New HiRISE images reveal mystery craters on Mars! Eat your heart out Cydonia!

[SOURCE 1] Official HiRISE blog
[SOURCE 2] Discover Magazine Article

I've not seen a thread on this yet and thought it was something you lot would love.... mystery craters on Mars! Two multiple impact 'bullseye' craters on Mars within spitting distance of each other?! How does that happen?

Crater One:
[atsimg]http://files.abovetopsecret.com/files/2653cbb19b972260.jpg[/atsimg]

Larger image showing the nearby, very similar Crater Two:
[atsimg]http://files.abovetopsecret.com/files/72497f5e094d7b43.jpg[/atsimg]

Please check out the 'official' explanation - I won't paste it all in for fear of falling foul of the new quoting rules.

Official explanation from [SOURCE 1] Official HiRISE blog

What caused the central pit within this impact crater: unusual subsurface layering or a lucky second impact?

I find their theories hard to accept... they're basically suggesting that with Crater One we're seeing a double impact crater - ie an impact that was later followed by another impact that hit dead center of the first, or an impact into a multi-layered material.

It seems incredibly improbable to have a 'bullseye' double impact, even more so when you take into account Crater Two....

Almost identical but with an off center (potential) second impact,. The ejecta from the impact (which *should* be there) is missing, and they speculate that periglacial modification is responsible (ie ancient glaciers eroded the ejecta, while somehow by-passing the craters themselves). I'm not a geologist and google isn't helping me out much... can anyone expand on this periglacial theory?

The official explanation is very much speculation: note the extensive use of words like 'may' and 'could have.' So far as I can figure out this has never been seen before, and now it's turned up twice in very close proximity. Of the two explanations the multi-layered sub-surface idea seems most probable (and helps explain having two similar structures so close-by each other).

My crazy speculation: these look vaguely like neolithic terraced mounds such as the one at Silbury Hill in the UK (WIKI Link). It's a bit of a stretch, but could these be intelligently made? It seems ridiculously unlikely that this could happen by chance, but I'm sure some of the more talented debunkers will put my naivety to shame.

Anyone got any theories? This is truly baffling me.

Edited to add embedded images.

[edit on 2-8-2010 by eightfold]

What sort of distances are we taLking about between the two craters, plus size of actual crater.

Would I bre right in assuming the larger crater was the second impact as it seems to have evidence of the blast effecting the landscape in terms of lines radiating out from the epicentre, and the little one doesn't. This would mean the second blast covered the effect of the first blast.


Could this be the result of a shield volcano that has never really eroded away. Plausible for two volcans to be near each other. The small blew, thhen years later the larger blew.
en.wikipedia.org...

[edit on 2-8-2010 by acrux]

The larger crater is around 700 meters in diameter, and the second, smaller, southerly crater is in the region of 1km away from it.

Here's a 'in context' map image with a scale...



I like your volcano suggestion and I'm going to do some research as to how they form and if this terracing effect is seen elsewhere - it's been a while since school geography. Having said that, these are apparently depressions *into* the surface, not mountain like mounds - I think there's a bit of an optical illusion going on. I made the same mistake with my Silbury Hill suggestion.

As to which crater came first, I'm not sure. If you're correct and the smaller one came first then that could explain the lack of ejecta around it, as it could've been 'drowned out' by the larger ejecta of the northerly crater.

I think we need some geologists!


[edit on 2-8-2010 by eightfold]

They are not craters.
Notice the shadows? If the shadow was cast into the middle there would be a solid edge to the shadow not a gradual fade out. Turn the pic on its head they are raised.

I tend to think that these the result of craters that impacted on a particular type of Martian soil that probably has an underlayer of frozen CO2 or water. After the initial impact, enough area was then exposed to such a degree that it allowed the underlayer to melt, creating another sunken area inside the original crater.

That would be my guess.

They are not craters look at the shadows...... They are raised

if you shoot at a rifle range that has a dirt berm then you will know what i am looking at and talking about, if you look at the first pic you will see a star burst pattern, on the surrounding ground, now this could be from an impact or an out ward explosion, i am thinking an volcano, for if it was an impact there would be no rise just a indent but this is of a rise.

I'm inclined to agree with the first NASA assessment — that it is a single strike that exposed multiple layering of dense and less-dense materials, probably layers of relatively loose surface soil and much denser ice.

This would account for the near-identical configuration of the second strike to the lower right. Same sort of impact layering, at what appears to be the same depths.

I'm a member of the IMCA (International Meteorite Collectors Association), and we frequently discuss impact anomalies — there are more weird craters than you might imagine, right here on Earth.

Take, for example, the most famous impact crater on the planet, the great Barringer Crater (aka Cañon Diablo or, simply, Meteor Crater) in Arizona. You have to see the thing from directly above to appreciate how odd it is...

[atsimg]http://files.abovetopsecret.com/images/member/44c0a44c5812.jpg[/atsimg]

The Barringer Crater, in case it doesn't immediately jump out at you, is square.

Some people argue, Oh, that's just due to erosion — However, wind and rain don't erode things square. Wind and rain tend to erode things round, obliterating right angles.

Try this, go dig two holes in your back yard, one perfectly square, and one perfectly circular. Turn on your water sprinkler and leave it on for 6 months. At the end of the 6 months, you won't have 1 square hole and 1 circular hole in your back yard, and you won't have 2 square holes. You'll have 2 circular craters.

So, given what we think we know about terrestrial erosion, the Barringer Crater should be perfectly circular following 50,000 years of Earthly erosion. Unless, perhaps, the Barringer Crater started out as a perfectly square excavation, and the climatic conditions of the Southwest simply didn't produce enough erosion to completely eliminate the right-angles.

One thing we know about Barringer is that no meteoritic mass was ever discovered or detected beneath the crater floor. The official explanation is that the giant iron meteor was completely destroyed on impact, scattering the whole area with tiny iron fragments, but no mass of iron underneath the crater floor, as has been discovered at other impact sites around the world.

Barringer Crater is a real mystery right here on Earth. But it's just a tourist attraction.

— Doc Velocity




[edit on 8/2/2010 by Doc Velocity]

[atsimg]http://files.abovetopsecret.com/images/member/f89c964fbecb.jpg[/atsimg]

that is it a little bit closer in a higher res....now definately a cratar if you ask me....and notice the ridges....what a beatiful shot

i would also say the inpact was so violent that the centre core would have been a lot hotter than on the exterior...therefore creating a ripple effect..in the icy surface of mars.

[edit on 033131p://f07Monday by plube]

[edit on 033131p://f08Monday by plube]

[edit on 033131p://f09Monday by plube]

It looks to me as a very large navel.

Is it just me, or is there a large hole heading down to the left at a 45* angle? If you look at the inner wall right where the shadow begins it seems taller than the wall section to the right.

Could this have just happened to hit a sinkhole or lava dome?

reply to post by Doc Velocity


Interesting. I visited Meteor Crater last year and they had this big meteorite on display that was about 2 ft across in the museum that I thought was the remains of meteor they found way under ground. I could be wrong though. I will say it was pretty amazing to see the crater close up.

The more I look at it the more I'm convinced it's a single impact into layered ground, which does also explain the second very similar impact nearby.

I was hoping for some giant-alien-nipple-of-doom to be honest, but no such luck.

Still, it's a very cool picture - a cropped high-res version of it is my current desktop background - as a previous poster said, the detail is ridiculous.

I can't see a tunnel anywhere tho - could you point out specifically where you mean blamethegreys?