If the “big bang” created the universe, and if nothing existed before the big bang, where did the big bang come from?
Imagine an infinite sea of energy filling empty space, with waves moving around in there, occasionally coming together and producing an intense pulse. Let’s say one particular pulse comes together and expands, creating our universe of space-time and matter. But there could well be other such pulses. To us, that pulse looks like a big bang; in a greater context, it’s a little ripple.
—David Bohm [Bohm]
Why do we observe the sky? Because the universe provides us with rich stories from a time long ago which provide us with experiments, comparisons, and measurement tools—just think of stars, black holes, or quasars. Being so far away, not only do those celestial objects tell us how things are, they also tell us how things were. This allows physicists to wonder about the consistency of laws and constants of the universe. Just because we formulated a law does not mean that it needs to hold true forever.
For the same reasons, physicists are interested in evolution on Earth: how early lifeforms on Earth developed can give us some hints about what natural laws billions of years ago were like. But what if we go further and further back?
At the beginning, there was the “big bang” (see Figure 3.24). The theory is that at one point, a singularity exploded into particles, which over time formed into atoms, and later stars and planets. Before the so-called “big bang” that brought our universe into existence (at least that is a current scientific theory), there was “nothingness.” If we start from our axiomatic system with entities having an identity in the form of properties, “nothingness” simply refers to a space where no entities exist—hence that space has no properties. 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 from Philosophy for Heroes: Knowledge, we can be sure that there is no beginning of the universe; even the so-called “big bang” would be merely 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 pure “nothingness” before the big bang, that nothingness would have had no properties that could have caused a big bang.
We are ultimately faced with the same issue as when we began 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 discovered early on that such a bowl is actually not empty, as there is still air in the bowl. 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 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 [Krauss, 2012, p. 169]
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 happen in a number of experiments.
You can create a vacuum and place two metal plates, facing each other, in the vacuum. 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 (or pull them together, depending on the setup), despite being in a vacuum and despite no other forces being at work (Casimir effect, see Figure 3.25). A macroscopic model that shows the same effect is a vibrating water bath into which you put two plates: the waves reflecting from the sides of the water bath push the plates together.
A black hole is basically a very heavy star, so heavy not even light escapes. In classical physics, anything within the so-called “event horizon,” the distance at which light can still escape the gravity of the black hole, is thought to vanish in the black hole forever. But this is not what we actually observe. In fact, when particle pairs are generated and split on the event horizon with the anti-matter particle falling into the black hole while the matter particle escapes in a stream of particles, the black hole slowly loses mass: anti-matter and matter particles cancel each other out. According to the theory, what is eventually left of a black hole is a normal star. This phenomena is called “Hawking radiation.”
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 that 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. Based on the ideas of David Bohm, studies point in the direction of infinite age of the universe [Ali and Das, 2015] and the spontaneous creation of the universe from “nothingness” [He et al., 2014]. This not only solves the problem why “our” universe is exactly how it is, but also would solve any issues arising from the idea of a big bang as a singularity and a beginning of everything.
An infinitely large (and infinitely old) universe would at least explain some of the mysteries about the universe, namely why we have certain natural laws that just happen to allow for stars, planets, and ultimately intelligent life to evolve. There might be other parts on this canvas where these laws are different and where no intelligent life is possible. Maybe most of this canvas is inhospitable for life, except for a certain corner with very specific natural laws—which just happens to be our part of the universe. So, even within an infinite universe, there could be finite spaces where intelligent life can ponder the question why the universe is “designed” exactly in such a way that it allows for them to exist. Some of the mysteries of the universe could then be simply solved by saying that things are as they are, because if they were not, we would not be here to observe them.
ANTHROPIC PRINCIPLE · The anthropic principle is the consideration of how the environment and natural laws just happen to support human life: only the inhabitants of those worlds that can sustain intelligent life can wonder why their own world happens to support intelligent life. If the conditions for intelligence were not met, there would be nobody wondering about it.
Did you know?
Looking into the future, the anthropic principle does not look that simple. Just because Earth made it possible for us to develop up to the point where we discovered the anthropic principle and Earth’s role in the universe, that does not mean it will automatically sustain human life in the future. That is up to us. Just like we have to learn how our bodies and minds work, we have to learn how the planet works.
→ Read more in Philosophy for Heroes: Epos [Lode, 2019]
Even though the big bang was caused by a very improbable event (a whole set of quantum fluctuations converging at one point), in an infinite universe, even very improbable events can happen infinite times. And an infinite number of big bangs would mean an infinite number of worlds where infinite copies of us sit an infinite amount of times thinking about this very question… ultimately, any idea of “identity” would lose its meaning: something without limits cannot be defined and thus has no properties. At the same time, infinity in this regard is a mathematical concept: a measurement, not a concept. Either way, at least for now, the universe still offers a lot of room for exploration.
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 a statement: this universe is finite. It is as large as the extent to which particles traveled since the big 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).
Yet, there could be an alternative. The hypothesis above assumed that in the infinite universe, the laws of the universe differ from place to place. There could be an infinite space where life, chemistry, maybe even basic physics are not possible. For example, if the gravitation constant were different, hydrogen atoms would not attract to each other and no stars could form. Likewise, there are dozens of other constants in the universe that are set just “right” to allow life. Some might assume that this is due to a supernatural creation, others assume that this is simply so because we are in a part of the universe where these constants happen to be that way. Like ecological niches where certain forms of life thrive, you could imagine the universe like an infinite jungle with different constants providing home for stars and even biological life. At this point, it is up to future philosophers, cosmologists, and physicists to expand our conceptual understanding of our existence.
What we call “nothingness” is still a region of space where the laws of physics apply. And in physics, nothingness is not stable. New particles are generated and destroyed at all times. It is conceivable that our “big bang” happened by accident some place within an infinite universe.
The book could end here if it were not for a strange oddity. Out of this jiggling chaos of the universe, life emerged on the third rock of a solar system located on a minor spiral arm of the Milky Way (see Figure 3.26)—a galaxy consisting of around 200 billion stars—which itself is part of a group of 100 other galaxies making up the Virgo Supercluster, which itself is part of the Laniakea Supercluster, consisting of 100,000 other galaxies, which again is part of the observable universe—which in turn spans more than 90 billion light years.
Let us now narrow our focus on the part of the universe that does support life and let us look at the bridge between physics and biology. How could life emerge from non-living matter?
|Figure 3.26:||This artist’s concept depicts the most up-to-date information about the shape of our own Milky Way galaxy. We live around a star, our sun, located about two-thirds of the way out from the center. Credits: NASA/JPL-Caltech/R. Hurt (SSC/Caltech)|