Interesting Readings on the Topic of Physics

Eric Scerri. (June 2013).Cracks in the Periodic Table.Scientific American, pp. 68 - 73.

Key Concepts: 1: The discovery of element 117 in 2010 completed for the first time the periodic table as we know it—at least until new discoveries will force chemists to extend it by adding a new row. 2: Some recent additions, however, may differ in their chemistry from the elements in the same column, breaking the periodic rule that had defined the table for a century and a half. 3: The surprising behavior may result from effects described by the special theory of relativity, which make some electron orbits tighter, among other effects. 4: Nuclear physicists continue in their quest to synthesize new elements, which will have new types of electron orbitals—and to understand their chemistry from studying a handful of short-lived atoms.

Vlatko Vedral. (2011, June). Living in a Quantum World. Scientific American, pp. 38 - 43.

Quantum mechanics is basically physics of the microscopic world - whereas classical physics is physics of the macroscopic world and the two have always been at odds. Classical physics describes time and space - where an object can never be in two places at the same time whereas quantum mechanics states that a particle can be in two locations at the same time.

Recent research is atrting to show quantum mechanics at the macroscopic level. Stephen Hawking thinks that the Theory of Relativity (Einstein) must give way to a deeper theory in which space and time do not exist. Also discussed is that gravity may not even exist at the quantum level.

Key Concepts: 1: Quantum mechanics is commonly said to be a theory of microscopic things: molecules, atoms, subatomic particles. 2: Nearly all physicists, though, think it applies to everything, no matter what the size. The reason its distinctive features tend to be hidden is not a simple matter of scale. 3: Over the past several years experimentalists have seen quantum effects in a growing number of macroscopic systems. 4: The quintessential quantum effect, entanglement, can occur in large systems as well as warm ones—including living organisms—even though molecular jiggling might be expected to disrupt entanglement.

Bob Weber. (June 6, 2011). Antimatter 'game-changer'. The Hamilton Spectator, p. A8.

Scientists were able to hold 308 antimatter Hydrogen atoms for more than 16 minutes, a first. This gives researchers the capability to describe the properties of antimatter (the opposite of matter). This is a very big achievement because when antimatter comes in contact with matter they annihilate each other in a very big burst of energy.

It has been postulated that when the Big Bang occurred some 14 billion years ago, there were equal amounts of matter and antimatter present - where did all the antimatter go?

George Musser. (2010, September). Could Time End? Scientific American, pp. 84 - 91.

Have you ever sat around and wished for time to speed up or slow down or stop? Well, the ultimate end to the universe, in one scenario some 20 billion (20 000 000 000 000) years in the future, is the end of time.

See: Ultimate Doomsday and Four Stages to the End of Time.

Key Concepts: 1: Einstein’s general theory of relativity predicts that time ends at moments called singularities, such as when matter reaches the center of a black hole or the universe collapses in a “big crunch.” Yet the theory also predicts that singularities are physically impossible. 2: A way to resolve this paradox is to consider time’s death as gradual rather than abrupt. Ttime might lose its many attributes one by one: its directionality, its notion of duration and its role in ordering events causally. Finally, time might give way to deeper, timeless physics.

Tamara M. Davis. (2010, July). Is the Universe Leaking Energy? Scientific American, pp. 38 - 47.

A much more difficult paper to comprehend. Terms used: Doppler Shifts (blueshifted & redshifted lights), Electromagnetic Waves, Entropy, Conservation Laws, and Symmetry. Scenarios include: differing Geometries: a steady geometry versus a geometry that changes in time (i.e.: space), the growth of Space (i.e.: the metaphor of the universe as an expanding rubber balloon should be taken with a grain a salt).

Key Concepts: 1: As the universe expands and distant galaxies recede from us, their light gets redshifted, thus becoming less energetic. 2: This seeming violation of the principle of conservation of energy is actually not in contradiction with accepted physical laws. 3: According to the author, the proper interpretation shows that the energy of individual photons is conserved. And phenomena taking place inside the galaxy generally conserve energy.

