[X] My Assistant

[Nirgal]

the latest dust devil pictures are so amazing that I spent the whole night
working on a colorization of the navcam pics.
... It is now 5 o'clock in the morning
This is still a work in progress but I'd like to share the first results here:

[glennwsmith]

Thanks for making these astounding images available. How can the thin Martian atmosphere churn things up so?

Glenn

[Guest_Edward Schmitz_*]

Thanks for making these astounding images available.  How can the thin Martian atmosphere churn things up so?

Glenn

It took a lot of enhancement even to see it, at all. I'm not knocking enhancement and I love the images. But if you we there, you might not even see it. Before launch, people were asking what would happen if the rover was hit by one. The team categorically said they were no threat.

[dvandorn]

Thanks for making these astounding images available.  How can the thin Martian atmosphere churn things up so?

Glenn

It took a lot of enhancement even to see it, at all. I'm not knocking enhancement and I love the images. But if you we there, you might not even see it. Before launch, people were asking what would happen if the rover was hit by one. The team categorically said they were no threat.

Well, yeah -- no threat to a deployed rover on the ground. The team *was* a little worried about dust devils (and high winds in general) at Gusev during EDL, though, according to reports I've read.

It appears that the dust devils are something of a seasonal phenonemon, since we hadn't seen much trace of them throughout the Martian fall and winter. But now, during early Spring, there are a lot of them.... we need to remember that in future mission planning, I think.

-the other Doug

[Nirgal]

It took a lot of enhancement even to see it, at all.  I'm not knocking enhancement and I love the images.  But if you we there, you might not even see it.  Before launch, people were asking what would happen if the rover was hit by one.  The team categorically said they were no threat.

ok, but we should also not underestimate the effect of fast motion of the
spinning air & dust, which sure would enhance the visiblity,
if we observed it live from the ground.
(I'm also curious if one could see the red tube of air/dust extending high against the dark sky if one were looking high enough.

And: what we see here are just the "babies".
Judging from Orbiter views, those things can become _huge_ (larger than the biggest tornadoes on earth,
according to this excellent article:
http://www.msss.com/mars_images/moc/8_10_9...eases/moc2_171/

As far as the damage potential for the rovers is concerned:
For tornadoes on earth, the "strength of damage potential" of a
tornado increases with the second power of maximum wind speed
(if I remember correctly)
i.e. 500 mph is roughly 25 (=5x5) times more dangerous than a 100 mph storm)
So, even in a thin atmosphere, such storms have the potential of being
dangerous, it all depends on the maximum wind speed ...
But I guess, little is known about the maximum wind speed of dust devils on mars

[dvandorn]

And: what we see here are just the "babies".
Judging from Orbiter views, those things can become _huge_ (larger than the biggest tornadoes on earth,
according to this excellent article:
http://www.msss.com/mars_images/moc/8_10_9...eases/moc2_171/

I've seen the kind of dark patch we see in Gusev in several other Martian craters, so I think these "baby" dust devils are controlled by the topography. I can easily imagine the circular crater rims of these large craters setting up instabilities that result in baby dust devils scouring these relatively small patches of ground.

I think the atmospheric processes that control the large dust devils are probably a little different from those that control these baby devils. But the fact that both species of dust devil exist on the same planet is indeed fascinating... *grin*...

-the other Doug