As far as we currently know, there is only one expanding bubble of spacetime dotted with trillions of galaxies – that is our universe. If there are others, we have no convincing evidence of their existence.
Having said that, theories of cosmology, quantum physics, and the philosophy of science themselves have some problems that could be solved if our “everything” mass wasn’t, well, everything.
This does not mean other universes Must be Out. But what if they did?
What is the universe?
It should be a simple question to answer. But different fields of science will have subtly different opinions about what the universe is.
Cosmologists would say It describes the total mass of objects (and the distance between them) that have been slowly expanding from a highly concentrated volume over the past 13.77 billion years, and have become increasingly turbulent with age.
It now spans 93 billion light-years from edge to edge, at least based on all the visible (and invisible) things we can detect in some way. Beyond this limit, there are either things we cannot see, or an infinite space of nothingness, or – in the unlikely scenario that all space is bent around itself – back and forth to the beginning across spherical hypertrophy Universe.
However, if we are talking about quantum physics, then the universe may refer to all fields and their particles, and their combined effects on each other. As a general rule, The universe (at least like ours) is a closed system, which means that it cannot suddenly lose or gain a great deal of energy.
Philosophically, the universe might be a separate set of fundamental laws that govern the behavior of everything we observe. The universe can be defined by its own rules that determine its unique speed of light, telling particles how to push or pull, or how space should expand.
What is the multiverse in cosmology?
A century of astronomical observations has told us a lot about the age, size and evolution of galaxies and stars, matter and the four dimensions that we sum up in spacetime.
One thing we know with great confidence is that everything we see now is expanding at an accelerating rate. This logically suggests that the universe, at least in which we live, was a lot smaller.
We can theoretically compress all the matter of the universe to the point where the concentration of energy from atoms is reduced to a mixture of particles and simpler forces so that we can no longer tell them apart. Which is smaller than that? Big shrug.
If we go by what is known as the periodic model of cosmology, then the original universe somehow predated our own. It could be quite similar, only running in reverse compared to ours, shrinking over time to a focused point only to bounce back for some reason. And for eternity, we might imagine the universes in question bouncing back and forth in the endless yo-yo effect of growth and collapse.
Or, if we go to what is known as a conformal cyclic model, universes expand over trillions or trillions of years until their cold, point-like particles spread out, for all mathematical purposes, everything feels like a whole new world.
If you don’t like those, there’s a chance our universe is a white hole – the hypothetical back end of a black hole from another universe. Which, logically, might just mean black holes In our universe they could all be parents, pinching new universes like cosmic amoebas.
What is the multiverse in quantum physics?
Early in the last century, physicists found theories describing matter as little things that only tell half the story. The other half is that matter behaves as if it also had wave properties.
What exactly this dual nature of reality means is still debated, but from a mathematical perspective, that wave describes the rise and fall of a game of chance. Possibility, you see, is built into the same mechanism that makes up the cogs of a universe like the rest of us.
Of course, this is not our everyday experience as large groups of atoms. When we send out a bucket of particles it’s called a rocket the moon Since it goes over 300,000 km, we don’t roll the dice. Old classical physics is as reliable as tomorrow’s sunrise.
But the closer we get to a region of space or time, the more we need to take into account the potential range of measurements we might find.
This randomness isn’t the result of things we don’t know – it’s because the universe itself hasn’t made up its mind yet. There is nothing in quantum mechanics that explains this transition either, which makes us imagine what all this means.
at 1957 PhD thesisAmerican physicist Hugh Everett He suggested that the range of possibilities are all as real as each other, and represent actual facts – separate universes, if you like – just like those we all know.
What ‘we’ means, and why ‘we’ ‘feel’ a group tangled above waves over another, is unclear, and in some ways represents a bigger problem To replace.
What is the multiverse in philosophy?
One of the most basic assumptions of science is that despite what your mother tells you, you are not special. nor any other person, or our planet, or – by extension – our universe.
While rare events do happen from time to time, we don’t answer the big questions with “it just happened this way”.
So why does our universe seem to be Just tug the right troop Which not only allow particles to appear, but freeze for long enough periods in atoms that they can undergo complex chemistry to produce thinking minds like ours?
Philosophically, the anthropic principle (or principles, since there are many different ways to spin an idea) suggests that we might reverse it. Without these conditions, no minds would rise to consider the astonishing turn of events.
If it was just one universe that “happened this way” early on a spring morning, that would be a huge coincidence. Really big.
But if there are infinite universes, with infinite combinations of forces pushing and pulling, some of them will inevitably give rise to minds that might just ask “Are we part of a multiverse?”
Will we discover other universes?
Since the exact definition of the universe depends on some kind of physical fence separating the influencing factors, it is hard to imagine ways in which we might observe siblings of our universe. If we did, we might as well see it as an extension of our universe anyway.
However, there can be some cheating that can give us a glimpse.
Any experiment to find someone has to rely on this “fence” that has some holes that allow particles or energy to seep through, either in our countryor far from it. Or, in the case of the universes in our past, massive events that left enough scar that not even a rebirth can erase.
Right now, we still don’t have good reason to believe that our everything bubble isn’t unique. As we’re still learning how our universe works, current gaps in physics can be filled in without any need to imagine a reality other than our own.
In countless other versions of this article scattered throughout the multiverse, however, the question of whether we’re alone may have a different answer.
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