Kei Hirose. (2010, June). The Earth's Missing Ingredient. Scientific American, pp. 76 - 83.

Not exactly a physics paper, but more of a geology paper. Did you know that the diameter of the earth is 12 756.32 km (depending on where you are standing). When you look at a cross-section of the Earth, the mantle is composed of 2 distinct sections with the lower mantle (Perovskite layer) being uniform in composition and consisting of 70% MgSiO3 (magnesium silicate), previouslt thought to be the most dense crystal arrangement known to exist.

Current research has shown the that the bottom portion of the lower mantle is now composed of Postperovskite, made up of the same elements but reduced in volume by 1.5% from the Perovskite layer above it. Postperovskite forms at pressures of around 120 gigapascals (1 gigapascal is the equivalent of 10 000 atmospheres), therefore around 1 200 000 atmospheric pressures and 2 500 kelvin.

Key Concepts: 1: At high pressures, the most common type of mineral in the earth’s lower mantle undergoes a structural change and becomes denser. 2: The existence of this denser phase implies that the mantle is more dynamic and carries heat more efficiently than previously thought. 3: Faster heat transport helps to explain why continents grew as fast as they did and even how the earth’s magnetic field evolved in a way that enabled life to move onto land.

Craig Callendar. (June 2010). Is Time an Illusion? Scientific American, pp. 58 - 65.

A very confusing paper on time. Does it even exist? See: How Time is Not Like Space and Who Needs Time, Anyway?

Key Concepts: 1: Time is an especially hot topic right now in physics. The search for a unified theory is forcing physicists to reexamine very basic assumptions, and few things are more basic than time. 2: Some physicists argue that there is no such thing as time. Others think time ought to be promoted rather than demoted. In between these two positions is the fascinating idea that time exists but is not fundamental. A static world somehow gives rise to the time we perceive. 3: Philosophers have debated such ideas since before the time of Socrates, but physicists are now making them concrete. According to one, time may arise from the way that the universe is partitioned; what we perceive as time reflects the relations among its pieces.

Graciela B. Gelmini, Alexander Kusenko, and Thomas J. Weiler. (2010, May). Through Neutrino Eyes. Scientific American, pp. 38 - 45.

A picture of what the sky would look like if you could see Neutrinos: The Sky in Neutrinos, from the Ice Cube Telescope. See: Neutrino Metamorphosis.

Key Concepts: 1: Neutrinos will give astronomers a type of x-ray vision far better than actual x-rays. Being the most unreactive type of subatomic particle, they pass through intervening matter as though it were hardly there— revealing the cores of stars and other dramatic but otherwise hidden places in the cosmos. 2: Alas, the very property that ¦makes neutrinos so useful means they tend to fly through detectors without registering. Only this year have instruments become sensitive enough to detect cosmic sources unequivocally. 3: Neutrinos come in multiple varieties and can metamorphose in midflight. This peculiar property provides additional information about their celestial origins.

____________. (2009, January 24). Nanotechnology: Tiny Matters. The Hamilton Spectator, pp. WR1 & WR2.

Just how small is small? You would require 100 000 nanometers stacked one on top of the other just to equal the thickness of a sheet of paper. Where can we find these small little things - these nanoparticles - probably everywhere when you look for them: in your house, your office, your closet and in your makeup drawer.

Nanotechnology is described by some as the new frontier. When get below 100 nanometers, the laws of classical physics breaks down and the laws of quantum physics takes over.

Andrew Maynard, chief science adviser to the Nanotechnology Project at the Woodrow Wilson International Center for Scholars notes: "No matter how hard you try to predict where the technology will go, something unpredictable will happen."

Rubi, J. Miguel. (2008, November). The Long Arm of the Second Law. Scientific American, pp. 62 - 67.

What is the Second Law of Thermodynamics, you ask?

