A REALLY BRIEF GUIDE TO THE UNIVERSE IN A NUTSHELL!
by: Scott LaFee
Some 13 years have passed since Stephen Hawking wrote “A Brief History of Time,” his keen-witted and much-publicized treatise on modern physics, cosmology and the universe. In that time, more than 10 million copies in 40 languages have re- portedly been sold, making “Brief History” arguably the most popular science book never read. Now Hawking has done it again, writing ‘The Universe in a Nutshell.” (Bantam, $35) It’s a sequel of sorts, another small book about a big subject
Or more precisely, a big subject getting bigger. That’s because the universe is expanding. Cosmologists peg the rate at roughly 53 kilometers (33 miles) per second per megaparsec — the distance light travels in 3.26 million years. This is called Hubble’s Constant. It means, among other things, that there’s a lot more universe to write about now than there was just a moment ago.
Such cosmic realities do not daunt Hawking. He is a master of containment, able to capture universal truths – or at least the scientific search for them — in a few score pages. Readers apparently appreciate such brevity. They have already made “Nut- shell” a best seller: “No. 6" last week on The New York Times’ Hardcover Non-fiction list. It’s quite possible, then, that there’s a copy for you under the Christmas tree. If so, could read it. But in this ever-growing universe with ever-more places to go and ever-more things to do, who has the time? If that describes you, we offer this
even-briefer guide to Hawking’s universe. It won’t make you even with Stephen, but you might feel smarter.
Shape of things to come.
Saint Augustine, a fifth-century philosopher and all-around smart guy, once said that he understood time until somebody asked him to explain it. As a result, Saint Augustine considered it good form not to get too hung up on the subject Time for him simply existed, except when it did not, which according to Saint Augustine was before God made heaven and earth.
This idea, says Hawking, is very close to the modem conception of time, which has evolved much over the years. Time began with the birth of the universe. That seems straightforward enough. But once begun, where did — or does—time go?
Sir Isaac Newton, who discovered the laws of gravitation and motion among other things, considered time to be like a railroad track upon and around which events happened. Time was separate from space and events. It stretched like a single line forward and back, future and past, toward infinity.
Albert Einstein’s theory of relativity, introduced in the early part of the 20th century, upset Newton’s 17th century apple cart because it posited that time and space are, in fact, inextricably connected. Numerous experiments have proved Ein-
stein to be astoundingly prescient, not just about the bonded-ness of space-time but
about other things like the universe being curved, rather than flat, due to distortions caused by the effects of matter and gravity. These observations have profound implications, says Hawking.
If the universe has shape, then so too does time because they are linked. And if time has shape — Hawking postulates something pear-like — it may be possible to trace light and time back to a singularity, a place where the density of matter is infinite. You can find singularities today. Black holes are, in part, singularities. The matter inside them is so compressed that the resulting gravity sucks in light and effectively renders time null and void. But nobody has ever actually seen a black hole. Only indirect evidence buttressed by theory points to their existence
This is particularly true of the so-called “initial singularity,” the entity from which the universe presumably emerged. Cosmologists don’t know what exactly caused the “Big Bang”, but they believe they know quite a bit about what happened afterward. Like, for example, that in the millionth-millionth-millionth-millionth of a second after the Big Bang, when the universe was the size of a pea, it was very, very hot: roughly 18 billion million million million degrees Fahrenheft.
In this rush of cosmic expansion, all matter, energy, time and space were created, though not as we know them today. Things tend to change over 16 or so billion years —the current estimated age of the universe. But while scientists are fairly comfortable with the big picture, they’re still sweating the small stuff. Classical physics and relativity theory do a pretty good job of explaining how the universe functions on a grand scale, but they come up short describing the operations of individual atoms and their subatomic particles.
This is the realm of quantum, Latin for the smallest amount of something that it is possible to have. The unseen quantum universe is a confounding place, governed by rules unlike anything in our everyday, reasonably comprehensible existence. This makes quantum science really hard to grasp, even among physicists. “I think I can safely say that nobody understands quantum mechanics,” said the late Richard Feynman, who actually won a Nobel Prize in 1965 for understanding it better than most.
