IPB

Welcome Guest ( Log In | Register )

2 Pages V   1 2 >  
Reply to this topicStart new topic
More Wet Gullies
Tom Tamlyn
post Apr 12 2010, 09:12 PM
Post #1


Member
***

Group: Members
Posts: 273
Joined: 1-July 05
From: New York City
Member No.: 424



A new paper argues that HiRISE photos show evidence for recent short-lived surface water flows. Neat pictures on Phil Plait's site (my source for the news).

It would be interesting to learn if there was any MGS coverage of the same area.

TTT
Go to the top of the page
 
+Quote Post
schaffman
post Apr 13 2010, 09:49 AM
Post #2


Junior Member
**

Group: Members
Posts: 55
Joined: 6-March 10
From: Cincinnati, OH
Member No.: 5246



These gully-like features in Russell crater were described by Nicholas Mangold and others in 2003 using MGS MOC and MOLA images:
Mangold, N.; Costard, F.; Forget, F. (2003). Debris Flows over Sand Dunes on Mars: Evidence for Liquid Water. J. Geophys. Res., 108(E4), 5027, doi:10.1029/2002JE001958.
Michael Carr also discusses them briefly in his book The Surface of Mars, 2006.

Tom

FULL INLINE QUOTE REMOVED - Admin
Go to the top of the page
 
+Quote Post
Tom Tamlyn
post Apr 14 2010, 12:46 AM
Post #3


Member
***

Group: Members
Posts: 273
Joined: 1-July 05
From: New York City
Member No.: 424



Thanks!
Go to the top of the page
 
+Quote Post
tharrison
post Apr 23 2010, 02:20 AM
Post #4


Junior Member
**

Group: Members
Posts: 46
Joined: 6-January 10
From: San Diego, CA
Member No.: 5163



QUOTE (Tom Tamlyn @ Apr 12 2010, 01:12 PM) *
It would be interesting to learn if there was any MGS coverage of the same area.


There are a number of MOC narrow-angle images of the Russel dune gullies as the area was monitored for change. MSSS put out a few captioned image releases of them:

http://www.msss.com/mars_images/moc/2003/04/27/index.html
http://www.msss.com/mars_images/moc/2005/05/08/index.html
http://www.msss.com/mars_images/moc/2005/11/05/


--------------------
Go to the top of the page
 
+Quote Post
ilbasso
post Apr 23 2010, 02:37 AM
Post #5


Member
***

Group: Members
Posts: 752
Joined: 23-October 04
From: Greensboro, NC USA
Member No.: 103



Say, were you guys the victims of those pranks in high school, too?

Oh, sorry. I thought this topic was More Wet Willies.


--------------------
Jonathan Ward
Manning the LCC at http://www.apollolaunchcontrol.com
Go to the top of the page
 
+Quote Post
Paolo
post May 3 2010, 05:15 PM
Post #6


Senior Member
****

Group: Members
Posts: 1339
Joined: 3-August 06
From: 43 35' 53" N 1 26' 35" E
Member No.: 1004



on arXiv today: Martian gullies: Produced by fluidization of dry material


--------------------
I'm one of the most durable and fervent advocates of space exploration, but my take is that we could do it robotically at far less cost and far greater quantity and quality of results.

James Van Allen
Go to the top of the page
 
+Quote Post
tharrison
post May 4 2010, 11:34 PM
Post #7


Junior Member
**

Group: Members
Posts: 46
Joined: 6-January 10
From: San Diego, CA
Member No.: 5163



QUOTE (Paolo @ May 3 2010, 10:15 AM) *


Someone has started a separate thread about this paper: http://www.unmannedspaceflight.com/index.p...ic=6584&hl=


--------------------
Go to the top of the page
 
+Quote Post
Dysgraphyk
post Dec 11 2013, 02:38 PM
Post #8


Newbie
*

Group: Members
Posts: 9
Joined: 27-August 12
Member No.: 6618



A new paper showing recurring dark streaks.
Nature comments : "Water seems to flow freely on Mars"

McEwen, A. S. et al. Nature Geosci. http://dx.doi.org/10.1038/ngeo2014 (2013).

QUOTE
River-like valleys attest to the flow of water on ancient Mars, but today the planet is dry and has an atmosphere that is too thin to support liquid water on the surface for long. However, intriguing clues suggest that water may still run across the surface from time to time.

In 2011, for example, researchers who analysed images from NASA's Mars Reconnaissance Orbiter (MRO) spacecraft observed dark streaks a few metres wide that appeared and lengthened at the warmest time of the year, then faded in cooler seasons, reappearing in subsequent years2. "This behaviour is easy to understand if these are seeps of water," says planetary scientist Alfred McEwen of the University of Arizona in Tucson, who led that study. "Water will darken most soils."

The streaks, known as recurring slope lineae, initially were found at seven sites in Mars's southern mid-latitudes. The water may have come from ice trapped about a metre below the surface; indeed, the MRO has spotted such ice in fresh impact craters at those latitudes.