The second law is the best known of the four laws of thermodynamics, the study of heat and energy. Whereas the first law states that you cannot get something for nothing, the second law states that you cannot even get something for something. Almost all processes lose some energy as heat, so to get something, you have to give something more. Such processes are irreversible; to undo them exacts a toll in energy. Consequently:
- Engines are inherently limited in their energy efficiency.
- Heat pumps tend to be more efficient than furnaces, because they move rather than generate heat.
- Erasing computer memory is an irreversible act, so it produces heat.

Many important physical and biochemical processes operate far from equilibrium, where the standard theory of thermodynamics dare not tread. The author and his colleagues have fixed this shortcoming with a theory of nonequilibrium thermodynamics.
Microfluidics
. Fluids flowing through microscopic channels are prone to effects that are negligible in larger channels, such as diffusion of molecules. The standard equations describing the fluids’ behavior are often intractable. But the new nonequilibrium theory of thermodynamics circumvents these complications and can readily
Chemical reactions. Chemical reactions and other processes such as crystallization are inherently nonlinear: they occur only when the energy exceeds a certain threshold. They become still more complex when they occur in a medium whose density and other properties vary. The nonequilibrium theory is nonetheless able to predict the reaction rates.
Molecular folding and unfolding. Strings of amino acids pack themselves into three-dimensional proteins whose shape helps to determine their biological function. The process is notoriously poorly understood. The nonequilibrium theory has recently had some success on the related problem of how RNA molecules unfold.
Cell membranes. Molecules weasel their way through cell membranes aided by various biochemical contraptions, such as ion channels and proteins that act as ratchets. Yet the speed of this process has long puzzled theorists. The nonequilibrium theory shows that features once seen as complications— large and sustained departures from equilibrium, as well as nonlinearities and fluctuations of density—are actually what enable the process.

Key Concepts: 1: Einstein’s general theory of relativity says that the universe began with the big bang singularity, a moment when all the matter we see was concentrated at a single point of infinite density. But the theory does not capture the fine, quantum structure of spacetime, which limits how tightly matter can be concentrated and how strong gravity can become. To figure out what really happened, physicists need a quantum theory of gravity. 2: A new approach closes this loophole and finds that the second law holds far from equilibrium. But the evolution from order to disorder can be unsteady, allowing for pockets of self-organization.

Bousso, Raphael and Joseph Polchinski. (2008, October). The String Theory Landscape. Scientific American, pp. 78 - 87.

The typical size of a String is near the Planck Length, 10 E-33 cm or 10 E-35 m, basically a point in space unless viewed under Planckian magnification.

In this version, space can be viewed as a landscape, with mountains, rolling hills and valleys with an estimated 10 E150 to 10 E500 possible configurations. These configurations (example: growth of a universe) may coexist side by side in different subuniverses, each large enough to be unaware of the other and each with its own set of physical laws that may be different from each other.

The whole universe can therefore be described as a foam of bubbles within bubbles, each with its own laws of physics. Extremely few of the bubbles are suitable for the formation of complex structures such as galaxies and life. Our entire visible universe (greater than 20 billion light years in diameter) is a relatively small region within one of these bubbles.

Key Concepts: 1: According to string theory, the laws of physics that we see operating in the world depend on how extra dimensions of space are curled up into a tiny bundle. 2: A map of all possible configurations of the extra dimensions produces a “landscape” wherein each
valley corresponds to a stable set of laws. 3: The entire visible universe exists within a region of space that is associated with a valley of the landscape that happens to produce laws of physics suitable for the evolution of life.

Achenbach, Joel. (2008, March). At the heart of all matter. The hunt for the God particle. National Geographic, pp. 90 - 105.

Did you know that a very large atomic smasher is currently coming on line under the Swiss-France border. The Large Hadron Collider (LHC) is a 17 mile long particle accelerator that will speed up protons to 99.9999991 % of the speed of light and then smash them together, creating particles and matter that were only found during the very first moments in the creation of the universe, or the Big Bang. Scientists will be able to detect Quarks and Gluons, subatomic particles that make up the proton but are looking for the elusive Higgs particle, a particle that is probably 100 to 200 times the mass of a proton but will only last less than a millionth of a billionth of a billionth of a second before decaying.

