Here’s a question for you.
What point in history would you travel back
to if our civilization had the technology
to traverse the cosmic stream of time and
space?
Would it be a trip to the construction of
the Great Pyramids of Giza - to see just exactly
what was going on?
Or would you swing on by the height of European
High Society - and spend your days drinking
wine at masquerade balls?
Well - the fiction of science has long speculated
the implications of time travel - but the
actual function of science has been fervently
opposed to the mechanics of the idea.
But - technically speaking - *could* we travel
through time and space?
And more importantly - do the impossibly strange
mechanics of black holes have something to
do with it?
Let’s find out.
Hello internet - what’s going on, and once
again welcome back to the most inquisitive
channel on YouTube - Life’s Biggest Questions.
As per usual, I’ll be your disembodied floating
voice Jack Finch - as today, we curiously
ask the question - Are Spinning Black Holes
The Key To Time Travel?
Roll the clip.
For the curious amongst you, that clip was
from David Tennant’s tenure as the Doctor
- as he battled the Master in the Last of
the Time Lords.
And that’s an interesting notion, isn’t
it?
Having a handheld device that could condense
the physical properties of a black hole.
Hmm - maybe they were on to something.
It leads us to our first elephant in the room
that we need to tackle though, before we get
into the whole black-hole timey-wimey hypothesis
- first we need to confront the question - is
time travel even possible?
Well, in actual fact - travelling forwards
in time is already surprisingly easy.
There you go.
A second just passed - we’re in the future.
Oh, it happened again!
But - of course, I’m talking theoretically
- and it’s thanks to Einstein’s super
special theory of relativity - which when
applied to the passage of time, describes
the fact that time passes at different rates
for people who are moving relative to one
another.
However, that effect only becomes large enough
to notice the closer you get to the speed
of light.
Okay, remember that part - because the speed
of light is incredibly important in this equation.
In the words of Einstein himself - the universe
has a speed limit - and that speed limit is
the speed of light - as in, nothing can travel
faster than 300 thousand kilometers per second
- due to the fact that it would take an infinite
amount of energy to do so - and thus the Cosmic
Speed Limit is dictated by the fastest possible
occurrence of energy.
Lightspeed.
Now, let’s lay down a little thought experiment
with that in mind.
Imagine our planet - and in a perfect circumference
is a train track that spans the entire width
of Earth.
Through immeasurable amounts of Energy - our
civilization has managed to power this train
to travel at a level just a tiny fraction
below that of the speed of light.
Of course, that would never happen - but this
is a thought experiment!
Now, imagine on that train - people are sat
comfortably in their carriages - watching
the Earth buzz by at just below 300 thousand
kilometers per second.
But then suddenly, a little girl on the carriage
jumps up out of her seat and runs down the
width of the train.
Oh no!
She’s moving at a certain speed - does that
mean her speed is added to the speed of the
train, and suddenly she’s travelling at
faster than the speed of light?
Does she disappear from time and space in
a bright burst of cosmic time-stuff?
No.
Of course not.
Because as far as she’s concerned - Einstein’s
theory of relativity is in action.
Time passes at different rates for people
who are moving relative to one another - and
her father gets up out of his seat and calls
her back.
*Stop running on this train, you’ll trip
over* - or something like that.
And everyone lives happily ever after.
However - there *is* something more to it.
Because if you were observing this train from
outside - you would see a vessel passing before
your eyes at just below the speed of light,
circling the planet at roughly 7 times per
second.
And what you’d be witnessing is theoretical
time travel, as everything that happened on
the train would appear to be in slow motion
- as the rest of the planet experienced hundreds
of years relative to perhaps just a week on
board the train.
All it takes is something really, really fast
- spinning at near the speed of light.
And you know what else functions in a similar
manner?
Where time dilates in a reminiscent fashion
to our super train?
Black holes, guys.
Black holes that spin really, really fast.
Now, of course - black holes are an enigma
of physics - so the following speculation
should be taken with a pinch of critical thinking
- but it appears that black holes as portals
aren’t as science-fiction-y as first thought.
It has long been the consensus that falling
through a black hole would be a very terrible
thing - given the fact that the unfathomable
cosmic force of it’s singularity tends to
obliterate all matter into a spiral of spaghetti.
But what has recently came to light - is that
all black holes aren’t created equally - and
some of them have some incredibly exciting
properties if you’re in the business of
traversing time and space.
For the vast majority of black holes - their
singularity is so hot and dense that any vessel
passing through it would be tidally stretched
and squeezed and then subsequently vaporized
- but for a supermassive black hole, like
Sagittarius A * which is located at the center
of our own galaxy - things are a little different.
And it’s thanks to its massive size and
relatively stable rotation that the effects
of travelling past it’s event horizon have
been recently theorized to be very small - if
not incredibly negligible.
In fact, any spacecraft and individuals on
board would perhaps not even detect the aforementioned
cosmic chaos - and slip safely past it’s
event horizon - to bravely go where no one
has gone before.
But what’s exactly down there?
What would we even be descending into?
Black holes are dead stars that have punched
a hole in the fabric of spacetime by overcoming
gravity itself - and their theoretical centre,
the singularity - is purely a mathematical
absolution.
It is dimensionless - where it has no place
for matter or density of any kind.
Is it condensed dark energy?
Is it antimatter?
That’d be really bad.
Is it the opposite end of a theoretical white
hole, punched into our perceived side of space-time?
You see - theoretically, actually breaching
a black hole’s event horizon *is* possible
- but what we’d be hurtling towards - that’s
anyone’s guess entirely.
The gravitational singularity of a black hole
is a one-dimensional point in spacetime which
contains a huge mass in an infinitesimally
small space - where both density and gravity
become theoretically infinite - and spacetime
curves into infinity and beyond - and where
the laws of physics as we know them cease
to operate.
Could it be an unknown scientific function
that moves really fast, much like the mechanics
of our time-travel train?
Possibly.
Because in the words of Kip Thorne - the singularity
is the one point where all laws of physics
break down.
And we have to approach this hypothetical
notion with a certain degree of humility - because
we don’t know.
Are Spinning Black Holes The Key To Time Travel?
We don’t know.
They could be, in certain specific scenarios
- or they could be the matter destroying cosmic
maws that we fear them to be.
To understand the singularity of a black hole
- also means to understand the beginning of
time itself.
Well, I suppose in that case - clock’s ticking.
Well, there we have it - our long and short
answer to the incredibly out-there question
- Are Spinning Black Holes The Key To Time
Travel?
Perhaps.
Let’s hope we find out.
Well, what did you guys think?
Do you agreed?
Disagree?
Have anything to add?
Let us know your thoughts down in the comment
section below - as well as any choice hypothetical
scenarios that you’d like to see in future
videos.
Before we depart, let’s take a quick look
at some of your more creative comments from
over the past few days.
Kieran Humphreys says --
--- What If Life’s Biggest Questions didn’t
answer my question ….
--- What a minute, is that a paradox?
Oh.
No.
Not another one.
Well on that note - that’s all we’ve got
time for in today’s video - that’s enough
paradoxical thinking for me.
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As per usual, I’ve been your disembodied
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until next time, you take it easy.
