The universe is a very strange place full
of mysteries and odd possibilities that, while scientists ceaselessly try to figure them
out, may remain complete unknowns forever no matter how advanced our civilization and
our science becomes. So here are ten bizarre possibilities regarding
the universe that we may never understand. 10. We May Never Know What Gravity Is One of the biggest mysteries in science is
the nature of gravity. For something that we interact with constantly,
we really don’t know that much about it. Newton tried to tackle the issue, but only
came up with a general way of expressing how it behaves, but not what it is. And even then, Newton was very slightly off. Einstein took that further, but he himself
spent his last decades trying to figure out just what gravity is, but again to no avail. Today, scientists know how gravity behaves
in the framework of space and time, and can predict it very accurately, but what the force
itself actually is remains an unknown. Ideas on this range from the existence of
an elementary particle, known as the graviton, that mediates the force of gravity. Trouble is, gravitons have never been found,
and there is doubt that they even exist. Another take on it is how Einstein described
gravity, as a warp in space-time, or an inherent acceleration towards massive objects. Trouble is this is an incomplete view, and
again simply describes how it behaves. Not what it is. Perhaps the most strange aspect of gravity
is that as far as a force of nature goes, it’s incredibly, incredibly weak. Look around you. Just to hold you to the ground, you need the
entire mass of planet earth to generate enough gravity to do it. Yet, we routinely defeat the force of gravity
when we launch space probes. Why it’s so weak adds to the mystery, and
recent work to determine if gravity is weak because it’s mostly leaking into other dimensions
came up negative. So gravity remains a great mystery, and while
we may someday understand it’s nature completely, there’s also a chance that we never will. 9. Is the Universe Infinite? We live in a sort bubble within the universe. We call it the observable universe, and beyond
it lies more of the universe that we can’t observe. This is a matter of the speed of light, objects
beyond a certain point cannot be seen because the universe hasn’t existed long enough
for the light from them to reach us. One open question within cosmology is how
much more universe there is beyond what we can see. Some think it’s not that much, yet others
think it could be substantial. But there is another idea, that it is infinite
and if that’s the case it introduces some very strange possibilities. In an infinite universe, it becomes plausible
that if you travel far enough you will run into another earth, slightly different, with
another you living on it. Still further and you may find another, again
slightly different, and so on leading to a kind of physical, real alternate reality all
existing within the same universe. Given that we will never be able to observe
the entire universe due to the expansion of the universe, this question may remain forever
open. 8. The Double Slit Experiment This strange aspect of our universe is one
of those kinds of things that make sense when expressed in the mathematical terms of physics,
but appears counterintuitive to a human. But the double slit experiment always yields
the same result, having been performed thousands of times. It has to do with the dual nature of particles
as both waves and particles. The idea is that you fire particles, say electrons,
at a baffle with two slits cut into it. Behind the baffle is a wall. You will see on the wall as the electrons
pass through the slits an interference pattern, indicating that the particle is behaving as
a wave, much like an ocean wave passing under a pier. However, when you put detectors on the other
side of the baffle and observe the particles the interference pattern on the wall disappears
and becomes two slits indicating that the particle is acting as particle, not a wave. In short, for all intents and purposes, the
act of merely observing it changes the outcome of the experiment. 7. Will the universe someday cease to exist? A great unknown within cosmology is what’s
eventually going to happen to the universe. In one view, it will simply go on forever
until literally all stars burn out, black holes evaporate, iron stars form and all goes
dark at some point but continue on infinitely. This in itself opens up very bizarre possibilities
of chance and infinite time, such as the formation of a boltzmann brain, where random fluctuations,
if given enough time will cause some kind of a consciousness to randomly appear in the
dead universe out of nowhere. But it could alternatively be that the universe
will someday meet an end. This debate is not settled within cosmology,
and there have been many potential ends of the universe advanced, but two possibilities
stand out. The first is if the proton is capable of decaying. This is an unknown, but if they indeed do