Why do scientists want to find the Higgs particle? Because scientists theorize that the Higgs particle is part of the Higgs Field, a fiels that pervades all space and imbues fundamental particles (protons, neutrons and electrons) with mass. Finding the Higgs particle will prove that the Higgs Field actually exists.

Did you know that scientists theorize that all of the universe, all the galaxies, stars and planets (of which there are trillions), once had no dimension at all - no up or down, left or right, no passage of time, and laws of physics beyond our vision. Our entire universe happened at the smallest imaginable scale, smaller than the smallest atom. Take everything we know is present and condense it into a space smaller than the smallest atom. How UNIMAGINABLE!!!!

Does antimatter exist? Scientists theorize that when the Big Bang occurred, energy should have condensed into equal amounts of matter and antimatter, which would have annihilated each other and there should be no matter left, just energy. We know that is not the case because the universe exists and a liitle bit more matter than antimatter formed. Maybe the LHC will help answer this question as to why there is more matter than antimater?

Scientists are also looking for the presence of Dark Matter. We cannot see Dark Matter but we can theorize that it exists by looking into the heavens. The motion of distant galaxies indicates that they are subject to more gravity than their visible matter could possible account for, therefore there must be something - Dark Matter - that fills the voids of space.

The Large Hadron Collider might also answer the most basic question: What is this place?

Read the article. It is very informative.

Kostelecky, Alan . (2004, September). The Search for Relativity Violoations. Scientific American, pp. 92 - 101.

An interesting paper. Have you ever wondered what a LORENTZ Symmetry (symmetry of space and time) is? Lorentz symmetry expresses the sameness of the laws of physics under rotations and under boosts, which are changes in velocity. This symmetry may be broken at very small distances, in the range of 10 E-34 to 10 E-17 of a meter, or in the area of the Planck constant (10 E-35 m) - the paper gives an example of this distance which is the equivalent of the thickness of one human hair realtive to the orbit of Neptune around the sun. So proving Lorentz symmetry violations is no easy feat. See: Breaking Spacetime Symmetries.

The article goes on to describe how to prove that there are LORENTZ symmetry and another spacetime symmetry called CPT symmetry (C - charge conjugation- the interchange of particles and antiparticles; P - parity inversion - reflection in na mirror; T - reversal of time).

For more information: See Spacetime Symmetry and Antihydrogen

For more information, go to: Nuclear Physics (click on the Nuclear Physics bubble) and Particle Physics (on the Nuclear Physics page, click on Particle Physics at the bottom).

Key Concepts: 1: Although special relativity is among the most fundamental and well verified of all physical theories, tiny violations of it could be predicted by theories that unify quantum mechanics, gravity and the other forces of nature. 2: Numerous experiments are under way to uncover such effects, but so far none have proved sensitive enough to succeed.

Gabriele Veneziano. (May 2004). the myth of The Beginning of Time. Scientific American, pp. 54 - 65.

Was the 'Big Bang' the Beginning of Time? No one will ever truly be able to answer this question but new theories using Quantum Effects and The String Theory open up the possibility of a 'Pre-Bang Universe'. See the 2 scenarios below.

Pre-Big Bang Scenario                                       Ekpyrotic Scenario

The Ekpyrotic ('conflagration') scenario relies on the idea that our universe is one of many D-branes floating within a higher dimensional space. The branes exert attractive forces on one another and occasionally collide. The big bang could be the impact of another brane with ours.

