article_snippet.sent: Among the features Messenger has revealed to scientists in the past month are patterns of distinctive hollows - each around a couple of hundred metres wide - in the bottom of a huge impact basin.
article_snippet.sent: Data sent back by Mercury suggests these cliffs, or lobate scarps as they are called, have formed as Mercury has cooled and contracted over time, creating dramatic tectonic faults on the surface.
article_snippet.sent: They are thought to have formed as Mercury cooled .
article_snippet.sent: Distinctive hollows on the floor of the Zeami impact basin on Mercury can be seen in this Messenger image .
article_snippet.sent: This image shows some of the mysterious irregularly shaped hollows on Mercury's surface in greater detail .