Q is for quantum
There are many kinds of quantum research: quantum algebra, quantum electro-dynamics (where Feynman earned his fame), even something called quantum cookery, which uses quantum equations to solve problems involving quantum entities without bothering to try to understand what is going on or what the equations really mean.
Quantum mechanics/quantum physics (the names are essentially synonymous) is the
field that codifies the laws governing the realm of the very small, atoms to Z part-icles. It includes ideas like the uncertainty principle, which states that one cannot simultaneously know both the position and velocity of a subatomic unit, and the existence of virtual particles, which are able to pop in and out of existence from nothing. However counter-intuitive it seems, quantum science has shown itself to be quite accurate at describing quantum objects (if objects they actually are) and predicting their behaviors. “Although quantum physics maybe weird,” said John Gribbin, an astrophysicist and author, “it works.” It works, in part, because quantum theory is enormously flexible. It can be a wave. It can be a particle. It can be whatever you want.
“Quantum physics sees that new properties emerge when simple things combine or relate,” write Ian Marshall and Danah Zohar in ‘Who’s Afraid of Schrodinger’s Cat?” “The whole is greater than the sum of its parts. There is always the possibility of becoming other or more than what is. Every quantum bit has the po-
tentiality to be here and there, now and then, a multiple capacity to act on the world.” Einstein and others didn’t much care for this sort of physical fluidity. Classical physics is pretty black and white. There are laws, and the universe follows them. You pretty much know what to expect most of the time. The variability and unpredictable of quantum physics, on the other hand, can be maddening. It was the reason why an exasperated Einstein once insisted that “God does not play dice!”
But there’s a bigger prob1cm. Even though most physicists today accept the broad
concepts of both quantum and relativity, they cannot figure out how exactly to get them both in the same equation. That’s because, like an angry and dysfunctional couple, quantum and relativity theories refuse to speak to one another. Their particular merits and inconsistencies make them mutually incompatible. They can not reside in peace under the same universe.
For more than 50 years, physicists have worked hard as marriage counselors, strug- gling to find common ground, an enduring bond that would unite quantum and relativity. They have not succeeded. Some skeptics say they aren’t even close, though Hawking is optimistic that the hardest work has already been done. The idea of a love connection between quantum and relativity theories is the recurrent dream
of many scientists. They even have a name for its imagined progeny: the Theory of Everything.
Mind your TOEs and P-branes
A Theory of Everything (TOE) would unify matter, forces and curved space-time into one fantastic picture of what happened from the split second alter the “Big Bang” It would also include a good accounting of quantum gravity, which hasn’t happened yet. One major difficulty is that quantum theory is formulated in a “fiat” space while general relativity involves curved space. Most physicists argue that a new and grander theory or concept is needed, something that incorporates both flat and curved. (In a really shallow and prosaic way, you can think of this particular challenge as trying to satisfy the appetites of both herbivores and carnivores with a
single food. One side demands only plants; the other side insists strictly upon meat. You need an edible that is both plant and meat or neither.)
Physicists have a few candidate solutions. One is called supersymxnetry. In it, every particle of force (bosons) and every particle of matter (fermions) has a matching partner that exists in a dimension beyond the four of space and time. The totality of these particles — and their intricate behaviors — would theoretically unify all of elementary physics. Unfortunately, no one has yet discovered any of these pre-sumed counter-particles. A better-known alternative is string theory, a term that actually encompasses several ideas. Strings are theoretical one-dimensional entities that form vibrating loops much smaller than particles. “A loop of string is as much smaller than an atom as an atom is smaller than the solar system,” said Gribbin. Such theoretical strings would represent the most fundamental stuff in the universe — until somebody found something smaller. Like the theory of supersymmetry, these strings exist in many dimensions, 10 or 11 are popular numbers. The reason nobody has ever seen these strings or extra dimensions, scientists explain, is that they are curled into very, very small packages that exist beyond our current perception. A lot of people like string theory because it naturally accounts for gravity, which is so much weaker than the other three forces (electromagnetic, weak and strong) that it is hard to bring into the mathematical fold. But like all quantum research, enormous obstacles remain.