Key Concepts: 1: Philosophers, theologians and scientists have long debated whether time is eternal or finite—that is, whether the universe has always existed or whether it had a definite genesis. Einstein’s general theory of relativity implies finiteness. An expanding universe must have begun at the big bang. 2: Yet general relativity ceases to be valid in the vicinity of the bang because quantum mechanics comes into play. Today’s leading candidate for a full quantum theory of gravity—string theory—introduces a minimal quantum of length as a new fundamental constant of nature, making the very concept of a bangian genesis untenable. 3: The bang still took place, but it did not involve a moment of infinite density, and the universe may have predated it. The symmetries of string theory suggest that time did not have a beginning and will not have an end. The universe could have begun almost empty and built up to the bang, or it might even have gone through a cycle of death and rebirth. In either case, the pre-bang epoch would have shaped the present-day cosmos.

Smolin, Lee. (2004, January). Atoms of Space and Time. Scientific American, pp. 66 - 75.

An article refering to Loop Quantum Gravity which predicts that space and time are made up of discrete pieces. These discrete pieces are measured by the Planck constant of 10 E-33 cm, therefore the smallest area of space is 10 E-66 cm E2 and the smallest volume of space is 10 E-99 cm E3. Based on these calculations every cm E3 of space has 10 E99 atoms of volume, a number so small that it dwarfs the actual size of the visible universe calculated at 10 E85 cm E3.

These calculations also state that time is not continuous but occurs in discrete intervals as well, the smallest tick of the clock known as the Planck time, or 10 E-43 of a second. Time does not exist between these ticks in the same way that there is no water in between two adjacent water molecules.

Can this concept ever be proven, and if so how? The theory predicts that high energy gamma rays travel faster through space time than lower energy gamma rays, albeit we could not measure this small difference, but over time the difference is cumulative. Therefore, gamma ray bursts from a distant star which have been travelling for billions of years if arriving at different times will be measurable by the GLAST satellite.

Key Concepts: 1: To understand the structure of space on the very smallest size scale, we must turn to a quantum theory of gravity. Gravity is involved because Einstein’s general theory of relativity reveals that gravity is paused by the warping of space and time. 2: By carefully combining the fundamental principles of quantum mechanics and general relativity, physicists are led to the theory of “loop quantum gravity.” In this theory, the allowed quantum states of space turn out to be related to diagrams of lines and nodes called spin networks. Quantum spacetime corresponds to similar diagrams called spin foams. 3: Loop quantum gravity predicts that space comes in discrete lumps, the smallest of which is about a cubic Planck length, or 10–99 cubic centimeter. Time proceeds in discrete ticks of about a Planck time, or 10 E–43 second. The effects of this discrete structure might be seen in experiments in the near future.

Ford, Lawrence H., Thomas A. Roman. (2000, January). Negative Energy, Wormholes and Warp Drive. Scientific American, pp. 46 - 53.

If you have watched Star Trek, you are bound to know that Captain Kirk has asked Scotty for more power on many time to jump to Warp speed. If you are a Deep Space Nine junkie, then you know all about Wormholes and how they allow people to move from one area of the universe to another instantaneously. Well, is all this possible or just made up by Hollywood?

These wild ideas are now thought to be possible because of the unique properties of space. Gravity is the space-time distortion produced by normal, positive energy or mass. What happens when there is Negative Energy? This is not pure science fiction or fantasyland but its effects have been produced in the laboratory. For a more detailed understanding of what Negative Energy is you have to read the article.

Negative Energy - or exotic matter - bends space-time, all sorts of amazing phenomena might become possible. This paper very rudely describes different types of space travel - Wormholes could be made big enough for a person to enter the mouth on Earth, walk a short distance in the Wormhole and exit the mouth in, say, the Andromeda Galaxy.

An interesting article well worth reading!

Stephen W. Hawking and Roger Penrose. (July 1996). The Nature of Space and Time. Scientific American, pp. 60 - 65.

Two of the smartest people on the planet, Stephen W. Hawking and Sir Roger Penrose, discuss the topics of Quantum Black Holes, Quantum Theory and Space-Time, Cosmology, and the physics of Reality.

Terms to know are: Physics Terminology


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