[X] My Assistant

[volcanopele]

Mars rarely impresses me lately, though I have to admit, HiRISE has taken some pretty nice images. This one impressed me:

Caught in Action: Avalanches on North Polar Scarps

This image shows dust clouds resulting from avalanches along cliffs near the north polar cap. Very cool stuff. I wonder what the trigger mechanism is since there appear to be several avalanches going off at the same time.

[tedstryk]

That is an amazing shot! So is the earth-moon shot (although whoever brightened the moon to make it visible got a little carried away).

[ElkGroveDan]

Interesting that these events were captured in color. Anyone know what the time separation is between color layers? It might be fun to pull apart the layers and examine them for particle movement.

[GuyMac]

That is an amazing shot! So is the earth-moon shot (although whoever brightened the moon to make it visible got a little carried away).

The EDRs are available, BTW; they are from observations PSP_005558_9040 and PSP_005558_9045. We don't have automated processing for non-Mars images beyond the EDR stage.

[djellison]

Here are the 4 I can find - in my tweak-IGB-to-make-it-a-bit-more-marslike guestimation. THe whites are a bit blue, but other than that I like it. North is 77 degrees clockwise from straight up, or 13 degrees above 'right'. These are numbered 1-4 going from East to West. There's one more, a little more East, but I think it's 'over' - its a lot more feint, perhaps it happened a few mins before the image was taken

There is a slight delay, I think, between the channels - but it'll be very small. Look at the CCD layout, ( http://hirise.seti.org/epo/hirise_lesson1_files/image017.png ) the ir, r and gb filters are perhaps one ccd's width apart, in the direction of motion - so 2000 pixels, 500 metres. THey start and stop the channels so they line up - but there will be a tiny delay because of the orbital speed. I can't recall what that is ( 2.5km/sec rings a bell- may be WAY off ) - so if that's right, 500m will be a 1/5th of a second. So, every pixel difference, would be 1.25 m/sec - if that 2.5km figure is right. I don't think it is - and it'll vary with altitude anyway.

Doug

Attached thumbnail(s)

 

[Stu]

Good god!!!! I actually swore when I saw those images! Just stunning!

Serious question Guy... when images like these come in, why don't you make a bigger deal of them in the general media? These deserve to be seen by many, many more people. NOT a criticism, just wondering.

[DataMiner]

Good god!!!! I actually swore when I saw those images! Just stunning!

Yeah, that's pretty much what we did too!

Serious question Guy... when images like these come in, why don't you make a bigger deal of them in the general media? These deserve to be seen by many, many more people. NOT a criticism, just wondering.

A lot of it seems to depend on what NASA wants to do. We do work with our own press people at the university, and we do much of this in coordination with NASA. But the big media events are pretty much all done through NASA. So the big events really only happen when NASA decides it's a good media event. Otherwise we just put out press releases like this. Sometimes the press picks them up and runs with it, and sometimes they don't. So we never really know how much coverage we'll get until the news outlets start calling and asking questions.

[Stu]

Thanks DataMiner, really appreciate the feedback. I don't want you or anyone thinking I was criticising, I just really believe that images like this, showing dynamic processess, movement, all at a familiar scale, are real gifts to NASA and Mars exploration. People can identify with images like this - unlike the people here on UMSF, they might not know what a "sedimentary boundary" or an "eroded outcrop" is, or why they're exciting or important, but they know what a cliff is, and what a landslide is, and what a puff of dust at the base of a cliff means, so I think images like these are godsends, they really are.

This morning I was at a primary (that's ages 5-11ish) school here in Cumbria in the north of England, doing a couple of my astronomy Outreach talks. Talked to a total of a hundred or so kids during the 3 hours I was there (one little girl, Molly, is absolutely determined to go to Mars when she grows up. I let her hold my tiny piece of martian meteorite; her smile was brighter than Venus at closest approach, I swear!). How I'd have loved to have shared this image with them!! It really brings Mars to life...

[Astro0]

Before - PSP_007140_2640 After - PSP_007338_2640
One is map projected, the other not so I had to fudge a bit for this animation, but you get the idea.

Avalanches in both!

Astro0

[djellison]

I figured out what caused them. It was the shock of Jason looking at a Mars image that resonated throughout the solar system and expressed itself as a seismic event on that ridge. If you hadn't have looked at it - there wouldn't be any landslides

Doug

[elakdawalla]

Whoah -- you're right, Astro0, there's an avalanche in the "before" picture too! Totally awesome. I had hoped to get this posted earlier today -- but now I'm glad I didn't, I'll have to point those other avalanches out!!

Can anybody get their head around why the views of the IRB image using the IAS viewer, look so greenish, and why the HiRISE team's versions are such a deep red? I assume it has something to do with the white frost deposits messing up the auto-stretches, but I would have thought that the frost would have sort of provided a "white point" that should have forced the darks toward a more natural color.

--Emily

[DataMiner]

Stu,

I certainly don't interpret your post as criticism, and even if I did, I personally have almost zero input on the subject! I'm mostly an observer when it comes to our press coverage. I am willing to take complements/flames on how well maintained/buggy the HiRISE PDS Node is, since I do have direct oversight of that! About the closest that I get to any press release material is sending out announcements to a few NASA internal lists about our data releases, pieces of which sometimes find their way into the press releases, but more often than not they are only used internally.

[djellison]

Well - from an old HiBlog entry

"What is the difference between “RGB” and “IRB”? The RGB products are different than the IRB products in that the IR channel has been replaced by a “synthetic blue” layer that creates an image that is somewhat closer to natural color. In many of the images, the infrared band does not contribute a lot of information. The bands in this product have also been stretched to provide better contrast. In other words, the RGB images are more aesthetic. The IRB product is a science product. It contains the IR, RED and BG layers."

I'll bet they made that from R and GB.

My technique - roughly - http://www.unmannedspaceflight.com/index.p...t=0#entry110381

Meanwhile - there IS disparity between the channels. Between the IR and the GB, I think there's motion. What's the orbital speed of MRO - we can calculate the speed at the front of the big one. It's certainly several pixels worth - if my 2.5km/sec guess is right, we're looking at several m/sec.

OK - more maths - I've found figures of 3 to 3.25km/sec - Let's call it 3.14 (what a nice number)

Assuming that the IR and the GB CCD's are, measured in pixels of CCD width, something like 2100 pixels apart. Very roughly. Thus 525 metres apart. Thus, 0.167 seconds.

So - one pixel difference, is 25cm in .167 seconds, or just about 1.5m/sec

Attached - a flick between IR and GB - I can see maybe 10 pixels of motion at some points on that 'front' - so 15m/sec. Other places, more like half that Very very rough maths - please pick holes in it - but I think we're talking a true ballpark figure there.


Doug

Attached thumbnail(s)

 

[ugordan]

If you hadn't have looked at it - there wouldn't be any landslides

So this is one of those quantum mechanics thingies? Ya know, changing the outcome by measuring it...

[djellison]

Think about it. Jason spends all his time look at Io images - and it's like a volcanic red-light district. He looks at ONE Mars picture...and bam. Only plausible explanation.