In the far reaches of the Universe, you’ll find amazing events, celestial bodies, and mind-blowing chemical reactions that, if we’re honest, we’re not close to, as some can be world-ending.
One of these is the quasar. Quasars are some of the brightest objects in the universe.
They are very distant galaxies, which means they are extremely old.
Some scientists believe that quasars existed even before our Universe was formed.
Are these theories true? And how about right now? Are quasars extinct, or do they exist on the very fabric of space that we are currently unable to reach?
- What Is A Quasar?
- History Of Quasars And How They Were Discovered
- Quasars In Recent Times
- What Is Causing Quasars To Disappear?
- Final Thoughts
- Frequently Asked Questions
What Is A Quasar?
Quasars stand for quasi-stellar radio course and are supermassive black holes believed to be at the center of galaxies.
These massive black holes are millions or billions times heavier than the Sun.
The gravitational force from such a huge object is enough to disrupt the surrounding gas and dust, creating a powerful jet of plasma.
This jet is visible across the entire electromagnetic spectrum.
Quasars are believed to be the result of collisions between two galaxies.
When galaxies collide, their central black holes merge together and form a new galaxy.
This merger creates a strong magnetic field around the newly formed black hole.
As the black hole spins, it emits jets of high-energy particles. These jets are seen as quasars.
This is what has been predicted to happen to our own galaxy The Milky Way, and our nearest sister galaxy – Andromeda. In around 5 billion years when the two galaxies collide, their emergence will create a quasar.
History Of Quasars And How They Were Discovered
The first quasars were discovered accidentally by telescope operators monitoring stars.
One example includes 3C 273, an elliptical galaxy located 2.5 million light-years away.
It was discovered in 1963 when astronomer James Dunlop noticed a strange object in his data – a rapid increase and decrease in intensity in the blue part of the spectrum.
He thought something might be moving past Earth so he went out and looked with a pair of binoculars.
Sure enough, there appeared to be an extra star located next to the active galactic nucleus.
Astronomers didn’t know what this was back then, but they knew it wasn’t normal.
They couldn’t see any other activity in the galaxy apart from this one point, so they gave their discovery the name 3C273.
But over time, observations of more and more quasars suggested these objects could produce large amounts of energy through nuclear fusion.
So, in 1971, researchers modified the Large Sky Area Multi-object Fiber Spectroscopic Telescope (LAMOST), a Chinese astronomical observatory, allowing them to conduct surveys of millions of galaxies.
As it turned out, they found many more unusual things besides quasars.
In fact, LAMOST identified 10,000 exoplanets orbiting distant stars, 100 million galaxies, and several hundred thousand globular clusters.
It’s hard to describe the results without showing them.
Quasars In Recent Times
In recent times, Astronomers believe that many of the discovered quasars are starting to disappear.
In 2014, Stephanie LaMassa from NASA found that a quasar had actually dimmed by a factor of 6.
This reduction in brightness had occurred in just a short 10 years, in which this process should take tens of thousands of years to enter a dormant state.
Other quasars have also experienced dramatic changes.
Most notably, SDSS J0818+1722 faded by 16 magnitudes within 8 years, while QSO BRI 1315-2648 lost around 20 percent of its emission since it was observed in 1998.
All four of these quasars sit in the center of nearby dwarf galaxies called M101, M82, NGC 253, and IC 342.
Whilst quasars definitely still exist, they were much more common billions of years ago, so we’re a little late to the party.
More than 2,000 known quasars existed in the early days.
What Is Causing Quasars To Disappear?
There are many theories as to why quasars are either reducing in brightness, or are disappearing entirely.
This quasar activity could, simply speaking, be that an active quasar dims and grows quiescent.
This doesn’t seem like a crazy idea; that something atrophies and grows smaller and smaller, or loses its ‘power’ over time, as this is the basis for all things in the universe.
The other explanation is the variation of dust and gas flowing onto the blackhole.
Because it’s unlikely that astronomers just so happened to catch the moment the quasar dies (like a one in one billion shot), perhaps it’s a simple flicker like a candle that gets tossed around in a gentle breeze.
However what is baffling is how something can happen in such a short time.
Astronomers expect this to happen, but over tens of thousands of years, not in less than a decade.
What’s also not understood is whether these quasars are entering a dormant state, or simply closing up shop for good.
Whilst the future of quasar discovery and research remains open, the next step is clear in that Astronomers will see if any of the recently discovered quasars begin to brighten up over the coming years.
Many people still wonder if these quasars really exist today, or if they’re just some weird phenomena.
The answer to both questions is obviously yes, based on the examples given above.
Perhaps the most common question about these quasars is whether they will ever return to being active again.
Unfortunately, we won’t know unless someone points our way.
To us, the only thing interesting about this phenomenon is the sheer amount of unknowns involved. We’re interested to find out where these quasars came from, why they’re changing, and why they’re fading away.
Frequently Asked Questions
How Do Pulsars And Quasars Differ?
The two types of objects have quite different properties.
Quasars are very energetic, producing up to five billion times the luminosity of normal stars.
Pulsars are much smaller, only emitting tiny amounts of power, but they spin around extremely rapidly.
Pulsars emit radio waves, with frequencies ranging from 0.1 Hz to 300 GHz.
They rotate once every 30 milliseconds to 5 seconds, depending on the size of the star.
Quasars instead radiate across the whole electromagnetic spectrum.
To What Distance Does A Quasar Make Its Host Galaxy Uninhabitable?
It depends. If a quasar is located near enough to its host galaxy, then the combination of light and heat may render any planets orbiting the host too hot for life.
However, if a quasar is far away, it could be that it has completely left the area, leaving no direct effect on the galaxy.
Can Other Stars Die Like Quasars?
No. Stars burn fuel, converting hydrogen into helium.
When their core runs dry, they collapse under gravity and form neutron stars or black holes.
These objects cannot convert matter into energy, so they slowly lose mass through Hawking radiation.
How Many Quasars Have Been Found?
To date, more than 750,000 quasars have been discovered.
Because of their vast distance from Earth, they can appear as if they did in the early stages of the universe.
Where Is The Nearest Quasar?
Astronomers have discovered that a quasar is located in the nearby galaxy of Markarian 231 which is 581 million light years away from The Milky Way.
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