New images show the scars of impacts on Mars

March 5th, 2011 - 6:35 pm ICT by ANI  

Washington, Mar 5 (ANI): Scientists say new image of an elongated impact crater on Mars suggest it was carved out by a train of objects hitting the surface at a shallow angle.

The image was one of many returned by the European Space Agency’s Mars Express probe of the planet’s heavily cratered southern highlands.

The large Huygens basin is about 450 km in diameter and lies in the heavily cratered southern highlands. In this area there are many impact scars but none perhaps are more intriguing than the ‘elongated craters’.

One of these craters is seen in this new image, which covers an area of 133 x 53 km at 21 degrees S / 55 degrees E. The scene was captured on 4 August 2010 and the smallest objects distinguishable by the camera are about 15 m across.

This unnamed elongated crater sits just to the south of the much larger Huygens basin. It is about 78 km in length, opens from just under 10 km wide at one end to 25 km at the other, and reaches a depth of 2 km.

Impact craters are generally round because the projectiles that create them push into the ground before the shockwave of the impact can explode outwards. So why is this one elongated?

The clue comes from the surrounding blanket of material, thrown out in the initial impact. This ‘ejecta blanket’ is shaped like a butterfly’s wings, with two distinct lobes. This hints that two projectiles, possibly halves of a once-intact body, slammed into the surface here.

In the crater itself, there are three deeper areas that could be evidence for more than two projectiles. In addition, a second elongated crater lies to the north-northwest. It can be seen in the wider contextual image and is in line with the one seen here, reinforcing the notion that these structures were the result of a train of projectiles. (ANI)

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