Physicists have been known to occupy their time asking silly questions and seeking answers to those questions. One question currently on their minds is "why does space exist?" Lee Smolin, professor of physics at Penn State University, wrote in his book Three roads to quantum gravity : "So, in the end, the most improbable and hence the most puzzling aspect of space is its very existence. ... If you look around at the world seeking mystery, you may reflect that one of the biggest mysteries is that we live in a world in which it is possible to look around, and see as far as we like."

We may find it strange, even amusing, that there are presumably sane people spending their lives seeking an explanation for the existence of space. Yet Isaac Newton's question as to why an apple falls from the tree does not sound so silly today. When the answer is found it would seem to be a natural question for people to ask.

The universe can't stand still

In 1917, Einstein realised that, according to his general theory of relativity, the universe could not remain static. It must either expand or shrink. Yet even he refused to believe in such a universe. The general belief was that the universe had existed from the infinite past, and that it would continue to exist indefinitely. There was no beginning: there would be no ending. This was the static or steady state universe concept.

The astronomers then also did not know the structure of the universe. Our sun is just one of the billions of stars out there. The star that is nearest from earth other than the sun is Alpha Centauri, 4.2 light years away. That is the distance light travels in that time at the speed of 299,792 km/sec. (it's not per hour). Light from the sun takes about eight minutes to reach the earth.

It was not until the 1930s that the origins of the universe became a hot topic for the world's scientists. By then, astronomers had started to realise that our neighbouring Andromeda galaxy, which is 2.2 million light years away, and other galaxies seen in the night sky were not part of our galaxy. They were separate galaxies. Our own Milky Way galaxy is just one among billions of galaxies in the universe. An average galaxy contains hundreds of billions of stars.

Ironically, in order to understand properly what took place on a cosmic scale, scientists had to refer to studies that were concerned with the subatomic world, such as Einstein's special and general relativity theories as well as quantum physics. As a result, the old view of a steady state universe was put aside, to be replaced by a universe that could not stand still.

Lawyer takes on natures laws

In 1929 Edwin Hubble (the Hubble Space Telescope was named after him) discovered that the universe was expanding. Hubble actually graduated in law from Oxford but gave up after practising for just one year. He then took up PhD study in astronomy at the University of Chicago.

There must be something that made him lose interest in man-made laws and turned to studying the laws of nature. Could it be his realisation that the laws of man are good only on earth while the laws of physics are valid in all corners of the universe? History has proved that he made the right choice. He went on to discover an important law in astrophysics now known to us as Hubble's law. This is probably the only time a lawyer has written a law which applies to the whole universe.

Hubble made his important discovery when he noticed that, in tune with the Doppler effect, the wavelengths of spectral lines from distant galaxies were red-shifted. Since the degree of redness is influenced by the distance of the galaxies — the further the galaxies the redder the spectral lines — it seems that other galaxies must be moving away from us. (In sound, the Doppler effect tells us whether an ambulance is moving towards us or away from us when we listen to the pitch of its siren.) This means that the universe is expanding. If the universe is expanding there must be a moment in the distant past when the universe began and started to expand.

More convincing evidence came when Arno Penzias and Robert Wilson discovered the cosmic microwave background (CMB) radiation in 1965. We can actually see this CMB radiation in our living room. When there is an interruption of TV transmission due to some fault, the screen will display the familiar annoying black/white spots and lines, sort of like someone throwing sand from the inside of the glass screen. Part of this signal is the CMB picked up by the aerial when the broadcasting station goes down. We will see how the CMB provides evidence on the birth of the universe.

The Big Bang

From astronomical observations including Hubble's, physicists developed the Big-Bang model of the universe. In this, the universe began in a state of rapid expansion from a condition of near infinite density and temperature. The primordial plasma, the stuff the infant universe was composed of, was mainly energy in the form of radiation. It also consisted of particles such as neutrinos, electrons, positrons, neutrons, protons, and photons. According to Einstein's E=mc ², energy and matter particles are interconvertible. Photon is light of all wavelengths, or more accurately energy in the form of electromagnetic radiation.

Today some 14 billion years later, the temperature of the photons is about 2.7K (about -270