First, the math of string theory is incredibly obtuse and hard to fully develop. Second, no experiment currently exists to test the idea. String theory is an answer in search of its question. The biggest TOE possibility of the moment, however, in-
volves phenomena called P-branes. The “P” refers to the number of dimensions exhibited by a brane, a theoretical quantum object. For example, a string is a P=1 brane; a membrane is P~=2 because it extends in two dimensions. Like strings, P-branes can exist in many and varying dimensions. Like string theory, P-branes appear to possess all of the critical attributes required to answer physics’ most vexing questions — and they seem to do so uniquely, elegantly.
But validating experiments of P-branes remain to be done. Hawking and others support a TOE called “M-theory.” It could be the ultimate answer, but, like most things quantum, data and evidence continue to be scarce.
But there’s a catch to all of this, one that Hawking doesn’t much discuss. The search for a Theory of Everything necessarily assumes that such a theory actually exists and that scientists, if they look hard enough, will find it. But what if it doesn’t exist? ‘There is no compelling scientific or philosophic reason why such a fundamental theory should exist,” write Marshall and Zohar. “It might equally well
be that any finitely describable theory is only approximately true. Perhaps beneath the quantum domain there is a world of pure chaos, without any fixed laws or symmetries.” If that’s the case, Hawking had better get cracking on brief book No.3.
Defining the universe from Hawking’s view
A glossary of words and phrases used in Stephen Hawking’s universe.
The idea that we see the universe the way it is because if it were any different, we wouldn’t be here to see it
Each type of matter particle in the universe has a corresponding anti-particle with the opposite charge. When a particle collides with its antiparticle, they annihilate each other, leaving only energy.
The singularity at the beginning of the universe, about 16 billion years ago.
A theoretical scenario in which the universe ultimately collapses into itself, all space and matter forming a new singularity.
A region of space- time from which nothing, not even light, can escape because gravity is so strong.
An object that can have a variety of dimensions.
Conservation of energy.
The law of physics that states that energy (or its equivalence in mass) can neither be created nor destroyed.
High-energy particles coming mostly from beyond the solar system, and mostly consisting of protons. Astronomers suspect that most of these particles form in super-nova explosions, which blast them out into the galaxy.
Dark matter .
Matter in space that is known to exist only from indirect observation of its gravitational effects. Dark matter consists of two types, hot and
cold, the former referring to particles moving at near the speed of light while the latter are much slower. As much as 90 percent of the universe consists of dark matter.
The edge of a black hole; the boundary of the region from which it is not possible to escape to infinity.
Driving factors in the behavior of physical objects. There are four: electromagnetic, which arises between particles with opposing electric charges; strong, which holds together the smallest subatomic particles to form the structures s needed to form atomic nuclei; weak, which affects all matter particles but not force-
carrying particles; and gravity.
An extension of Albert Einstein’s earlier special relativity theory that deals with frames of reference that are accelerated rather than inertial. It incorporates the effects of gravity, explaining the force in terms of curved, four-
The quantity of matter in a body; its inertia or resistance to acceleration in free space.
Microwave background radiation .
The radiation from the glowing of the hot, early universe. It has cooled and shifted so much that it no longer appears as light, but as micro waves.
The indivisible unit, the smallest measure of something.
A point in space-time in which matter is infinitely dense.
Einstein’s theory that says the laws of science should be the same to all observers, no matter how they are moving, in the absence of gravitational fields. If two objects or systems are moving uniformly in relation to each other, it is impossible to determine anything about their momentum except that it is relative. The mathematical equation is E-mc2, with E signifying energy, m referring to mass and c the velocity of light. Energy and mass are interchangeable. The speed of light is constant in a vacuum and independent of either its source or an observer. In relativity theory, moving objects appear to be shortened in the direction of the motion to an observer at rest, a clock in motion appears to run more slowly than a stationary clock to an observer at rest, and the mass of an object increases with its velocity.
Standard model of cosmology.Big bang theory combined with standard model of particle physics.
Standard model of particle physics.
A unifying theory for the three non-gravitational forces and their effect on matter.
Energy that is present even in apparently empty space.
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