Image: Curiosity's arm over 'Marimba' target on mount sharp

NASA's Curiosity Mars rover began close-up investigation of a target called "Marimba," on lower Mount Sharp, during the week preceding the fourth anniversary of the mission's dramatic sky-crane landing.

Oklahoma geology group links earthquakes to oil waste wells

The Oklahoma Geological Survey said Tuesday it is "very likely" that most of the state's recent earthquakes were triggered by the subsurface injection of wastewater from oil and natural gas drilling operations.

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