Beneath the Appalachian Trail, an underground thread of earth-green mineral runs from Georgia up to Nova Scotia—geologists and locals refer to it as “the serpentine chain.” It is mirrored by an almost identical vein of verdant serpentinite all the way across the Atlantic Ocean, this one running through the mountains of Ireland, Wales, and Scotland, all the way up to the Arctic. Legend has it that serpentinite was a valuable commodity to ancient Celts and some even believed it contained mystical powers. These twin mineral trails are reminders of the ordinary miracle of continental drift, the kind of thing you learn about in grade school but can so easily forget as an adult that to recall it instills a fresh sense of awe.

“More than two hundred and fifty million years ago the mountains of Great Britain fit together like a jigsaw puzzle,” the Appalachian novelist Sharyn McCrumb has written. “The first Appalachian journey was the one made by the mountains themselves.” Most of the nicknames given to the Northern Irish singer-songwriter Van Morrison and his music seem at first to be playfully contradictory—“The Belfast Cowboy,” troubador of “Caledonia soul music” or “Celtic blues.” They are nods to his dual influences of American R&B and the older Gaelic traditions of his home, jokes about the impossibility of reconciling them. But zoom out 250 million years, or maybe just 250 million miles, and the odd idea of a Belfast cowboy starts to make its own kind of sense.

When Van Morrison first began to sketch the songs that would become his 1968 masterpiece Astral Weeks—released 50 years ago this week—he was gazing across that very divide, temporarily back in Belfast but itching to go west. Though he was still in his early 20s, he was already a music-industry veteran: The anarchic, raw-throated dynamo had been the frontman of the influential (if only semi-successful) garage rock band Them, most notable for popularizing the Morrison-penned “Gloria,” a proto-punk standard that would later be interpolated by everyone from the Doors to Patti Smith. But shortly before Them broke up, they toured America, and it was at a gig in San Francisco that Morrison met Janet Rigsbee, a 19-year-old model who happened to be attending her very first rock concert that night. “I looked at him, he looked at me, and it was alchemical whammo,” she later recalled—a description of falling in love as good as any poet’s. They were inseparable for the rest of the tour, but the band’s work visas were not extended, and so Morrison and his bandmates reluctantly returned to Ireland. He moved back in with his parents, bought a reel-to-reel, and spent his days fumbling with some new songs that were suffused with transcontinental longing and the spiritual ennui of being aimless and 22. “He pined for Janet,” Ryan H. Walsh writes of these days in his recent book about Astral Weeks, “trying to figure out what would come next.”

Maybe a solo career. In 1967, Morrison was summoned back to New York by Them fan and producer Bert Berns, who thought Morrison could become something like a “rock and roll version of the Irish poet Brendan Behan.” Why not, nothing else to do. They laid down some tracks that Morrison was not entirely satisfied with. Then immigration laws dictated that Morrison return to Ireland, though if Berns could turn one of the songs into a hit, Morrison could probably get another work visa to return to the States. “The singer told Janet that if she heard him on the radio,” writes Walsh, “it meant he was on his way to find her.” Before long, “Brown Eyed Girl” was unavoidable, and so Morrison, and the strange new songs in his head, came west.

If you buy into the cult of Astral Weeks even a little bit, celebrating its temporal anniversary is absurdly beside the point—like trying to determine the precise moment a seed sprouted green so you can wish a tree a happy birthday. Astral Weeks was largely misunderstood in its time, and it certainly wasn’t commercially successful when it came out in 1968. It didn’t chart, failed to produce a single, and according to Walsh, wasn’t even mentioned in Rolling Stone’s roundup of the best music of 1968. Even then it seemed to exist outside of time. “In historical terms it didn’t make sense,” the critic Greil Marcus writes of Astral Weeks in his lyrical book on Morrison, When That Rough God Goes Riding. “It didn’t, in that small-minded way art and politics are so often linked, reflect the great events of the day. … It refused to speak the language of the time, and in the way that time has been rewritten into a single rotting cliché of VIETNAM STUDENT RIOTS LBJ LSD SEXUAL REVOLUTION BLACK POWER NIXON.”

And so as we near the end of this year of sequentially celebrating the 50th anniversary of every single thing that happened in that tumultuous and singular year, it is worth asking why listening to Astral Weeks still feels more vivid and immediate than an exercise in late-’60s nostalgia. Instead it exists in what Marcus has called “a kind of continual present,” cropping up in the most unexpected places, snaking through the past 50 years of pop culture like a subterranean mineral trail.

