By Mark Sykes | CEO and Director, Planetary Science Institute -
For decades, the American program for solar-system exploration has been a constant source of discoveries, deepening humanity's understanding not only of neighboring worlds, but also our own planet. Astronomers are now discovering hundreds of worlds around other stars, while at the same time those observations and others are providing new insights into how our solar system formed and evolved. We can now ask the question of whether life has arisen on Mars and beneath the surfaces of Europa, Ganymede, the dwarf planet Ceres and other solar system bodies.
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