIwQc)
Gehigarriak:
(i) Quantum Gravity Research – What Is Reality? (http://mikenormaneconomics.blogspot.com.es/2018/01/quantum-gravity-research-what-is-reality.html
Bideoa: Whai is reality?
(https://www.youtube.com/watch?v=w0ztlIAYTCU&feature=youtu.be)
(ii) Deep Thoughts
(http://kleeirwindeepthoughts.blogspot.com.es/)
Gizarte zientzia (Robotika eta kapitalismoa)
Stephen Hawking Says We Should Really Be Scared Of Capitalism, Not Robots
Gehigarria:
Pavilina Tcherneva-k robotikaz:
Nekazaritza, Industria, Zerbitzuak, Robotika,… eta job guarantee (lan bermea)
