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Welcome back to Cosmos in a pod space and astronomy series.

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You know, it's amazing to think that out there in the universe

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there are objects shining brighter than an entire galaxy.

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Yeah, it's pretty hard to wrap your head around.

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It really is.

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I mean, we're talking trillions of stars worth of light,

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all packed into a space smaller than our solar system.

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It's crazy.

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It really is.

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Sounds impossible, right?

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Yeah, you wouldn't think it's possible.

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Well, that's the mind boggling reality of quasars,

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the cosmic lighthouses we're diving into today.

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Yeah, quasars are fascinating objects,

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and they really push the limits of what we thought

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was possible in the universe.

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So let's break this down a bit.

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OK.

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What exactly is a quasar?

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I mean, quasi-stellar object, it sounds like something straight

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out of Star Trek.

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Yeah, it does have a kind of sci-fi ring to it.

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It really does.

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Well, the name actually comes from how

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they were first discovered.

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Astronomers were looking out into the universe

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and they saw these points of light

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kind of like stars, but when they studied the light

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more closely, it was way off.

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What do you mean, way off?

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I mean, the spectra, the fingerprints of the light,

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they were unlike anything they'd seen before.

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Oh, so it wasn't just regular starlight?

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Nope, not at all.

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So they call them quasi-stellar objects, basically.

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Star-like, but not quite.

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OK, so like cosmic imposters then.

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They look like stars, but are hiding something

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much more intense.

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Exactly.

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And what they're hiding is a supermassive black hole,

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millions or even billions of times the mass of our sun.

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Whoa, hold on.

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Black holes are supposed to be black, right?

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They suck everything in, even light.

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So how can they be the source of so much light, so much energy?

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Yeah, that's the part that really blows your mind.

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See, when matter falls into a black hole,

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it doesn't just disappear quietly.

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It gets whipped around at incredible speeds,

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forming the swirling disk around the black hole.

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Like a whirlpool.

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Exactly.

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It's called an accretion disk.

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And as all that matter swirls around,

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it gets heated up to millions of degrees.

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Just from friction.

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Friction and the intense gravitational forces.

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All that superheated matter emits a ridiculous amount

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of energy across the entire electromagnetic spectrum.

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From radio waves to gamma rays, it's

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like the ultimate cosmic light show.

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So it's not the black hole itself that's shining,

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but the stuff falling into it.

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It's like the black hole's last meal

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is putting on a spectacular performance

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before it's gone forever.

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Yeah, that's a great way to put it.

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And that performance is incredibly

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efficient at converting matter into energy.

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It makes nuclear fusion, the process powering our sun,

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look like a firefly compared to a supernova.

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OK, now that is just mind blowing.

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So we've got these supermassive black holes

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surrounded by glowing swirling disks of matter.

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But how did we figure out that it was

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black holes behind all this?

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Well, it took a lot of detective work.

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Scientists saw this incredible energy output coming

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from an unbelievably small area.

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Right.

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And they knew that the only thing that could pack

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that much mass and energy into such a tight space

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had to be a supermassive black hole.

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It's amazing how we can piece together these cosmic puzzles

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from, what, billions of light years away?

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It is.

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It's really remarkable what we can learn

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from the light that reaches us.

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Absolutely.

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But here's another puzzle.

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How did those supermassive black holes form in the first place?

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Yeah, that's one of the biggest mysteries in astrophysics.

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We know smaller black holes form when massive stars die

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and collapse under their own gravity.

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But supermassive black holes are a different breed.

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They're millions or even billions of times more massive.

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So how do you go from a regular size black hole

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to a supermassive one?

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Is it just like a cosmic growth spurt?

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Do they just eat a ton of stuff?

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Well, there are a few ideas out there.

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One theory is that they start small and just gobble up

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a ton of matter over billions of years.

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So they're just constantly eating and growing.

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Yeah, like a cosmic vacuum cleaner

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on a never-ending feast.

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That makes sense.

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But is there another way?

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Could they maybe skip the whole growing up phase

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and just form as supermassive black holes

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right from the get-go?

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Yeah, that's another possibility.

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Some scientists think that in the very early universe,

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right after the Big Bang, giant clouds of gas

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could have collapsed directly into supermassive black holes.

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Whoa, so they just kind of popped into existence

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fully formed.

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Potentially, yeah.

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It's still a bit of a mystery.

