Why does Mars never look like any of it's Maps?

[Stonius]

By way of comparison, below is a photo I took the other night alongside what is as near as I can tell, the Google Mars version of the same thing. Not the best pic, admittedly, but I always have a devil of a time trying to identify surface features.

Planispheres will show what the Mars looks like at any given time, but won't identify features. Google Earth (Mars) will identify features, but won't tell you which particular ones were pointing towards you when you were observing.

Maybe there's some software that does both, but regardless, why does Mars never really look like the maps we have of it? Does it change over time with those dust storms and martian weather?

Best, Markus

[Lee]

I can see the two dark linear features in yours and the google image.... the google stuff is likely based on Hubble or imagers in Mars orbit - better resolution.

[Stonius]

There's stuff missing though. If the orientation is correct (there's no guarantee), the triangular dark patch at 7 oclock is absent or moved and intrudes much more into the disk than the brownish blob at 6 oclock on the Google Mars version.

Also, the dark area surrounding valles marineris (3 oclock) is much more extensive and straddles both hemispheres.

I would have thought that they are big changes that I don't think can be put down to resolution alone.

Best

Markus

[Wavytone]

Markus,

The sands of mars have a range of colours from light rusty red through to a very dark material which results in the markings you see.

But the lighter material is very fine and is blown around in the dust storms and covers over the darker material, hence the features you see change.

In addition to that many of the markings we see from earth are huge fields of sand dunes which move, slowly blown by the wind just as they do on earth.

See for example https://apod.nasa.gov/apod/ap160720.html

[mental4astro]

Markus,

I too have thought about this. I did think that it could be the Martian atmosphere, and while it is a factor, it really is not a major one.

Since reading your original post yesterday, my brain has been "number crunching" for possible reasons. And I think I've come up with the main reason - resolution!

And it was thinking about the New Horizon's approach images of Pluto that cemented this thinking for me.

If you think about all the bodies in our solar system, they all have a lot of surface detail. However, from Earth, this detail is modest at best (Jupiter), or the vaguest of shades (Ganymede). Of course Jupiter is larger, but when you look at the resolution per square minute of arc, or better still per square second of arc, the amount of actual detail is exactly the same between Jupiter and Ganymede. Same with Mars. The tyranny of distance is the killer as all these details get all mashed up and merged into one blurry blob.

Remember the images from Pluto as New Horizons approached? The first pics that showed a disk showed bugger all detail (nil resolution really). As the probe got closer and closer, the resolution of the cameras was able to finally begin to distinguish the details until we were able to get the details that blew our socks off! :eyepop:

The Moon is much the same. From Earth, we just cannot make out the Apollo landing sites - distance means we don't have the resolution capacity to do so. Not even the HST can see the Apollo landing sites.

Add to Mars its surface compositions, and all we get at the dark and light patches, with the curiosity of these dark patches appearing "green", which I think is a curiosity of light with red and green being complimentary colours - there is nothing green on Mars... The over all red colouration of Mars, this goes a long way to reducing contrast and hence lower resolution as well.

If you were on Mars looking back at Earth, you would also have the same problem resolving detail. Of course there are some differences between Earth and Mars, but the same resolution issues apply, and this would also mean that you would also encounter the same blurring and merging of details so that you would not see the same surface detail that is even visible from the Moon, littlelone the ISS.

Alex.

[N1]

Markus, have you tried Calsky?
(https://www.calsky.com/cs.cgi/Planets/5/1?)
It does just that.

Mouse-over to identify features.

[Stonius]

Ah, Mirko, you saved my sanity. Thank you! All of this came out of my frustration with knowing whether I was definitely looking at the things I thought I was looking at and being unable to verify. Now looking at that map, I am suprised to discover that I can make out Mark Watson's fictitious journey from Schiaparelli to Acidalia Planitia. :-)

Thanks

Markus

[Stonius]

I guess it would be pretty easy to differentiate the two. Resolution is fairly constant, but if features are actually changing, you should be able to see changes over time, maybe even animate them.

Best,

Markus

[mental4astro]

Sorry Markus, between which two?

There is an easy way to check for any changes related to dust storms - comparing before and after images of Mars. Not now because of the current storm happening, but between previous dust storm events.

However, regarding changes due to shifting dust features, these would be dimensionally insignificant to what we can resolve from here on Earth. Multiple dust events would need to occur before we are able to notice changes.

Hmmm, maybe this is what happened to all the Martian canals... :question:

[bojan]

There is another old but good one, Mars Previewer II (https://www.softpedia.com/get/Science-CAD/Mars-Previewer.shtml), doesn't need web access, doesn't work on W'7, but XP is fine though (or w'7 in XP mode)

[Stonius]

Yes, that's pretty much what I was trying to say, albeit poorly :-)

Markus

[kinetic]

Markus,

the closest sim I have used in the past has been JPLs Solar System Simulator.https://space.jpl.nasa.gov/
Mars the other night was amazing. I had a mate over with 3 of his kids and
both of mine. We had a ball. 4 planets in ten minutes. Saturn and Mars
the favourites. Mars in the eyepiece looked exactly like the sim.
This is what we saw
https://space.jpl.nasa.gov/cgi-bin/wspace?tbody=499&vbody=399&month=8&day=28&year=2018&hour=10&minute=00&rfov=45&fovmul=-1&bfov=30&showac=1

Steve