The Beginning of the Universe

The Big Bang

One of the most famous theory about the formation of the Universe is the Big Bang. During the Big Bang, all matter and energy, even space itself, were concentrated in a single point causing a tremendous explosion. A millionth after the Big Bang, the temperature of the Universe was over 10 million million degrees. It was contain large amount of energy in form of photons - little "packets", or particles of radiation. Under suitable conditions, high-energy photons can turn into particles of matter. And that is what happened in the early stages of the Universe. These particles of matter are protons, antiprotons, neutrons, antineutrons, electrons and positrons. These are some of the particles we know it today that make up the Universe.

All of the subatomic particles - protons, neutrons and electrons - had been formed by the instant it was created and the Universe began expanding and cooling. After about three minutes, its temperature had dropped to about 1,000 million degrees. Then protons and neutrons began combining to form the central cores, or nuclei, of atoms, such as helium. The Universe was then made up of radiation and matter, in the form of protons, helium nuclei and electrons.

After several hundred thousand years the temperature had fallen to about 3,000'C. The protons were now able to capture and hold on to electrons. The protons became atoms of hydrogen, and the helium nuclei became helium atoms. With fewer particles about and the Universe greatly expanded, radiation could travel over vast distances without being either absorbed or deflected. And the Universe have become transparent.

Another theory proposed is that after the Big Bang was the INFLATION followed by the Quark Era where quarks and electrons are formed and the quarks combine to become protons and neutrons while the electrons combine with these newly formed products of quarks to form atoms of hydrogen and helium -- the basic materials of the universe. These basic materials later combine to form superclusters of galaxies which are racing away from all the the other clusters at incredible speeds.

Proving the Big Bang

In 1948, scientist calculated that if the universe begun with an explosion, the radiation from that initial blast should have cooled to about three degrees above absolute zero, the coldest possible temperature(-270'C). This radiation has continued traveling since that time. It has been spreading out through larger and larger volumes of space as the Universe has continued to expand. In the 1940s there was no way of detecting this radiation. By the 1960s the technology was available and a team of researchers at Princeton University, USA, began the search for the 'cosmic background radiation'. At the same time, researchers at Bell Laboratories in New Jersey were studying radio signals coming from particular parts of the Milky Way. Their work was hampered by background interference that seemed to be coming from every direction. It turned out that the interference was actually the cosmic background radiation.

Although the theory appears to be correct, its leaves many questions to be answered. One that can never be answered is what happened before the big bang, because space and time themselves have no meaning at the moment of the big bang. And we can never know the answer to the biggest biggest question of all - why did the universe explode into existence.

Another Theory of the Universe

There is another known theory today known as the Steady State theory, there was no big bang. The universe always existed and always will exist. It envisaged a universe in which old galaxies were continually disappearing beyond the farthest that we can see, to be constantly replaced by new galaxies made from matter that spontaneously popped into existence from nothing. Both theories seem equally incredible to non-scientist, but to scientists the really important question was any evidence for them.

If the steady-state theory is correct, then the universe should have looked the same millions of years ago as it looks now. But astronomers have found that the old universe did not looked the same as it does now. Galaxies were distributed through space differently in the early universe and there were more quasars than now. This shows that the steady-state theory does not appear to be correct.

Spot facts:
 
 
 
 

-Astronomers reckon that the speed of a galaxy increases by about 55km per second for each megaparsec(3,260,000 light years) of distance. This value is the Hubble constant.	-From their red shifts, the most distant quasars appear to be travelling at over 270,000 km per second, or more than 90 per of the speed of light. This places them more than 13 billion light years away	-The first atomic nuclei began forming just three minutes after the Universe was born
-When the Universe is 100 times older than it is now, all the stars will be dead and the galaxies will be fading.	-It requires only about 1 gram of matter in every 40 million million cubic kilometres of space to "close" the Universe -stop it from expanding.	-In 1965, scientist Arno Penzias and Robert Wilson were testing a radio antenna when they detected strange energy emissions. They searched for the source of these emmisions and soon made a staggering discovery: the universe had a very weak level of radiation. The existence of radiation confirmed that the Big Bang had left a cool afterglow in space. In 1978, Penzias and Wilson won the Nobel Prize for discovering this important fact about the beginning of the Universe.