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But either way, you end up with these behemoths lurking

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in the hearts of galaxies.

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So we're not entirely sure how they form,

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but we know they're there powering

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these crazy bright quasars.

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But here's another thought.

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If these quasars are so bright, can't we

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see them from really far away?

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You're catching on quickly.

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That's exactly right.

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OK, cool.

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Because quasars are so luminous, we

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can see them across vast cosmic distances.

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We're at Kalfar.

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We're talking billions of light years away.

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When we observe these quasars, we're

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literally looking back in time.

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Wait, so we're seeing these quasars

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as they were billions of years ago, like a time machine?

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It is like a time machine.

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It's pretty incredible.

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So what can these ancient quasars

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tell us about the early universe?

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They give us clues about a time when the universe was much

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younger and more chaotic, a period called

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the epoch of reionization.

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Imagine the early universe as this fog of neutral hydrogen.

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Quasars were like cosmic lighthouses blasting

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through that fog, stripping electrons

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from the hydrogen atoms, and making the universe transparent

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to light.

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So these quasars weren't just shining bright.

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They were actually changing the very fabric

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of the early universe.

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That's right.

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They were clearing the fog for stars and galaxies

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to form as we know them today.

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That's amazing.

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But hold on.

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How do we even find these quasars in the first place?

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They're billions of light years away.

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Well, it's definitely a challenge.

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But we've got some pretty clever tools to help us.

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One of the main ones is something called redshift.

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Redshift.

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Yeah, imagine the universe is like a giant balloon that's

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expanding.

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As light travels through this expanding space,

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its wavelength gets stretched, shifting towards the red end

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of the spectrum.

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OK, I think I'm following.

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So the farther away a quasar is, the more its light is stretched,

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the redder it appears.

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You got it.

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And quasars are so far away, their light

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can be extremely redshifted.

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By measuring that amount of redshift,

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we can calculate how far away the quasar is.

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And that tells us how far back in time we're seeing it.

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Wow.

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So redshift is like a cosmic yardstick,

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helping us measure the vast distances to these quasars.

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Exactly.

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And besides redshift, quasars have these unique fingerprints

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in their light called spectral lines.

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Fingerprints.

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Yeah, specific patterns of bright and dark lines

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that tell us about the chemical composition

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and the movement of the material swirling around the black hole.

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So redshift tells us how far away they are.

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And their spectral fingerprints confirm

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that they are indeed quasars.

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That's right.

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It's amazing how much information

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we can get from light that's traveled for billions of years.

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It really is.

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OK.

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So we've talked about what quasars are, how they form,

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how we find them.

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But are there any famous quasars out there, any that really

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stand out from the cosmic crowd?

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Oh, absolutely.

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There's 3C273, for example.

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It was the first quasar ever discovered back in the 1960s.

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The OG quasar.

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You could say that.

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It's still one of the brightest we can see from Earth.

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Wow.

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What about some of the more distant ones, the ones pushing

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the limits of what we can observe?

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Well, there's this one.

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ULASJ1342 plus 0928.

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It's the current record holder for the most distant quasar

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ever found.

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So how far back in time are we seeing that one?

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We're seeing it as it was just 690 million years

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after the Big Bang.

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Wow.

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It's like peering into the universe's infancy.

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OK.

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I got to ask, any real heavy hitters in the quasar world?

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Oh, you want a heavy hitter?

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Let's talk about TON618.

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This one's an absolute monster.

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Good boy.

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Here we go.

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Remember how we talked about our sun being big?

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Well, imagine a black hole over 66 billion times more massive

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than our sun.

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That's just incomprehensible.

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I know, right?

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That's what's at the heart of TON618,

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a hyperluminous quasar that puts everything else to shame.

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66 billion times the mass of our sun.

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It's like comparing a grain of sand to Mount Everest.

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OK, but here's a question.

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Are quasars just loners out there in the vastness of space,

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or do they have any companions?

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That's a great question.

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And it leads us to the fascinating relationship

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between quasars and their host galaxies.

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OK.

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They're not just isolated phenomena.

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They're embedded within galaxies,

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and they have a huge impact on their surroundings.

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Interesting.

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So it's not just the galaxy providing fuel for the quasar,

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but the quasar is also influencing the galaxy.

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Exactly.

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It's a complex dance between the quasar and its host galaxy,

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and that's what we'll explore further in this deep dive.

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Well, I'm definitely ready to keep

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dancing over this topic.

