|+ Visit the NASA portal|
If you're just joining us, we've had two webcasts the end of September and early October.
This is our first webcast of the fall challenge and today we'll be talking about how to analyze a HiRISE image.
If you've never joined us for the challenge yet or this is your first time to view a webcast, we have a couple webcasts archived from our spring challenge.
So I encourage you to go to the website and look at those.
Today what we'll do is be analyzing the HiRISE image.
Can I have the next slide, please?
And basically to analyze HiRISE image what we want to you do is get a feeling for where the image is taken. Because the HiRISE image is so close up you don't see the surrounding area very well.
We want you to swait yourself on Mars and ask yourself, where is this image located and what are the features?
Is it located within a canyon or crater or large volcano whereon Mars is this?
Is the surface seem very old or young, are there lots of craters surrounding this area or very few craters.
Then I'd like you to be able to look at the full HiRISE image and when you do that, you'll see the image but you won't see a huge amount of detail. But I want you to pick out some prominent features and what can these features tell you about the geology of the area. Then I'd like to you zoom in on some of those interesting areas and tell us what you -- describe the area and say what do these features look like, what are the textures of the area.
Keep zooming in until you're zoomed in at full resolution and describe some of the things about the image that you haven't seen before.
Are there interesting textures about the surface, do you see gullies, do you see boulders at high reds laoution, do you see different textures?
And then finally, we'd like you to look at the color image, which is the central portion of the HiRISE and central 20%.
And that gives you quite a bit of information about what the surface is made of, what is the composition is made of.
What it will tell you is are there differences that reflect different compositions, usually within the surface. So I'd like to you look at that.
So next slide please.
So what we'll do is we'll start in by looking at a couple HiRISE images.
We'll be looking from the broad areas to swait you to let you know where these features are located, then we'll progressively zoom in and finally look at the color images.
So we'll start by looking at gullies and craters.
There is a purple area to the right, that is a large impact basin called basin.
And the gullies are located to the west of that large impact crater.
It's located in the ancient crater.
If you zoom in on some of the other context images or Viking images in HiWeb you'll see there's lots of craters in this area.
The image on the right shows another image.
The HiRISE images we'll show you next is the image as outlined on the white box and you can see the next image I'll be showing you is located on the north slope of an impact crater.
So when you zoom in to HiRISE image the top part of the impact crater you can see a ridge of boulders at the very top of the image and then there's a smoother area and then as you go down you start to see the head waters of the gullies.
The gullies start at different elevations down the slope, some start from the fine layers, some just start from the top of the crater rim. Next slide.
If we look at this slide, this is the color image.
The top of the image is near the top of the crater rim.
It has like a blueish color and the center part shows more of a gold color.
If you look closely, if you have downloaded our presentation.
You'll see the patterns in that slope and those are likely caused by permafrost conditions with ice in the subsurface moving around the soil into patterns and then the gully is farther in the surface.
So likely the surface composition has changed from the top through the middle toward the bottom.
Next slide, please. OK.
And lastly this is the middle and end part of the -- of the gullies, the lower elevation.
And you can see the middle part -- most of the image shows the middle part of the gully which has a defined channel.
I'm going to get down to the bottom and it starts to form the deposit of material. So all that material that was removed from the crater slope is being deposited down near the bottom of the crater.
So let's look at another HiRISE image.
This image is actually suggested by Steve's class of leap charter academy in New Jersey and this was actually suggested during the spring challenge, but we still need a image caption for this one.
Any group out there that would like to help us write an image caption, you can do so. This is a black and white image here, you can see the red star.
That star is located on the southwestern plank of Mons.
So the image is of a fracture system off the flank of this large volcano. So let's move to the next one.
Now this is the HiRISE image of that area, it's right at the intersection of those two fractures.
You can see the one on the right on the top is the much shallower than the one that dominates most of the HiRISE image.
Below you can see an image that gives a perspective of this area, you can see the deeper area with the fracture going across.
As we zoom into this image, next slide, please, we can see that the deeper part of the cavern, the one that was running from the top left to the bottom right, is the a much deeper cavern. If you look at the upper parts of the walls, you can see some light and dark regions.