What is it about Astral Weeks that inspires this kind of hallowed tone? And even more puzzlingly, why does it keep regenerating its own fan base? In When That Rough God Goes Riding, Marcus marvels, “A few years ago, in a class I was teaching, four students out of sixteen, none of them older than twenty-one, named it as the album they most loved. How did it reach these people, just in the sense of from here to there, of roundabout? How did it enter their lives, music that was made well before they were born and yet spoke a common language?”

Across space and time it links a secret society of people: dreamers, romantics, doomed souls, defiantly persistent stutterers—and the love that loves that loves that loves—in the language of the heart. “It made me trust in beauty,” Bruce Springsteen once said of Astral Weeks, one of his favorite records. “It gave me a sense of the divine.” (He loved it so much that, in tribute, he sought out Astral Weeks bassist Richard Davis to play on his first two albums. “Astral Weeks was like a religion to us,” said E Street guitarist Steven Van Zandt.) “I based the first 15 minutes of Taxi Driver on Astral Weeks,” Martin Scorsese said while promoting his 1978 movie The Last Waltz. Just a week ago, I heard it at a sold-out multiplex as Astral Weeks’ centerpiece, “Madame George,” scored a particularly unsettling scene in Steve McQueen’s stylish heist film Widows. A few weeks before that, when asked in an interview which he would choose if he could only listen to a single song for the rest of his life, Harry Styles answered, “‘Madame George’ by Van Morrison”—no doubt sending a whole new generation of devotees to search for it on Spotify.

“My friends, my friends, my friends … who I love, I love, I love, I love,” Philip Seymour Hoffman muttered at the 2006 Oscars, overflowing with nervous joy as he accepted his Academy Award for Best Actor. “You know the Van Morrison song? I love, I love, I love. And he keeps repeating it like that?” The song, of course, was “Madame George,” which the late Lester Bangs—whom the late Hoffman himself played in Almost Famous—once called “possibly one of the most compassionate pieces of music ever made.” Astral Weeks moves in mysterious ways.

Astral Weeks was recorded in Manhattan over just three sessions, late fall 1968. “Most of these songs were first or second takes,” Morrison said years later of the recording. “There was kind of a run through to actually get the routine right and get the progression right, and then we just recorded it.” But the process was not all spontaneity. As the musician and writer Ryan H. Walsh chronicles in his excellent book Astral Weeks: A Secret History of 1968 (released earlier this year), plenty of behind-the-scenes preparation went into those sessions, too.

Most happened in Boston, of all places. In the summer of 1968, Morrison and his new wife Janet moved into a small, decrepit apartment in Cambridge—“not a wonderful place to live,” in Janet’s telling. But it had a kitchen table, space enough for Morrison to strum an acoustic guitar for hours at a time and amble toward the compositions that would become Astral Weeks. The songs weren’t written so much as channeled from someplace else. “Van liked to work in a sort of stream-of-consciousness way back then,” Janet remembers, “letting the tape recorder continue to run while he just sort of played guitar and improvised, trying various things for 20 minutes or so at a time. Then we would go back, listen, and decide what was good, what to keep, tidy up rhyme schemes, and try it out again.”

Walsh’s book isn’t an analysis of the finished record so much as a conjuring of the atmosphere in which it was dreamed up—an approach that augments the album’s aura rather than draining it of its magic. (“And I’ll be satisfied not to read in between the lines,” as Van the Man himself sings.) And so we are transported back to the beer-soaked Boston clubs where Morrison and a hastily assembled backing band first debuted this gorgeously meandering material. Only one of the Boston players (the flutist John Payne) would appear on the finished album, though; producer Lewis Merenstein insisted on a more accomplished ensemble of session players, including the revered jazz bassist Rich Davis, drummer Connie Kay (who lent the lightest touch of percussion to these songs), and guitarist Jay Berliner. For all the mysticism around the album’s legacy, most members of the band had been working mostly commercial sessions in those days. Notes Walsh, “Consulting his work diary from that year, guitarist Jay Berliner notes he had just recorded jingles for both Noxzema and Pringles potato chips before showing up to start working on one of the most celebrated albums of all time.”

And yet it’s a tension of opposites that continues to animate Astral Weeks, the uncomfortable proximity of beauty to ugliness, tranquility to violence, heaven to earth. “What he lacked in glamour he made up in strangeness,” Greil Marcus writes, “or rather his strangeness made glamour impossible, and at the same time captivated some who felt strange themselves.” “He was a hateful little guy,” one Warner Bros. executive remembers of the man who wrote these songs that seemed to glow with such otherworldly benevolence; Marcus quotes another critic who says, “Van always looked to me like a half-homicidal leprechaun who lived under the bridge.”

