Astronomers have a problem. The comets in our solar system formed some 4.5 billion years ago in its frigid outer regions, beyond the current orbit of Jupiter. These "dirty snowballs" naturally contain ...

The protostar EC 53 (circled) in Serpens shows one set of winds and scattered light emanating from its protoplanetary disk. (The disk itself is too small and shrouded in dust to appear.) Astronomers ...