We also see some dark streaks and then the rest of the wall is fairly bright and is probably containing a lot of debris that's sheding off the top.
Next slide, please.
This is a close up of some of the top area.
These are more resistant to erosion than other layers.
You can see the top part of the plateau, this is like a a fairly dusty area, that's fairly easily erode able.
So it's very different than the cliff wall.
And also the very upper part of the cliff wall you can see a little bright layer and dark layer going through it.
These are likely made up of different materials, some are more resistant, some just have different coloration which suggest different compositions.
Next slide, please.
Now this is the part of a color image, and the color image you can see a lot of variations, you can see the overall cast of the image is kind of a gold cast, you can see some dark areas and see some hints of dark layering as you go down the slope.
If you very in really far, you can see boulders.
Even at this area you can see boulders going down the slope.
Next slide, please.
This is a close up of one of those dark streaks earlier. These are slope streaks.
And they're from removal of the dust layer and the bright area.
And it's found there's darker material underneath it and they -- because these slopes are so steep, the material -- the dust rolls or just moves down the slope under gravitational forces and leaves a dark streak as it does so.
And this is just a close up picture of using the HiRISE image of this intersection of the two caverns.
And next slide.
And just another area of this -- of this intersection showing the wall of the deeper cavern.
And you can see that there's various dark lines which may or may not are horizontal, some are not.
There's some distinctive resist ant areas down the slope.
Now I'll turn it over to Doctor Davatzes.
First of all, if you're joining us here today, please be sure to get your questions in earlier.
We'll talk about further examples of how to answer the image.
Make sure to get your questions in early.
And, also, I wanted to let you know that the slides are on line for reference, so you can follow along with us on the webcast, but you can also download this entire presentation from the web.
That's on that page that you used to sign in.
Let's go back to analyzing some of these images here. As Ginny mentioned, we are now looking at an image of dune fields from an area near the south polar region.
On the lower last of this image, you can see a black and white image which shows the south pole is that center portion of the image, a brighter feature, that is actually the south pole. Let me see if I can show it here.
It's kind of -- it's a little trick toy work.
But that's the south pole. And then down at the lower portion of the image down here is where this image that we're looking at today.
On the right side is -- the star shows this is within a crater.
So now let's move onto the next slide to we can look at the image itself.
So here's the full-scale image of this south polar dune field.
This boundary here marks the boundary of the dune field.
The outer portion of the crater floor.
And you can see a few of these wavy features in through here.
These are actually the individual dunes of the crater.
And this broad overall scale we can see some Jen textures, we see there's some darker areas, darker patches, especially right in through here and up a little up through here.
We see all these dark spots. But it's a hard to tell what they are, if we zoom in a little more we can tell more about this area, the geologic history of this area.
Let's move to the next slide.
Here we've zoomed in a bit more.
On the right side here you can see a box, which outlines the area that we're looking at on the left side.
And again these bright white lines mark the crust of these dune fields, of the dune.
And then we see these dark streaks again.
And what they appear to do, they appear to be sliding down the side of these dunes.
So these bright white lines mark a peak, and then these black lines are coming out of the deep wall of the dunes.
If we zoom in even closer, we can see in detail what these black streaks actually look like.
We can see they start as a larger spot and then form little streaking lines that come down the wall.
Now as we move from observing different characteristics of this area to interpreting what this might mean, sometimes you think that maybe what these are is actually material, icy material, either carbon die oxide.
So what happens is that ice just did he naoej the surface actually changes from on ice to a gas, and as it does that, it may form a small geyser and pull material from the underlying areas beneath this frosted cover to the surface.
That's bringing this dark material.
That dark material then comes up and then slides down the surface of the dune.
And so we see this is happening all along the crust of one of these individual dunes right in through here. The other thing we can see is that on top of these dunes are even smaller dunes.
We can see some down through here and some over here, and we can see multiple stages of winds that are forming these dunes.
These are all aeolian processes making these.
And aeolian means wind-driven.
