An up-close look at faraway worlds. (Part 1 of 5)

An up-close look at faraway worlds. (Part 1 of 5)

Jupiter's massive gravitational force helped shape life on Earth. (Part 3 of 5)

Jupiter's massive gravitational force helped shape life on Earth. (Part 3 of 5)

NASA's Cassini explores Saturn for 13 years, looping through its icy rings and flying by its moons. The probe captures stunning ring-moon interactions, but when it finds the ingredients for life on the moon Enceladus, a bittersweet decision is made. (Part 3 of 5)

NASA's Cassini explores Saturn for 13 years, looping through its icy rings and flying by its moons. The probe captures stunning ring-moon interactions, but when it finds the ingredients for life on the moon Enceladus, a bittersweet decision is made. (Part 3 of 5)

In the far reaches of the solar system, Uranus and Neptune dazzle with unexpected rings, supersonic winds and dozens of moons. And NASA's New Horizons gets a stunning up-close view of Pluto before venturing deep into the Kuiper Belt. (Part 4 of 5)

In the far reaches of the solar system, Uranus and Neptune dazzle with unexpected rings, supersonic winds and dozens of moons. And NASA's New Horizons gets a stunning up-close view of Pluto before venturing deep into the Kuiper Belt. (Part 4 of 5)

Following a trail of fossils found in all the wrong places -- beech trees in Antarctica, redwoods and hippo-like mammals in the Arctic -- uncover the bizarre history of the poles, from miles-thick ice sheets to warm polar forests teeming with life.

Following a trail of fossils found in all the wrong places -- beech trees in Antarctica, redwoods and hippo-like mammals in the Arctic -- uncover the bizarre history of the poles, from miles-thick ice sheets to warm polar forests teeming with life.

In the far reaches of the solar system, Uranus and Neptune dazzle with unexpected rings, supersonic winds and dozens of moons. And NASA's New Horizons gets a stunning up-close view of Pluto before venturing deep into the Kuiper Belt. (Part 4 of 5)

In the far reaches of the solar system, Uranus and Neptune dazzle with unexpected rings, supersonic winds and dozens of moons. And NASA's New Horizons gets a stunning up-close view of Pluto before venturing deep into the Kuiper Belt. (Part 4 of 5)

Following a trail of fossils found in all the wrong places -- beech trees in Antarctica, redwoods and hippo-like mammals in the Arctic -- uncover the bizarre history of the poles, from miles-thick ice sheets to warm polar forests teeming with life.

Following a trail of fossils found in all the wrong places -- beech trees in Antarctica, redwoods and hippo-like mammals in the Arctic -- uncover the bizarre history of the poles, from miles-thick ice sheets to warm polar forests teeming with life.

How humans tamed the fearsome canine over tens of thousands of years.

How humans tamed the fearsome canine over tens of thousands of years.

Did humans ever really succeed in domesticating the cat? Can science tell us more about a relationship that predates history?

Did humans ever really succeed in domesticating the cat? Can science tell us more about a relationship that predates history?

In the far reaches of the solar system, Uranus and Neptune dazzle with unexpected rings, supersonic winds and dozens of moons. And NASA's New Horizons gets a stunning up-close view of Pluto before venturing deep into the Kuiper Belt. (Part 4 of 5)

Following a trail of fossils found in all the wrong places -- beech trees in Antarctica, redwoods and hippo-like mammals in the Arctic -- uncover the bizarre history of the poles, from miles-thick ice sheets to warm polar forests teeming with life.

How humans tamed the fearsome canine over tens of thousands of years.

Did humans ever really succeed in domesticating the cat? Can science tell us more about a relationship that predates history?