New Neptune Moon Discovered

[Buster's Uncle]

An Astronomer Followed a Whim -- and Discovered a New Moon for Neptune
By Megan Garber | The Atlantic – 16 hours ago...

A composite Hubble Space Telescope picture showing the location of Neptune's newly discovered moon, S/2004 N 1 (NASA/ESA/SETI Institute)

It started when Mark Showalter followed a whim. On July 1, the SETI Institute astronomer was studying -- as one does, when one is a SETI Institute astronomer -- archival pictures from the Hubble Space Telescope. The images were of Neptune, and Showalter was analyzing the faint arcs, or segments of rings, that surround the ice giant. Here was the whim: 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. It's named, for the moment, S/2004 N 1. And the little thing is tiny: Showalter estimates it to be, at the most, 12 miles across, making it the smallest moon we know of in the Neptunian system. It is in fact so small, and so dim, that it's about 100 million times fainter than the faintest star that can be seen with the naked eye -- a body so miniscule that it escaped even the eagle eyes of NASA's Voyager 2 spacecraft, which flew past Neptune in 1989, surveying the planet's system of moons and rings.

The body did not, however, escape the gaze of Mark Showalter -- who also helped to discover Pan, a moon of Saturn; Mab and Cupid, two moons of Uranus; and Styx and Kerberos, two moons of Pluto. The images he used for this latest discovery have been in the public domain for years, Showalter points out, so "anyone," he says, "could have discovered this."

But nobody had discovered it -- until the astronomer, armed with curiosity and enough education to trust it, let his eyes travel toward a tiny, white dot.

Which is a nice lesson for the rest of us. Showalter's discovery is an eloquent testament to the power of human intuition. And it's also a nice reminder of the newness, and freshness, of our explorations into space. As we fix our gaze on distant solar systems -- and on the life that may, or may not, exist within them -- it's worth remembering how much we still have left to discover about our own little corner of the universe.

http://finance.yahoo.com/news/astronomer-followed-whim-discovered-moon-224511162.html

[Buster's Uncle]

Tiny New Moon Discovered Around Neptune
SPACE.com
by Miriam Kramer, Staff Writer  3 hours ago  Science, Social Science, & HumanitiesHubble Space TelescopeNASA
 

This diagram shows the orbits of several moons located close to the planet Neptune.

The Hubble Space Telescope has revealed a small, never-before-seen moon around Neptune, boosting the giant blue planet's total satellite count to 14 satellites, new photos reveal.

The newfound Neptune moon — called S/2004 N 1 — was discovered July 1 during a fresh analysis of older Hubble Space Telescope images, scientists said. The newly discovered satellite is Neptune's smallest known moon and is just 12 miles (19 kilometers) wide.

Hubble telescope scientists announced the new Neptune moon's discovery today (July 15). The small satellite wasn't easy to find.

"The moons and arcs [segments of rings around the planet] orbit very quickly, so we had to devise a way to follow their motion in order to bring out the details of the system," SETI Institute scientist Mark Showalter, the moon's discoverer, said in a statement. "It's the same reason a sports photographer tracks a running athlete — the athlete stays in focus, but the background blurs."

In order to find the moon, Showalter dug through archival photos taken by Hubble from 2004 to 2009. The newly found moon appears in about 150 of those photos. By plotting a circular orbit of the moon, Showalter saw that the tiny satellite fully orbits Neptune every 23 hours.

The tiny moon is so small and hard to see that it even evaded NASA's Voyager 2 spacecraft when it flew by Neptune in 1989. At the time, Voyager 2 revealed six previously unknown moons in orbit around the blue planet, NASA officials have said.

S/2004 N 1 is so small that it's about 100 million times fainter than the dimmest star that can be seen with the naked eye, NASA officials said.

At 1,680 miles (2,700 km) across, Neptune's biggest moon is Triton. It is the only large moon in the solar system that has a retrograde orbit, meaning that it orbits in the opposite direction of its host planet's rotation, scientists have found.

Because of this strange orbit, some experts suspect that Triton is a dwarf planet caught in Neptune's gravitational pull.

"This capture would have gravitationally torn up any original satellite system Neptune possessed," Hubble officials wrote in a statement. "Many of the moons now seen orbiting the planet probably formed after Triton settled into its unusual retrograde orbit about Neptune."

The Hubble Space Telescope launched in 1990 and has been beaming back amazing images of celestial sights ever since. NASA officials hope to keep the venerable space telescope in operation until at least 2018 when its successor, the James Webb Space Telescope, is expected to launch.

http://news.yahoo.com/tiny-moon-discovered-around-neptune-112749544.html