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.