Welcome back to Cosmos in a pod space and astronomy series.
You know, it's amazing to think that out there in the universe
there are objects shining brighter than an entire galaxy.
Yeah, it's pretty hard to wrap your head around.
It really is.
I mean, we're talking trillions of stars worth of light,
all packed into a space smaller than our solar system.
It's crazy.
It really is.
Sounds impossible, right?
Yeah, you wouldn't think it's possible.
Well, that's the mind boggling reality of quasars,
the cosmic lighthouses we're diving into today.
Yeah, quasars are fascinating objects,
and they really push the limits of what we thought
was possible in the universe.
So let's break this down a bit.
OK.
What exactly is a quasar?
I mean, quasi-stellar object, it sounds like something straight
out of Star Trek.
Yeah, it does have a kind of sci-fi ring to it.
It really does.
Well, the name actually comes from how
they were first discovered.
Astronomers were looking out into the universe
and they saw these points of light
kind of like stars, but when they studied the light
more closely, it was way off.
What do you mean, way off?
I mean, the spectra, the fingerprints of the light,
they were unlike anything they'd seen before.
Oh, so it wasn't just regular starlight?
Nope, not at all.
So they call them quasi-stellar objects, basically.
Star-like, but not quite.
OK, so like cosmic imposters then.
They look like stars, but are hiding something
much more intense.
Exactly.
And what they're hiding is a supermassive black hole,
millions or even billions of times the mass of our sun.
Whoa, hold on.
Black holes are supposed to be black, right?
They suck everything in, even light.
So how can they be the source of so much light, so much energy?
Yeah, that's the part that really blows your mind.
See, when matter falls into a black hole,
it doesn't just disappear quietly.
It gets whipped around at incredible speeds,
forming the swirling disk around the black hole.
Like a whirlpool.
Exactly.
It's called an accretion disk.
And as all that matter swirls around,
it gets heated up to millions of degrees.
Just from friction.
Friction and the intense gravitational forces.
All that superheated matter emits a ridiculous amount
of energy across the entire electromagnetic spectrum.
From radio waves to gamma rays, it's
like the ultimate cosmic light show.
So it's not the black hole itself that's shining,
but the stuff falling into it.
It's like the black hole's last meal
is putting on a spectacular performance
before it's gone forever.
Yeah, that's a great way to put it.
And that performance is incredibly
efficient at converting matter into energy.
It makes nuclear fusion, the process powering our sun,
look like a firefly compared to a supernova.
OK, now that is just mind blowing.
So we've got these supermassive black holes
surrounded by glowing swirling disks of matter.
But how did we figure out that it was
black holes behind all this?
Well, it took a lot of detective work.
Scientists saw this incredible energy output coming
from an unbelievably small area.
Right.
And they knew that the only thing that could pack
that much mass and energy into such a tight space
had to be a supermassive black hole.
It's amazing how we can piece together these cosmic puzzles
from, what, billions of light years away?
It is.
It's really remarkable what we can learn
from the light that reaches us.
Absolutely.
But here's another puzzle.
How did those supermassive black holes form in the first place?
Yeah, that's one of the biggest mysteries in astrophysics.
We know smaller black holes form when massive stars die
and collapse under their own gravity.
But supermassive black holes are a different breed.
They're millions or even billions of times more massive.
So how do you go from a regular size black hole
to a supermassive one?
Is it just like a cosmic growth spurt?
Do they just eat a ton of stuff?
Well, there are a few ideas out there.
One theory is that they start small and just gobble up
a ton of matter over billions of years.
So they're just constantly eating and growing.
Yeah, like a cosmic vacuum cleaner
on a never-ending feast.
That makes sense.
But is there another way?
Could they maybe skip the whole growing up phase
and just form as supermassive black holes
right from the get-go?
Yeah, that's another possibility.
Some scientists think that in the very early universe,
right after the Big Bang, giant clouds of gas
could have collapsed directly into supermassive black holes.
Whoa, so they just kind of popped into existence
fully formed.
Potentially, yeah.
It's still a bit of a mystery.
But either way, you end up with these behemoths lurking
in the hearts of galaxies.
So we're not entirely sure how they form,
but we know they're there powering
these crazy bright quasars.
But here's another thought.
If these quasars are so bright, can't we
see them from really far away?
You're catching on quickly.
That's exactly right.
OK, cool.
Because quasars are so luminous, we
can see them across vast cosmic distances.
We're at Kalfar.
We're talking billions of light years away.
When we observe these quasars, we're
literally looking back in time.
Wait, so we're seeing these quasars
as they were billions of years ago, like a time machine?
It is like a time machine.
It's pretty incredible.
So what can these ancient quasars
tell us about the early universe?
They give us clues about a time when the universe was much
younger and more chaotic, a period called
the epoch of reionization.
Imagine the early universe as this fog of neutral hydrogen.
Quasars were like cosmic lighthouses blasting
through that fog, stripping electrons
from the hydrogen atoms, and making the universe transparent
to light.
