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Black Holes are among the most mysterious
objects in the sky but, how dangerous are
they?
I want to explore this question a little now
on kNews!
Hey guys Lukas here, welcome to kNews and
as always a big shout out to my crowdfunding
buddies, my kNews boosters on Patreon.
Thanks for your thrust!
Hold hold hold, before I talk about the Dark
Side let me give you a quick update on recent
rocket launches.
For the US there was a SpaceX Falcon 9 that
launched on June 29th from Cape Canaveral.
Up top was another Dragon Spacecraft part
of the Commercial Resupply Services for the
International Space Station.
It’s number 15 already but still an older
version 1 capsule.
Sadly no Dragon 2 yet guys.
But speaking of Dragon 2 there is some progress
being made.
SpaceX new spaceship was recently put to the
test in NASA's biggest vacuum chamber that
can simulate the rigors of space like temperature
gradients.
It basically gets toasted on one side and
the heat stripped away from the other to stress
the entire body as it bends and twists from
the expansion forces.
I’m not sure of the outcome yet but I guess
it is unlikely for it to break since, well
SpaceX flies upper stages and Dragons in space
already and nothing teared apart so far.
So I assume they know what they are doing.
Dragon looks a little rough in this image
but that is going to change as there are some
parts missing and SpaceX will make sure it
looks pretty on its maiden flight.
Another launch happened in China a little
earlier on June 27th, more precisely in Xichang.
It’s a Long March 2C carrying three satellites
of type Yaogan and a secondary payload for
the Shanghai Micro Satellite Engineering Center
called Weina.
I’m not entirely sure what it does but Yaogan
are part of China’s spicy reconnaissance
fleet in low earth orbit.
And lastly there was an Electron which was
pushed back and delayed which is still supposed
to launch from New Zealand.
While the company Rocket Lab is based in the
US I still count that one for them because,
well I like Kiwis because they sound like
kNews.
Ontop are multiple Kiwi sized nanosatellites
from different entities and I want to highlight
Irvine 01, which was built by US students
in a joint project called the Irvine CubeSat
STEM Program.
The satellite will take pictures of Venus
and other stars to make use of the so called
parallax effect as it orbits earth.
Close stars like Venus shift much more than
distant ones so one can derive a 3 dimensional
map of the sky, using just the information
from its images.
Such 3D maps also give important clues to
maybe invisible things in space.
Things we cannot see through regular telescopes,
hiding and lurking behind a cover of darkness.
Yes, these are of course black holes I’m
talking about.
I personally find the name black hole a little
misleading but it got stuck for what is essentially
just a black star.
A star forms from collapsing gas clouds in
space very similar to gas giants like Jupiter.
What you see here is a litte simulation I
wrote based on Newtonian physics and this
shall just prove that all further animations
- with the simulation icon to the lower right
- are not just made up but act very similar
if not identical to real planets and stars.
I could in fact never control the movements
of so many objects by hand and if you are
still sceptical you can of course look for
errors in some of the celestial body movements.
They are all equal in mass and occupy a region
that is roughly as big as our inner solar
system.
Back at a star formation the amount of gas
collapsing into a single object is much bigger
than that of a gas giant so that the star
generates enough pressure in its core for
fusion to begin.
Fusing atom cores or nuclei together requires
immense forces because they repel each other
as they are made of Protons and Neutrons and
are therefore positively charged.
Once they get close enough though, other forces
that keep the Protons themselves holding together
take over and the two cores snap together
rapidly as if a barrier was crushed.
Depending on what elements fuse this process
releases a lot of energy which heats up the
star’s core to many many millions of degrees
Celcius.
Life would actually be impossible near any
star if there wasn’t that thousands of kilometers
thick gas cloud covering the hot inner regions,
which is also necessary to generate that pressure
in first place.
So we don’t have to fear that this cloud
could be blown away off our sun anytime soon
since the star would not be able to sustain
such a strong fusion without it.
But, at some point, as a star’s fusion gets
more intense with age, the core temperature
gets hotter and hotter fusing elements together
even at the most outer layers.
This is where a star blows up to many times
its size until its core extinguishes causing
the entire star to collapse.
This collapse or implosion causes some massive
star clouds to bounce back exploding into
outer space, a supernova.
It spreads the new elements it created around
the galaxy causing nearby gas clouds to collapse
in a billion year chain reaction forming new
stars and systems as the universe ages.
Just btw. a supernova, while similar, is not
directly related to a nova.
The terms got a little mixed up right there
since a regular nova is a star explosion caused
by one star feeding from another, and not
one star blowing up on its own.
Anyways, the remains most commonly shrink
forming a white or black dwarf star.
For extremely massive stars however, this
is where it gets really interesting.
The dwarf they leave behind ia a Neutron Star
where you couldn’t lift a single scoop of
matter with the strongest of machines.
A cubic meter has a mass of millions of tons.
Unimaginably heavy.
Such a Neutron Star is the only glimpse we
have at the formation of black holes.
They are essentially the last step before
matter collapses into the abyss.
Into nothing, a single point with zero space,
the famous singularity.
