A Guide to Understanding Nothing
Nothing is a physical concept, because it’s the absence of something. "What we’ve learned over the last hundred years," Lawrence Krauss says, "is that nothing is much more complicated than we would’ve imagined otherwise."
How could the universe be created out of nothing? This question has so perplexed mankind that we have come up with a fantastic assortment of myths to explain the how and the why of existence.
The stories that tend to resonate with us employ metaphors that are based on human scale, or the observable world around us. Quantum mechanics doesn't offer that. And yet, "the universe doesn't care about our common sense," says Lawrence Krauss, whose book A Universe From Nothing: Why There is Something Rather than Nothing led to one of the fiercest intellectual battle royals of the past year, which Krauss attributes to his alleged encroachment into the field of philosophy.
What's the Big Idea?
What is nothing?
The simplest kind of nothing is "an infinite empty space," Krauss tells Big Think. This type of nothing, the dark infinite void of the Bible, is not filled with any particles or radiation. It's just nothing. However, due to the laws of quantum mechanics and relativity, Krauss says, "we now know that empty space is a boiling bubbling brew of virtual particles that are popping in and out of existence at every moment."
Krauss says the idea of "empty space with stuff in it" and the idea of "empty space with nothing in it" are actually "different versions of the same thing." We have come to understand a more complicated version of nothing because the laws of quantum mechanics guarantee that if you wait long enough, nothing will eventually produce something.
But if this is true, where did space come from? As Krauss points out, "once you apply the laws of quantum mechanics to gravity itself, then space itself becomes a quantum mechanical variable and fluctuates in and out of existence and you can literally, by the laws of quantum mechanics, create universes."
What about the laws of physics? The laws of nature? These laws themselves are somehow something. "That is not at all obvious or clear or necessary, says Krauss. In fact, "we now have good reason to believe that even the laws of physics themselves are kind of arbitrary."
For instance, there may be an infinite number of universes, and in each universe that has been created, the laws of physics are different. "The laws themselves come into existence when the universe comes into existence," Krauss says. In other words, there is no pre-existing fundamental law. Anything that can happen, does happen.
So what are we left with? No laws, no space, no time, no particles, no radiation. That’s a pretty good definition of nothing.
Krauss acknowledges that when he talks about "virtual particles popping in and out of existence on a timescale so short you can’t see them," he might sound like some kind of philosopher or priest "talking about angels on the head of a pin or something."
However, while we can’t see virtual particles directly, Krauss points out that we can measure their effects indirectly. And this is the key to understanding modern physics. For every particle that exists in nature, there is a likelihood that out of empty space, particle-anti-particle pairs will be created spontaneously and they will exist for a very short time before they disappear. "The fact that we can actually calculate them is what’s responsible for at least one Nobel Prize," Krauss says. Why? If we include the effects of virtual particles, "we can predict from first principles the results of an observation to nine decimal places and get it right, Krauss says. "There's nowhere else in science where you can do that."
What's the Significance?
Now that we have a better understanding of nothing, we still need to answer the question of why we need to bother getting out of bed in the morning. After all, quantum mechanics can be quite dispiriting to some. As Richard Dawkins wrote in his afterward to A Universe From Nothing:
Even the last remaining trump card of the theologian, ‘Why is there something rather than nothing?,’ shrivels up before your eyes as you read these pages. If ‘On the Origin of Species’ was biology’s deadliest blow to supernaturalism, we may come to see ‘A Universe From Nothing’ as the equivalent from cosmology. The title means exactly what it says. And what it says is devastating.
That is not to say that Krauss embraces a pessimistic worldview, or, as some have charged, a reckless indifference to the great moral questions that arise from the idea of creation from nothing. I, for one, don't think that criticism is fair.
Sure, we're insignificant, Krauss tells us, but we're also quite precious. Krauss sees it as "spiritually uplifting" that we get to determine our own future, as opposed to having to simply fulfill the purpose of our creator, like some kind of mannequin. "That makes our future more precious," he says.
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