Since ancient time mankind has looked to the stars, the
universe has always been a source of passion and mystery.
Where do we come from? How was the Cosmos born? What
might the universe contain? Our universe began with the Big
Bang but what was before it? What followed directly after it
came to existence? These are the questions humanity is
preoccupied with since we looked up and pondered. We remain
fascinated by the expanse of the cosmos, an enormousness
that transcends the limits of human imagination and we
continue to discover more about its creation, shape and size.
Cosmologists are retracing the history of the universe,
searching for answers. Back to its origin the Big Bang, an initial
singularity, from this point energy, matter, space and time all
emerged and with them the understanding of laws of physics.
According to the theory, space and time emerged 13.8 billion
years ago and the energy and matter initially present have
become less and less dense as the universe expanded. After the
inflationary epoch at around 10−32, and the separation of the
four known fundamental forces, the universe gradually cooled
and continued to expand, allowing the first subatomic particles
and simple atoms to form.
Ancient Greeks believed that, Indian philosophers came with a
cosmological model by placing the earth at the center. Over the
centuries, more astronomical observations led to develop the
heliocentric model with Sun at the center of the Solar System, a
theory by Nicolaus Copernicus. Further research led to the
realization that the Sun is one of the hundreds of billions of
stars in the Milky Way, which is one of at least hundreds of
billions of galaxies in the universe. Many of the stars in our
galaxy have planets. Galaxies are not distributed uniformly in
space, meaning that the universe has neither an edge nor a
center. Galaxies are distributed in clusters and super clusters
which form immense filaments and void in space. Discoveries in
the early 20th century have suggested that the universe had a
beginning and space has been expanding since then and
currently still enlarging at an increasing rate.
In the beginning there was only darkness or what we call as the
‘Dark Ages’, the first stars that emitted light and enhanced the
universe didn’t appear until 200 million years after the Big
Bang. The question that remains- is our universe infinitely large
or is it finite? What is the shape of universe? In order to
acknowledge the shape of universe we live in we need to
understand the curvature of space. Imagine we live in a space
that’s curved but because we are part of that space we
wouldn’t notice the curvature. Therefore, there are three
general possibilities for the geography of the universe. First, it’s
a spherical or closed universe, if our universe is a sphere with a
positive curvature then it would continue to expand and
eventually shrink back to nothing, back to the big bang which
would mean the universe is finite. Second a hyperbolic universe
which is complicated and very different, we’d have a universe
with no bounds and would expand forever. Third possibility, a
completely flat universe. Stars and planets emerge, galaxies
filled with solar systems, energy penetrates the cosmos in the
form of radiation but something intangible is there that shapes
the universe. A substance no scientist has ever seen nor will
ever be able to directly observe is the ‘Dark Matter’. Dark
matter pervades the universe. It is something we can neither
see nor touch but dark matter is the only explanation for the
motion of celestial bodies and galaxies, this invisible matter
holds the universe together.
With the help of telescopes scientists look back billions of years
but when they gaze back in time, they eventually hit a limit.
Scientists can observe the earliest light which occurred 200
million years after the Big Bang, the first 200 million years after
the creation of our universe is still hidden from us. Even today
Telescopes keep getting larger and their resolution continues to
increase. An extremely large telescope is under construction in
the Atacama Desert in Chile when it goes into operation in 2024
the ELT will be the largest optical telescope in the world. But
the keenest eyes to the sky are located in outer space like “The
Hubble Space Telescope” launched in 1990. It helped us to peer
deeper into the universe giving images of strange and enticing
landscapes of light, star dust and clouds of gas shaped by
cosmic wind and radiation. Similarly another one is “The James
Webb Telescope” is an international collaboration between
NASA, the European space agency and the Canadian space
agency. It will be launched into orbit 1.5 million kilo meters
away from earth. The telescope will offer a view of farthest
reaches of the universe and examine the birth of stars and
galaxies into the cosmic dawn.
By analyzing the universe we are also engaged in a search of
our own origins. Just a few decades before, many believed that
our solar system is unique but it turns out it’s just a tiny grain of
sand on an immense Galactic beach. Finding life in outer space
would be the greatest discovery of all time, it would provide
response to the humanity’s most enduring question- ‘’Are we
alone in the universe? ‘’Is there another planet similar to earth
providing favorable conditions for survival? There are many
competing hypotheses about the ultimate fate of the universe
and about what, if anything preceded the Big Bang, while other
physicists and philosophers refuse to postulate. Some physicists
have suggested various multiverse hypotheses, in which our
universe might be one among many universes that likewise
exist.
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