kw: book reviews, nonfiction, geology, cosmology, astronomy, nucleosynthesis, cooking
This chart was mentioned in How to Make an Apple Pie From Scratch: In Search of the Recipe for Our Universe, From the Origins of Atoms to the Big Bang, by Harry Cliff. The book's title, indeed its raison d'être, is a humorous aside by Carl Sagan on an episode of Cosmos: "If you wish to make an apple pie from scratch, you must first invent the universe."
Harry Cliff is a particle physicist and researcher on the Large Hadron Collider, specifically the experiment/detector called LHCb. The "b" means "beauty", for the Beauty Quark, which most physicists now call the Bottom Quark (the "t" and "b" quarks were initially called "truth" and "beauty"). The short answer to "What is 'scratch'?" would be, "Something smaller than a quark." Quarks are what we call the (possibly) indivisible bits that make up protons and neutrons, which with electrons, form atoms.
I think of the book as a microscope that uses higher and higher powers to probe the makeup of the universe. Dr. Cliff actually began his investigation by obtaining an apple pie and pyrolizing a few grams. That gave him a rough estimate of the phases present, gas/vapor, liquid, and solid. The final product of pyrolysis is charcoal, although he found later that he didn't cook it hot enough; his charcoal still had some volatile stuff in it. It matters little: the end product was mainly carbon, the "gateway element" to producing the entire suite of elements from hydrogen and helium. The chart above shows the various "ovens" in which the elements were made.
Much of the book is history, the history of the discovery of the chemical elements during the Enlightenment, then the discovery of subatomic particles a bit more than a century ago. Although I've read the stories again and again (because writers seem compelled to cover it all every time), I find it enjoyable to rehearse the way alchemy became chemistry, and experiments with "cathode rays" and pitchblende came together to discover that atoms (from "a-tomos", "un-cuttable") are actually cuttable, and the "easy" sub-parts are further cuttable.
The reason for this omission is soon apparent. The author's quarry is smaller compared to an atom of lead than that atom is to a sports arena.
An ordinary light microscope "maxes out" when viewing items smaller than half a micrometer (or micron, or µ). An E. coli bacterium is about 2µx6µ. The photons of green light, with a wavelength of 0.55µ, have an energy of 2.25 eV. One eV, or one electron volt, is the energy of an electron that has "fallen" across the gap between an anode and a cathode when the voltage is 1V. Photon energies in the range 1.75 eV to 3.1 eV are used by the retinas of our eyes to detect "light". Things smaller than about 0.5µ, or 500 nm (nanometers), can only be studied using "light" of a shorter wavelength. And here is the important principle: shorter wavelength means higher energy per photon (or other particle).
Why is it hard to "see" an atom? It is because they are so much smaller than the wavelength of visible light. The lead atoms in the image above are about 0.35 nm across. That's 0.00035µ. The silicon atoms in the surface below them are much smaller, with an interatomic spacing of 0.078nm. An electron microscope with beam voltage of a million volts uses electrons with energy of 1 MeV (million eV), and a wavelength of 0.0012 nm. However, such an electron beam simply blows off most of the electrons from the atoms you want to look at, while a more "modest" beam of about 16,000 volts, and a useful magnification of a million, can produce images without causing total disruption. The STM technique sidesteps this by using atomic forces to get higher-resolution information, with a limit in the range of 10 to 20 million X magnification.
When the biggest constituents of atoms were discovered, electrons, protons, and neutrons, they were soon found to be a whole lot smaller than the atoms. One analogy states that an atom of hydrogen magnified to the size of a stadium (a magnification of two trillion) would be "seen" to be an electron cloud with a speck at its center the size of a small pea, perhaps 6mm diameter: the proton.
How do you "see" a proton? Since it is about 50,000 times smaller than the atom, you would need 50,000 times the energy. At a minimum, 16,000 eV x 50,000 or 800,000,000 eV, just under a billion eV (GeV). Now, let's think a minute. A million-volt power supply needs a lot of insulation. In radio, the rule of thumb is that in dry air a spark will jump about a centimeter per 10,000V. So a million-volt potential can jump at least a meter. I remember seeing a picture of an early million-volt electron microscope. It was eight feet high. What do you do with a billion volts? Such a voltage can jump a few miles. Indeed, lightning has voltages in the billion-to-ten-billion-volt range.
