Astronomer finds new moon orbiting Neptune

CAPE CANAVERAL, Florida - An astronomer studying archived images of Neptune taken by the Hubble Space Telescope has found a 14th moon orbiting the planet, NASA said on Monday. Estimated to be about 12 miles (20 km) in diameter, the moon is located about 65,400 miles (105,251 km) from Neptune.

Astronomer Mark Showalter, with the SETI Institute in Mountain View, California, was searching Hubble images for moons inside faint ring fragments circling Neptune when he decided to run his analysis program on a broader part of the sky. "We had been processing the data for quite some time and it was on a whim that I said, 'OK, let's just look out further. I changed my program so that instead of stopping just outside the ring system it processed the data all the way out, walked away from my computer and waited an hour while it did all the processing for me. When I came back, I looked at the image and there was this extra dot that wasn't supposed to be there," Showalter said.

[link to news.yahoo.com]

I thought we were technically more advanced than this - not to know about a moon orbiting one of our own home planets. Has it always been there, or just appeared from nowhere?