Cool Astrophysics Quotes

Some species of snakes have small pits on their heads that pick up infrared rays from tasty warm-blooded prey, readily revealed at night against the rapidly cooling surroundings

As the cosmos continues to cool—dropping below a hundred million degrees—protons fuse with protons as well as with neutrons, forming atomic nuclei and hatching a universe in which ninety percent of these nuclei are hydrogen and ten percent are helium, along with trace amounts of deuterium (“heavy” hydrogen), tritium (even heavier hydrogen), and lithium.

For the first billion years, the universe continued to expand and cool as matter gravitated into the massive concentrations we call galaxies. Nearly a hundred billion of them formed, each containing hundreds of billions of stars that undergo thermonuclear fusion in their cores. Those stars with more than about ten times the mass of the Sun achieve sufficient pressure and temperature in their cores to manufacture dozens of elements heavier than hydrogen, including those that compose planets and whatever life may thrive upon them. These elements would be stunningly useless were they to remain where they formed. But high-mass stars fortuitously explode, scattering their chemically enriched guts throughout the galaxy. After nine billion years of such enrichment, in an undistinguished part of the universe (the outskirts of the Virgo Supercluster) in an undistinguished galaxy (the Milky Way) in an undistinguished region (the Orion Arm), an undistinguished star (the Sun) was born. The

The stuff of life, in other words, arose in places and times somewhat more accessible to our telescopic investigations. Since most of us spend our lives confined to a narrow strip near Earth’s surface, we tend to think of the cosmos as a lofty, empyrean realm far beyond our reach and relevance. We forget that only a thin sliver of atmosphere separates us from the rest of the universe. But science continues to show just how intimately connected life on Earth is to extraterrestrial processes. In particular, several recent findings have further illuminated the cosmic origins of life’s key ingredients. Take the element phosphorus, for example. It is a critical constituent of DNA, as well as of our cells, teeth and bones. Astronomers have long struggled to trace its buildup through cosmic history, because the imprint of phosphorus is difficult to discern in old, cool stars in the outskirts of our galaxy. (Some of these stellar “time capsules” contain the ashes of their forebears, the very first generation of stars that formed near the dawn of time.) But in a paper published in December in The Astrophysical Journal Letters, a research team reported that it had measured the abundance of phosphorus in 13 such stars, using data taken with the Hubble Space Telescope. Their findings highlight the dominant role of so-called hypernovae, explosions even more energetic than supernovae that spell the demise of massive stars, in making the elements