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Are We Alone?
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| SETI – Radio Telescope |
Radio telescopes have been scanning the regions of space
since 1977. We are yet to receive signals that points to a communication from
intelligent life. There are 60 million potentially habitable planets in our
Milky way alone. And there are billions of galaxies in the known universe.
Cosmic Rays
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| Cosmic Rays shower |
These are high energy photons that streams through the
galaxy and interacts with the air molecules high in Earth’s upper atmosphere
creating showers of charged particles. The origin has been a mystery and
scientist suggested that remains of supernova might be their source when they
explode marking the death of biggest stars. Or the particles could be
accelerated by black holes from outside of our galaxy. The energy of these
photons is higher than anything what most powerful particle colliders on Earth
can produce.
Dark Matter/ Dark Energy
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| Big Band Timeline |
Dark matter is hypothetical mass/energy existing in the
universe that is causing the expansion. Since gravity is attractive force, the
universe would collapse if not for this undetected energy. Roughly 68% of the
universe is dark energy and dark matter makes up about 27%. What we can observe
is only 5% of the universe. Since it absorbs light, dark matter cant be seen.
Einstein tried tacking this issue by introducing a cosmological constant but he
gave up the notion and described as the biggest mistake of his life.
Re-Ionization of Universe
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| Dark Energy Formation Timeline |
Re-ionization refers to the period in history of universe
after Big Bang event when the universe was opaque and dense, turned into a
transparent universe from the neutral intergalactic medium through ionization.
The universe was initially unobservable because of the neutral medium, any
short wavelength radiation emitted would be absorbed quickly by atomic gases.
Physicists believe the gravitational collapse of over-dense region gave rise to
first stars, galaxies and quasars.
Exploding Stars
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| Exploding Star |
When a star runs out of fuel, it explodes into a supernova,
expelling debris up to velocity of 30,000 km/s. the mechanics of how and what
happens in the core of exploding star is a mystery.
Black Holes
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| Black Hole |
When a large star with massive mass explodes and the
gravitational force collapses on itself, a black hole is formed. The pull from
gravity is so extreme that even the light particles can not escape and since we
cannot see it, its called a black hole. Scientist believe that some of
the smallest black holes are just one atom in size but their mass is of a large
mountain. Black holes were first hypothesized from Einstein’s theory of
relativity which deduced it’s existence though mathematical formulas from the
theory. Since black holes cannot be seen, indirect measurements gives an idea
of its existence. Light from other sources will bend near a black hole.
Physicists study this bending of light to find existence of a black hole.
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| A stellar-mass black hole in orbit with a companion star located about 6,000 light years from Earth. |
Ultimate fate of Universe
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| Story of the universe |
There are possible outcomes that physicists believe will be
the outcome of the universe. Some believe the theory that universe is flat and
will expand for ever while some believe it is tied to the physical properties of
mass/energy in the universe. There are several theories explaining the fate
such as Big Rip, Big Crunch, Big Bounce, multiverse, Flat vacuum, cosmic
uncertainty, Big freeze, Big heat death etc.
~Blog admin~
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