From “8 modern astronomy mysteries scientists still can’t explain” (MSNBC.com) we learn,
Why is the solar system so bizarre?
As astronomers and space observatories discover alien planets around other stars, researchers have been keen to understand the unique characteristics of our solar system.
For instance, while extremely varied, the four innermost planets have rocky outer shells and metallic cores. The four outermost planets are vastly different and each possess their own identifiable features. Scientists have studied the process of planetary formation in hopes of grasping how our solar system came to be, but the answers have not been simple.
“Looming over all the attempts to explain planetary diversity, however, is the chilling specter of random chance,” wrote Richard Kerr, a staff writer at Science. “Computer simulations show that the chaos of caroming planetesimals in our still-forming planetary system could just as easily have led to three or five terrestrial planets instead of four.”
But the search for alien worlds could help scientists hoping to gain insights into the planets closer to home.
“Help might come from planets orbiting other stars,” Kerr wrote. “As exoplanet hunters get beyond stamp-collecting planets solely by orbit and mass, they will have a far larger number of planetary outcomes to consider, beyond what our local neighborhood can offer. Perhaps patterns will emerge from inchoate diversity.”
Here’s a bet that patterns won’t do much for the randomness thesis.