decay the universe will effectively end when they do, given that all matter in the universe
will simply dissolve. Another possibility is that the universe itself
is somewhat unstable in that it doesn’t exist at its true vacuum state. If something were to happen within the universe
that pushed some part of it to the true vacuum, the results would be disastrous. Expanding at the speed of light, the entire
universe would be ripped apart as it moved to the true vacuum. This could dramatically alter how the universe
works, such as how gravity functions, or how matter is structured. The universe as we knew it at least, would
no longer exist and we very likely wouldn’t survive it. Thankfully, the timeframes for this to happen
are very likely far longer than our species can exist within the universe. 6. What set off the big bang? Regarding the big bang, generally, the earlier
you go in that process, the less it is understood by current science. Known as the Planck Epoch, when applied to
the first moments of the big bang, the theories that physicists rely on to describe the universe,
particularly Einstein’s General Relativity, no longer predict what exactly happened. What can be done is somewhat informed speculation
based on evidence of the Big Bang, such as the cosmic microwave background radiation,
and there exists several scenarios that might someday prove to explain what exactly happened. One possibility comes from string theory and
its variants, where the universe is suspended on a kind of membrane. When this membrane collided with another membrane,
that impact set off the big bang. Others include that the whole thing was set
off as a result of quantum fluctuations, or that the universe is one of many in a kind
of multiverse where universes bud like flowers on a tree off of other universes. Also suggestions have been made that the universe
is the other side of a black hole, known as a white hole where matter leaves the black
hole. Whatever the case may be, because we have
no way of seeing what happened during the Planck Epoch, it’s entirely possible we
may never fully understand what exactly happened. 5. Spooky Action at a Distance We often view the universe as a place of immense
distance. Any two objects can be separated by almost
unfathomable distances,so distant that they can’t ever even observe each other. But that absolute concept of separation is
not necessarily set in stone in the quantum mechanical world. In fact, separated particles can be connected
to each other through a phenomenon of quantum mechanics over vast distances and influence
each other instantaneously, so long as they had some physical interaction in the past
that entangled them. Einstein called it spooky action at a distance
and absolutely hated the idea, but the phenomenon of quantum entanglement is real and has been
experimentally proven. Put simply, if one particle changes behaviour
such as its spin, the other reacts instantaneously, no matter how far away it is. Unfortunately, this behavior cannot be predicted,
meaning that it can’t be used to convey information, the universe does not allow information
to propagate faster than light. Exactly how this occurs depends on what interpretation
one holds of quantum mechanics, though ultimately we may never know exactly how particles do
this. Just simply that they do. 4. 11 Dimensions of Space and Time Regarding our last entry, one of the ways
quantum entanglement might work is that particles might not be connected spatially in the dimensions
we perceive, but might be closely connected in another dimension that we can’t perceive. While it’s still very much up in the air
whether other dimensions exist, or how many there could be, there are hypothetical possibilities,
particularly within the realm of string theory. One interpretation involves 11 dimensions,
ten of space and one of time. The reason we do not see these other dimensions
of space is because they are curled up, and thus imperceptible to us. But at the very first moments of the big bang,
they may not have been, and may have played a role. Whether this is the case or not, or whether
other dimensions even exist at all, could remain open forever. 3. Time Travel Is Possible -- At Least in one
Direction Is time travel possible? The arguments against traveling to the past
are numerous, especially because it would violate causality. It’s the old what happens if you go back
in time and kill your own grandfather scenario. Would you cease to exist? But that’s only part of the story of time
travel, and it may not be as set in stone as you might think. Now travel to the future is easy, it’s literally
built into the universe and you’re doing it right now as the clock ticks. Because of relativity however, very high accelerations
can affect time in a process called time dilation, that allows you, in your frame of reference,
to travel into the future simply by accelerating. This is exemplified by the twin paradox, where
one twin stays on earth, and another twin travels through space at relativistic speeds