So all of these dunes are forming on top of existing dunes.
We can see multiple layers upon layers of this geologic history. If we move to the next slide, next week see the color of this area. Again, here are some of these dark spots that are again probably some sort of sublimation of ice or gas. Around these dark spots are brighter area.
So the color can actually give us more of an indication of what's going on, and the dune face itself is actually yellow.
It's providing us more clues that, yes, that is probably material being brought up from beneath the surface.
So move onto the next slide.
So now what we've done is we've kind of taken you through just a brief example of how to -- how to analyze these images.
Maybe, let's stop for a moment and do some introductions of the two of us and return back.
I'm Doctor Alex Davatzes.
>> I'm Doctor Ginny Gulick.
>> As soon as I take you through a little more about the next steps that we'll be doing in this process, please remember to submit questions you may have into the chat room so we can answer those.
So let's shift back to that slide.
So what we're going to do now is we've just finished taking about 25 of your images that you guys have suggested and we're putting them up on a website right now that you can actually use to look at your image and do the same thing we did in the last few slides.
Actually look at the big, broad-scale image and zoom closer and closer and analyze the image.
What we're doing now is setting up the website and Doctor Gulick will send you an e-mail as to how to access this website. We have 25 images currently and about five more are planned to be taken in the next month. So those will all be up shortly.
Just a reminder the challenge will end December 14th.
We'll need your full reports then.
And so let's take a look at what you will see when you log into the site.
So at the top of this website, there's going to -- in the main part of the image here, the image will be right here that you'll see.
And you'll be able to download either the broad scale image or full-scale image.
Next slide, please, next step.
Then what you'll be able to do is actually download report form from the website.
So up where you see the red arrow is where you'll click, and this will download the report form, you'll be able to fill that out.
And the questions are set up so they'll try to help you get to the point where you can actually write a figure caption. Actually, the last image that I just discussed, a student from Hungry actually captioned it. So as soon as you fill out this report, you can use the white button to upload it.
You can upload a figure caption just to the -- let's see, just to the right of that button.
So, for example, if your image doesn't get taken or you want to look at some of the images from the spring challenge and write a figure caption, you can do that.
You don't have to write a figure caption for your own image, but you can do it for any of them.
You can post it on the web and you'll get credit for that for all the world to see.
Again, you'll see the red arrow is moved here.
What we also set up was a discussion group, if we don't get to your questions today during the webcast, we've set up a Google group where we can answer questions.
You can also try to answer each other's questions and talk about ideas and have an exchange of ideas.
Part of the scientific process. We hope that will be helpful to you, as well.
That gives you a clue with how to go on with the next step. Again, this week you will get an e-mail telling you how to access the images, then you'll be able to go to those images, download the report and fill out the report and caption the figure captions.
Once you do that, we'll start posting new student images.
If you haven't seen those, go to the main HiRISE website, type students and you'll see all of the student images of the week that have been posted so far.
So next slide.
Do we have any questions?
>> OK. We don't have an abundance of questions.
People have sort of checked in, checked out and so forth.
But hopefully those who are in the chat room now can go ahead and put some questions in and we'll pass them on.
I have one from W. Pen.
How do you submit the written report, do you e-mail it?
>> I think Doctor Davatzes just answered that question.
You go to the website that we'll provide you, and then up above on each image you will see download the report.
So you'll download the report, it's a Word document.
Once you're finished, you staef and upload it from your computer to -- to our website.
And so that's basically how you do it.
It's very easy.
It's menu driven, so if you have any questions, you can feel free to e-mail us and we'll try to help you through the process.
Michelle from Mrs. J.'s class has several questions.
Have you found water on Mars?
>> Well, we haven't found liquid water on Mars.
But there's definitely water in the form of ice.
But that's something we're still looking for.
>> Following up, she says, where?
>> Like I said, there's water ice on the polar caps but no liquid ice.
>> A lot of the things we talked about show there's ice below the surface.
We talked about the sublimation of the ice.
Ginny described a terrain she saw another the dunes.
That's another indicator there's ice below the surface and there's also ice at the poles.
