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Book Summary: Elemental

Author: Tim James

Substory: Formation Of Stars

All matter in the Universe has a gravity field to it, which means everything is pulling on everything else. We don’t feel it but our bodies are loosely gravitating to the objects in the room around us and they are being drawn back toward us in return.

The reason you don’t notice this effect is because gravity is a very weak force (you need an entire planet’s worth to hold things in place), but while gravity might be weak it is infinite and has been around since the beginning.

Within the first half-second after the big-bang expansion started, the earliest particles called photons and neutrinos (Appendix II again) began colliding, forming the protons, neutrons, and electrons we already know about. A few hundred seconds after that, the protons and neutrons joined up, creating hydrogen and helium nuclei with a tiny bit of lithium and beryllium thrown in (elements 3 and 4). Then, for the next 380,000 years, nothing happened.

During this time the Universe was a buffet of free-floating nuclei and electrons. You wouldn’t have been able to see anything in front of your face because there was light in all directions and all of reality would have looked like a milky fog.

Then, after about 1.6 million years, the temperature dropped to a breezy thousand degrees and electrons got snagged by nuclei, forming clouds of hydrogen and helium atoms. The Universe finally became see-through and gravity began exerting its influence.

As the hydrogen/helium clouds started collapsing under their own weight, their gravity fields became more concentrated, pulling more and more atoms into the mix. Over millions of years, these clouds condensed into swirling knots across the Universe, getting hotter and hotter until they whipped themselves into such a frenzy that the nuclei of the atoms began to fuse.

Gravity pulled things inward while the heat from fusion at the core pushed outward. When a truce was finally reached between these forces, the result was a stable sphere of nuclear explosion. The very first sun.

The core of a sun like ours reaches a temperature of about 16 million°C, hot enough to vibrate hydrogen and helium atoms into each other and mash them into heavier elements like oxygen and carbon. Bigger and fiercer stars can go even further, burning carbon atoms into magnesium and then fusing all the way up to iron (element 26). This is how the light elements are made.