So these quasars weren't just shining bright.
They were actually changing the very fabric
of the early universe.
That's right.
They were clearing the fog for stars and galaxies
to form as we know them today.
That's amazing.
But hold on.
How do we even find these quasars in the first place?
They're billions of light years away.
Well, it's definitely a challenge.
But we've got some pretty clever tools to help us.
One of the main ones is something called redshift.
Redshift.
Yeah, imagine the universe is like a giant balloon that's
expanding.
As light travels through this expanding space,
its wavelength gets stretched, shifting towards the red end
of the spectrum.
OK, I think I'm following.
So the farther away a quasar is, the more its light is stretched,
the redder it appears.
You got it.
And quasars are so far away, their light
can be extremely redshifted.
By measuring that amount of redshift,
we can calculate how far away the quasar is.
And that tells us how far back in time we're seeing it.
Wow.
So redshift is like a cosmic yardstick,
helping us measure the vast distances to these quasars.
Exactly.
And besides redshift, quasars have these unique fingerprints
in their light called spectral lines.
Fingerprints.
Yeah, specific patterns of bright and dark lines
that tell us about the chemical composition
and the movement of the material swirling around the black hole.
So redshift tells us how far away they are.
And their spectral fingerprints confirm
that they are indeed quasars.
That's right.
It's amazing how much information
we can get from light that's traveled for billions of years.
It really is.
OK.
So we've talked about what quasars are, how they form,
how we find them.
But are there any famous quasars out there, any that really
stand out from the cosmic crowd?
Oh, absolutely.
There's 3C273, for example.
It was the first quasar ever discovered back in the 1960s.
The OG quasar.
You could say that.
It's still one of the brightest we can see from Earth.
Wow.
What about some of the more distant ones, the ones pushing
the limits of what we can observe?
Well, there's this one.
ULASJ1342 plus 0928.
It's the current record holder for the most distant quasar
ever found.
So how far back in time are we seeing that one?
We're seeing it as it was just 690 million years
after the Big Bang.
Wow.
It's like peering into the universe's infancy.
OK.
I got to ask, any real heavy hitters in the quasar world?
Oh, you want a heavy hitter?
Let's talk about TON618.
This one's an absolute monster.
Good boy.
Here we go.
Remember how we talked about our sun being big?
Well, imagine a black hole over 66 billion times more massive
than our sun.
That's just incomprehensible.
I know, right?
That's what's at the heart of TON618,
a hyperluminous quasar that puts everything else to shame.
66 billion times the mass of our sun.
It's like comparing a grain of sand to Mount Everest.
OK, but here's a question.
Are quasars just loners out there in the vastness of space,
or do they have any companions?
That's a great question.
And it leads us to the fascinating relationship
between quasars and their host galaxies.
OK.
They're not just isolated phenomena.
They're embedded within galaxies,
and they have a huge impact on their surroundings.
Interesting.
So it's not just the galaxy providing fuel for the quasar,
but the quasar is also influencing the galaxy.
Exactly.
It's a complex dance between the quasar and its host galaxy,
and that's what we'll explore further in this deep dive.
Well, I'm definitely ready to keep
dancing over this topic.
It's captivating.
It is, and there's so much more to uncover.
So we've talked about how quasars
are fueled by these supermassive black holes gobbling up matter,
but it's not exactly a clean and tidy process.
It's more like a cosmic food fight with energy blasting out
in all directions.
OK, so it's not just light pouring out then.
What else is going on in this cosmic free-for-all?
Well, think of it this way.
As the black hole devours all this matter,
it releases these incredibly powerful winds and jets
of particles.
It's not just a light show.
It's a cosmic hurricane, this torrent of energy
that can actually push gas and dust away
from the black hole.
Whoa, hold on.
So the black hole, this thing with insane gravity pulling
everything in, is also pushing stuff out at crazy speeds.
You got it.
It's like this cosmic tug of war.
It really is.
And these outflows of energy, these cosmic winds,
they can have a huge impact on the galaxy
surrounding the quasar.
So what kind of impact are we talking?
Well, they can actually blow gas and dust
away from the black hole, sometimes even out
of the entire galaxy.
Seriously?
And here's the kicker, that gas and dust is the stuff
that new stars are made of.
Oh, wow.
So the quasar is basically pushing away
its own food supply.
It's like it's on a diet, but it's blowing its food
across the whole galaxy.
Yeah, that's one way to think about it.
And this whole process, it's called feedback.
Feedback?
Yeah.
And it plays a crucial role in how galaxies evolve.
By pushing away the gassy dust, the quasar
can actually stop new stars from forming
in its host galaxy.
Wait, so the quasar, powered by this black hole that's
supposed to be sucking everything in,
is actually preventing new stars from being born.
Exactly.
It might seem kind of counterintuitive,
but that's the beauty of astrophysics.
The universe is full of these unexpected twists and turns.
It really is, yeah.
And this feedback process actually
helps explain why we see fewer quasars in the nearby universe.
Oh, how so?
