Astronomer follows a whim and finds a new moon

Mark Showalter, an astronomer at the SETI Institute, has a knack for discovering moons. He helped find one of Saturn’s moons, two of Pluto’s and two of Uranus’. He’s so practiced at it that it seems he can find them more or less by happy accident, which is what happened with his latest discovery.

Earlier this month, Showalter was going over archived pictures of Neptune from the Hubble Space Telescope, focusing on the ring segments that surround the planet. Then, on a whim, he went a little further.

Showalter had a thought that he should look beyond the ring segments ... and, when he did so, he discovered a tiny, white dot about 65,400 miles from the planet. The dot he spotted was located between the orbits of the Neptunian moons Larissa and Proteus. And Showalter noticed that the dot appeared repeatedly in more than 150 archival photographs of Neptune taken by Hubble between 2004 and 2009.

Here, now, is why whims can be worth following: the dot, it turns out, is another moon for Neptune -- the planet's fourteenth that we've discovered. [The Atlantic]