Entries in gravity (41)
In the 16th century, Kepler and Brahe founded a field that was to become one of the most important disciplines of our times: Physics as we know it today, the mother of all the Sciences. Since then we learned a great deal about the world around us. Still, physics amounts to only a handful of beautiful and profound ideas - in Einstein’s words, “God’s thoughts”... We will present a bird’s eye view of physics - with the benefit of hindsight - and talk about a few key principles upon which our modern understanding of the physical world is based.
But what are these ideas or divine thoughts? Are they the same or of the same kind as the first principles discussed by Aristotle? This is where philosophy will step in to clarify—and, of course, to further complicate—the role and the place of physics. We will call upon both Plato and Aristotle to discuss the most fundamental principles of knowledge, in the sense in which knowledge has been conceived in the West. But we will also talk about mythos, or thinking based on ambiguity that challenges the so-called rational, or scientific discourse.
This lecture will be a conversation between philosophy and physics in a different way than the previous ones.
First, we will discuss what string theory is. It purports to be the ultimate unifying framework of the physical laws. This theory emerged as a response to several overwhelming puzzles that arise within traditional physics—the puzzles that suggest that the laws of physics we love and rely on are logically inconsistent; that they are incompatible with each other. In recent years string theory made a great deal of progress in understanding black holes, in cosmology, and particle physics. We will review these advances and present a simple, powerful, and yet preposterous story of what string theory is. We will also discuss the importance of experimental evidence as opposed to logical and conceptual consistency.
Next, we will consider whether or not philosophy is useful. In doing so, we will return to its origins in Ancient Greece, and in particular, to Plato and Aristotle, but also draw on ideas of a contemporary French philosopher Gilles Deleuze. We will also have to confront the question of what philosophy is, as well as what makes one a philosopher.
Finally, we will comment on the convergences and the differences between these two kinds of knowledge.
In recent years, powerful telescopes have pushed observational cosmology into its golden age. In a span of a decade astrophysicists have successfully charted out the entire history of our universe - all 14 billion years. We can now say that we have seen the edge of the cosmos!
Yet, in doing so, we have to accept and understand strange forms of energy – somewhat cryptically called dark matter and dark energy. We also run up against several curious and profound puzzles: the anthropic principle and the question of what time is. Driven in such a way beyond physics, we need to call upon philosophy, and are lead, strangely enough, to the Ancient Greeks, and, in particular, to Aristotle’s notion of time. We are bound to confront the concepts of entropy and chaos, and the issue of whether time flows in a certain direction.
During this lecture we will look at some of the most recent—quite remarkable—pictures of deep space, as well as discuss the questions of the grand coincidence, of the beginning of time, and of order and disorder in the universe.
In the 1920's, soon after Einstein proposed his new theory of gravity, theoretical physicists realized that this theory predicted the existence of esoteric astrophysical objects they called black holes. These are collapsed massive stars which warp time and space around them as much as they skew human imagination... Black holes push our understanding of the material world, of time, and of consciousness to its limits, driving physics into the realm of philosophy. In the past few years, we have discovered billions and billions of black holes all around us, scattered across the universe. We now know that these violent, extraordinary entities play a key role in the evolution of the universe, and of life... To understand black holes we need to go beyond traditional physics towards crazy ideas of string theory, but also those of Ancient Greek philosophy. Looking at recent photos of black holes we will discuss these strange entities and their philosophical significance.
Here's a slideshow I prepared from some of the most amazing detailed pictures taken by the Hubble Space Telescope. In commemoration of the telescope's 20th anniversary, these images were released with associated description by hubblesite.org.