Star stuff 'R' us

 kw: book reviews, nonfiction, science, chemistry, cosmology, biology, philosophy

Let's take powers of ten, in time, looking back to the beginning:

• 13.8 billion years ago, everything began. Starting with the "Big Bang", or whatever it was, in some tiny fraction of a second all energy and matter appeared and sorted themselves out, becoming something like 10⁸⁰ "elementary" particles; either protons, neutrons, and electrons, or electrons plus quarks. Initially something like a thousand times that many particles of both "matter" and "antimatter" formed, and some tiny imbalance resulted in all the matter presently in existence. At least the visible or potentially visible stuff. This is accompanied by a much greater number of bosons such as photons.
• 1.38 billion years ago, we find that our Galaxy has appeared (10 billion years earlier) and then our solar system (just over 3 billion years earlier), and then once Earth settled down, life that either began as bacteria or soon became bacterial and archaean (AKA prokaryotes); and finally eukaryotic cells (larger cells with a nucleus) had arisen, such that almost anything big enough for us to see was composed of them (though they were, as we are, vastly outnumbered by the tinier prokaryotes).
• 138 million years ago it's already getting late in the Age of Dinosaurs: the familiar Tyrannosaurs plus Triceratops, Iguanodon, and sauropods such as Argentinosaurus stalked the land, pterosaurs flew hither and yon, and the seas were filled with ammonites (like an octopus with a big, coiled shell), mosasaurs and plesiosaurs. Flowering plants had recently evolved and were spreading everywhere.
• 13.8 million years ago it's the middle of the Miocene; mountain building is going on, and the continents have formed something similar to their modern configuration. A minor branch of mammals, the primates, has produced a few species larger than a rat, up to the size of a squirrel monkey.
• 1.38 million years ago, it's the middle Pleistocene. The ice ages began a million years earlier, and the Gorilla-Chimp-Hominin divide occurred in the range of 6-9 million years earlier. Homo erectus appeared 2 million years ago and by 1.38 million, was speciating into a few hominid species, although Neanderthals had yet to appear.
• 138,000 years ago, Neanderthals are all over Europe and Asia, while all archaic Homo sapiens are still in Africa.
• 13,800 years ago: It's been about 20,000 years since Neanderthals became extinct (or assimilated with H. sapiens). It's the middle of the Late Glacial Interstadial, a warm period that lasted about 1,800 years, followed by the colder Younger Dryas era. Humans are already on every continent except Antarctica (and maybe there also at times!). 
• 1,380 years ago: As I write this, that would be 643 AD (or CE), almost 160 years before Charlemagne unified the Holy Roman Empire. Anything resembling "science" is a millennium in the future.
• 138 years ago, in 1843, Queen Victoria had recently begun her 63-year reign; Louis Pasteur began to teach; the first Opium War had just ended in China; the first immigrant from Japan arrived in the United States. The germ theory of disease is still 50 years in the future.

That's a good place to stop the timeline, because 13.8 years ago almost anyone who can read this was alive and can remember numerous world events. It's also a useful backdrop to the much different history developed in What's Gotten Into You: The Story of Your Body's Atoms, from the Big Bang Through Last Night's Dinner, by Dan Levitt. 

Note that there is no question mark in the title; it is not a question but a statement, an affirmation. Wind back to 13.8 billion years ago, and the first atoms were produced soon after, very soon. They are nearly all still with us. If we pull back to look at the Universe as a whole, nearly 75% by mass is hydrogen and 25% is helium. About 1% is everything else, all the other 90-odd elements that have been formed since stars began to shine. Subtract that 1%, and you have the composition of the Universe 13.7 (or maybe 13.6) billion years ago.

The core of an atom is its nucleus. For hydrogen, it's almost always a single proton. Two other forms (isotopes) of hydrogen have one and two added neutrons, respectively. Helium almost always has two protons and two neutrons; a rare isotope of helium has one neutron. Nearly all the atoms of hydrogen and helium that were produced in the extremely early universe are still in existence. About 1% of them have been compounded (fused) into other atoms, of almost 100 elements and several hundred isotopes. The book tells about the step-by-step discovery of how the stars "cooked" the other elements. Without that cooking, there would be no carbon, oxygen, nitrogen, and other elements that it takes to make Earth and the other planets, and also all living things including us. Note that the atoms in the stars, in planets, in us, probably don't have their "original" electrons. Those can move from atom to atom, and chemistry is what we call the movements of electrons.

So, what has gotten into you, and into me? Primarily water (60+% of our bodies are water), composed of hydrogen from the early universe and oxygen cooked up in a large star that later blew up as a supernova. In whatever way elements were produced in stars, the way they got back into the universe to become planets and people was by supernova explosions…well, some amount of lighter elements got out of stars in a more gentle way as they shed their outer layers in the late stages of being a red giant. But anything heavier than iron had to come from a supernova, created during the eruption, and most elements heavier than oxygen also were expelled during supernova eruptions.

Chapters in the book detail the discoveries of organic chemicals, and RNA and DNA, and other molecules of life, a story that is still unfolding. The story of all the parts that have to work together for a cell to function is one of the most complex tales there is. Every cell in your body is as complex as Chicago, but operates millions of times faster. Even bacterial cells are only "simpler" by comparison: one cell of the "simple" bacterium E. coli contains 20,000 "factories" called ribosomes, that produce proteins under the direction of bits of RNA copied from the DNA "library". And the same cell contains thousands of other active bits called organelles with sundry functions. A typical cell in our body is 15,000 times as large (in volume; 25x the diameter) as an E. coli cell, and contains dozens of organelles that the bacterium doesn't have (or need). All are made from either primordial hydrogen or from the forty or so other elements, ejected by supernovae, which were brought together on this planet to become living things. THAT is what has gotten into us.

Reading this book was joyful. I hope you read it and will agree.