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An in-depth look at how NASA is preparing for its most ambitious and dangerous mission yet: to land a human being on the surface of Mars.
When the sun flares up, billions of tons of superheated gas and intense radiation are propelled toward Earth; experts are trying to predict what is coming toward the Earth and how to prepare for this threat.
The discovery of exoplanets pushes scientists to reexamine the origin of the Solar System; the evidence infers a tale of unrestrained collisions and chaos.