Black holes have been the holy grail of cosmology since the time Einstein conceptualized them
in his Theory of General Relativity.
Well as it turned out, thanks to Dr. Stephen Hawking we know that not only do they exist
but are so enigmatic and powerful that they bow to no rules of physics and challenge the
theory of general relativity as well.
Over the years, they have challenged the most brilliant minds of humanity and continue to
do so with their mysterious existence.
Even Stephen Hawking found himself wrong about them more than once.
What makes them move?
Are they ageless entities that will live beyond the time of the Universe?
And what exactly would cause your death if you ever fell into one?
Watch this video till the end to find out!
Stephen Hawking was Wrong, Black holes have a lifespan
When it comes to cosmology, perhaps there is no bigger name after Einstein than Stephen
Hawking.
An icon of Modern physics, his contributions changed what we know of the universe and helped
us get closer to the biggest enigma of cosmology, black holes.
However, being a great scientist is not just about always being right but also recognizing
the mistakes you made over the course and correcting them.
Stephen Hawking played a crucial part in the discovery of the black holes but even he now
and then got something wrong about them.
You cannot blame the guy; black holes are such an anomaly that they defy every single
rule of physics so you cannot hit the bulls’ eye with every calculation regarding them
and there would be some wild swings here and there.
Since the 1970s, Dr. Hawking had insisted that black holes are super concentrations
of gravity created by burned-out stars.
According to him, these space monsters swallow up matter and energy that never reappear,
except as an unrecognizable flash of heat.
But in 2004, during the 17th International Conference on General Relativity and Gravitation
in Dublin, Dr. Hawking admitted that he was wrong.
A major question in theoretical physics that existed since Hawking discovered black holes
radiating thermally in 1974 was, “is information lost in black hole evaporation?”
According to Hawking in 2004, it was finally solved.
He corrected himself by saying that his new discovery has made him realize that information
about matter swallowed up in a black hole isn't really lost after all.
Stephen Hawking found out that the quantum effects would cause a black hole to radiate
at a steady rate.
That means that unlike as believed before, a black hole isn’t a cosmic god that is
eternal as the classic black hole theory had suggested.
Instead, a black hole eventually disintegrates and disgorges the matter and energy in a distorted
form.
All Black Holes are not Black If you explain a black hole to a person who
may have not ever heard of it before.
He may imagine it as a big black sphere of eternal void in space, devouring anything
coming its way.
Or they may imagine it as an actual black hole, like the ones you may have seen in the
Looney Tunes show.
However, not all black holes are black spheres in space.
As light can still be emitted from the region outside the event horizon.
In fact, some black holes tend to be the shiniest, brightest known objects in the universe.
Astronomers call them quasars.
If you do not know what a quasar is, here’s a simple explanation.
A quasar is essentially a supermassive black hole feeding on a huge amount of gas at the
center of a distant galaxy.
That makes quasars a different breed of black holes that are generally formed by the collision
of two galaxies, gorging on the inflowing material in the gaseous form.
As the gas spirals around it and falls in, the gas heats up in the process that leads
it to emit radiation across the electromagnetic spectrum.
This radiation is immensely bright and the whole galaxy lights up like a stadium hosting
the super bowl only millions of millions of times brighter, making the black hole look
not… black.
Coincidentally, there is another reason a black hole may not seem black.
It can be because of the way it may distort time.
This is more of a perception trick but due to the immense gravity of a black hole, it
can make things heading towards it look stationary from far away.
For example, a spaceship heading straight towards a black hole can appear standing still
to a third party, never actually reaching the black hole.
Similarly, a light source that has been sucked by a black hole could look eternally floating
in the space between the observer and the black hole.
This bright object would keep getting redder and redder, then fainter and fainter until
it would eventually disappear.
Astronomers call it “red shifting.”
Nope, Black Holes aren’t a Hole Either As we discussed before black holes aren’t
actually a hole or a portal, as they draw in Looney Tunes, in the space-time continuum.
It is instead a region of space where time and space just get very weird and incomprehensible.
We still do not know exactly what lies beyond the event horizon and unfortunately have no
feasible way to figure out that mystery for now.
Yet, there are still some scientists who do believe that certain black holes can be portals
to other places in the Universe, aka Wormholes!
Black holes aren’t Universe’s Vacuum Cleaner On paper, black holes sound like a vacuum
cleaning service of the cosmos.
Due to their nature of being a singularity, a ball of nothing but extremely crushing gravity,
they are so powerful that it distorts space and time around them.
