'Now and Then,' the Beatles' Last Song, Is Here, Thanks to Peter Jackson's AI

Following a lot of hype--and a quarter-century of work--"Now and Then," presumably the last song to feature all four original Beatles, is here. The track dropped Thursday and the music video, directed by Peter Jackson, hit YouTube on Friday. Sweet and haunting, it's full of piano and strings, and it wouldn't have been possible without the machine learning technology Jackson used on the docuseries Get Back. How the AI technology became the thing that saved the song is a bit of a journey. Years after John Lennon died in 1980, his wife, the musician and multimedia artist Yoko Ono, told his bandmate Paul McCartney that she had a demo tape Lennon had recorded at their apartment in the Dakota in New York City.