A Brief History of Time

Stephen Hawking’s

Stephen Hawking, considered the world’s most brilliant theoretical physicist since Einstein, here addresses the questions that have forever haunted mankind: How did mankind, the earth, our solar system, our galaxy, the other galaxies, and the universe begin and when -- and why?  Is there a “Master Plan” or do random forces rule events?  He judiciously avoids any statements that might incur the wrath of the world’s religions; rather, he forces the reader to reach his/her own conclusions – thus expanding his reader-audience to include people of all persuasions, but the beauty of this relatively brief treatise is to help us better understand the confounding mysteries of the universe in which we live and to assess mankind’s place in it – a Must Read for all inquisitive minds.

A mathematician and physicist, Hawking uses scientific observations of “time” to consider the possibilities. “Time,” is “an indefinite continuous duration regarded as that in which events take place.” (The Unabridged Oxford Dictionary).  As Hawking notes, it is now generally agreed that time moves both forward and backward in “arrows” and is not absolute, and, further, each observer has his own measure of time, and that space and time are inexorably linked, and, thus, called “space-time”; and gravity bends both, which (among other things) gives rise to the conclusion that the universe had a beginning (in a Big Bang, some 10,000 (now  14,000) million years ago and a habitable earth in approximately half of that time) and likely will end (in a Big Crunch in another 10,000M years).  Hawking (a humble genius who is compelled to give attributions to all contributors, recalling the axiom that “All history is biography”) begins this observational journey with Aristotle, the Greek philosopher (and Plato’s student) and winds his way forward through scientific minds to the present.   A few of the highlights follow. 

ARISTOTLE (c. 340 B.C.) While living in an era of paganism, he determined that the earth is round from its shadow on the moon, but placed the earth at the center of our solar system.  PTOLMEY (c.200 A.D.) created a model of the solar system on the same basis, which was used until 1500, holding that the earth (not the sun) was the center of our solar system.

COPERNICUS (c. 1500), who lived in a fiercely Catholic Western World at the time when the first King James Bible was compiled, was the first to place the sun at the center of our solar system, but his views were too heretical for him to safely publish his works, although he did publish mitigated versions under assumed names.  He was forced to abjure his findings to save his life.

GALILEO (1564-1642), who lived under the Pope’s rule, was the first to have a telescope, and was the first to publicly support Copernicus’ sun-centered universe and his books make him perhaps “the person most responsible for the birth of modern science [physics],” in Hawking’s view.  He argued that, where the Bible conflicted with common sense, it was being allegorical, which enraged the Church; the Church commanded him not to publicly support Copernicus’ doctrine; in 1616, he was brought before the Inquisition and was sentenced to house arrest for life (keeping him out of circulation) and was required to renounce Copernicanism (presumably at the peril of his life), and, of course, he complied.  His later books were smuggled to Holland to be published, but he was buried in a criminal’s grave in as much disgrace as the Church could then impose.  The Church allowed his remains to be exhumed and moved in 1737 to a location facing Michelangelo's, although no Church authorities attended the ceremony.  ROEMER (c. 1676) determined that light travels at finite speeds, and he calculated its speed at 140K miles/second (very close to the now-agreed speed of 186K miles/second).

ISAAC NEWTON (1642-1727) wrote “Natural Philosophy of Mathematics,” which Hawking dubs “the most important single work ever published in physical sciences.” Newton postulated a law of universal gravitation, which demands that the universe must either be continuously contracting or expanding. Newton’s calculations of the movements of the planets in our solar system (Solar System) were “amazingly accurate”, and his laws of gravity “put an end to the idea of absolute position and space,” and gave rise to Einstein’s later linkage of space and time (“space-time”).

