According to a conjecture called cosmic inflation, just after the Big Bang, before many of the fundamental physics forces had even taken hold, the size of the universe mushroomed from next to nothing to the size of a dime; at an expansion rate faster than the speed of light.
The vast expanse of interstellar space is supposed to be too cold for most chemical reactions to occur. The more frigid it gets, the harder it is to spark a chemical reaction, for lack of energy – the very definition of cold. Yet a vast variety of complex organic molecules are formed in space. Some reactions transpire on the surface of cosmic dust grains, or with a little help from gamma rays or stray high-energy electrons. But most happen beyond the laws of chemistry.
That complex life could evolve on Earth involved a set of fantastic coincidences. One of them was the prolonged pummeling of the planet for 800 million years, starting over 4.5 billion years ago. Seeding the planet with cosmic debris was essential to its evolution, as was what was taken off in the process. One benefit of bombardment was ridding Earth of most of its chlorine.
The solar system’s innermost planet has the most eccentric orbit. It wobbles around the Sun every 88 days, with one-and-a-half rotations during that time. Mercury’s temperature range is also the most extreme: from 700 K during the day to 100 K at night. Yet it likely has life.