|
Posted on 01/12/2014 1:52:59 PM PST by BenLurkin
Janus and Epimetheus travel in nearly the same track, about 94,100 miles (151,500 km) out from Saturn. They occasionally pass each other, their gravity causing them to switch speeds and positions as they do; Janus goes faster and higher one time, slower and lower the next – but the two never come within more than about 6,200 miles of each other.
The two moons switch positions roughly every four years.
This scenario is referred to in astrophysics as a 1:1 resonance. Astronomers were initially confused when the moons were discovered in 1966 as it wasn’t known at the time that there were actually two separate moons in a single orbit. (This wasn’t confirmed until Voyager 1′s visit to Saturn in 1980.) It’s been suggested that Janus and Epimetheus will eventually come to orbit a single Lagrangian point around Saturn instead of trading places… in about another 20 million years.
The view above looks toward the Saturn-facing side of Janus. Covered in both dark and light colored material, Janus’ surface is thought to be coated with a layer of fine dust that slides down its steeper slopes, revealing the brighter ice beneath.
Incomplete link.
Here’s the correct one.
http://www.universetoday.com/108039/a-distant-view-of-janus-one-of-saturns-dancing-moons/
If we ever get real space travel, I would love to watch the switch happen
Thx
“Janus goes faster and higher one time, slower and lower the next”
This is backwards. Should be faster and lower one time and slower and higher the next. Kepler’s 3rd Law. The lower orbit is swifter.
|
...that isn’t a moon...
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.
