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At Big Think: The 4 fundamental meanings of “nothing” in science

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All the things that surround and compose us didn’t always exist. But describing their origin depends on what ‘nothing’ means.

KEY TAKEAWAYS

  • Most of us, when we talk about nothing, refer to a state where the thing we’re referring to doesn’t yet exist. 
  • But absolute nothingness, where space, time, and/or the laws of physics don’t exist, is only a philosophical construct, without physical meaning. 
  • Does the Universe truly create something from nothing? That depends on what your definition of nothing is, and which of the four definitions you’re using.

Ethan Siegel writes:

The Universe, as we see it today, sure is full of “stuff.” Everything we see, feel, and interact with is made of subatomic particles at the most fundamental level, and they’ve assembled into large structures — humans, planets, stars, galaxies, and galaxy clusters — over the Universe’s history. They all obey the same laws of physics, and exist in the context of the same spacetime that everything occupies.

All of the things that we see and experience in the Universe today have only been around for a finite amount of time. The Universe didn’t always have galaxies, stars, or atoms, and so they must have arisen at some point. But what did they come from? While the obvious answer might seem to be “something,” that’s not necessarily true; they may have arisen from nothing. What does “nothing” mean to a scientist in that context? Depending on who you ask, you might get one of four different answers. Here’s what they all mean.

1.) A condition where the raw ingredients to create your “something” didn’t exist. You can’t have galaxies, stars, planets, or humans without the particles necessary to build them. Everything we know of and interact with is made of subatomic matter particles; those are the raw ingredients that our Universe as we know it is built out of.

But how did we wind up with a matter-filled Universe, instead of one with equal amounts of matter and antimatter? That’s the first scientific meaning of getting something from nothing.

The origin of the matter-antimatter asymmetry — a puzzle known in the physics community as baryogenesis — is one of the greatest unsolved problems in physics today.

The Universe is an amazing place, and the way it came to be today is something very much worth being thankful for. (Credit: NASA, ESA, and The Hubble Heritage Team (STScI/AURA))

2.) Nothingness is the void of empty space. Perhaps you prefer a definition of nothing that contains literally “no things” in it at all. If you follow that line of thinking, then the first definition is inadequate: it clearly contains “something.” In order to achieve nothingness, you’ll have to get rid of every fundamental constituent of matter. Every quantum of radiation has to go. Every particle and antiparticle, from the ghostly neutrino to whatever dark matter is, must be removed.

But certain physical entities still remain, even under that highly restrictive and imaginative scenario. The laws of physics are still there, which means that quantum fields still permeate the Universe. That includes the electromagnetic field, the gravitational field, the Higgs field, and the fields arising from the nuclear forces. Spacetime is still there, governed by General Relativity. The fundamental constants are all still in place, all with the same values we observe them to have.

And, perhaps most importantly, the zero-point energy of space is still there, and it’s still at its current, positive, non-zero value. Today, this manifests itself as dark energy; before the Big Bang, this manifested in the form of cosmic inflation, whose end gave rise to the entire Universe. This is where the phrase, “a Universe from nothing” comes from. Even without matter or radiation of any type, this form of “nothing” still leads to a fascinating Universe.

3.) Nothingness as the ideal lowest-energy state possible for spacetime. Right now, our Universe has a zero-point energy, or an energy inherent to space itself, that’s at a positive, non-zero value. We do not know whether this is the true “ground state” of the Universe, i.e., the lowest energy state possible, or whether we can still go lower. It’s possible that we’re in a false vacuum state, and that the true vacuum, or the true lowest-energy state, will either be closer to zero or may actually go all the way to zero (or below).

To transition there from our current state would likely lead to a catastrophe that forever altered the Universe: a nightmare scenario known as vacuum decay

4.) Nothingness only occurs when you remove the entire Universe and the laws that govern it. This is the most extreme case of all: a case that steps out of reality — out of space, time, and physics itself — to imagine a Platonic ideal of nothingness. We can conceive of removing everything we can imagine: space, time, and the governing rules of reality. Physicists have no definition for anything here; this is pure philosophical nothingness.

In the context of physics, this creates a problem: we cannot make any sense of this sort of nothingness. We’d be compelled to assume that there is such a thing as a state that can exist outside of space and time, and that spacetime itself, as well as the rules that govern all of the physical entities we know of, can then emerge from this hypothesized, idealized state.

A number of questions arise immediately when we start thinking along these lines, with no definitive answers. They include:

  • How does spacetime emerge at a particular location or instant, when there’s no such thing as “space” (for location) or “time” (for instant)?
  • Can we truly imagine something being “outside” the Universe if we don’t have space, or “having a beginning” if we don’t have time?
  • From where would the rules governing particles and their interactions arise?

This final definition of nothing, while it certainly feels the most philosophically satisfying, may not have a meaning at all. It could just be a logical construct borne out of our inadequate human intuition.

Everything we know of certainly came from nothing. The key is to understand how.

Complete article at Big Think.

Evidence from cosmological observations, coupled with Einstein’s General Theory of Relativity and research into the physics of the singularity out of which the universe began most strongly argues that matter and energy, space and time all came into existence from “nothing,” as in the 4th definition. Since this true nothingness could not give rise to something, then the origin of our universe is consistent with that of a Creator whose existence is transcendent to space, time, and matter. The God of the Bible is described in this way as the Creator who also possesses the volition to decide to create the specific, contingent, finely-tuned physical parameters of our physical universe that allow life to flourish on planet Earth.

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