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It's captivating.

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It is, and there's so much more to uncover.

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So we've talked about how quasars

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are fueled by these supermassive black holes gobbling up matter,

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but it's not exactly a clean and tidy process.

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It's more like a cosmic food fight with energy blasting out

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in all directions.

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OK, so it's not just light pouring out then.

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What else is going on in this cosmic free-for-all?

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Well, think of it this way.

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As the black hole devours all this matter,

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it releases these incredibly powerful winds and jets

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of particles.

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It's not just a light show.

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It's a cosmic hurricane, this torrent of energy

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that can actually push gas and dust away

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from the black hole.

271
00:09:11,200 --> 00:09:11,880
Whoa, hold on.

272
00:09:11,880 --> 00:09:15,200
So the black hole, this thing with insane gravity pulling

273
00:09:15,200 --> 00:09:18,680
everything in, is also pushing stuff out at crazy speeds.

274
00:09:18,680 --> 00:09:19,400
You got it.

275
00:09:19,400 --> 00:09:21,360
It's like this cosmic tug of war.

276
00:09:21,360 --> 00:09:22,320
It really is.

277
00:09:22,320 --> 00:09:25,660
And these outflows of energy, these cosmic winds,

278
00:09:25,660 --> 00:09:27,920
they can have a huge impact on the galaxy

279
00:09:27,920 --> 00:09:29,120
surrounding the quasar.

280
00:09:29,120 --> 00:09:30,880
So what kind of impact are we talking?

281
00:09:30,880 --> 00:09:33,560
Well, they can actually blow gas and dust

282
00:09:33,560 --> 00:09:35,720
away from the black hole, sometimes even out

283
00:09:35,720 --> 00:09:36,800
of the entire galaxy.

284
00:09:36,800 --> 00:09:37,680
Seriously?

285
00:09:37,680 --> 00:09:40,840
And here's the kicker, that gas and dust is the stuff

286
00:09:40,840 --> 00:09:42,200
that new stars are made of.

287
00:09:42,200 --> 00:09:42,760
Oh, wow.

288
00:09:42,760 --> 00:09:44,720
So the quasar is basically pushing away

289
00:09:44,720 --> 00:09:46,320
its own food supply.

290
00:09:46,320 --> 00:09:48,920
It's like it's on a diet, but it's blowing its food

291
00:09:48,920 --> 00:09:50,400
across the whole galaxy.

292
00:09:50,400 --> 00:09:52,020
Yeah, that's one way to think about it.

293
00:09:52,020 --> 00:09:54,360
And this whole process, it's called feedback.

294
00:09:54,360 --> 00:09:55,080
Feedback?

295
00:09:55,080 --> 00:09:55,580
Yeah.

296
00:09:55,580 --> 00:09:58,560
And it plays a crucial role in how galaxies evolve.

297
00:09:58,560 --> 00:10:00,800
By pushing away the gassy dust, the quasar

298
00:10:00,800 --> 00:10:03,400
can actually stop new stars from forming

299
00:10:03,400 --> 00:10:04,840
in its host galaxy.

300
00:10:04,840 --> 00:10:07,900
Wait, so the quasar, powered by this black hole that's

301
00:10:07,900 --> 00:10:09,760
supposed to be sucking everything in,

302
00:10:09,760 --> 00:10:12,400
is actually preventing new stars from being born.

303
00:10:12,400 --> 00:10:13,280
Exactly.

304
00:10:13,280 --> 00:10:15,080
It might seem kind of counterintuitive,

305
00:10:15,080 --> 00:10:17,560
but that's the beauty of astrophysics.

306
00:10:17,560 --> 00:10:21,040
The universe is full of these unexpected twists and turns.

307
00:10:21,040 --> 00:10:22,120
It really is, yeah.

308
00:10:22,120 --> 00:10:23,760
And this feedback process actually

309
00:10:23,760 --> 00:10:27,640
helps explain why we see fewer quasars in the nearby universe.

310
00:10:27,640 --> 00:10:28,400
Oh, how so?

311
00:10:28,400 --> 00:10:30,840
Because they've already blown away their food supply,

312
00:10:30,840 --> 00:10:32,960
they've dimmed down, gone quiet.

313
00:10:32,960 --> 00:10:33,480
I see.

