DCB wrote:Long story short
: Voyager 2 took some pictures of Neptune in 1989.
20 years later, amateur astronomer Ted notices a moon.
The moon itself was noticed in 1989 -- but only in a handful of frames of film -- and named in 1991.What Ted discovered were previously unnoticed images of it casting a shadow on Neptune and then, following that lead, more picturess of the moon itself that had also never been noticed before. Still pretty darn cool, though.
More cool: it's theorized that Despina is essentially a rubble pile made up of leftover chunks of original moons of Neptune which no longer exist. Those moons formed at the same time as Neptune but were destroyed by gravitational perturbations caused by the capture of Triton, which formed somewhere else entirely and only later settled into Neptunian space. Triton, you see, is the only large moon in the solar system which orbits in the opposite direction from its host planet's rotation, hence how we know it was not originally part of Neptune's system.
Poor little Despina is slowly spiralling downward towards Neptune and will likely break apart again, either into a planetary ring or by crashing into the planet itself, so enjoy it while you can!
Thanks for posting this. We need more straight-up (and non-controversial) science around these parts.