Did you ever stand outside looking up at the stars, and then down at the ground, and then wonder to yourself, “How did this planet come into being?”
Of course we all know the standard “theory” about how planets are formed—a star begins to coalesce out of a cloud of gas and dust. Over millions of years this action goes on until things get hot enough in the center to turn on the nuclear furnace that stokes the burning “machine” we call a star. The leftovers are where planets come into being. There’s LOTS of stuff left over after a star forms— grains of dust and chunks of ice and clouds of gases and so on. The ice and clouds nearest the star are pretty much “burned off” by the heat from the newborn stellar creation, but the rocks and dust grains stick around. In fact, they start to stick together. IF this goes on for long enough you get bigger and bigger “hunks” of stuff out there trundling around the stars. Eventually these hunks form worlds.
That’s the “potted” history of planetary formation. But, how do we observe this going on in other stellar systems today? The Spitzer Space Telescope has just released some observations that reveal large dust clouds around several stars. They likely formed when rocky, embryonic planet “seeds” crashed together, sending debris flying out through space.
It’s a chaotic scenario, but a plausible one. And, the scientists using Spitzer are looking for such dusty disks around many nearby stars to see just where collisions are affecting planetary formation in the neighborhood. Before Spitzer, only a few dozen planet-forming discs had been observed around stars older than a few million years. Spitzer’s uniquely sensitive infrared vision allows it to sense the dim heat from thousands of discs of various ages.
So, the next time you find yourself out there gazing at the stars and marveling at their seeming serenity, remember this: it’s not all as serene as you think. Somewhere around a newborn star is a scene of remarkable chaos. And born out of that chaos in a few million or billion years might be another Earth, and maybe another being to gaze skyward and wonder what’s happening “out there.”
