In Search of the Big Bang

In Search of the Big Bang

Author: John Gribbin

Publisher: Penguin

Pages: 346

John Gribbin is a renowned science writer who has a direct appeal on the general public. His style, full of clarity and fluid explanation of even difficult concepts marks him apart from other writers of the bunch. However, this one piece is an exception to the rule. The narration is terse at several sections, which might also be due to the fuzzy perception of concepts even by experts of the field. How can one account for the existence of a quantum fluctuation, an act of creating something from nothing? What is the difference between believing that God created universe from nothing and that the universe spontaneously originated from a quantum fluctuation in vacuum? Though Gribbin makes fun of the Pope’s comment at a science seminar in Vatican in 1981 when he advised great scientists, including Hawking who was present, to avoid going for the origin of the Universe as it is in the purview of the meta-physicists, we can’t help feeling that Science has a lot more to go forward in at least trying to explain the events which unfolded not at the beginning, but even after the elapse of a time period after the event. Cosmology abounds with theories which can be tested at only very high energies which occur only very near in time to the Big Bang. The author valiantly defends such theories as if it is common sense, but in several cases, it is just the contrary.

However, several concepts are clearly spelt out. An example is the elucidation of the second law of thermodynamics, which is also called “The Supreme Law of Nature”. Heat always flow from a hotter object to a cooler one, states the law. This creates an arrow of time in which processes can occur only in one direction. Though physical processes are time invariant, meaning that they happen in the same way, even if time is reversed, the second law defines the direction in which time flows.

The description of Edmond Halley’s works in Chapter 3 is thrilling. Ptolemy and Hipparchus had created star maps in the beginning of the Christian era. But in 1718, Halley realized that three stars – Sirius, Procyon and Arcturus – were not in the places where Ptolemy had seen them. The differences in positions were much too great to be dismissed as error by the ancients. Arcturus, for example, appeared in 1718 to be twice the width of the full Moon away from the position in Ptolemy’s writings. Halley inferred that Arcturus, and the other stars, had moved over the centuries since the Greeks recorded their positions.

Parsec, the unit of measurement of distances to stars is clearly explained. Since the radius of the Earth’s orbit is 150 million km, observations made 6 months apart, from opposite sides of the Sun, are at the ends of a baseline 300 million km (2 AU) long. It is a matter of simple geometry to calculate how far away a star would have to be, in order to show a certain parallax displacement across such a baseline. One parallax second of arc, or parsec for short, is the distance to a star which would show a displacement of 1 second or arc from opposite ends of a baseline equal to the distance from the Earth to the Sun. A parsec is a little more than 30,000 billion km, and is 3.26 light years.

Distance to other distant stars are galaxies are made with the help of a class of stars called Cepheid stars which vary in brightness. These pulsate, swelling up and then shrinking in upon themselves, repeating the process over a regular cycle during which their light waxes and wanes. There is a unique relationship between the brightness and period which holds true for all cepheids. This helps to fix the brightness of a distant star. The name is derived from Delta Cephei, which was one of the first identified as a variable.

One of the issues which had puzzled me for years was why powerful telescopes were always made with mirrors instead of lenses. Gribbin clears the issue with one shot. Bigger lenses are bent out of shape by their own weight, whereas mirrors are advantageous because no light is passing through, the back can be supported by a frame work to hold the mirror in shape.

Edwin Hubble postulated in 1929 that the universe is expanding and the expansion is proportional to distance. The constant of proportionality is called Hubble’s constant. Since this value changes over time, some scientist prefer to call it Hubble’s parameter. George Gamow and Ralph Alpher established the Big Bang theory in 1940s to explain the origin of the universe, which was improved by Alan Guth, with his inflationary model.

Overall rating: 3 star (How apt to rate a cosmological book in number of stars !!).