Here it gets fun. Particle accelerators finesse the situation by using magnets and rhythmic pulses to take a bunch (that's the scientific term) of electrons or other charged particles from an "easy" energy of 10,000 eV to higher and higher energies. It's sort of like swatting a tetherball again and again to make it go around faster and faster, except these "tetherballs" are soon going 99% of the speed of light, or more.
When I worked at Cal Tech (as a machinist), I worked part of the time in a room with a dismantled synchrotron about 30 feet in diameter. Energetic electrons or protons lose energy when you turn them to go around in a circle, so the more energy you want, the bigger the circle has to be. The LHC, where Dr. Cliff works, is about 8.5 miles in diameter. It produces beams of protons with energies that exceed 10 trillion eV. It also runs them in both directions, and steers them into head-on collisions, so you get enormous penetration. All that to "see" the insides of particles a few thousand times smaller than protons, which is what it took to prove the existence of the Higgs Boson (but not see into its insides…if it has any).
Chapters and chapters earlier, the author discussed where the atoms came from. The chart that begins this article shows where. Things we can eat, and we ourselves, are primarily CHON, that is, Carbon, Hydrogen, Oxygen, and Nitrogen. Hydrogen makes up 75% of the weight of the matter in the universe. Or, at least, of the matter that is either visible or potentially visible because it can respond to electromagnetic energy ("light"). We need to ignore dark matter and dark energy here, because we still have no idea how to interact with them. Most carbon and nitrogen are made in "dwarf" stars, main sequence stars smaller than 1.25 times the mass of the Sun. The jury is still out on whether the white dwarf stars that result from the demise of a main sequence dwarf star have to be blasted apart to release carbon and nitrogen, or if the red giant phase releases enough to amount for what we see in the sky. Most oxygen, at least most of it that gets into the interstellar medium, is forged during supernova explosions. So at an atomic level, that's where the basic ingredients of the apple pie arise.
The reason for using big atom smashers like LHC to dig into the protons for their smaller bits (quarks and gluons, mainly), and into the quantum fields that modulate (or create) their properties such as mass, is that we aren't really back to "scratch" yet. By the end of the book, if we have understood it all (I am not quite there yet), we have the beginnings of matter traced back to the end of the first one-trillionth of a second after the Big Bang.
Does that sound pretty good? Not to a cosmologist! The Big Bang is thought to have begun with everything we might call space and time located within a radius of about the Planck Length, which is about 1.6x10-35 meters. The initial "Bang" got rolling in Planck Time, or about 5.4x10-44 seconds. Let's just call it 10-45 sec., and compare it to a trillionth, or 10-12 sec. There are about 1033 Planck Times in a trillionth of a second; a little matter of a billion trillion trillion of them. A lot happened that we will be hard pressed to probe. The author describes the ultimate particle accelerator, wrapped around the center of the galaxy (where it has a chance of being gravitationally stable), with a diameter of several thousand light years. The biggest we have a chance of building might wrap the Earth at the equator. The particle bunches would circle the planet seven times per second, so we have long enough lives to do experiments with it, with energies as high as perhaps 50,000 TeV. That's still a long way from the Planck Energy, but it might be close enough to be "interesting".
Future beings with very long lifetimes—because each experiment takes a million years or more—might probe the Planck Length using the Galactic Collider. But beyond a certain level of energy, the only output of the experiment will be tiny black holes. According to Hawking's principle, such a black hole would soon explode into a shower of energetic particles, but they would carry no information about what was going on inside, so the fancy machine would simply be a huge fireworks generator.
The book ends with a description for beginning from scratch, to the point where matter exists, including a middling size planet with apple trees and wheat fields and such. Then it ends with a pretty good recipe for making an apple pie. There ain't a quark anywhere that can explain the great taste of fresh apple pie.
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