SCIENCE IN THE XXI^ST CENTURY

SPECIAL ISSUE 1999

J.BECHTOLD:

"If history is any guide, advances in science will continue at an ever increasing rate. One of the most amazing advances I’ve seen in my life is the development and proliferation of computers. I think the impact of fast computers, increased data storage capability, the internet, etc. on all areas of science has still not been completely realized. (Certainly this is true in astronomy.) My children were avid computer users in preschool, before they could read; I was 17 or 18 before I had even seen a computer. I can hardly imagine how future generations, who will have grown up with computers, will exploit information technology."

"I agree with J. Maddox’s opinion. History shows that every time that men have thought that he knows everything, facts have proven him to be wrong. Different sciences progress at different rates and we are for sure at a privileged time in the sense that most likely our interpretation of most natural phenomena is along the correct track. However, we still have a long way to go. We must not forget that most people in the world still live in very primitive conditions and do not care about science. They have benefited very little from scientific knowledge. If life on earth is expected to continue as we know it, I think that the urgent problems to solve are in the social, agricultural and ecological sciences. How can we produce food in an ecologically sound manner to feed all the starving people? I think that this is the qualitative leap in technology that we need. If we do not solve this problem, there is be very little time left for scientists on earth to solve other interesting but socially irrelevant problems."

"I tend to agree that there is still an enormous amount to be learned, although I am reluctant to prophesize revolutions. Certainly in astronomy and particularly in my field, observational cosmology, the rate of new developments has been astonishing in the past few years, and one might see that as a revolution. But as I suggested above I think we still have a long way to go before we really understand the whole process of galaxy formation and evolution, and perhaps a longer way still before we really understand the fundamental cosmology that is the underpinning of everything we study."

"I agree with Maddox. A counterview was presented in a widely-publicised book "The End of Science" by John Horgan which claimed we would soon have covered the territory, e.g. in cosmology, and run out of things to do. I found Horgan’s case unappealing. It consisted with interviews with distinguished scientists at the end of their careers, some of whom were no longer forward-looking. Cosmology won’t stop when we’ve measured the fundamental parameters because we’ll then face a new set of questions that arise from their values. The wonderful thing about science is that knowledge is boundless; each time a project is nearing completion, a new landscape appears for us to study. It just requires mental adjustment to find it.

Revolutions are hard to predict though. Across all of science, it’s hard to comment with authority! Within cosmology, I’d say the existence and physical origin of non-baryonic dark matter and a cosmological constant would be the most revolutionary developments to hope for soon."

"This century has been tremendously rich in fundamental discoveries for the physical and astrophysical sciences. Of particular relevance for astronomy are the decades around 1930, with the fundamental characterization by Hubble of the size and structure of the space-time and its formalization in the framework of the General Relativity, and during the sixties, with many important discoveries about the physical constituents of the universe (the millimeter and X-ray background radiations, high-redshift quasars and radio-galaxies demonstrating an evolutionary universe, the formulation of the basic physical laws ruling the formation of cosmic structures as an effect of gravity, and so on).

There is widespread consensus that decades of astrophysical investigation and discoveries add continuous support to the Big Bang Standard Model, envisaging an expanding universe originated roughly 15 billion years ago and evolving out of a peculiarly hot, dense, and undifferentiated plasma condition. What is presently subject to active discussion is, rather than this general scheme, the details through which the cosmic plasma cooled and condensed under the effect of gravity to the presently observed highly differentiated universe.

After all these (apparent) successes, it is hard to avoid the conclusion that the "general scheme and fundamental facts" are basically understood, while only the details are matter of investigation. Consider, however, that similar feelings were common among scientists of all epochs, starting from the ancient Greeks! One striking example is the feeling of "everything understood" in the scientific and philosophic culture at the end of the Nineteen century, just before the scientific revolutions of the present century.

An example of a drastic modification of the present picture of the world would be to discover that the Big Bang was not a single, unique event, but one of an endless series of Big Bangs followed by "Big Crunches", implying again an infinite time and vanishing the concept of the origin. I am personally skeptical this could ever been proven, even assumed it could make sense after all (see the problem of the increasing entropy from cycle to cycle, and the present observational evidence for an open ever expanding universe).

Perhaps the fundamental physics might be closer to a revolution comparable to that of the Theory of Relativity, for example by discovering a new physics unifying the fundamental forces of nature (in particular gravity with the other forces). However, all these statements may include a bias: the deeper one is working in a specific scientific field, the more difficult it is for him to imagine revolutions in that area. After all, most of the revolutions in the physical sciences during this century came from either very young people (e.g. those working at the fundamentals of Quantum Physics, Born, Dirac, Eisenberg, Pauli, Fermi, and most others) or "outsiders", non-academicians, as were the young Einstein and the people making the two fundamental discoveries in cosmology, Edwin Hubble for the expanding universe and the two engineers, Penzias and Wilson, for the cosmic microwave background."

"I would agree with Maddox, that we have a lot left to learn. Without going outside the boundaries of astronomy, how can we presume to think that we know most of it when we have no idea what form 90% of the universe is in !"

"I’m certainly not in the position to give an informed answer on this one, but I’m happy to give a half-baked one. We are living at a time where scientific and technological advances appear to be being made at an ever increasing rates. A lot of this is due to the increasing power and sophistication of digital computers and their peripherals. I see no evidence that we are close to any fundamental limits in this area; indeed, it is more likely that we are at the beginning of what could justifiably be termed a computing revolution. The first steps towards designing computers built on quantum mechanical, rather than digital, principles are being made, and may in the relatively near future make current computers seem even punier than the first mechanical computing machines appear to us now. Given the complex simulations, virtual realities and artificial intelligences realised by current devices, I find it impossible to comprehend the capabilities of such future machines. I’m sailing dangerously close to science fiction here, but one can clearly envisage a time when the borderlines between virtual and ‘real’ realities, and between computer and human brains may become significantly blurred. As a scientist I find this exciting, but as a human being I find it rather chilling. On this basis alone — and there are very many scientific disciplines, including fundamental physics, where we remain quite remarkably ignorant — it seems hard to argue against John Maddox’s thesis."

"I do not believe we can be sure we have understood even the barest outline of how the Universe came to the structured form we now observe. Some people argue that observations of the Cosmic Microwave Background over the next two decades will "solve" cosmology. While I agree that if these measurements turn out to coincide with some version of the current standard paradigm, this will immeasurably enhance our confidence that it is correct, I would not be at all surprised if no version fits. As for galaxy formation, I think we may soon understand in broad outline how galaxies came to look the way they are, but I doubt we will ever be able to predict their detailed structure ab initio any more than we can hope to predict detailed weather patterns from a model for the global evolution of the Earth’s atmosphere."