Feeds

Star-watchers: Famous moon left half-smeared by dirty ring

'Irregular grindings' responsible, apparently

Securing Web Applications Made Simple and Scalable

A well-known moon has been smeared half-dark by dirt coming from an enormous ring, according to reports.

Long-exposure shot of Iapetus, moon of Saturn, taken by the Cassini probe. Credit: NASA

The dirt boundary of Iapetus.

Science magazine has the story, quoting "ring specialist" Joseph Burns as saying: "It's nice to finally see a smoking gun that tells us exactly what happened."

Burns and his colleagues have long been interested in Iapetus, eighth moon of the famously ringy gas giant Saturn. Ever since it was discovered in the 17th century astronomers have been aware that the strange satellite had a bright face and a dark face, but have been unsure why this should be so.

The answer, it seems, is a previously unsuspected ring of dust, further out than the other rings of Saturn, which deposits an endless shower of dirt onto the leading face of Iapetus. As the moon is tidally locked - it doesn't spin about its own axis, instead always keeping the same face to its primary - all this dust settles on just one side.

Science reports that the new dirty ring's discovery was announced at an astronomers' conference in Puerto Rico yesterday. It seems that the new and record-breakingly large ring was detected by the Spitzer infrared space telescope orbiting the Earth.

The boffinry mag describes the process by which the doughnut-shaped dirt-cloud is continually replenished, even as much of it gets deposited on the grubby face of Iapetus:

At least three dozen or so "irregular" satellites, including Phoebe, whiz every which way within the giant ring. As wandering asteroids and comets hit these objects, they kick off debris, which in turn collide with other debris and strike yet more satellites. So the grinding down of irregular satellites produces the dust ring.

The dirty-ring moonsmear issue may not be confined to Iapetus, the scientists said. NASA boffins said that other moons both Saturnine and Jovian showed signs of similar darkening. ®

HP ProLiant Gen8: Integrated lifecycle automation

More from The Register

next story
ALIEN BODY FOUND ON MARS: Curiosity rover snaps extraterrestrial
And NASA kept evidence to itself for over a month
Malaysian Airlines flight MH17 claimed lives of HIV/AIDS cure scientists
Researchers, advocates, health workers among those on shot-down plane
Mwa-ha-ha-ha! Eccentric billionaire Musk gets his PRIVATE SPACEPORT
In the Lone Star State, perhaps appropriately enough
Diary note: Pluto's close-up is a year from … now!
New Horizons is less than a year from the dwarf planet
Forty-five years ago: FOOTPRINTS are FOUND ON MOON
NASA won't be back any time soon, though
NASA: ALIENS and NEW EARTHS will be ours inside 20 years
ETs, habitable planets will soon pop up with our new 'scopes
prev story

Whitepapers

Top three mobile application threats
Prevent sensitive data leakage over insecure channels or stolen mobile devices.
The Essential Guide to IT Transformation
ServiceNow discusses three IT transformations that can help CIO's automate IT services to transform IT and the enterprise.
Mobile application security vulnerability report
The alarming realities regarding the sheer number of applications vulnerable to attack, and the most common and easily addressable vulnerability errors.
How modern custom applications can spur business growth
Learn how to create, deploy and manage custom applications without consuming or expanding the need for scarce, expensive IT resources.
Consolidation: the foundation for IT and business transformation
In this whitepaper learn how effective consolidation of IT and business resources can enable multiple, meaningful business benefits.