Task: Text Simplification
Input (English): a dark albedo feature about across has been named olbers in honour of vesta 's discoverer , but it does not appear in elevation maps as a fresh crater would , and its nature is presently unknown , perhaps an old basaltic surface.
Output (English): a dark albedo feature about across has been named olbers in honour of vesta 's discoverer , but it does not appear in elevation maps as a fresh crater -lrb- a large , bowl-shaped cavity found on the surface of the ground -rrb- would , and its nature is presently unknown , perhaps an old basaltic surface.