>> There's also gullies, those are recent and they were formed by liquid water.
We don't know how recent.
They could be 100 years ago, could be yesterday or could be longer, or could be 1,000 or more.
They're fresh, so they're not ancient features.
>> Between Trinity and Michelle.
They have questions, they sort of summarize how much water do you think is on Mars or in the area?
>> Well east of the volcano.
That area is a series of fractures, integrated fractures along the Valles Marineris area.
It's likely there was water there early ago, but probably not so recently now.
>> Also, just a plug, if you are interested in that area, we took one from the HiRISE challenge in the spring. If you go to the spring website, there's a link to that on the main HiRISE page, you can actually see that image and write a caption, if you'd like to see that. >> OK.
I'm trying to answer someone who is having trouble getting on the video.
We have a question, we're having trouble analyzing the images because there is no scale on the image. We'd like to know the elevation and scale of the pixels.
The go to windows are hard for us to understand.
Is there any Google Earth life planned to make it easier to find?
>> If you look at the browse images, you will see there is a scale bar on the browse images.
So that should help. That's probably all we have right now.
But there will be information the actual scale of the image as posted along with the image.
>> All images are about six kilometers across, or most of them are.
And so that will give you a pretty good idea of what type of scale you're looking at. As far as elevation changes, we need to use stereo images.
You can also use another scale, it will give you a little idea.
There's also a profile on HiWeb.
If you've used HiWeb to suggest your image, you can actually go back into HiWeb and there it will give you some information, you can try clicking around on some of the buttons and you can experiment with using this elevation profile and also give you the broad context of where this image is located.
Same person, question, maybe clarifying a little.
The in and out method.
We can't do them on our small screen. >> Well, that can be difficult.
The basic thing is what we use as geologists, find something you know is a negative/positive feature and then look at where the sunlight is coming from.
If it's a negative feature and there's a shadow cast on one side, just think about where the sun is associated and then the sun is coming -- or the slope is facing the area that's -- that the sun is illuminating.
Just remember that craters are generally easy to see on the surface and those are negatives. Then you look at the craters and go to the other features and see if it's a positive feature or negative features. >> When these images are released, they're released with the information about where the sun is coming from, then you can use that information to see where the shadows are to tell you if it's down, a negative feature or a positive feature.
We're running out of questions here, except people who are having some problem getting into the video.
I'm not sure what the problem is, they're saying the password.
Maybe they're talking about accessing the website.
Maybe this is a good time to talk about registering. >> So if you have registered for this -- for this quest challenge, this HiRISE Quest challenge, you will have been sent an e-mail about how to access HiWeb and user name password associated with that.
But also for the new website that will have the images suggested during this challenge for the fall challenge, that will be password protected.
And I will be sending you all an e-mail that have registered information -- sorry, there was a little bit of an interruption here.
>> Information on how to access that.
It will be password protected.
I have not sent that out yet because the website is not ready.
For those of you who participated in the spring challenge, anyone can go to the spring website.
I'm just making sure that folks that are having a little trouble with the video know that sometimes the fire wall issues in their schools and things like that can be a problem. Anyway, the archive of this webcast will be up shortly after we're done and there shouldn't be any fire wall issues with getting a look at it at that point.
I think -- let me just do a fetch here.
I have gotten a couple of people saying we have to go to class.
Any closing words that you have?
>> Let me just remind you that this webcast will be archived, but we also have an archived webcast from the spring challenge, which talks about how to use HiWeb and questions about Mars.
You can check that out.
We also did two webcasts earlier during September and October that answered some questions.
So if you have any questions, you might also be able to look at those and that will provide you more information.
>> Of course, you're always welcome to e-mail us if you have specific questions.
>> OK. Well, thank you very much for joining us here today.
And we thank you for answering the questions.
Again, there is the chat area open that you can ask questions from.
Don't forget to register, if you haven't already.
We'll see you next time.
Hopefully you'll be watching as the new images are posted.
If you have any questions, get back to us!
Bye. >> Bye.
NASA Official: Liza Coe
Last Updated: May 2005
+ Contact Us