(TED is on its annual two-week vacation. During the break, we’re posting playlists from the TEDTalks archive. We’ll be back with new talks Monday!)

The wonderful thing about the universe is not just how big it is, but how every time we look into it we find something new and extraordinary. Here are four talks about the vastness of space, and the things that may or may not be found in it.

1) Planetary scientist Carolyn Porco shows images from the Cassini voyage to Saturn, focusing on its largest moon, Titan, and on frozen Enceladus, which seems to shoot jets of ice.

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2) Stephen Hawking asks some Big Questions about our universe — How did the universe begin? How did life begin? Are we alone? — and discusses how we might go about answering them.

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3) Filmmaker David Hoffman shares footage from his feature-length documentary Sputnik Mania, which shows how the Soviet Union’s launch of Sputnik in 1957 led to both the space race and the arms race — and jump-started science and math education around the world.

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4) Humorist John Hodgman rambles through a new story about aliens, physics, time, space and the way all of these somehow contribute to a sweet, perfect memory of falling in love.

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Playlist by Becca McClain