Full disclosure, I’m not a physicist, but
to get an idea how this is possible at all
one has to know that the size of matter as
we know it, is only based on the fundamental
forces of nature.
A solid surface looks solid to us because
of the way light bounces of it and it feels
solid because of how the surface atoms interact
with our body’s.
We can’t push our hand through it because
there is a force stopping us.
And it is nothing but a force.
The force is strong in that one.
Given enough pressure you could push your
hand through everything assuming that the
force would not crush the hand itself.
What I try to say is even the smallest of
elements that take up a certain space do that
based on these strange forces, that just exist
with yet unknown origin.
This hopefully helps to illustrate that when
the outside pressure caused my gravity wins,
they can collapse indefinitely like the hand
moved through the wall.
There is no known boundary or limit to how
small matter or energy can be compressed by
gravity.
Thinking about black holes it is therefore
important to know that these are giant stars,
carrying the same mass, just collapsed into
spaces so small that we cannot see them anymore.
What we instead see or not s...not observe,
is a region surrounding them where the gravity
gets so intense that everything that falls
behind it is trapped forever, even light.
The distance from the singularity where this
region begins is the so called Schwarzschild
or Schwarzschild radius and it can range from
just a few kilometers for small black holes
up to millions of kilometers for supermassive
ones like the one holding our galaxy together
in the center of our milky way.
The literal translation of Schwarzschild from
German btw. is Black Shield Radius which is
ironically quite fitting.
However, it is actually a German astrophysicist’s
name: Karl Schwarzschild.
So it’s not a term you would translate.
While the inner workings of a black hole are
unknown and matter of speculation, everything
outside the Schwarzschild-Radius is very well
understood.
The gravity of a black hole is not different
to that of stars and other bodies even ourselves.
The black hole in our galaxy’s center is
not sucking up the galaxy as one would maybe
imagine.
The tens of billions of stars just orbit it
on peaceful and stable trajectories like our
solar system does for now billions of years
with a couple dozen rounds trips so far.
The dangerous black holes I want to talk about
are not the giant ones in the centers of galaxies.
I want to talk about relatively small rogue
black holes that zip around the milky way
like our sun does.
Unlike our sun they are invisible and they
can only be observed indirectly by either
a glowing disc of matter surrounding them,
or the warp in spacetime they create.
Gravity warps spacetime forming a giant 3-dimensional
funnel a little like this.
This funnel is the reason for why we are glued
to our planet’s surface and don’t fall
off into space.
So keeping track and mapping the 3D space
of our surrounding stars is therefore vital
to find such rogue black holes.
The danger does not lie in the black hole
itself though.
At least according to my simulations.
A direct hit with our sun or our earth is
very unlikely due to their incredibly small
size but that doesn’t means its harmless.
Our solar system balanced itself out of billions
of years and is much more fragile that one
would imagine.
To illustrate this I can again use my little
simulation tool and plug in the numbers for
our solar system.
It now shows how the real orbiting bodies
would be affected by a flyby of the most lightest
of black holes, just a couple times heavier
than our sun.
The camera is locked to the sun so the point
it leaves behind is its origin as it gets
attracted towards the incoming threat.
And here it comes from the top.
Woah.
It really scared the hell out of me when I
saw this.
I never really thought about the dangers of
just a seemingly innocent flyby.
The black hole would fling most of the solar
system’s planets into deep space and separate
us from our host star or as seen here throw
us directly into it.
Our future friends on Mars are not much better
off.
I simulated it hundreds of years into the
future at it will end up crashing into the
sun as well as Jupiter gives it its final
gravity assist.
This means just moving to a neighbouring planet
is not the final solution to safe humanity
and possibly life for an eternity.
We have to move out to different stars in
the long run if we want to sustain us and
our surroundings.
But falling into the sun has actually a rather
low chance and I use this for the dramatic
effect.
The by far most common outcome in all the
simulations I ran is a slingshot into deep
space.
Black holes are multiple times more heavy
than our sun so such slingshots are incredibly
powerful.
Now, I don’t want to leave you worrying
about such a dark future.
We as humans are thankfully very good at dealing
with never before seen problems and science
will allow us to identify such threats long
before they actually put our lifes at risk.
We would become the Guardians of the Earth
as we’d use our knowledge of fusion power
to create our own sun.
Or multiple ones!
Double sun power!
But seriously, we could fuse hydrogen like
the sun does to warm up the planet even without
a star so I am very positive that even such
a worst case scenario would not be the end
of all life as we know it.
The foundations to this are currently laid
at many places and one of them is ITER or
International Thermonuclear Experimental Reactor.
The biggest ever experimental fusion reactor
that is supposed to generate power is being
built in europe as I speak.
But the first step would probably be to seek
shelter below the ground to make use of our
own planet’s heat source, the by nuclear
fission driven thermal activities deep down
below the earth’s crust.
For that we’d need boring machines and what
not which is of course also being worked on,
but that’s maybe a story for another video.
Have you ever thought about black holes flying
by our sun?
Tell me what you think!
Okay, that shall conclude this episode and
I hope to see you in the next one if you like.
Auf Wiedersehen and thank you for watching!
