And This Mysterious Mound is Where?

Mystery mounds - we know it's a mystery, but please give us a clue? (HiRISE/NASA)
Mystery mounds - we know it's a mystery, but please give us a clue? (HiRISE/NASA)

The High Resolution Imaging Science Experiment (HiRISE) on board the Mars Reconnaissance Orbiter is a stunning piece of kit. It is generating a vast quantity of images, all lovingly displayed on the HiRISE and other NASA websites. New views of the Mars landscape appear almost daily, with technical information on the projected scene, a polished display image, raw files and a little bit of text telling us what we are looking at. So far so good. That was until recently… Generally speaking, articles with compelling images do rather well online, plus I’m a big believer in “a picture speaks a thousand words,” so I jumped on the chance of running an article about some mysterious shapes that have recently been seen on the planet. Obviously the writer of the HiRISE image was of the same mind by letting the picture do the talking and… well, forgetting to mention where these mysterious features were located…. a mystery indeed…

First and foremost is it’s all about the resolution of HiRISE – today I saw a picture measuring in at 25 cm per pixel. Not bad for a satellite orbiting the Red Planet 250 km above. Since its orbital insertion in 2006, the MRO has returned super-sharp pictures of Mars dunes, eroding mesas, avalanches and bouncing rocks. It has been a joy working on these articles. Although I love sifting through the most recent papers about supermassive black holes, superstrings, quantum physics and plasma dynamics, I much prefer discussing a topic with plenty of pictures to refer to. This is why HiRISE is my favourite Mars instrument, all it does is take pictures.

But unfortunately, today’s article “The Mysterious Mars Mounds” was a little harder to compose. I’ve noticed this with a few of the NASA mission pages of late, there appears to be a slight watering down of the facts. Take today’s HiRISE “image of the day” for example (I’ll include some text from the site and some hints as to where my issues are):

The origin of the mounds was unclear, so we hoped that a HiRISE image with higher resolution and color would solve the mystery (where were the mounds located?). The HiRISE image shows much more detail on the mounds and other rough textures, indicating that this is an eroded bedrock surface, perhaps exposed by removal of an overlying layer of fine-grained materials by the wind (if we know where they are, perhaps we might hazard a guess?).

But how did the rocks form, and why did they erode onto mounds? It could have been lava or impact ejecta or fluvial sediments, perhaps altered and indurated by groundwater (well it depends on where they are: the poles? Equator? Atop Olympus Mons?). The mounds could be due to how it was deposited—like hummocky impact ejecta—or how it was indurated. In other words, we haven’t solved the mystery! (and you still haven’t revealed where the lumps are on the Martian surface!)

Thank goodness for Google Mars. After a minor excursion to the Red Planet (yes, it did feel like a long trip), I managed to match up the geography of the mini static map on the HiRISE page with a scene on the map. It wasn’t perfect, as the crater in question was sandwiched between two mountains and a plain, so I described the location of these mounds: Close to the Mars equator, south of Elysium Planitia (oh yes!).

I forgot my point… no I haven’t. NASA, please, please, please, please make your postings a tad more detailed. Remember, you are the entry level for news, please make it a little easier for us to report on your discoveries but including all the facts. Thanks.

Right, bed time 🙂

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