Help Shape the Future of Space Exploration

Join The Planetary Society Now Join Now!

Join our eNewsletter for updates & action alerts

   Please leave this field empty
Blogs

Headshot of Emily Lakdawalla

Door 5 in the 2010 advent calendar

Posted by Emily Lakdawalla

05-12-2010 17:45 CST

Topics:

Time to open the fifth door in the advent calendar. Until the New Year, I'll be opening a door onto a different landscape from somewhere in the solar system. Where in the solar system is this meandering river?

Door 5

NASA / JPL / Emily Lakdawalla

Door 5
At full resolution, the image is 150 meters per pixel; the area shown is 222 kilometers square.
It's not a river, of course. It's one of Venus' enigmatic canali. Venus' canali (singular: canale) look much more like Earth's river valleys than the Moon's sinuous rilles do. This one is about 2 kilometers wide and the part of it in this image is nearly 200 kilometers long.

Venus does have some sinuous rilles that look much like those on the Moon: deep single channels, often originating in steep-walled pits, which get shallower and narrower along their lengths until they peter out. Sinuous rilles on both the Moon and Venus are presumed to have a volcanic origin. Canali are much longer than sinuous rilles; the longest one wanders 7,000 kilometers across Venus without changing in width. And they can meander and anastomose and have cutoff oxbows and even have tributaries and distributaries just like the braided channels of Earth's rivers. Look closely at this one and you'll see some faint tributaries, and I think I see a shallow one that actually crosses the main one, which really makes no sense.

This is Venus -- hot, volcanically surfaced Venus -- so a channel really can't conceivably have had anything liquid flowing in it other than some kind of lava. But why do canali look so different from lunar-type sinuous rilles? How can they have constant width throughout thousands of kilometers of length? How can lava have been flowing long enough to create braided channels, meanders, and oxbows? It's all very mysterious.

Elsewhere in the image, you can see little pimples of shield volcanoes that are about 2 or 3 kilometers across. And there's lots of wrinkle ridges, trending generally north to south.

In just a bit less than 24 hours, Venus will have not one but two orbiters. Akatsuki starts firing its engines to enter orbit at 23:49 UTC on December 6. You can be sure I'll be posting updates about that tomorrow!The Planetary Society Blog 2010 Advent Calendar


 
See other posts from December 2010

 

Or read more blog entries about:

Comments:

Leave a Comment:

You must be logged in to submit a comment. Log in now.
Facebook Twitter Email RSS AddThis

Blog Search

LightSail - Flight by Light

Support LightSail!

In 2016, The Planetary Society’s LightSail program will take the technology a step further.

I want to help!

Featured Images

The Face of a Comet

Antares
Hayabusa 2 and DCAM3
Hayabusa 2 at Gate Position
More Images

Featured Video

View Larger »

Space in Images

Pretty pictures and
awe-inspiring science.

See More

Join the New Millennium Committee

Let’s invent the future together!

Become a Member

Connect With Us

Facebook! Twitter! Google+ and more…
Continue the conversation with our online community!