ebnelson wrote:
I was not aware that they had been observed and discussed for so long.

Alex writes:
Yes, the streaks were originally seen (sporadically) in the lower resolution Viking orbital imagery. A concentrated mapping effort at higher resolution had to await the MOC aboard Mars Observer, which failed, and later Mars Global Surveyor. One thing to bear in mind, though, is that while the streaks seem to found primarily in the equatorial regions, they do not seem prefer specific geologic units. In fact, when one plots the features as a function of geologic unit, the distribution is almost random. The observed spatial distribution is just as, if not more, supportive of one favoring areas of net dust influx.

ebnelson wrote:
The lack of erosive traits is interesting.
I hope we will get cameras there that can show gradations in a higher degree of accuracy in the future.

Alex writes:
The proposed high-resolution imager (HRI) for the 2005 Mars Reconnaissance Orbiter (MRO), which will possess cm-scale resolution, could further constrain the lack of flow margin relief and any possible entrained debris sorting patterns.

ebnelson wrote:
It sounds like the "blackness" is a figment of the limitation of the technology.

Alex writes:
Actually the "blackness" (i.e., low albedo) of the streaks is real, not a "figment of the limitation of the technology."

ebnelson wrote:
Or is there a way to extrapolate out more data points from the dark streaks themselves?

Alex writes:
As for "extrapolat[ion]", I'm not sure. However, high spatial resolution spectrometers (ca. 100 m) such as the THEMIS IR aboard 2001 Mars Odyssey might be able to correlate the dark features to the geochemical composition of exposed Martian bedrock. That, combined with thermal inertia measurements, could help nail down whether these streaks correlate to areas of net dust infall, which would stregnthen the prevailing model.

ebnelson wrote:
Good luck in Europe,
Ed

Alex writes:
Thanks. For the record, I'll be visiting with colleagues from ASI (Italy) in Torino and CNES (France) in Lyon to discuss upcoming science on Mars Express, 2005 MRO, and the 2007 NetLander missions before heading off to the 52nd IAF Congress in Toulouse.

Alex R. Blackwell
University of Hawaii