The Big Bang and the First Cause

In general, we Filipinos are very unscientific and uninformed about technical matters. We are also very superstitious. We tend to believe in the supernatural. Even in the way we conduct investigations, we reason out in very childish ways.

Starting this week, we shall start this column De Rerum Natura (On the Nature of Things). This column will try to enlighten the reader in the scientific method. It will attempt to explain the origin of things. It will clarify the natural causes of events that seem to befuddle us. It will criticize some decisions of national importance as to its scientific merit. It will analyze for the reader the issues that arise out of scientific innovations. It will do all these in layman’s language rather than the specialized gibberish of science. We will try our best to explain things without the use of technical jargon. Due to the limitation of space, our explanation will be as concise as possible

Do people understand the meaning of the Big Bang or the origins of the universe? Or the fundamental constituent of matter, the quarks? Now that Pakistan has the nuclear bomb, what is the significance of a possible confrontation with India? What is the military capability of each country? Are the weapons capable of reaching us? Should we support our scientists? What is the best public policy regarding the support of research and development? We will try to answer questions like these in succeeding columns.

The column will also answer practical questions. Like how do CDs work. The comparative quality of original CDs compared to pirated ones and other issues of technical nature confronting the consumer. Or deal with the quality of various computer models.

We will also deal with the technical aspects of everyday news. Do we understand the meaning of weather forecasts or the description of earthquake intensities? Questions like these will be the topics of this column.

I have chosen De Rerum Natura as the title of the column. It is borrowed from the title of a long poem by Lucretius...

This terror, then, this darkness of the mind,

Not sunrise with its flaring spokes of light,

Nor glittering arrows of morning can disperse,

But only Nature’s aspect and her law,

Which, teaching us, hath this exordium:

Nothing from nothing ever yet was born.

* * *

What we know now is that the universe is about 15 billion years old. Before its birth, all the matter and energy are concentrated in a region of about a one-peso coin. Then followed a big fireball, a tremendous explosion. The one-peso coin expanded to a ball the size of the earth in a few minutes.

This is known as the Big Bang. Initially, there was nothing but pure energy. Almost immediately some of this energy was transformed into elementary particles known as quarks (the fundamental constituent of all matter). When the universe became cool enough, the quarks became confined into what is known as hadrons, namely, protons and neutrons. Then the neutrons and protons combined to form atomic nuclei, including helium and deuterium. Then at about 300,000 years after the fireball, neutral atoms began to coalesce into stars. When the universe was about one-fifth the present size, the young galaxies were formed. The earth was born in a supernova explosion. Life emanated from the seas and through evolution man finally emerged. In general, this is the story and the rest are details. And the evidence is solid.

This was not guesswork but a result of experiment over many years. In 1912 Slipher measured the spectra from the nebulae, showing that many were Doppler-shifted (like the change in the tune of the whistle of a train when it is moving toward or away from us). This demonstrated that nebulae were moving away from the earth. By 1924, 41 nebulae were measured, and 36 of these were found to be receding. A key advance in cosmology came with the development of a means to measure the distance to these nebulae. Shapley used Cepheids, bright stars that pulsate at regular intervals between a few days and a month. The period of their variability is correlated with their absolute luminosity.

From 1923 to 1929, Hubble was able to resolve Cepheids in M31 (the Andromeda galaxy) with the 100" telescope at Mt Wilson. He developed a new distance measure using the brightest star for more distant galaxies. He correlated these measurements with Slipher’s nebulae to discover a proportionality between velocity v and distance d, that is, Hubbles law v=Hd. This is evidence that the universe is expanding. Thus, the farther the nebulae, the greater is its velocity. The constant of proportionality H is called Hubble’s constant. Working with a horn antenna (7.35 cm) at Bell Labs, Penzias and Wilson fortuitously discovered an isotropic radio background, a relic leftover from the primordial fireball. This cosmic microwave background radiation is key evidence for the Hot Big Bang model. The temperature of this blackbody radiation is today measured to be T = 2.73K (that is rather cold considering that absolute zero is -270C).

Since the mid-1960s, the scientifically informed religious were thrilled because of the accumulating evidence that the universe started some 12 to 15 billion years ago in a big bang. All matter, as well as space-time, started at the big bang. Some of the religious believe that this is the moment of creation. They believe that the universe could not have started uncaused and the cause was God or the Creator or the First Cause.