New Moon System Around Uranus

An anonymous reader writes "Astronomers have discovered two of the smallest moons yet found around Uranus. The new moons, uncovered by NASA's Hubble Space Telescope, are about 8 to 10 miles across (12 to 16 km) -- about the size of San Francisco. The two moons are so faint they eluded detection by the Voyager 2 spacecraft, which discovered 10 small satellites when it flew by the gas giant planet in 1986. The newly detected moons are orbiting even closer to the planet than the five major Uranian satellites, which are several hundred miles wide. The two new satellites are the first inner moons of Uranus discovered from an Earth-based telescope in more than 50 years. "It's a testament to how much our Earth-based instruments have improved in 20 plus years that we can now see such faint objects 1.7 billion miles (2.8 billion km) away," says Mark Showalter, a senior research associate at Stanford University. 'The inner swarm of 13 satellites is unlike any other system of planetary moons,' says co-investigator Jack Lissauer. 'The larger moons must be gravitationally perturbing the smaller moons. The region is so crowded that these moons could be gravitationally unstable. So, we are trying to understand how the moons can coexist with each other.'"

Comments

"Moons are unstable"

[turkeyphant]

If these moons are gravitationally astatic, stochastic motion could account for their motion in this deterministic system. We all know how complication three-body motion is, so with the number of objects affected by various gravitational fields out there, it would be incredibly hard to predict any movement at all. I wish them good luck in trying to precisely "understand how the moons can coexist with each other".

Is it not possible that these moons are so unstable that they will have relatively short lifespans? Might they soon end up crashing into the planet's surface or interact together and get flung off out of the solar system?

Why is NASA...

[rexguo]

...so eager to take Hubble down, when it's still contributing so much to astrophysics? The new space telescope isn't even ready for launch yet, and who knows if it will work at first go? I'd rather have Hubble as backup until the new one is working smoothly and flawlessly before even thinking about bringing it down. Capitalism and politics just don't mix well with science.