It’s a well-known phenomenon. You hear that song on the radio, and it takes you back to your senior prom, your first concert, summer camp or some other event relegated to memory. It activates that memory and makes it new again. You know you can never go back there again, but in that moment, you remember what it was like to be there.

You smile a little smile, and maybe you get choked up a little, too. It’s the essence of “bittersweet.”

Because music is such a potent reminder of the past, it hurts to realize it’s going to stay there. That’s what happened a couple of years ago, when a large number of famed musicians from my childhood all left us: David Bowie, Glen Frey of the Eagles, Prince, George Michael, Leonard Cohen, Merle Haggard, Keith Emerson and Greg Lake of ELP, Leon Russell.

It wasn’t just the year the music died, it was a year a part of us died, because with their deaths, we knew they’d never be making new music again. We’d never get another chance to see them in concert. Even if their bands had broken up, there had always been a chance they’d get back together, at least for a reunion show. No more. I remember thinking about that when John Lennon died. There would never be a Beatles reunion. Maybe there wouldn’t have been one, anyway, but there had always been that hope.

Hope is about the future; memories are about the past. They work best in tandem, and when we lose one part of that equation, we’re a little worse off for it.

We didn’t just lose musicians in 2016. My childhood sitcoms were decimated by the deaths of Florence Henderson (The Brady Bunch), William Christopher (M*A*S*H), Abe Vigoda and Ron Glass (Barney Miller), Alan Thicke (Growing Pains) and Garry Marshall (creator of Happy Days, Laverne and Shirley and Mork & Mindy).

They live on in reruns, but in some ways, that’s just as hard, because whenever you see them, there’s a chance you’ll be reminded that they’re no longer with us.

This happens to me a lot, with music, TV shows, landmarks, mementos, old photographs.

I see movies starring Alan Rickman or Robin Williams, and I can’t help but be reminded how much I valued their talents … and now, they’re no longer here.

TAKEN FOR GRANTED

You take things for granted when you’re young, at least I did. When I first became aware of things, I assumed they’d always been that way and that they always would be. I think the first time I realized they wouldn’t was when I moved back to my hometown, Fresno, at age 15, after six years away. The radio station formats had changed. The big discount department store called White Front, where everyone had shopped, was gone. The Lesterburger fast food chain, which had been ubiquitous in the 1960s, had gone out of business, too. It all seemed surreal, impossible even.

Three more years passed, and there was a new freeway and a new football stadium. Both were big improvements, but I still remember sitting on the splintery wooden seats at the old stadium and watching Fresno State’s football team rout Los Angeles State (back when it had a football team). The splinters aren’t a pleasant memory, but the game itself is, and they’re tied together in my soon-to-be-55-year-old mind.

Going south on a trip to San Diego last weekend on U.S. 101, I passed through the area where I lived for six years as a child and young teenager: Woodland Hills. I was reminded of riding in my parents’ Buick LeSabre down that same Ventura Freeway to see the Dodgers play every summer in the 1970s. People mention Bill Buckner’s error on his gimpy leg for the Red Sox in the 1986 series, and it triggers memories of when he was my next-door neighbor in Southern California, making circus catches in the outfield for the Dodgers before that leg slowed him down.

When I went back to Fresno as an adult a year or two ago, I went back to eat at the first Me-N-Ed’s pizza parlor on Blackstone, where my folks introduced me to my favorite pizza (cheese and black olives) when I was 5 or 6. Yes, it’s still there, and that’s comforting. But it also reminds me that my parents aren’t, and that will never stop hurting.

When I see high school football games, I remember when I used to cover them as a reporter for the Tulare Advance-Register. When I drive by my old office, I remember when I used to work there.

"BACK IN MY DAY"

Then there’s the music.

Whenever I hear the Eagles’ Best of My Love, I remember sitting by the radio in my room, listening to the week’s top 40 countdown and wondering what would be No. 1 that week.

When I hear Have You Never Been Mellow? by Olivia Newton John, I think of riding to summer school at A.E. Wright Middle School, the ride so much longer than it needed to be because of all the stops they made in the canyons and foothills west of the San Fernando Valley. And me, sitting there, my legs cramped and hurting because, even at that age, I was far too tall to fit comfortably in bus seats designed for third-graders.

Maybe it’s because I’ve done so much historical writing that these memories hit me so often, but I think it’s the other way around: The feeling that the past is somehow slipping away has prompted me to keep some portion of it alive, if only in recorded memory. I suspect it happens to a lot of people like this, even if they don’t write any of it down, and that’s why our elders reminisce so often about the way things used to be “back in my day.”

My dad did that, and now I’m doing it, too.

It’s bittersweet to remember the things that are gone, but the alternative, forgetting them, is far worse.