314
00:10:33,480 --> 00:10:35,880
So all those seemingly peaceful galaxies

315
00:10:35,880 --> 00:10:38,000
we see around us today, they might

316
00:10:38,000 --> 00:10:40,480
have had a wild quasar-powered past.

317
00:10:40,480 --> 00:10:41,440
Precisely.

318
00:10:41,440 --> 00:10:44,960
We believe that most, if not all, big galaxies

319
00:10:44,960 --> 00:10:47,720
have gone through a quasar phase at some point in their history.

320
00:10:47,720 --> 00:10:48,320
Wow.

321
00:10:48,320 --> 00:10:51,320
So they've had their crazy, energetic youth,

322
00:10:51,320 --> 00:10:54,040
and now they've settled down into a more, I guess,

323
00:10:54,040 --> 00:10:55,520
mature, quieter state.

324
00:10:55,520 --> 00:10:56,800
That's a great way to put it.

325
00:10:56,800 --> 00:11:00,520
It's amazing to think that these incredibly distant, incredibly

326
00:11:00,520 --> 00:11:04,400
powerful objects can tell us so much about the galaxies around us,

327
00:11:04,400 --> 00:11:05,600
even our own Milky Way.

328
00:11:05,600 --> 00:11:08,200
Yeah, it really highlights how interconnected everything

329
00:11:08,200 --> 00:11:09,400
is in the universe.

330
00:11:09,400 --> 00:11:11,000
It does, yeah.

331
00:11:11,000 --> 00:11:12,840
But as much as we've learned about quasars,

332
00:11:12,840 --> 00:11:14,760
I'm sure there's still plenty of mysteries

333
00:11:14,760 --> 00:11:15,960
to keep you guys up at night.

334
00:11:15,960 --> 00:11:16,760
Oh, absolutely.

335
00:11:16,760 --> 00:11:19,080
There's always more to learn, more to discover.

336
00:11:19,080 --> 00:11:20,400
OK, so lay it on me.

337
00:11:20,400 --> 00:11:21,640
Yeah.

338
00:11:21,640 --> 00:11:24,080
What are some of the big questions that still puzzle

339
00:11:24,080 --> 00:11:26,720
scientists about quasars?

340
00:11:26,720 --> 00:11:28,280
Well, one of the biggest head scratchers

341
00:11:28,280 --> 00:11:32,040
is how supermassive black holes grow so quickly

342
00:11:32,040 --> 00:11:33,400
in the early universe.

343
00:11:33,400 --> 00:11:35,760
Remember those distant quasars we were talking about,

344
00:11:35,760 --> 00:11:38,520
the ones we see just a billion years after the Big Bang?

345
00:11:38,520 --> 00:11:39,040
Yeah.

346
00:11:39,040 --> 00:11:41,720
They already have black holes billions of times

347
00:11:41,720 --> 00:11:43,400
the mass of our sun.

348
00:11:43,400 --> 00:11:44,520
Yeah, that's crazy.

349
00:11:44,520 --> 00:11:46,960
How do they get so big so fast?

350
00:11:46,960 --> 00:11:49,280
I mean, is there some kind of cosmic growth formula

351
00:11:49,280 --> 00:11:50,400
we're missing here?

352
00:11:50,400 --> 00:11:51,960
That's what we're trying to figure out.

353
00:11:51,960 --> 00:11:53,680
Our current models really struggle

354
00:11:53,680 --> 00:11:55,320
to explain how those black holes could

355
00:11:55,320 --> 00:11:58,440
have packed on so much weight in such a short amount of time.

356
00:11:58,440 --> 00:12:01,400
It's like finding a dinosaur skeleton in a kindergarten

357
00:12:01,400 --> 00:12:02,000
playground.

358
00:12:02,000 --> 00:12:03,920
It just doesn't fit the timeline.

359
00:12:03,920 --> 00:12:05,560
I love that analogy.

360
00:12:05,560 --> 00:12:08,480
So there's something fundamental we're not understanding

361
00:12:08,480 --> 00:12:12,040
about how black holes form and grow in the early universe.

362
00:12:12,040 --> 00:12:13,200
It seems that way, yeah.

363
00:12:13,200 --> 00:12:15,480
It's one of the most active areas of research

364
00:12:15,480 --> 00:12:16,880
in astrophysics right now.

365
00:12:16,880 --> 00:12:17,440
I bet.

366
00:12:17,440 --> 00:12:21,080
OK, so what about the trigger for a quasar

367
00:12:21,080 --> 00:12:22,960
to switch on in the first place?

