John H Conway on the creation of his Game of Life.
Richard Feynman on the differences of merely knowing how to reason mathematically and understanding how and why things are physically analyzed in the way they are.
Richard Feynman amuses himself with an old puzzle – why do mirrors seem to switch left and right, but not top and bottom?
The Big Bang
Every day beautiful and miraculous objects suddenly appear, from snowflakes on a cold winter morning to vibrant rainbows after a late-afternoon summer shower. Yet no one but the most ardent fundamentalists would suggest that each and every such object is lovingly and painstakingly and, most important, purposefully created by a divine intelligence. In fact, many laypeople as well as scientists revel in our ability to explain how snowflakes and rainbows can spontaneously appear, based on simple, elegant laws of physics. —Lawrence Krauss, A Universe from Nothing, p.xi
Before the so-called “big bang” that brought our universe into existence (or at least that is a current scientific theory), there was “nothingness.” But what is that? And what caused nothingness to become something?
If we start from our axiomatic system (see Philosophy for Heroes: Part 1: Knowledge), then there is no room for “nothingness” in the conventional sense. While we cannot use pure philosophy to decide what exactly existed before our universe, we can make general statements about entities, properties, and their effects. By applying philosophical principles of Objectivism, we can be sure that there is no beginning of the universe; even the so-called “big bang” would be just a result of the properties of “something” which existed before the big bang and which had the properties to create a big bang. If there had been “nothingness” before the big bang, that nothingness would have no properties that could cause a big bang.
We are ultimately faced with the same issue as when we first started to discuss philosophy: we first need to clearly define what we are speaking about when we use words like “big bang,” “nothingness,” or “universe.” We have to be careful not to take on a view of the universe that is based on pure linguistics or intuitive interpretations of the words and instead take care to start from a common,clear basis of definitions.
The intuitive understanding of nothingness is that when you have a bowl of apples and empty that bowl, there is “nothing” left in the bowl. Of course, scientists early discovered that it is actually not empty, there is still air in the bowl and that if you take any space and pump out the air, you are left with “true” nothingness: a vacuum. But this view of constructed nothingness is based on the classical view of physics. At this point, I want to stress that as students of reality, we need to get away from the idea that everything starts with our intuitive understanding of the world. We need to be careful to be objective at all times, especially when it comes to non-intuitive questions from philosophy and physics. When one removes all entities from a box by pumping out the air and creating a vacuum, that does not mean that the space inside the box is left with no properties. While you might be unable to “move” space in the conventional sense of a thing, it would still fit in our definition of an entity. There is no requirement for the universe having to have a clean, property-less canvas on which it draws its entities; the canvas itself can have properties.
In quantum gravity, universes can, and indeed always will, spontaneously appear from nothing. Such universes need not be empty, but can have matter and radiation in them, as long as the total energy, including the negative energy associated with gravity, is zero. —Lawrence Krauss, A Universe from Nothing, p169
One of these properties of space is that it can spontaneously create two particles that cancel each other out energetically. This has been shown to actually happen in a number of experiments. For example, you can create a vacuum and place two metal plates in them facing each other. According to classical physics, nothing special should happen. Measurements have shown, though, that there is a force to push those plates away from each other, despite being in a vacuum and despite no other forces being at work. Likewise, we can detect the Hawking radiation emitted by black holes. If particles are generated at the event horizon of a black hole, one can fall into the black hole while the other escapes, ultimately canceling out the black hole in the long term.
While we have argued that a part of space can be an entity because it has properties, we need to examine this more closely. What exactly is the universe? Is it everything exists? Is it the canvas on which other entities are “painted”? This question looks difficult to answer and depends on the context. The concept of “universe” is used in various ways. In the classical sense, the universe is everything that came into existence resulting from the big bang. That is then simply a set of entities, not an entity itself. An alternate view is that the universe is everything that exists, but not as a set, rather as a whole entity consisting of loosely connected particles. Likewise, if we use the idea from above that the universe is a canvas, it would be infinitely large.
Either it is a set and thus not an entity, or it is “everything” and thus cannot interact with other entities and thus the attribute “concept” loses its meaning, as there is only one universe in existence. Or it is infinite and thus has no identity either. Infinity has some strange consequences, though. An infinite universe would mean that there were an infinite number of big bangs, that produced an infinite number of worlds where a copy of us sits an infinite amount of times thinking about this question.
If we ignore the larger canvas and quantum theory for a moment and focus on the universe as simply the product of the big bang, we can at least make some statements. First, this universe is finite. It is as large as particles traveled since the bing bang. If there were no big bang and if the universe were infinite, the night sky would be either brightly lit with the light of “infinite suns” or the suns would all have to be so far from each other that, from an observer’s point of view, there are only a limited number of suns visible at any point in time (which does not correlate with our observations).
Ultimately, we are faced with a difficult problem. At this point, it is up to future philosophers, cosmologists, and physicists to expand our conceptual understanding of the world. Everything points to a fundamental understanding of reality that is missing. Maybe ultimately, we will discover that the universe is but a closed fractal that does not so much go into infinity as it goes into itself. But at this point, we can only wonder about the mysteries we will unravel in the future.
[…] when we allow for the dynamics of gravity and quantum mechanics, we find that [our] commonsense notion is no longer true. This is the beauty of science, and it should not be threatening. Science simply forces us to revise what is sensible to accommodate the universe, rather than vice versa. —Lawrence Krauss, A Universe from Nothing, p151
Lawrence Krauss gives a talk on our current picture of the universe, how it will end, and how it could have come from nothing. Krauss is the author of many bestselling books on Physics and Cosmology, including “The Physics of Star Trek.”
Every day there are news reports of new health advice, but how can you know if they’re right? Doctor and epidemiologist Ben Goldacre shows us, at high speed, the ways evidence can be distorted, from the blindingly obvious nutrition claims to the very subtle tricks of the pharmaceutical industry.
Basil J. Hiley, born 1935, is a British quantum physicist and professor emeritus of the University of London.