But what gold he turned out to be guarding. The title track that kicks off Astral Weeks is an invocation, a departure, a spaceship made of nothing but rose garlands that is somehow, miraculously, functional. The trick is to travel light: Davis’s dewdrop bass notes, the weightless flutter of flute, and a single, gently strummed chord are all the song needs to take intergalactic flight. “If I ventured in the slipstream, between the viaducts of your dream,” Morrison asks, “… could you find me?” This is “Tears in Heaven” for people who, try as they might, can’t believe in something as straightforward as heaven. Instead we enter a dreamscape where “immobile steel rims crack” and Lead Belly returns from the dead to say … what, exactly? “Lay me down in silence easy,” Morrison coos. “To be born again.”

His voice is cracked but, as Leonard Cohen says, that’s how the light gets in. Morrison’s singing on Astral Weeks is rife with what Lester Bangs lovingly calls “verbal tics,” these moments when he begins to sputter in ecstasy or pain—“My t-tongue gets tied every, every, every time I try to speak,” he stammers on the stately “Cypress Avenue,” “and my insides shake just like a leaf on a tree.” This is the verbal phenomenon that Philip Seymour Hoffman referenced in his “I love, I love, I love” speech, and one of the enduring charms of this music is the way it transforms verbal awkwardness into a kind of state of grace.

Although the phrase “song cycle” gets thrown around a lot, it’s hardly ever as appropriate as it is here, given the cyclical, almost seasonal turn of Astral Weeks and its thematic fascination with rebirth. That makes it especially hard to extricate any of these songs from one another, but if I absolutely had to choose only one, what I’d take with me is “Ballerina.” It’s one of the first songs he wrote for Janet, before he went back to Belfast, and it unfolds like a waking daydream of flight. “And if somebody, not just anybody wanted to get close to you … for instance me, babe,” Morrison sings, the high strings of Berliner’s guitar trembling beneath the suave surface of the vocals. It’s all in that moment: the false casualness of seduction and a heartbeat’s fluttering apprehension, threatening to betray the whole charade. New love. But there is such deep comfort to the song too: “A crowd will catch you,” he assures, “just like a- just like a- just like a- just like a baaaalllllleri-na.”

When I listen now it reminds me of a time several years ago when someone asked whether I wanted to hear the good news or the bad news first. I answered as I always do. “The bad news is that we are all falling, all the time,” she said. “The good news is there’s no ground.”

He had started calling her Janet Planet, “probably because it rhymed.” She admitted years later that she never liked that “silly” name—she now goes by Janet Morrison Minto—but at the time it was the sort of thing you just went with. She went with it. They married. They moved to Woodstock, partially to be neighbors with Bob Dylan. Morrison put pictures of her next to liner notes and on album covers—that’s her on the horse on the dappled cover of Tupelo Honey, a record Greil Marcus has called “propaganda for the notion of leaving the strife of the previous decade behind and starting a new life, free of care.”

But propaganda tells only one side of the story—and a flat story at that. It was around this time that Marcus went to Woodstock to interview Morrison’s neighbor Robbie Robertson, and ended up talking to his wife Dominique. “Look at all this,” she said, gesturing toward the country landscape, the idyllic dream of the ’60s. “It’s everything people ought to want, and I hate it. … There’s nothing here but dope, music, and beauty. If you’re a woman, and you don’t make music and you don’t use dope, there’s nothing here at all.”

Moondance was the first album Morrison made after moving to that Edenic nowhere, and it was everything Astral Weeks was not—most importantly, commercially successful. Morrison was intent on making Moondance a rebuttal to its predecessor: Although the Astral Weeks session players did come upstate to run through new material, Morrison wanted a radical change, so he sent them all packing, brought in a more pop-minded band, and decided to produce the record himself. The result was more palatable and radio-friendly and spawned classics like “And It Stoned Me,” “Caravan,” and “Into the Mystic.” This record and the two that followed, His Band and the Street Choir and Tupelo Honey, weren’t exactly transmissions from the astral plane. But they did make him a star.

Janet Planet and Van Morrison divorced in 1973, when their only child, Shana, was young. (She would grow up to become a singer and would eventually serve as the opening act for some of her father’s late-career tours.) “I was confusing the music with the man,” Janet would say much later. “The music was everything you could hope for as a romantic. The man was a prickly bear.” When interviewing her for his book, Walsh tracked her down via her Etsy shop where she sells—what else?—homemade love beads. (Perhaps at least some of the hippie myth was rooted in reality.) But she’s not exactly trying to cash in on her role as Mrs. Astral Weeks. “Being a muse is a thankless job, and the pay is lousy,” she told Walsh. Truer words!

