Physicists and Lyricists on Time and Space
A most interesting audience gathered yesterday at the third and now traditional Café Scientifique at the Dark and Light Beer House, organized by the International Science and Technology Centre (ISTC), the InformNauka agency and the Uspekhi Fiziki (Successes of Physics) Foundation, headed by Academician V.L. Ginzburg. Not only science journalists from the most varied publications and astrophysicists, but science-fiction writers, too came to the café. A make up of such an unusual order dictated the far from usual theme for the café: ‘Travel through space and time – a dream or reality?’ It arose because this year, 2005, is World Physics Year, celebrating the 100th anniversary of Einstein’s theory of relativity. In this way the Café Scientifique has made its own modest contribution to the celebration of World Physics Year, which is underway all over the world.
Questions of time and space have occupied the minds of humans for many decades. It was interesting to hear the point of view on this problem both of specialists in astrophysics, quantum mechanics and cosmology, and science-fiction writers who are inspired by science to create works of literature.
Space and time. We are more or less clear on the first, but is it possible to give a precise definition of time? This question was put to the house by co-host of the Café, Liubov Strelnikova. It should be said that the question stumped those present, as no one actually put forward a precise definition. Those present believe that time relates to a number of undefined concepts. Anatoly Mikhailovich Cherepaschuk, Corresponding Member of RAS, Director of the Sternberg State Astronomical Institute defined time as a concept that arose together with matter at the moment when the Universe was born. Alexander Viktorovich Berkov from the Chair of Theoretical Atomic Physics of MEPhI reminded the audience that time is the fourth coordinate and that we live in a four-dimensional world. The humanitarian Alexei Ananchenko from the Ministry of Education and Science believes that time is an abstraction that characterizes the change in an object. And the writer Vadim Kirpichev believes categorically that space and time are nothing but attributes of our thought processes. Finally, many shared the viewpoint that it is impossible to give a precise definition of time; all the processes that are linked with it are too complex, including those in biological objects. So there is no definition but time exists and nothing stops us from discussing and writing about it.
As far as the science-fiction writers are concerned, they, as always, look ahead of science. ‘Overcoming time and space was always a dream of humanity and writers have reflected this dream as best they could. And it is here that the science-fiction writers found Einstein’s theory of relativity very useful,’ stated science-fiction critic and Editor-in-Chief of the Zvezdnaya Doroga almanac Alexander Roife. ‘At the same time the science-fiction writers so wanted their characters to fly faster than light that they even dreamt up hyperspace, for which, if I am not mistaken, there is no analogue in the real physical picture of the world.’ ‘Science-fiction writers are already tired of what the physicists have still to discover,’ believes Elena Kleschenko, science-fiction writer and science journalist. ‘Travel to another time and into parallel worlds, and “zero transportation” are now run of the mill for science fiction writers. In the hundred years that Einstein’s theory of relativity has been around, writers have studied all possible means of displacement in time and space, all complexities that would arise with it, and all psychological and social consequences. It’s about time that the physicists threw us some more material!’ Science-fiction writer Sergey Chekmaev stressed that popularization of scientific achievements is far from being the priority task of science-fiction writers, whatever scientists and journalists may think about the subject. ‘Science fiction has to signal the danger that scientific achievements could bring to humanity,’ Sergey believes.
Incidentally, the scientists conceded that science fiction has always served as a stimulus for the development of astronomy. ‘Demand for science fiction today has never been so high,’ believes Cherepaschuk. ‘Progress today in astrophysics is so great and so headlong that to comprehend obtained data a thought process in the field of the fantastic is simply essential.’ And it should be said that in modern astronomy the most fantastic of things are becoming a reality. Take the project to construct a 100-meter telescope, developed by the European Union. By the way, the largest diameter of mirror in today’s telescopes is 10 meters. This means that very soon our knowledge of the Universe will be noticeably supplemented and we shall uncover a host of secrets.
But it is clear even today that there are active models of ‘time machines’ in the Universe. We are talking of black holes. Astronomers observe them using indirect data, while physicists still doubt their existence. However, Cherepaschuk has no such doubt: ‘Einstein’s theory of relativity forecast four holes and in the Universe today there are already a hundred candidates for black holes.’
The term black hole is understood to be an area of space and time, for which the second cosmic speed is equal to the speed of light. Thus, the gravity field of a black hole is so strong that not even light can get out of it. (By way of a reminder, the second cosmic speed is what a body should possess to be able to overcome the attracting force of a massive body and fly away – for the Earth it is 11.2km/s). Density of matter in a black hole is colossal. If we were to compress the Earth to a sphere with a radius of 1cm, we would obtain just such a density of matter.
As the course of time depends on gravity, the flow of time near to a black hole for an outside observer slows and all processes come to a standstill. The physical boundary of a black hole is the horizon of events upon which the course of time comes to a stop from the point of view of a remote observer. But a cosmonaut, entering beneath the horizon of events, sees the future of our Universe. There is clearly a principal opportunity to create a time machine.
A.M. Cherepaschuk spoke on such complex and fantastic matters, and in such a beautiful and spirited way, that all wanted to listen and listen. He spoke also of so-called mole holes, tunnels in space and time, travelling over which it is possible to travel in time. Mole holes can only arise from a vacuum, an environment with negative gravity and minimal energy. No one has detected these holes; they have only been discovered on paper. However, astrophysicists are optimistic in their outlook. Incidentally, all those present were given a copy of Cherepaschuk’s popular book Black Holes in the Universe, published by Vek-2 and signed by the author.
The well-known astrophysicist and populariser of science Vladimir Surdin voiced his own views on the matter. In his opinion, we can learn about our past and our future if we learn to listen to signals from extraterrestrial civilisations. The international conference Horizons of Astronomy and SETI is devoted to these very questions; it is to be held at the end of September in a specialized astrophysics laboratory in the Caucasus, in the Nizhny Arkhyz settlement, and where the entire astrophysics world will gather.
‘This is the first time at the Café for me,’ said Surdin. ‘But I’m afraid…If an aeroplane were to fall onto this building now, then all those professionally involved in the popularisation of science in Russia will be destroyed.’ Thankfully there were no falling aircraft and we are all fine; and yet the point was clearly made. There are indeed very few science journalists and scientists who write popularly about science. Let’s hope that this is just for now.
Despite the complexity of the subjects
Sergey Komarov | alfa