McEwen and his colleagues have now found the reappearing streaks near the equator, including in the gargantuan Valles Marineris canyon that lies just south of it. The MRO has turned up 12 new sites each of which has hundreds or thousands of streaks within 25 degrees of the equator. The temperatures there are relatively warm throughout the year, says McEwen, and without a mechanism for replenishment, any subsurface ice would probably already have sublimated.

He says that this suggests that water may come from groundwater deep in the crust (...)

But even though McEwen says that water is the most likely explanation for the streaks, he is not sure of the sources. Some of the streaks seem to begin at the tops of ridges, too close to the surface to easily be explained by subsurface aquifers. So the water may come instead from atmospheric water vapour that is pulled into salts in the soil and later released.

"It is quite difficult to understand how [the streaks] can occur with the current understanding of Mars," says Gerhard Kminek, vice-chair of COSPAR's planetary protection panel and planetary protection officer at the European Space Agency. "And that makes it more interesting of course."


source : Nature news


--------------------
Go to the top of the page
 
+Quote Post
nprev
post Dec 12 2013, 03:43 PM
Post #9


Senior Member
****

Group: Moderator
Posts: 6949
Joined: 8-December 05
From: Los Angeles
Member No.: 602



Interesting idea, but still a long way from proof.

I often wish for an orbiter capable of capturing events in real-time, not only for this phenomenon but also for the landslides in the polar regions, dust devils, etc. What seem to be dynamic processes are much easier to understand if you catch them in the act.


--------------------
A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.
Go to the top of the page
 
+Quote Post
0101Morpheus
post Dec 12 2013, 10:42 PM
Post #10


Junior Member
**

Group: Members
Posts: 48
Joined: 16-October 12
From: Pennsylvania
Member No.: 6711



Maybe NASA should land the next rover near a gully to clear it up.
Go to the top of the page
 
+Quote Post
ngunn
post Dec 12 2013, 11:07 PM
Post #11


Senior Member
****

Group: Members
Posts: 3093
Joined: 4-November 05
From: North Wales
Member No.: 542



Well, we already have a rover sniffing for organics in retreating scarps. Maybe it will also find ice subliming there and not just minerals with a lot of water of crystallisation. On the other hand the water in the gullies could come from the breakdown of hydrated minerals rather than melting ice.
Go to the top of the page
 
+Quote Post
serpens
post Dec 13 2013, 12:49 AM
Post #12


Member
***

Group: Members
Posts: 382
Joined: 17-February 09
Member No.: 4605



Breakdown of hydrated minerals on the polar side of dark, probably basaltic dunes at temperatures no higher that say 20 celcius for a brief period? What hydrated minerals are you proposing or are you thinking minerals in frozen brines?
Go to the top of the page
 
+Quote Post
Phil Stooke
post Dec 13 2013, 12:59 AM
Post #13


Senior Member
****

Group: Members
Posts: 5551
Joined: 5-April 05
From: Canada
Member No.: 227



I can't yet see these features as anything but dry granular flows. I'm willing to be shown I am wrong...

Phil



--------------------
... because the Solar System ain't gonna map itself.
Go to the top of the page
 
+Quote Post
Gerald
post Dec 13 2013, 01:15 AM
Post #14


Member
***

Group: Members
Posts: 718
Joined: 7-December 12
Member No.: 6780



QUOTE (serpens @ Dec 13 2013, 01:49 AM) *
Breakdown of hydrated minerals on the polar side of dark, probably basaltic dunes at temperatures no higher that say 20 celcius for a brief period? What hydrated minerals are you proposing or are you thinking minerals in frozen brines?

The only hydrated mineral with that property I know of is meridianiite decomposing in epsomite and water. This should be possible to distinguish from basalt, i.e. confirmed or discarded.
Go to the top of the page
 
+Quote Post
nprev
post Dec 13 2013, 01:36 AM
Post #15


Senior Member
****

Group: Moderator
Posts: 6949
Joined: 8-December 05
From: Los Angeles
Member No.: 602



Again, speed of propagation is a critical parameter which we are currently not well equipped to measure.


--------------------
A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.
Go to the top of the page
 
+Quote Post

2 Pages V   1 2 >
Reply to this topicStart new topic

 



RSS Lo-Fi Version Time is now: 30th July 2014 - 01:11 PM
RULES AND GUIDELINES
Please read the Forum Rules and Guidelines before posting.

IMAGE COPYRIGHT
Images posted on UnmannedSpaceflight.com may be copyrighted. Do not reproduce without permission. Read here for further information on space images and copyright.

OPINIONS AND MODERATION
Opinions expressed on UnmannedSpaceflight.com are those of the individual posters and do not necessarily reflect the opinions of UnmannedSpaceflight.com or The Planetary Society. The all-volunteer UnmannedSpaceflight.com moderation team is wholly independent of The Planetary Society. The Planetary Society has no influence over decisions made by the UnmannedSpaceflight.com moderators.
SUPPORT THE FORUM
Unmannedspaceflight.com is a project of the Planetary Society and is funded by donations from visitors and members. Help keep this forum up and running by contributing here.