Adam Frank

Eclipses are not particularly rare in the universe. One occurs every time a planet, its orbiting moon, and its sun line up. Nearly every planet has a sun, and astronomers have reason to believe that many of them have moons, so shadows are bound to be cast on one world or another as the years pass.
But solar eclipses like the one that millions of Americans will watch on April 8—in which a blood-red ring and shimmering corona emerge to surround a blackened sun—are a cosmic fluke.

The whole universe is humming. Actually, the whole universe is Mongolian throat singing. Every star, every planet, every continent, every building, every person is vibrating along to the slow cosmic beat.That’s the takeaway from yesterday’s remarkable announcement that scientists have detected a “cosmic background” of ripples in the structure of space and time.

Pity the poor astronomer. Biologists can hold examples of life in their hands. Geologists can fill specimen cabinets with rocks. Even physicists get to probe subatomic particles in laboratories built here on Earth. But across its millennia-long history, astronomy has always been a science of separation. No astronomer has stood on the shores of an alien exoplanet orbiting a distant star or viewed an interstellar nebula up close.

Almost a century ago, the revolutionary idea of the biosphere gained a foothold in science. Defined as the collective activity of all life on Earth—the tapestry of actions of every microbe, plant, and animal—the biosphere had profound implications for our understanding of planetary evolution.