00:00These eerie objects are called quasars. They're some of the brightest and most powerful objects
00:05in the Universe. They lurk in the depths of space, consuming entire galaxies with their
00:10insatiable hunger. But what are quasars, where do they come from, and most importantly, are
00:17they dangerous to us?
00:20Picture a supermassive black hole. A cosmic monster so massive that it can swallow entire
00:26stars and bend the fabric of time. Usually, there's such a black hole in the center of
00:32every galaxy. That includes our own Milky Way galaxy. Ours is named Sagittarius A-star.
00:39Sounds like the name of a hipster coffee shop, but in reality, it's a terrifying celestial
00:44body which is 4 million times heavier than our Sun. You can even see it online. For the
00:49first time, we took a photo of this black hole in May 2022. Ah, but don't worry, even
00:55though it's supermassive, it's not going to swallow us up anytime soon. This black
01:00hole is relatively small, and it's too tiny to eat an entire galaxy. So it's more like
01:06a cosmic vacuum cleaner that sucks up stars or gas that gets too close.
01:11But there are black holes in the centers of galaxies that are way heavier and more dangerous
01:16than ours. They can weigh millions or even billions of times more than our own Sun. Now,
01:23imagine one of these monsters. Usually, they're surrounded by a swirling, glowing disk of
01:27gas and dust, like water swirling down a drain. It's called an accretion disk, and it's where
01:33the magic of quasars happens. As material from the accretion disk falls toward the center,
01:39it heats up to millions of degrees, releasing vast amounts of energy in the form of radiation.
01:45And this radiation is what we observe as a quasar. So, basically, the more material a
01:50black hole can consume from its surroundings, the brighter its quasar will be. This is what
01:56makes them so bright and powerful, shining like beacons in the night sky.
02:02And just imagine, some black holes can actually make entire galaxies their meal. Now, combine
02:07their ravenous appetite with some intense radiation, and you'll get a truly awe-inspiring
02:13display of cosmic power. No wonder we can see them, even though they're some of the
02:17most distant objects in the universe. Quasars were discovered in the late 1950s by accident.
02:24Astronomers were just chilling and looking at the sky, when suddenly, they stumbled upon
02:28something strange – radio signals that had no visible source. By 1960, hundreds of these
02:34strange objects had been found. Astronomers named them quasars, short for quasi-stellar
02:41radio source. These objects were small and far away, but their energy output was immense
02:47and difficult to explain. Some thought that these were new types of stars. Others even
02:52proposed wild things, like quasars being made of antimatter, or being the end of a wormhole.
02:59But all these theories were discarded. A scientist named Martin Schmitt was the first one to
03:03get to the truth. However, many astronomers didn't believe him. Schmitt had to do a lot
03:08of extra work and gather lots of evidence to prove his theory. And finally, he prevailed.
03:14And that's how we discovered quasars. Don't you love the scientific method? And since
03:20then, astronomers have been captivated by these objects. Why? Because they have some
03:24pretty eerie qualities. You could call them quasi-quasars. For example, they kinda defy
03:31the laws of physics. They emit jets of particles that travel at speeds close to the speed of
03:37light. These particles move so fast that they can even distort the very fabric of space
03:42and time. But sometimes, they also help us confirm the laws of physics. Imagine driving
03:48a car. As you drive, objects in the rear window start to appear smaller and smaller until
03:54they disappear from view entirely. That's exactly what happens with quasars. Except they're
04:00moving away from us at incredibly fast speeds, up to 90% the speed of light. Wonder why they're
04:06trying so hard to sprint away from us. But in any case, this helps us confirm that the
04:11universe does expand for real. Another eerie thing about quasars is that
04:16they're incredibly old. Some even date back to the time when galaxies were forming or
04:22to the birth of our universe. Additionally, quasars are some of the most distant objects
04:27that we can observe in the universe. Some of them are located billions of light years
04:31away from us. This means that when we observe a quasar, we're actually seeing light that
04:37was emitted billions of years ago, when the Earth was much younger and different than
04:41it is today. And that's why they work like cosmic time capsules. Studying them gives
04:47us a glimpse into the distant past. You see, galaxies are like giant cities, with
04:52stars and planets serving as the inhabitants. But just like cities evolve over time, galaxies
04:58also undergo changes as they age. And that's where quasars come in. They're like the urban
05:03planners of the universe. They shape the galaxies through their powerful gravitational
05:08influence. By eating galaxies and releasing intense radiation, they can trigger star formation
05:15and shape the structure of the galaxy itself. It's like the cosmic equivalent of a master
05:20chef or a leaf blower, you pick. For example, let's take galaxy mergers. Here
05:26are two massive entities coming together, swirling and spinning around each other. As
05:31they get closer and closer, their gravitational pull becomes stronger, and they start to merge
05:37into a new, bigger galaxy. It's a beautiful and dramatic process, one that can take millions
05:42of years to complete. But all this doesn't go without consequences.
05:47The gas and dust within the galaxies collide, creating massive shockwaves that trigger the
05:52birth of new stars and even supermassive black holes. And this is where the quasars come
05:58into play. Some quasars may be born during these galactic get-togethers. And thanks to
06:04this, they help us study the effects of this process and the evolution of galaxies over
06:09time. But it's not all serious science and no fun.
06:13For example, how about gravitational lensing? Now that's something straight out of a sci-fi
06:18movie. It happens when the gravity of a massive object, like a quasar, bends the path of light
06:25from a more distant object, like a galaxy, behind it. It's like having a really big
06:30magnifying glass in space. When you combine a quasar with gravitational lensing, you get
06:36some seriously awesome cosmic eye candy. The result is kinda like a funhouse mirror, where
06:42objects appear warped and twisted in strange and mesmerizing ways.
06:47Gravitational lensing isn't just for show. It's also a powerful tool for astronomers
06:51to study the distribution of dark matter and the structure of the universe. And that's
06:56not all. Some scientists have proposed that quasars could help us build the map of the
07:02universe. They can work like giant neon road signs. Turn left at the quasar and you'll
07:07reach your destination. They're like lighthouses that help us navigate through space. By analyzing
07:13the light from different quasars, astronomers can determine the distances between them and
07:18create a 3D map of the universe. And the best part? Quasars are located throughout
07:24the entire universe. That's why this cosmic map can give us a comprehensive view of the
07:29universe on a scale that was previously unimaginable. Who knew that a giant galaxy eater could be
07:35so useful? There's still a lot we don't know about these mysterious objects.
07:40In 2007, a team of astronomers made an astonishing discovery. The first true binary quasar. Basically,
07:48this means two huge quasars spiraling around each other. What's more, they were hiding
07:53in plain sight. For years, scientists had known about this radio source, but had never
07:59realized that it actually comes from one lovely couple. The astronomers also estimated that
08:04this pair may have a mass of about 100 billion suns. They're super distant, though, at an
08:10astounding 12 billion light-years away from our blue planet. Overall, quasars are a fascinating
08:17and complex phenomenon that continues to baffle and intrigue scientists. They may be
08:22cosmic galaxy eaters, but they're also playing a critical role in the formation and evolution
08:27of the universe. And who knows, maybe one day they'll become one of the keys to unlocking
08:33the mysteries of our universe. Oh, you crazy quasars!
08:37That's it for today! So hey, if you pacified your curiosity, then give the video a like
08:42and share it with your friends. Or if you want more, just click on these videos and
08:46stay on the Bright Side!
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