Still, when she was tracked down in 1998 for an L.A. Times profile, the woman formerly known as Janet Planet seemed to have made her peace with the past. “I want anyone who still cares to know that I actually found what I went off looking for,” she said. “A happy life.”

The record itself doesn’t find such a comforting finale; 50 years on, the search goes on ad infinitum. The last song, “Slim Slow Slider,” is its most morose, disturbing, and death-obsessed. “I know you’re dying, baby,” Morrison sings as the composition begins to topple around him, like a shoddily built house, “and I know you know it too.” Is it a literal death, like the one that haunts him in his weirdest song up until then, “T.B. Sheets”? Is it the dissolution of a relationship? No matter—it’s the fixation with mortality that makes it so evocative, so compulsively replayable. “After the last notes fade, a flip of the platter results in being ‘born again,’” Walsh writes. “Astral Weeks contains a built-in mechanism for reincarnation.”

How embarrassing—for the first 25 years of my life I mistakenly thought this album was called Astralwerks! But perhaps it is fitting, given how easy it is to internalize the corporate machinations of the music industry and how increasingly difficult it is to come into contact with the art it occasionally helps bring into being. All this means is that, until about six years ago, I’d never really heard Astral Weeks. Then I did.

I had heard Van Morrison prior to that, though—mostly against my will. When I was young I associated his music with authority figures, parents, soft-rock radio stations that put me to sleep in the backseat of the car. Most odiously, in high school, I had a vice principal who would serenade the entire school with a performance of “Brown Eyed Girl” at our annual end-of-the-year assembly. He did not have a particularly good voice, and years later I still don’t understand why he insisted on singing for us, except for the fact when you are in a position of power you don’t need a reason to do anything. The more musically literate of us, who knew when to hear it coming, would plug our ears during the part about what went on behind the stadium.

Success releases you into the atmosphere, to be interpreted and sometimes made grotesque. Success hitches you to a moment, a context, a story: “VIETNAM STUDENT RIOTS LBJ LSD SEXUAL REVOLUTION.” Failure can liberate a record from meaning something so fixed in time and space. Morrison’s most canonical early-’70s records are so rooted in a particular temporality because they spin a myth that people actually bought: that there could be transcendence in the countryside, in the happily-ever-after of a nuclear family, that there was such a thing as The Seventies and The Sixties and that the former would therefore make good on the promise of the latter. But Astral Weeks doesn’t pin things down like that. It doesn’t let you off so easy.

So, until about six years ago, I’d never really heard Astral Weeks. Then I did: I was 25, and then 26. I had just moved to a new city and didn’t keep regular work hours so it felt like I lived outside both space and time. It was a season I had enough time to watch almost all 24 hours of The Clock. It was a season I found myself falling down at several different parties, when I wasn’t even drunk—just going to sit and there wasn’t even a chair there. It was like I couldn’t find my footing on the surface of the earth. I experimented for the first time with different strains of meditation, as one would with drugs: You breathe in you breathe out, you breathe in you breathe out, you breathe in you … I read too many advice columns. I cried sometimes in public. I felt flayed, unprotected, wide open to the world. Of course this was when Astral Weeks found me. It made my broken parts feel beautiful. It made my stutter steps feel like a kind of dance. I felt the crowd would catch me, and it did.

“For me there is always a sense of worry when I put the album on again,” Greil Marcus writes, and can I ever relate. “Will it sound as true, will it sound as good as before, will there come a time when I will be listening to the end of ‘Madame George’ and suddenly it’s already there, I’ve heard it, it has nothing left to tell me—and that has never happened.”

So far I can say the same. Astral Weeks finds its way back into my life cyclically, like a harvest, and it is one of those records that makes me feel more curious about the world. It’s a talisman, a worry stone. It inspires me to pull strange threads. To cancel plans and instead read the Wikipedia pages of out-of-fashion occultists, watch old Polish movies that make me wonder all sorts of things about my ancestors, and Google the properties of certain Appalachian minerals. And so I come to Sharyn McCrumb’s article about the intercontinental secrets of rock. “For years I have been fascinated by the ‘Serpentine Road’ from the southern United States to Canada to Ireland, Cornwall, Wales, and Scotland,” writes one of the commenters on the article, likely an American of Celtic descent. “Just to look at various forms of Serpentine is to feel a sense of home.”