1- What is Cosmology?
Cosmology is the science that studies the universe as a whole, where it came
from, its present status, and what will become of it in the future (its final
fate). It is a fact that most religions are also very interested in the same
questions. This has led to some strong contrasts in the past, and some of them
are still very strong now.
Religious people -especially all kinds of fundamentalists- are convinced that only they know the whole truth, and that science should not interfere. On the other hands many scientists believe that science and religions are complementary and can coexist together, as long as religions accept to review some of its beliefs that were based on what was known in the past, beliefs that cannot be accepted anymore now. As an example, there are no doubts that the earth is much more ancient that what the Bible would like us to believe.
Cosmology went, until now, through four phases:
- Until the 17th century it was the domain of the philosophers and religious
leaders.
- The invention of the telescope in the 1600s allowed Galileo Galilei -relying
on the work of Nicolaus Copernicus and Johannes Kepler- to explore the nearby
universe in a scientific way. Isaac Newton then laid down the laws governing
the motion of celestial bodies.
- The use of great and powerful telescopes at the beginning of the 20th century
allowed scientists to explore the universe in depth. Edwin Hubble put an end
at the idea that the universe was static and eternal. He showed, instead,
that all the galaxies are moving away from the earth with tremendous velocities.
That the universe was expanding confirmed Einstein's theory of general relativity
that space-time was not flat and linear but, instead, that it was dynamic
and curved. From this it was deduced that the universe began with an explosion
later on called "Big Bang".
- In the last few years the use of space satellites carrying new and better
instruments gave the astronomers a mass of precise information that allowed
them to find the age and the composition of the universe, as well as estimate
the possibility of its future death.
This ever-increasing expansion means that the universe is getting colder
with time. If this goes on, the universe will end in a "big freeze"
and total darkness, and all life will die. Fortunately this will only happen
-if it does- in the faraway future.