Humanity, it seems, has an inherent desire to feel important. At one time,
we even placed ourselves at the centre of the universe with the longstanding geocentric model
of the solar system. And, even when Copernicus’ heliocentric model showed that to be untrue,
many people still believed our sun, at least, was at the centre of everything.
But now we know differently… we know that we’re not at the centre of the universe and, in fact,
we’re beginning to suspect that this universe might not even be the only universe there is.
This is Unveiled, and today we’re answering the extraordinary question;
what if humanity lives in a Level One multiverse?
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Some ideas in science truly push the boundaries of our knowledge and threaten to rewrite all
we’ve believed before. But the general concept of the multiverse is beginning to go beyond that.
We’re almost a quarter of the way through the twenty-first century now, and the idea of the
multiverse, or of multiple universes, is becoming more and more accepted. It’s still a controversial
prediction in physics, for sure, but there’s also an increasing number of researchers who suggest
that a multiverse is logical, and sometimes even unavoidable. For example, today’s scientists have
a pretty good idea that the universe is inflating, and most theories indicate that it should be flat…
two conditions which, in themselves, theoretically allow for a multiverse. Meanwhile, year by year,
we’re getting a better understanding of quantum physics, which can be applied in a variety of
ways to further flesh the theory out. For the renowned physicist Max Tegmark, then,
we can start to think deeper… to ask not whether there is a multiverse, but to enquire which
level of multiverse we’re actually living in? Tegmark’s model of the multiverse is perhaps
one of the simplest out there, on paper. He suggests that there are four different levels
to the multiverse… each one bigger than the last, and expanding on the previous level’s foundation.
Tegmark’s first stage, Level One, has often been described as the least controversial of all of
them. Even so, it’s what we’ll be focussing on for this video. So, what is a Level One multiverse?
Firstly, it ties in again with various evidence that points towards our universe being both flat
and infinite, with a seemingly even distribution of matter. The crux of Tegmark’s first level,
then, is that if the universe really is infinite, it should mean that all particle arrangements,
no matter how unlikely, will occur again and again - given enough time and distance. This
kind of multiverse is still contained, in a manner of speaking, within one structure,
and all of it is still bound by the same fundamental rules of physics…
it’s just that because there’s no end to that structure, there’s no end to what’s possible. And,
if particles have aligned in this way once already (that is, in the way in which we all appreciate
them in our lives) then they can do so again and again and again to infinity… and they can do so in
every other possible way, too, forever. At the heart of this model of reality,
there’s the fact that astronomers are, in a sense, aware of two universes:
the observable and the unobservable. The notion of the observable universe is closely linked to
what’s known as the Hubble Volume, which refers to the part of the universe that holds everything we
can see. However, because we’re also aware that space is expanding faster than the speed of light,
we know there’s another unknowable universe out there, too… existing beyond what we can see.
It’s here, according to a Level One multiverse, that plays host
to a limitless number of particle possibilities, including repeats. Potentially endless repeats.
While not strictly the same thing, here’s where the idea of parallel worlds usually comes in.
Because, in Tegmark’s Level One, there’s a genuine theoretical possibility that there are other
versions of you existing on the same plane of reality, just very far away. Tegmark has actually
calculated an upper limit for how far from our universe your potential doppelganger could be…
suggesting that they could mathematically reside ten to the power of ten, to the power
of twenty-eight (or twenty-nine) meters away. When said out loud that doesn’t sound so far,
but in reality, it’s a distance so vast that we may never, ever be able to breach it - no
matter what technology we were to develop. But, of course, between here and that imagined
place that’s identical to here, there could (or perhaps should) also be whole universes
with changes made, large or small. In the words of Tegmark himself, from a 2005 paper
titled “The Multiverse Hierarchy” in which he outlines the proposed multiverse Levels,
“there are infinitely many other regions the size of our observable universe, where every possible
cosmic history is played out”. Among other things, this means that there is - according to the Level
One model - an earth where Germany won World War Two, one where World War Two never happened,
one where Abraham Lincoln was never assassinated, a solar system where humans already live on Mars,
and presumably a solar system where Martians already live on Earth.
Perhaps the most tantalizing aspect about all of this, though, is that these other worlds
and histories don’t exist on alternate dimensions or higher planes of reality.
They exist in the same general place as we do, and the only thing separating us from them is the many
lightyears of space between us. Nevertheless, the implication is that, hypothetically,
if we could surpass the speed of light and travel the universe in a cosmic rush,
we could theoretically visit all the other universes that are just like this one.
Here today, then, this version of the multiverse - the Level One multiverse - is only unreachable to
us because of its vastness. But it also seemingly implies something else faintly mind-blowing…
that space has no end or edge to it. That, even if we could travel at any speed - millions of times
faster than lightspeed, for example - no one could ever reach an outer edge
of the Level One multiverse. And yet, just to melt the brain even further,
this type of multiverse also implies that every probability can happen. So, if there is a nonzero
chance of humanity (or any group) ever developing a workaround to this problem of infinity, then
it will happen eventually… meaning that someone, somewhere should be able to achieve the seemingly
impossible and (despite us saying that no-one should ever be able to do it, just a few seconds
ago) they will get to the edge of the multiverse. But finally, how could all of this make us feel?
Well, another inherent assumption with this particular model is that universes like ours…
are common. That if you travel far enough, you will find this place we call home again… with
Tegmark noting that we can reasonably consider our universe to be typical in terms of its arrangement
of matter. So, if a Level One multiverse were proved, it might feasibly lead to a massive sense
of listlessness or demotivation among the general public here on Earth. After all, if there really
are infinite versions of everyone, then nobody is unique anymore. And, therefore, if you were
to spend your life lazing around, then that would be fine… because there’s always another one of the
endless, possible versions of you out there that will become president instead, or cure disease,
or travel to their version of the moon. In some way, your success and failure is guaranteed
because it will certainly happen somewhere. It’s a massive psychological shift from those
early cosmological theories mentioned at the top of this video, wherein humanity at one time placed
itself at the centre of the universe. In a Level One multiverse, by comparison, we’re not only
not at the centre of anything… we’re also but a speck on the infinite scope of reality. But,
on the other hand, this realisation could also be exhilarating. It would tell us that every
possible physical and biological formation does exist somewhere in space. That there are
planets out there that double up as perfect utopias. Heaven-like worlds populated by
always-happy lifeforms. Of course, one person’s version of paradise may differ from another’s…
but with literally endless options out there, all iterations really are covered.
As with most multiverse proposals, it can all sound a little sci-fi at times… but, again,
many scientists argue that the theories (or, significant parts of the theories, at least)
do make sense. Max Tegmark has gone so far to argue that if you believe in quantum physics,
then you should also believe in a multiverse. For now, what we know for sure
is that there’s the observable universe, and that there’s more universe beyond that.
What lies on the other end of the light could very well be an unending supply of other worlds.
Keep your eyes peeled for our follow up videos looking at Tegmark Levels two, three and four…
but, for now, that’s what would happen if humanity lived in a Level One multiverse.
What do you think? Is there anything we missed? Let us know in the comments, check out these other
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