Life as we know it depends on liquid water. So the rover will probably spend a lot of time poking around Mount Sharp's lower reaches, where Mars-orbiting spacecraft have spotted signs of minerals that form in the presence of water, such as clays and sulfates.
But there are reasons to climb higher. If Curiosity gets about 2,300 feet (700 meters) up the mountain, for example, it will cross a boundary, encountering layers that don't show signs of hydrated minerals. Higher still are strata that appear to have been deposited by the wind in a rhythmic pattern, perhaps indicating climate cycles, Grotzinger said.
Studying these higher layers could help scientists better understand why Mars shifted from a relatively wet world billions of years ago to the dry and desolate planet we know today — a transition marked by what Grotzinger dubbed the "Great Desiccation Event."
"The question is, what was that event? What was that trigger? What happened environmentally?" Grotzinger told SPACE.com. "My hope is that we'll get some insight into this Great Desiccation Event."
Mount Sharp is comparable in shape to the huge volcanoes of Hawaii, with gentle slopes that Curiosity can tackle. The rover might be able to climb all the way to the top, given enough time, researchers have said. But summitting the peak is not high on the MSL team's priority list at the moment.
Building a mountain
Curiosity's rovings could help solve another mystery: exactly how Mount Sharp formed. While Grotzinger and other scientists have some ideas, the jury is still out.
What does seem clear is that the 96-mile-wide (154-km) Gale Crater, which formed after an asteroid impact long ago, was once entirely filled in. Mount Sharp is thus the remnant of a much larger mound, the bit that has yet to be whittled away by erosion.