But that doesn’t mean they suck everything like a giant vacuum cleaner!
Even though black holes are extreme in many ways, they don’t have infinite mass.
That means even though they have an immense amount of gravity, their force is still determined
by the amount of mass that particular black hole has.
Stellar black holes, for example, only have the mass of a very massive star.
So just like an object can orbit around a massive star without being pulled towards
its center, the same objects can happily orbit around a stellar black hole forever.
But we would still advise to not get super close to a black hole though.
The story would be very different from there on.
They Like to Move It, Move It When black holes were first discovered, people
believed that they were a sort of a fixed point in space-time destined to drag all nearby
matter and energy towards them to their eventual fate.
However, as we noticed they do not suck everything all the time and similarly they do not like
to stay stationary either.
Like galaxies, stars, planets, and everything else in the cosmos, black holes like to travel
across the universe as well.
In fact, this is why two black holes would collide or merge.
Frankly, that is exactly how we found out about their mobility because the very first
gravitational wave detected in 2015 was the result of a collision between two black holes
that ended up merging.
Not All Stars become Black Holes A lot of people believed that all stars end
their life cycle as black holes but astronomers have proved long ago that it isn’t true.
Stellar black holes are definitely formed when massive stars run out of fuel and collapse
in on themselves leading to a cataclysmic implosion but that fate isn’t sealed for
every star.
For example, our sun or any other star of similar size would likely end as a white dwarf.
Even more massive stars have no certainty to end up as a black hole, if the star’s
core manages to resist the gravitational collapse, it becomes a neutron star instead.
It is believed that a star has to be at least 20 times the mass of the sun before it can
be anywhere close to ending up as a stellar black hole.
Also, we are still figuring out where the supermassive black holes come from, they could
or could not be formed from stars.
Spaghettification doesn’t happen at Event Horizon
As a Black Hole’s gravity is so immensely powerful that it distorts time, any object
falling into it would look spaghettified from a safe distance.
Spaghettification is the effect of amplification until the object is eventually ripped into
a string of individual atoms.
Researchers tend to believe that spaghettification always happens at the event horizon of the
black hole.
However, that is not the case.
Though spaghettification is a real phenomenon related to black holes, exactly where it occurs
can vary from black hole to black hole depending on its size.
For example, in the case of supermassive black holes, it would happen way later after passing
the event horizon.
Black Holes Can Actually be Seen Though it is a fact that once the light has
passed the event horizon there is no hope for it to escape due to the near infinite
strength of gravity in there, that fact doesn’t make a black hole invisible.
We can still observe black holes by observing how stars around them move.
This was the method used to spot Sagittarius A* for the first time.
In fact, now we can photograph these suckers, pun intended.
(E: show pic of Sagittarius A*) See?
Telescopes can also spot black holes by spotting the large accretion disk of stars, gas and
other materials spiraling towards the center as they did in the case of the M87 supermassive
black hole.
The material in the accretion disk is heated by friction as it swirls near light speeds
and emits electromagnetic radiation.
You Won’t Die Because of being Crushed in a Black Hole
Though it is true that nobody could survive the immensely crushing gravity of a black
hole, surprisingly that won’t be the reason for your death if you ever fell into a black
hole.
It is in fact, the spaghettification that would disintegrate you before gravity can
squeeze your insides out.
We discussed what spaghettification is earlier in this video.
So, as you can imagine, before you could get any close to the black hole to be compressed
by its immense gravity, the process of being amplified would tear you apart into molecules.
And it will happen long before you could feel the weight of the entire universe crushing
you in your last moments.
Hadron Collider Didn’t Create Black Holes Since the conceptualization of the Large Hadron
Collider, the world’s biggest particle accelerator, there have been rumors and fear among the
general public and certain parts of the science community that the particle accelerator would
be powerful enough to create tiny black holes that would end up destroying us all.
But the scientists of the LHC, credited for proving the existence of the Higgs Boson Particle,
successfully demonstrated that it wasn’t the case.
The particle collisions that occur at the LHC are nothing different than collisions
that happen in nature on our very earth all the time.
LHC only makes them happen in isolation so physicists can observe and study them.
In fact, even if we could harness all the mass of every single object in our solar system,
it won’t be anywhere sufficient to create a stellar black hole.
Some people were also worried about the LHC creating microscopic black holes but even
cosmologists aren’t sure if they actually exist.
So, what do you think, do tiny black holes exist in the universe?
Did we miss any theory in this list?
Tell us in the comments Please give us a thumbs up if we kept you
engaged and subscribe to our channel so you don't miss a thing.