First eight HiWishes
Posted: 1 April
The first batch of pictures of Mars to be chosen by the public and imaged as part of the HiWish project using the HiRISE camera on NASA’s Mars Reconnaissance Orbiter (MRO), have revealed collapsing volcanoes, boulder strewn plains and dune-filled valleys on the red planet.
HiWish was launched in January inviting members of the public to log onto its website at http://uahirise.org/hiwish and suggest regions of Mars that they would like to see MRO’s High Resolution Imaging Science Experiment (HiRISE) image. So far 1,000 suggestions have been received, and you can still log on and suggest your own ideas, describing why you think they would make scientifically valuable images. Given that only one percent of the planet has been imaged so far by HiRISE, which can see objects as small as a metre across, there is still practically an entire planet left for you to help explore!
As a taster of what is possible, here are the first eight images released as part of the HiWish project. All images: NASA/JPL/University of Arizona.
An ancient system of valleys, Samara Valles extends in total over 1,000 kilometres across the southern highlands, gently sloping towards Mars’ northern lowlands in Chryse Basin. The valley floors are hundreds of metres wide, and as can be seen in this close-up section captured by HiRISE, dunes of fine dust ripple across the surface. The valley walls exhibit sedimentary layering and deposits that describe the geological history of the site and its formation. To see a full image of Samara Valles, click here.
In the northernmost regions of Utopia Planitia, thousands of boulders litter the landscape, with ‘blotches’ of boulders lining the rim of an ancient crater, now filled in with dust and yet more boulders. The boulders themselves are ejecta debris, excavated by this impact and others in the region. To see the full, wider picture click here.
Straddling the northern lowlands and the southern highlands, this lobate debris apron in Deuteronilus Mensae is full of pure ice and is residue of one of the red planet’s past episodes of glaciation, when ice reached down to nearly the mid-latitudes as the tilt of the planet changed to a high obliquity around ten million years ago. The apron is extending from an elevated region of land called a mesa, with ice rich flows down the mesa’s slopes linking the two. To see the full image, click here.
On the northern flank of Olympus Mons, the largest volcano in the Solar System, a seven kilometre high cliff is crumbling underneath the weight of the volcano. Harder layers of lava persist, while in the cavities between them are soft layers of dust and volcanic ash. The crumbling cliff has formed a giant landslide, which can be better seen on the wider image, here.
This bumpy, eroded terrain is found on the floor of Palos Crater, weathered by water erosion from a time long ago when the a river running in the 180-kilometre long valley Tinto Vallis breached the walls of Palos Crater. The taller stretches or terrain are composed of denser, harder rock of layered fluvial sediments that are not as easily eroded as the softer rock between them that has been worn down. If you look closely, you can see that the erosion extends down to an even smaller scale, with metre-sized polygonal blocks etched into the taller rock. For the full image, click here.
Dust conceals a hill outside a 30-kilometre wide crater in Zephyria Tholus, a hill that has uncertain origins. Based on observations from MRO’s predecessor, Mars Global Surveyor, the hill had been hypothesised as being a volcano. Taking the opportunity to prove that hypothesis, this HiWish image was thwarted by thick layers of dust covering the bedrock, hiding its true origin. For a look at the full image, click here.
You could be forgiven for thinking you are looking at a close-up of Saturn’s rings, but these concentric arcs are actually icy layers at Mars’ north pole, which are layered with deposits that record how Mars’ climate has changed over millions, even billions of years. Seen here are the edges of the layers in the one-kilometre thick ice sheet, which are ending at a gently curving slope. For the full image, see here.
A region filled with plateaus and mesas called Aureum Chaos reveals volcanic and sedimentary deposits stacked up in layers along cliff faces. The mesas may have formed when either ice or groundwater departed the reason, causing part of the land to sink or be weather away, leaving deep gorges amidst the plateaus. The deposits buried in the cliff faces may reveal exactly what happened here. Also, if you look carefully, you can see dark lines running down the cliffs – these are tracks left by boulders that have rolled down the cliff walls to the valleys below. For the full image, click here.
The Universe under one roof. European AstroFest returns to London on February 7 & 8, 2014. The UK's favourite astronomy conference and exhibition. Visit the official website site for more details.
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