EINSTEIN (1879-1955), propounded the renowned formula: E=mc squared, where E is energy; m is mass, and c is the speed of light, and held that nothing moves faster than light.  Gravitational force depends on the mass of the two bodies.  His Theory of Relativity (Relativity or TOR) “put an end to the idea of absolute time” and held that each observer has his own measure of time, and, further, that space and time are inexorably linked as “space-time” and that gravity bends both and that the universe had a beginning (in a Big Bang) and likely will have an end (in a Big Crunch).  Fearing the anti-God implications, Einstein held to a concept that the universe is static and not random, saying, “God does not play dice,” ingratiating himself a deist if not a theist.  Hawking advises that most scientists today disagree and hold that the universe is not static and its movements are random. (See quantum mechanics below.)  Einstein later reluctantly agreed with the preponderance of opinion, calling this (his “cosmological constant”) “the biggest mistake of my life.”  Earlier versions of the Biblical book of Genesis cited 4900 B.C./C.E. as the time of creation (and, hence, the universe’s) and 2900 as the date of Noah’s Arc (although these dates are not often included in recently published Bibles).  The last Ice Age was 10,000 B.C.  Today, scientists generally agree that our universe was formed some 14,000 million years ago and that it should collapse in another 10,000 million years and that the earth was created some 4.5 billion years ago.  Einstein’s TOR predicted that space-time began at the Big Bang and would end at the Big Crunch, i.e., at a singularity inside a black hole.  (A singularity is defined as “a point in the universe where the theory itself breaks down,” i.e., a single event as to that specific set of circumstances). According to TOR, if light cannot move from one region of the universe to another, no information can either.   Who was this mental giant, Einstein?  A German Jew, who, upon seeing Hitler’s emergence, perspicaciously leftGermany in 1933, and became deeply involved politics when he urged Pres. Roosevelt to develop the atom bomb; after WWII, he fought even harder against nuclear war.  He was devoted to the Zionist causes (thus helping the Jews escape further persecutions), and he felt compelled to renounce his congenital devotion to pacifism, as Hitler had raised anti-Semitism and brutality to unparalleled levels.  Upon being offered the Presidency of Israel, he declined, saying, “Equations are more important to me, because politics is for the present but equations are for eternity” -- and so is a quiet, loving life, one might add.

HUBBLE (c. 1929), whose telescope was much improved, could measure the light-shifts from the stars, and he observed that the galaxies are moving rapidly away from us, which, he concluded, implied that there had been a “Big Bang” at the beginning of the universe (10,000 million years ago), confirming Einstein’s Relativity.  Hubble is credited with “discovering the expansion of the universe”; While Einstein first disagreed, he later agreed. See above.

HEISENBERG (c. 1950) introduced the uncertainty principle, which holds that it is impossible to determine exactly (1) the position and (2) the velocity of a particle (or object) at the same moment.

Quantum mechanics predicts a number of different possible outcomes or randomness in science and in the universe.  “Quantum” means a specified portion of something.  “Quanta” means packets (of particles or whatever).  A “quantum state” means a combination of position and velocity.  Quantum mechanics holds that all particles are waves (and, hence, vice versa) and that everything in the universe can be described in terms of particles.  Relativity deals with a macro view of the universe, while QM deals with a micro view.  A smooth linkage of these two theories may hold the key to the answers to our remaining key questions about the universe.

Light is comprised of waves, but it behaves as if it were comprised of particles.

Atoms are the basic units of chemistry and biology, from which all matter and we are made.  Atoms, once thought to be the smallest basic element and “indivisible”, are now known to be comprised of electrons, neutrons and protons.  A molecule is a group of atoms.  Atoms are comprised of three quarks, one each of red, blue and green; quarks are subatomic particles having electric charges of one third to two thirds of the electron.  Quarks are now believed to the fundamental units of all matter.  There are antiquarks (as there are antibodies for all matter); there are six types of quarks and six types of antiquarks.

PAULI’s “exclusive principle” states that similar particles cannot exist in the same state, and that every particle has a anti-particle, which prevents them from collapsing to a state of high density.  Hawking speculates that “There could be a whole world of anti-persons and anti-selves” who would cancel each other out (“in a flash of light”), if they met and touched.  Pauli observed that there are “force carrying particles” of four types: “gravitational forces” (the weakest but most ubiquitous); “electromagnetic forces” (including positive and negative forces that are attracted to each other but which repel everything else), and that large bodies, like the sun, have roughly equal quantities of positive and negative particles, which effectively cancel each other out and maintain a balance;  “the weak nuclear forces” which are responsible for radioactivity; and “strong nuclear forces” which hold quarks together.

Our solar system (Solar System), then, includes the Sun, at its center, Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and the ice ball, Pluto.  The Sun, of course,  is a “star”; i.e., a body that was formed by gases (mostly hydrogen), which have collapsed on themselves; then, heated up; stabilized, and radiate a brilliant glow until they eventually burn out. After the Big Bang occurred about 14,000M years ago, our Solar System evolved about 4.5 billion years ago.  Our Earth took 2 billion years to cool before the first, one-celled life began to evolve.  Our Sun has some 5,000 million years left; long before that (in 600 million years or so), the earth is predicted to be sucked into the Sun by the force of its gravitational pull; however, all life on the earth would be extinguished by the Sun’s heat (fried as it were) in some 200 million years – long before the universe ends in a Big Crunch in about 10,000 million years.  Our Sun is only eight light minutes (or 88 million miles) away. (Light travels at 186K miles/second, 11+ million miles/minute, 88 million miles in eight minutes, and 6 million million miles/light year.)  The nearest star, other than our Sun, is Proxima Centauri, which is only four light years (about 23 million million miles) from earth.  Most stars are 300-400 light years away; that’s about 1,800 million million miles (300 x 600MM).  Our galaxy has some 200 million stars.  There are believed to be 200 million galaxies in the universe.  Our galaxy, the  Milky Way, is  100,000 light years in diameter.

