Chris Lintott and Maggie Aderin-Pocock report on the reaction to the dramatic announcement of the discovery of phosphine gas in the clouds of Venus, a gas that could be a sign of life. Venus remains an inhospitable and unlikely host. But if not Venus, where in the solar system is the best place to look for alien life? Chris and Maggie investigate the latest missions to Mars and the icy moons of Jupiter and Saturn. Away from the search for life, Pete Lawrencepreviews the best meteor showers of the year.

In the third episode, the discovery of extraterrestrial life might face an impossible challenge: the physics of the universe itself; but using cutting-edge tech, experts might be on the verge of a groundbreaking find -- and the evidence could already be in hand.

Have planet hunters finally found proof of other Earth like worlds? Astronomers have now discovered over two hundred alien worlds, beyond our solar system, that were unknown just a decade ago. Discover planets that rage with fiery hurricanes and bizarre planets covered by water so dense that it forms a kind of hot ice. Among these weird worlds, Earth actually seems like the oddball.

In changing seas and oceans, cephalopods like the cuttlefish and the giant Pacific octopus must rely on their remarkable intelligence to survive. Their alien appearance comes with astonishing resources, independence, and invention. And there's still so much to learn about these rarely seen legends of the deep.

Cosmic rays capable of destroying human DNA are hurtling through outer space like subatomic bullets, causing space crews radiation damage.
Cosmic rays are intergalactic alien interlopers on our Milky Way. But the source of their power is a mystery. Are they coming from other galaxies? Are they coming from things in between the galaxies? Where do cosmic rays come from? Truth is, the most powerful ones, we haven't got a clue. The race is on to solve the mystery of the fastest particles in the universe.