368
00:12:22,960 --> 00:12:24,240
We talk about galaxy mergers.

369
00:12:24,240 --> 00:12:24,760
Right.

370
00:12:24,760 --> 00:12:26,000
But is that the only way?

371
00:12:26,000 --> 00:12:28,400
Well, galaxy mergers are definitely a major player.

372
00:12:28,400 --> 00:12:31,960
When galaxies collide, it can send a huge amount of gas

373
00:12:31,960 --> 00:12:35,120
and dust spiraling toward the central black hole,

374
00:12:35,120 --> 00:12:37,360
fueling that quasar outburst.

375
00:12:37,360 --> 00:12:39,000
But it might not be the only way.

376
00:12:39,000 --> 00:12:39,520
OK.

377
00:12:39,520 --> 00:12:41,280
We're also looking at other possibilities,

378
00:12:41,280 --> 00:12:44,120
like instabilities within the galaxy itself.

379
00:12:44,120 --> 00:12:44,960
Oh, interesting.

380
00:12:44,960 --> 00:12:47,480
Or even interactions with nearby galaxies,

381
00:12:47,480 --> 00:12:50,700
things that could sort of kickstart that quasar engine.

382
00:12:50,700 --> 00:12:53,160
So it's not a one size fits all situation.

383
00:12:53,160 --> 00:12:53,640
Right.

384
00:12:53,640 --> 00:12:57,280
It's more like a cosmic recipe with multiple ingredients

385
00:12:57,280 --> 00:13:00,280
that can lead to a quasar lighting up the universe.

386
00:13:00,280 --> 00:13:01,320
That's a great analogy.

387
00:13:01,320 --> 00:13:04,320
And we're still trying to figure out the exact recipe,

388
00:13:04,320 --> 00:13:07,120
the sequence of events that leads to a quasar switching on

389
00:13:07,120 --> 00:13:08,480
and then eventually fading away.

390
00:13:08,480 --> 00:13:08,840
Right.

391
00:13:08,840 --> 00:13:11,280
It's like we've got this puzzle with a few pieces still

392
00:13:11,280 --> 00:13:12,200
missing.

393
00:13:12,200 --> 00:13:13,400
The mystery continues.

394
00:13:13,400 --> 00:13:16,400
But we're getting closer to the full picture all the time.

395
00:13:16,400 --> 00:13:18,920
It's exciting to think there's still so much to learn

396
00:13:18,920 --> 00:13:20,600
about these amazing objects.

397
00:13:20,600 --> 00:13:21,400
Absolutely.

398
00:13:21,400 --> 00:13:25,040
Quasars are like windows into the most extreme environments

399
00:13:25,040 --> 00:13:26,200
in the universe.

400
00:13:26,200 --> 00:13:29,600
They're pushing the boundaries of what we know about physics

401
00:13:29,600 --> 00:13:31,520
and the cosmos.

402
00:13:31,520 --> 00:13:33,160
And they're just so cool to think about.

403
00:13:33,160 --> 00:13:34,200
They really are.

404
00:13:34,200 --> 00:13:36,480
I mean, so to sum it all up, quasars

405
00:13:36,480 --> 00:13:38,840
are more than just bright lights in the distant universe.

406
00:13:38,840 --> 00:13:39,360
Right.

407
00:13:39,360 --> 00:13:42,320
They're these powerful engines of galactic evolution.

408
00:13:42,320 --> 00:13:42,820
Yeah.

409
00:13:42,820 --> 00:13:44,880
They're shaping the galaxies they inhabit.

410
00:13:44,880 --> 00:13:47,840
And they're giving us clues about the very early universe.

411
00:13:47,840 --> 00:13:48,920
It's incredible, isn't it?

412
00:13:48,920 --> 00:13:49,640
It is.

413
00:13:49,640 --> 00:13:52,680
It really is mind blowing when you think about objects

414
00:13:52,680 --> 00:13:56,240
so far away, being able to tell so much about the universe

415
00:13:56,240 --> 00:13:56,840
we live in.

416
00:13:56,840 --> 00:13:57,600
I know.

417
00:13:57,600 --> 00:13:58,720
It's incredible, isn't it?

418
00:13:58,720 --> 00:13:59,760
The sheer scale of it all.