Because they've already blown away their food supply,
they've dimmed down, gone quiet.
I see.
So all those seemingly peaceful galaxies
we see around us today, they might
have had a wild quasar-powered past.
Precisely.
We believe that most, if not all, big galaxies
have gone through a quasar phase at some point in their history.
Wow.
So they've had their crazy, energetic youth,
and now they've settled down into a more, I guess,
mature, quieter state.
That's a great way to put it.
It's amazing to think that these incredibly distant, incredibly
powerful objects can tell us so much about the galaxies around us,
even our own Milky Way.
Yeah, it really highlights how interconnected everything
is in the universe.
It does, yeah.
But as much as we've learned about quasars,
I'm sure there's still plenty of mysteries
to keep you guys up at night.
Oh, absolutely.
There's always more to learn, more to discover.
OK, so lay it on me.
Yeah.
What are some of the big questions that still puzzle
scientists about quasars?
Well, one of the biggest head scratchers
is how supermassive black holes grow so quickly
in the early universe.
Remember those distant quasars we were talking about,
the ones we see just a billion years after the Big Bang?
Yeah.
They already have black holes billions of times
the mass of our sun.
Yeah, that's crazy.
How do they get so big so fast?
I mean, is there some kind of cosmic growth formula
we're missing here?
That's what we're trying to figure out.
Our current models really struggle
to explain how those black holes could
have packed on so much weight in such a short amount of time.
It's like finding a dinosaur skeleton in a kindergarten
playground.
It just doesn't fit the timeline.
I love that analogy.
So there's something fundamental we're not understanding
about how black holes form and grow in the early universe.
It seems that way, yeah.
It's one of the most active areas of research
in astrophysics right now.
I bet.
OK, so what about the trigger for a quasar
to switch on in the first place?
We talk about galaxy mergers.
Right.
But is that the only way?
Well, galaxy mergers are definitely a major player.
When galaxies collide, it can send a huge amount of gas
and dust spiraling toward the central black hole,
fueling that quasar outburst.
But it might not be the only way.
OK.
We're also looking at other possibilities,
like instabilities within the galaxy itself.
Oh, interesting.
Or even interactions with nearby galaxies,
things that could sort of kickstart that quasar engine.
So it's not a one size fits all situation.
Right.
It's more like a cosmic recipe with multiple ingredients
that can lead to a quasar lighting up the universe.
That's a great analogy.
And we're still trying to figure out the exact recipe,
the sequence of events that leads to a quasar switching on
and then eventually fading away.
Right.
It's like we've got this puzzle with a few pieces still
missing.
The mystery continues.
But we're getting closer to the full picture all the time.
It's exciting to think there's still so much to learn
about these amazing objects.
Absolutely.
Quasars are like windows into the most extreme environments
in the universe.
They're pushing the boundaries of what we know about physics
and the cosmos.
And they're just so cool to think about.
They really are.
I mean, so to sum it all up, quasars
are more than just bright lights in the distant universe.
Right.
They're these powerful engines of galactic evolution.
Yeah.
They're shaping the galaxies they inhabit.
And they're giving us clues about the very early universe.
It's incredible, isn't it?
It is.
It really is mind blowing when you think about objects
so far away, being able to tell so much about the universe
we live in.
I know.
It's incredible, isn't it?
The sheer scale of it all.
These quasars fueled by black holes
that could swallow our entire solar system
without even a hiccup.
And they've been shining their light across the cosmos
for billions of years.
It's humbling, almost.
We're just these tiny specks trying
to understand these forces of nature that
are just so, so immense.
And it makes you wonder what else is out there.
Absolutely.
And that's what keeps us going as scientists,
that constant thirst for knowledge and understanding.
Every new discovery just opens up even more questions
and pushes us to re-examine what we thought
we knew about the universe.
I'm glad you mentioned that.
Because I think back to when we started
this deep dive into quasars, I thought
they were just these bright lights in the distant universe.
Right.
But now I realize there's so much more than that.
They're these powerful engines of galactic evolution,
shaping the galaxies they inhabit.
And they're giving us these invaluable clues
about the very early universe.
Exactly.
They're like time capsules, carrying information
about the universe's past, a time when everything was
so much more energetic and chaotic.
And who would have thought that these seemingly destructive
objects, these black holes, could actually
play such a crucial role in the birth and growth of galaxies?
I know, right?
It's a great example of how the universe is
full of these unexpected twists and turns.
It's full of paradoxes.
And that's part of what makes it so captivating, I think.
I couldn't agree more.
And for everyone listening out there,
I really hope this deep dive has sparked your own curiosity
and wonder about the universe and our place in it.
It certainly has for me.
Me too.
And if you're eager for more of these mind-blowing explorations
of the cosmos, be sure to subscribe to Cosmos
to a pod wherever you get your podcasts.
And hey, while you're at it, check out our YouTube channel
for even more cosmic content, including
stunning visuals and animations that
will bring these incredible objects to life.
Until next time, keep looking up and keep exploring.