Feeds

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

'Irregular grindings' responsible, apparently

High performance access to file storage

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. ®

High performance access to file storage

More from The Register

next story
Video games make you NASTY AND VIOLENT
Especially if you are bad at them and keep losing
Elon Musk's LEAKY THRUSTER gas stalls Space Station supply run
Helium seeps from Falcon 9 first stage, delays new legs for NASA robonaut
Solar-powered aircraft unveiled for round-the-world flight
It's going to be a slow and sleepy flight for the pilots
Russian deputy PM: 'We are coming to the Moon FOREVER'
Plans to annex Earth's satellite with permanent base by 2030
LOHAN's Punch and Judy show relaunches Thursday
Weather looking good for second pop at test flights
Discovery time for 200m WONDER MATERIALS shaved from 4 MILLENNIA... to 4 years
Alloy, Alloy: Boffins in speed-classification breakthrough
India's GPS alternative launches second satellite
Closed satnav system due to have all seven birds aloft by 2016
Curiosity finds not-very-Australian-shaped rock on Mars
File under 'messianic pastries' and move on, people
prev story

Whitepapers

Mainstay ROI - Does application security pay?
In this whitepaper learn how you and your enterprise might benefit from better software security.
Five 3D headsets to be won!
We were so impressed by the Durovis Dive headset we’ve asked the company to give some away to Reg readers.
3 Big data security analytics techniques
Applying these Big Data security analytics techniques can help you make your business safer by detecting attacks early, before significant damage is done.
The benefits of software based PBX
Why you should break free from your proprietary PBX and how to leverage your existing server hardware.
Mobile application security study
Download this report to see the alarming realities regarding the sheer number of applications vulnerable to attack, as well as the most common and easily addressable vulnerability errors.