Exoplanet statistics have been accumulating since 1995 (and especially since january 1996) the statistics are observationally biased. it is easier to detect hot jupiters. but even allowing for the bias, the picture is very strange massive planets in near circular orbits at jupiter-distance are rare what is more common is eccentric (oval) orbits and massive planets getting cooked closer even than mercury-distance. other systems dont seem to sort themselves out into nice circular stable configurations analogous to us. It represents a physical puzzle. what are the current guesses about why?