This strange image was captured by the Mars Reconnaissance Orbiter’s (MRO) camera–the amazing High Resolution Imaging Science Experiment (HiRISE)–as it passed over one of the largest volcanoes in the Solar System, Pavonis Mons.
Located near the equator of Mars, atop the Tharsis bulge, Pavonis Mons is the second highest volcano after the huge Olympus Mons (towering over the Martian surface 27 km high). Pavonis Mons is still much higher than anything the Earth can muster, towering 14km into the atmosphere (compare that with the altitude of Mt. Everest’s peak height of 8.85 km).
So why is this picture so blurry? Is HiRISE suffering a malfunction? Did mission control send the wrong commands? Actually, HiRISE is working just fine. It’s the dust-covered surface that’s blurred.
As the ancient volcano is reaching so high into the Martian atmosphere, the air becomes very thin. The atmosphere was already thin; the average ground level atmospheric pressure is less than 1% of the Earth’s. At Pavonis Mons’ peak, the atmospheric pressure is ten-times thinner. Therefore any wind at these altitudes is extremely weak.
The extreme planet-wide dust storms that regularly engulf Mars dump huge quantities of dust on the top of the Martian volcanoes, but when the dust settles, there’s nothing to transport it elsewhere. Therefore, the thick layer of fine material remains where it is, tickled by the light-weight winds, rarely moving.
In the high resolution image, you can see some resolved features such as the odd impact crater and small ripples. Other than that, it’s a thick, smooth dust blanket that covers the Pavonis Mons summit, hiding any interesting geology for below, giving the impression any images of the summit are out of focus…
For more, check out The Blurry Summit of Mars’ Pavonis Mons on the Universe Today.