A genial tour of the universe and its mysteries.
According to Einsteinian and other theories of relativity, light should take about 8.5 minutes to zoom from the sun to Earth. Yet, as New Scientist cosmology consultant Chown (The Ascent of Gravity: The Quest to Understand the Force that Explains Everything, 2017, etc.) notes, it takes much longer—30,000 years, in fact. The delay has to do with the density of the sun and the circuitous route that light must take in order to leave: “Photons are like Christmas shoppers fighting their way down a crowded street,” writes the author. “They cannot go in a straight line but are forced to zigzag.” In the case of light from the sun, it can advance no more than a centimeter before pinging elsewhere, and before you know it—well, as Chown notes, the light now bathing us was born during the last Ice Age. The author writes with gods-for-clods, rocks-for-jocks enthusiasm: “Some slime molds have thirteen sexes. (And you think you have difficulty finding and keeping a partner!).” Though the rhetorical ploy gets old, there’s plenty for more advanced students to ponder, such as Chown’s passing note that all life is really cellular life. Indeed, there are lots of moments that will stir the imaginations of meditative stoners. For example, the air we breathe was also very likely breathed by Marilyn Monroe, Julius Caesar, and “the last Tyrannosaurus Rex ever to have stalked the earth.” Also, the laws of probability suggest that the number of possible earths and their possible inhabitants are uncountably unknowable: “There are an infinite number of galaxies that look just like our own galaxy containing an infinite number of versions of you, whose lives, up until this moment, have been absolutely identical to yours.”
Heavy stuff lightly spun—just the thing for the science buff in the house.