HAWKING, at p. 36, analogizes space-time to expanding circles, like ripples spreading on the surface of a pond, with each circle growing larger.  By drawing vertical lines from the center or beginning point (the event), light or time-cones are created.  Space-time, being driven by light that moves in similar circular patterns, forms cones as well.  The “event” or “present” is at the beginning point.  Two light cones emerge: one is the Past Light Cone and the other is the Future Light Cone.  Events are reached by the “set of lights” that emanate from it.  Places that are not reached by those sets of lights are called “Elsewhere”.

In 2000, scientists described the universe in terms of two basic, but partial, theories: Einstein’s Relativity and quantum mechanics (QM).  The former describes gravity on large scales from a few miles to millions of millions of miles. QM deals only with extremely small scales, e.g., millionths of an inch and even  as a "nano" or one-billionth.  Hawking maintains that both TOR and QM cannot be correct, and a new theory is needed (“a quantum theory of gravity” that incorporates Relativity and QM.

Black holes, the main province of Hawking’s research, are stars that have collapsed on themselves and became so dense that gravitational pull is so strong that not even light can escape.  Black holes emit radiation and, therefore, lose energy and, therefore, should shrink at an increasing rate and likely eventually disappear in a tremendous explosion.  (Energy is proportional to mass – E=mc(squared).)  As black holes emit radiation, they are not really black, but, rather, glow.

Entropy is a fundamental law of the universe, and it holds that disorder increases when things are left to themselves; entropy is disorder and always increases with time; it is a form of Murphy’s Law: Whatever can go wrong will go wrong.

Arrows of time (pp. 184 et seq).  The laws of science do not distinguish between the forward and backward directions of time.  There are at least three “arrows of time”: (1) the thermodynamic arrow (the direction of time in which disorder increases); (2) the psychological arrow (the direction of time in which we remember the past and not the future; (3) the cosmological arrow (the direction in which the universe expands rather than contracts.  Hawking has shown that (1) and (2) are essentially the same and that both point in the same direction of time.  There is no unique measure of time that is agreeable to all observers; rather, each observer has his own measure of time.  (See, for example, the graphics on pp. 26-27.)  Nothing travels faster than light, but, if we could go faster than light, we could go backwards and/or forward in time, as space-time is curved, and time does not travel in a straight line, and it may actually double back on itself.  Wormholes (or thin tubes of space-time) may make it possible to link, bridge, or jump between, different regions of space-time, thus circumventing our inability to go faster than light, and going to the past or future.

The reality of unreality, and vice versa, emerges from Hawking’s discussions of particles, antiparticles and virtual particles.  He flirts with the question, to recall the divine poet, Edgar Allan Poe:

“Is all that we see or seem, but a dream within a dream?”

Is the object or the reflection the real reality?  This blend of physics and metaphysics hauntingly echoes the speculations of philosophers Kant and Hegel (c. 1800 and 1820, respectively) and of religious-philosopher, Mary Baker Eddy, the founder of Christian Science, who postulated (c. 1890) that tangible matter is unreal and that the intangible is the real form of things, in effect opting for the mirrored-reflection over the object reflected.  Mark Twain suggested as much in his posthumously published novel, The Mysterious Stranger (c.1900).

The core issue of Hawking’s scientific inquiries seems to revolve around the question: Why do the universe and we exist?  The exploration of that leads to another fundamental question:  Are the universe, our galaxy, our Solar System, our Earth products of random events or part of some master plan?  He is careful to reach no conclusions, and, considering the power of religions, he avoids giving any opinions about God or gods in general or about any of the many faiths on the globe, but he concedes that most scientists today believe that we, and all that we know, are products of random events and will end in a random manner – i.e., originating with the Big Bang and ending in the Big Crunch, a la Einstein, Hubble, Friedman and many others -- be it planned or unplanned.

Tribute to Hawking.  Hawking, who holds’ Isaac Newton’s chair as Lucasian Professor of Mathematics at the University of Cambridge, is widely regarded as the world’s most brilliant theoretical physicist since Einstein.  This book has sold about one copy for every 750 persons on the planet. Hawking’s ability to discuss mathematics and physics with words, and laymen’s words at that, rather than via the incomprehensible formulas, from which the concepts emanate, is truly amazing. I had the pleasure to meet him briefly in Aspen, Colorado, where he lectured.  By all means, dear reader, read this book!!!