and when he gets back, he’s no longer the same age as his twin. Even on smaller scales, satellites in orbit
have to be corrected for minute amounts of time dilation. So, in short, if you go extremely fast in
space, you will travel forward in time at a different rate than someone sitting here
on earth. Trouble is, if you go 500 years into the future,
you have no way of ever getting back to your own time. Or do you? The answer is maybe, but it wouldn’t be
easy, and in all practicality is likely impossible. But this may not mean that backwards time
travel is strictly impossible in the universe. Hypotheses exist that under very special conditions,
such as if you had a rotating cylinder of infinite length, or under certain conditions
involving traversing a black hole or wormhole not through space, but time, might allow you
to at least in principle travel backwards. But, that we do not appear to see time travelers
from the future visiting suggests we will never figure out backwards time travel, or
it’s illegal, or we simply go extinct before we figure it out. 2. The Universe Will Someday Be Mostly Invisible In this option, we actually do understand
what’s happening, or least parts of it. But in the very far future, anyone that might
exist very well may not understand the vast majority of the universe in the way we do. This is because as the universe ages, and
continues its expansion, everything but your local group of galaxies will be so distant
that light cannot travel fast enough to make up for the expansion of the universe in between. Essentially a civilization existing in the
old age of the universe will have no idea that countless other galaxies exist in the
universe because they will be invisible. They may not even be able to determine that
a big bang ever happened, or know anything about the universe as it is today. They may be able to study their local group
of galaxies and glean some clues about the nature of the universe, but even worse an
isolated rogue star system in the intergalactic medium might not even have that option available
to them. They would essentially be marooned on their
world until the effective end of the universe itself, never knowing very much about it at
all. One. The Many Worlds Interpretation It’s possible to take a completely different
approach to the concept of parallel universes; different from the concept of a multiverse. In the 1950’s Hugh Everett hypothesized
that other universes could exist hovering, for lack of a better term, alongside our own,
constantly splitting off from each other and that events in those universes may all have
different outcomes. This leads to some strange ideas, such as
that in a parallel universe the dinosaurs did not undergo a mass extinction event, and
humans never evolved as a result leading to a modern earth still dominated by dinosaurs,
perhaps even intelligent ones. Other possibilities are well explored in science
fiction, from everything from what might have happend if the allies had been defeated in
world war II to evil alternate universe Spock with a beard. This may seem far fetched, and it is, but
not the underlying reasons why Everett hypothesized the possibility. Within Quantum mechanics is a question, one
related to the double slit experiment. Why does quantum matter behave so strangely? Why do particles take different forms? Niels Bohr hypothesized that these particles
don’t actually exist in any one state at all, but all possible states and that observing
the particle forces it to pick a state. But that’s only one take on it. In Everett’s interpretation, when a particle
chooses a state it actually causes a split in the universe itself, creating an entirely
new universe branching off from another, explaining why particles can be measured in different
states because they exist in all possible states spread across parallel universes. In the world of the big above the quantum
level, this means that there could be universes in which you are dead, or a very different
person. Whether these parallel universes exist or
not is an open question, and probably will never be answered as it doesn’t seem possible
we could ever detect or measure these other timelines. But this concept of collapsing wave functions
can be taken to an even more profound level. Some have asked the question does the entire
universe have a wave function? Would it even exist if it weren’t being
observed? It’s hard to believe that would be the case,
but it is a question, by its nature, we probably cannot ever answer for sure. Thanks for listening! I am futurist and science fiction author John
Michael Godier currently musing about alternative universe JMG again, the one without the goatee
that streams on twitch instead of making youtube videos and drives a malibu instead of a lebaron. I don’t think I like that guy at all and
be sure to check out his books at your favorite alternate universe online book retailer and
subscribe to my channels for regular, in-depth explorations into the interesting, weird and
unknown aspects of this amazing universe in which we live.
