Quasars
Hi everyone, welcome back. In this post we are going to learn about "Quasars". They are mysterious objects that has revolutionized our understanding of the universe in many ways. Everything in this universe is interconnected in some ways we have noticed, other ways we haven't. It will be evident in this post. Let's start!
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| Credits: NASA, ESA and J. Olmsted (STScI) |
The discovery of these started in the 1950s when they started seeing the sky through radio telescopes which detect radio waves and help in the discovery of objects which cannot be seen through the naked eye or if they are too far and faint to detect.
These were discovered due to the use of radio telescopes in
1960. The first discovery was made during "Lunar occultation" (when
the moon appears to pass in front of a star, planet, etc.) with the help of
"Parks radio telescope". They detected an object which emitted so
much radiation but cannot be seen through visible light by further research
they found out that these objects were very luminous and very small. The credit
for discovering them goes to Maarten
Schmidt.
When
astronomers started looking into the same object periodically. They recognized
that they were moving very fast from us like millions of light-years away each
time. This was connected with how the universe expands so people started
connecting these with black holes, white holes, wormholes, etc. and further it
led to the discovery of Blazars, and Radioactive galaxies; which will come up
later.
Astronomers
were clueless; as years passed and technology increased, they could detect so
many of them. It never had a name so “Hong -yee Chiu” in 1964 termed those very
unique extremely luminous and very small objects as quasars or quasi-stellar
objects.
The
questions that arose during those times are: how are they formed, What could create
so many radio waves? The answer always took a negative form; Maybe they are not
bright maybe our perspective was wrong.
In 1980,
astronomers were able to connect it with black holes, and the mystery of what
that bright line passing through the center of supermassive black holes in the center
of galaxies was cleared along with it.
There is a
supermassive black hole at the center of every galaxy. The gravity over there
is tremendous. The materials come close to form a cresctian disk around them.
It heats up so much that it blasts out enormous amounts of radiation, this
magnetic environment produces two jets that flow into the universe with so much
radiation and light, and this is called an AGN (active galactic nucleus).
We can
observe quasars, blazars, and radio-active galaxies just by looking at AGN from
different perspectives: perpendicularly, they are radio-active galaxies, at an
angle, they are quasars, and right down the barrel of the jet, they are
blazars. It was agreed upon by all that all of them are the same object, as stated
by the "Active Galactic Theory" then people realized that they
discovered black holes even before Einstein!
When a black
hole runs out of food the jets also runs out of them so they stop working until
they consume some other material they start over again. Our Milky way galaxy has
a supermassive black hole in its center and it is out of fuel so there is no
AGN resulting in no quasar. But there is a high possibility that we would
obtain a Quasar in the future.
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