- #1
cosmo_boy
- 14
- 0
Hi, everybody,
I am planning to write an article titled "cosmology: the scinece on the universe".
So far I have written about 40 pages. I want to share/check
my ideas with you. Abstract of the article looks as follows:
Every object in the universe, living or non living, changes with time
and it makes sense to talk about its birth and death. Modern scientific
theories tell us how stars and planets form, how galaxies cluster, how
life originates on the Earth, but the question of how the universe came into
being is difficult to address. This is because unlike other
objects, we have a single universe and the problem becomes further complicated
by the fact that we are also part of the universe so there is no way
to study the universe objectively. We do not have multiple copies of the
universe to perform experiments; nor does our life period compare with the
physical process of cosmic importance. This puts strong constraints on
our understanding of the universe. Unlike other sciences which
fragment knowledge into parts, in order to make a complete picture of
the universe, in cosmology we put bits and pieces of various kinds of
knowledge together and this makes the job of cosmology very difficult.
We have experienced that physics which (classical mechanics) works very well
in our daily life (length scale, say 1 cm) fails badly at atomic scales
($ \approx 10^{-8}$ cm) and we need quantum corrections. In spite of this,
in cosmology we stretch physics which has been tested at far below galactic
scales ($ \approx 10^{14}$ cm) to cosmological scales ($ \approx 10^{28}$ cm).
This puts a question mark on the reliability of modern cosmology.
Nevertheless, in the absence of any other option we do this extrapolation and
draw a picture of the large scale structure of the universe. One can always
ask: why do we need to study the universe as a whole ? Because what matters
to us is, what is in our neighborhood. However, this is not true. There are
many cosmological consequences which we observe in our life. Apart from
cosmological events, what else can produce this copious amount of hydrogen,
helium, lithium and other light elements which we observe in the universe. We
do not know what else apart from the early universe, which was supposed to be
in thermal equlibrium at very high temperature, could produce the radiation
(CMBR) which we receive equally from all directions. It is far from a
coincidence that life, which we know, has not been here billions of years ago.
This is because this form of life needs higher elements and it takes billions
of years to synthesize these deep in the core of stars. There are many reasons
to believe that the universe does evolve in time. Now one of the big questions
is: does the universe also follow the same destiny which is followed by other
objects in it i.e., cycle of birth and death. This idea is not very new.
Plato proposed a long time back that the universe is analogous to a gigantic
living being. We know birth and death are nothing but some kinds of changes
which take place in physical objects in the universe. Will this logic work
with the universe ? Yes, but for that we will need a bigger universe or
multiverse which can accommodate our universe. I think it will never be
possible to answer questions like the birth and death of the universe. In this
article we will mostly forget about the birth and death of the universe and
will focus mainly on what happens in the life of the universe. We will be
mainly concerned about that part of space-time which is accessible to us or
which we can probe with our physical devices. There are many mysteries in the
universe: what is dark matter and dark energy ? Does general theory of
relativity work on cosmological scales ? How to explain the big bang ? How the
universe will end ? Why are physical parameters in the universe fine tuned ?
In order to answer these and many such questions, there have been proposed
many new concepts like the concepts of extra dimensions, scalar fields,
tachyons, supersymmetry etc.
We hope many of these concepts will be verified in the near future.
We do not have a consistent theory of quantum gravity
which we believe will solve many puzzles of the universe. Cosmology is the
science of the universe and the universe includes everything and this puts
limitations on our understanding of the universe, so certain aspects of
cosmology are not science at all ! This article is mainly concerned about
those aspects of the universe which can be explained on the basis of the
known laws of physics. However, we will not stop ourself from discussing
sceptical ideas also.
... to be continue
I am planning to write an article titled "cosmology: the scinece on the universe".
So far I have written about 40 pages. I want to share/check
my ideas with you. Abstract of the article looks as follows:
Every object in the universe, living or non living, changes with time
and it makes sense to talk about its birth and death. Modern scientific
theories tell us how stars and planets form, how galaxies cluster, how
life originates on the Earth, but the question of how the universe came into
being is difficult to address. This is because unlike other
objects, we have a single universe and the problem becomes further complicated
by the fact that we are also part of the universe so there is no way
to study the universe objectively. We do not have multiple copies of the
universe to perform experiments; nor does our life period compare with the
physical process of cosmic importance. This puts strong constraints on
our understanding of the universe. Unlike other sciences which
fragment knowledge into parts, in order to make a complete picture of
the universe, in cosmology we put bits and pieces of various kinds of
knowledge together and this makes the job of cosmology very difficult.
We have experienced that physics which (classical mechanics) works very well
in our daily life (length scale, say 1 cm) fails badly at atomic scales
($ \approx 10^{-8}$ cm) and we need quantum corrections. In spite of this,
in cosmology we stretch physics which has been tested at far below galactic
scales ($ \approx 10^{14}$ cm) to cosmological scales ($ \approx 10^{28}$ cm).
This puts a question mark on the reliability of modern cosmology.
Nevertheless, in the absence of any other option we do this extrapolation and
draw a picture of the large scale structure of the universe. One can always
ask: why do we need to study the universe as a whole ? Because what matters
to us is, what is in our neighborhood. However, this is not true. There are
many cosmological consequences which we observe in our life. Apart from
cosmological events, what else can produce this copious amount of hydrogen,
helium, lithium and other light elements which we observe in the universe. We
do not know what else apart from the early universe, which was supposed to be
in thermal equlibrium at very high temperature, could produce the radiation
(CMBR) which we receive equally from all directions. It is far from a
coincidence that life, which we know, has not been here billions of years ago.
This is because this form of life needs higher elements and it takes billions
of years to synthesize these deep in the core of stars. There are many reasons
to believe that the universe does evolve in time. Now one of the big questions
is: does the universe also follow the same destiny which is followed by other
objects in it i.e., cycle of birth and death. This idea is not very new.
Plato proposed a long time back that the universe is analogous to a gigantic
living being. We know birth and death are nothing but some kinds of changes
which take place in physical objects in the universe. Will this logic work
with the universe ? Yes, but for that we will need a bigger universe or
multiverse which can accommodate our universe. I think it will never be
possible to answer questions like the birth and death of the universe. In this
article we will mostly forget about the birth and death of the universe and
will focus mainly on what happens in the life of the universe. We will be
mainly concerned about that part of space-time which is accessible to us or
which we can probe with our physical devices. There are many mysteries in the
universe: what is dark matter and dark energy ? Does general theory of
relativity work on cosmological scales ? How to explain the big bang ? How the
universe will end ? Why are physical parameters in the universe fine tuned ?
In order to answer these and many such questions, there have been proposed
many new concepts like the concepts of extra dimensions, scalar fields,
tachyons, supersymmetry etc.
We hope many of these concepts will be verified in the near future.
We do not have a consistent theory of quantum gravity
which we believe will solve many puzzles of the universe. Cosmology is the
science of the universe and the universe includes everything and this puts
limitations on our understanding of the universe, so certain aspects of
cosmology are not science at all ! This article is mainly concerned about
those aspects of the universe which can be explained on the basis of the
known laws of physics. However, we will not stop ourself from discussing
sceptical ideas also.
... to be continue
