Over the past 10-plus years, the music of Sigur Rós has evoked the most mind-stretching, heart-pounding regions of the soul. But all those vast washes of existential beauty, even at their finest, can feel alienating. Jónsi Birgisson’s debut solo full-length, Go, flies to an even more enchanting and exotic locale: home. Granted, the Sigur Rós sound has always drawn comparisons to the band’s native Iceland. But Birgisson’s home, as depicted in Go, isn’t a place so much as a fleeting play of impressions: Like a garden growing toward the sun, the album warms itself on the vibrant arrangements and piano of Nico Muhly, who also suffuses each song with a cinematic scope that flickers with flute, brass, strings, and skittering electronics. Birgisson’s boyfriend, Alex Somers, who collaborated with him on last year’s ambient Riceboy Sleeps, co-produces, and there’s a bit of that album’s drifting-cloud atmosphere hanging over Go, even on the bubbling opener “Go Do,” in which Birgisson trills in his sweetest, most joyous voice, “You should always know that we can do anything.” With its nurturing harmony and emotional hospitality, Go feels less like an album than a musical nest.