Astronomers are used to finding all kinds of wild things in outer space -- black holes, colliding galaxies, stars spinning hundreds of times a second, even a 21-piece comet now on its way to smashing into Jupiter. Still, the giant glowing hoops that showed up in a Hubble Space Telescope picture released last week prompted veteran sky watchers to chatter like awestruck kids. "It's bizarre," said Christopher Burrows of the Space Telescope Science Institute in Baltimore, Maryland. "It's the neatest thing I've ever seen."
It's also among the most puzzling. Two huge hoops -- each a few light-years in diameter --...