419
00:13:59,760 --> 00:14:01,960
These quasars fueled by black holes

420
00:14:01,960 --> 00:14:05,000
that could swallow our entire solar system

421
00:14:05,000 --> 00:14:06,680
without even a hiccup.

422
00:14:06,680 --> 00:14:09,960
And they've been shining their light across the cosmos

423
00:14:09,960 --> 00:14:11,680
for billions of years.

424
00:14:11,680 --> 00:14:13,560
It's humbling, almost.

425
00:14:13,560 --> 00:14:15,600
We're just these tiny specks trying

426
00:14:15,600 --> 00:14:17,520
to understand these forces of nature that

427
00:14:17,520 --> 00:14:19,800
are just so, so immense.

428
00:14:19,800 --> 00:14:21,720
And it makes you wonder what else is out there.

429
00:14:21,720 --> 00:14:22,400
Absolutely.

430
00:14:22,400 --> 00:14:25,040
And that's what keeps us going as scientists,

431
00:14:25,040 --> 00:14:28,080
that constant thirst for knowledge and understanding.

432
00:14:28,080 --> 00:14:32,080
Every new discovery just opens up even more questions

433
00:14:32,080 --> 00:14:34,320
and pushes us to re-examine what we thought

434
00:14:34,320 --> 00:14:36,040
we knew about the universe.

435
00:14:36,040 --> 00:14:37,160
I'm glad you mentioned that.

436
00:14:37,160 --> 00:14:38,760
Because I think back to when we started

437
00:14:38,760 --> 00:14:40,600
this deep dive into quasars, I thought

438
00:14:40,600 --> 00:14:43,520
they were just these bright lights in the distant universe.

439
00:14:43,520 --> 00:14:44,080
Right.

440
00:14:44,080 --> 00:14:47,280
But now I realize there's so much more than that.

441
00:14:47,280 --> 00:14:50,600
They're these powerful engines of galactic evolution,

442
00:14:50,600 --> 00:14:52,760
shaping the galaxies they inhabit.

443
00:14:52,760 --> 00:14:55,800
And they're giving us these invaluable clues

444
00:14:55,800 --> 00:14:57,280
about the very early universe.

445
00:14:57,280 --> 00:14:57,880
Exactly.

446
00:14:57,880 --> 00:15:00,160
They're like time capsules, carrying information

447
00:15:00,160 --> 00:15:02,680
about the universe's past, a time when everything was

448
00:15:02,680 --> 00:15:04,960
so much more energetic and chaotic.

449
00:15:04,960 --> 00:15:07,440
And who would have thought that these seemingly destructive

450
00:15:07,440 --> 00:15:09,760
objects, these black holes, could actually

451
00:15:09,760 --> 00:15:13,280
play such a crucial role in the birth and growth of galaxies?

452
00:15:13,280 --> 00:15:14,400
I know, right?

453
00:15:14,400 --> 00:15:16,520
It's a great example of how the universe is

454
00:15:16,520 --> 00:15:19,360
full of these unexpected twists and turns.

455
00:15:19,360 --> 00:15:20,480
It's full of paradoxes.

456
00:15:20,480 --> 00:15:23,400
And that's part of what makes it so captivating, I think.

457
00:15:23,400 --> 00:15:24,760
I couldn't agree more.

458
00:15:24,760 --> 00:15:26,600
And for everyone listening out there,

459
00:15:26,600 --> 00:15:30,000
I really hope this deep dive has sparked your own curiosity

460
00:15:30,000 --> 00:15:33,080
and wonder about the universe and our place in it.

461
00:15:33,080 --> 00:15:34,480
It certainly has for me.

462
00:15:34,480 --> 00:15:35,760
Me too.

463
00:15:35,760 --> 00:15:38,780
And if you're eager for more of these mind-blowing explorations

464
00:15:38,780 --> 00:15:41,320
of the cosmos, be sure to subscribe to Cosmos

465
00:15:41,320 --> 00:15:43,360
to a pod wherever you get your podcasts.

466
00:15:43,360 --> 00:15:45,980
And hey, while you're at it, check out our YouTube channel

467
00:15:45,980 --> 00:15:48,400
for even more cosmic content, including

468
00:15:48,400 --> 00:15:50,200
stunning visuals and animations that

469
00:15:50,200 --> 00:15:52,720
will bring these incredible objects to life.

470
00:15:52,720 --> 00:16:17,320
Until next time, keep looking up and keep exploring.