Category: HiRISE images

HiRISE images

Lumpy bumpy dunes

A piece of Mars: These funny shaped dunes were formed by winds blowing from two directions - one from the top of the frame and one from the upper right. Both winds make steep slopes (slip faces) on the downwind ...

Changing winds

A piece of Mars: There are two sets of ripples here: tan ones and gray ones, each oriented to a different wind (scene is 300x225 m, or 984x738 ft). The gray ones sit on top of the tan ones, so ...

Missing bedrock

A piece of Mars: Wind flow on Mars can be quite dramatic. Here, a single wind-sculpted hill stands 1.5 km (0.93 mi) wide and 600 m (1970 ft) high (color shows elevation). That sounds big, but vastly larger is the ...

Holes around rocks

A piece of Mars: This scene (509x382 m, or 1670x1253 ft), aside from showing some lovely rippled dunes, has many car-sized boulders in it. Some are surrounded by ditches in the sand, like little moats. Why? The sand is blown ...

Which wind came first?

A piece of Mars: This scene (3.9x2.5 km or 2.4x1.6 mi) shows a surface carved by two different winds: one blowing from the right and one blowing from the bottom right. They've formed overlapping sets of streamlined rocks called yardangs. ...

How the wind turns

A piece of Mars: The two shadowed hills in the upper part of this frame (497x373 m or 1631x1224 ft across) rest on a flat plain covered in large ripples. On the plain the ripples are aligned north-south, formed perpendicular ...

Wind within vs. wind without

A piece of Mars: Dunes outside the crater are straight but the ones inside the crater look like a spiderweb. Why? This image shows just how much the topography of a crater wall can affect the wind, which produces a ...

What on Mars?

A piece of Mars: What on Mars is this (the scene is 600x450 m, or 0.37x0.28 mi)? It can be hard to tell. The lines are ridges of windblown dunes or ripples, the dark gray stuff is active sand blowing ...

Small dunes up high, big dunes down low

A piece of Mars: This 1018x1352 m (0.63x0.84 mi) dune-covered scene has split topography: the the bottom part is up on a plateau, and the upper part is in a broad valley. The dunes up on the plateau are smaller ...

Summery dune

A piece of Mars: Last December I blogged about a picture of a sand dune taken in early northern spring. This is the same dune, without frost, now that summer has come to the northern hemisphere and all the frost ...