For centuries, the stars have been used as a guide, their shimmering specks in the sky leading the way through darkness. They have been imbued with subjective meaning and held up as a mirror for the human condition.

Celebrities, the stars of the earthly realm, have played a not-so-different role: We look to them as models, or cautionary tales, and treat their waxing and waning relevance as a barometer of public opinion.

In 2021, the upward trajectories of several celebrities could not be ignored. Their names dominated headlines, their outfits were incessantly emulated. Some, you might say, ruffled the very fabric of our space-time continuum. (Who could have seen a Pete Davidson and Kim Kardashian love story existing in this dimension?)

During a year when a return to normalcy was the most exciting thing most people could imagine, it was a balm to see celebrities return to their normally abnormal lives. Some just simply shined brighter than others.

Here, we chart the stars that rose — or flamed out — in another dark year.

Celebrities that are good at being celebrities

The barrier to becoming a celebrity has arguably never been so low. But to become a celebrity whose glimmer lasts longer than a news cycle? The field narrows considerably.

Lil Nas X led the charge of stars who “understood the assignment,” to use a phrase that should probably be retired in 2022. In terms of creating cultural moments, impeccably reading the room on Twitter and seeming to actually have fun with his newfound mega-stardom, no one else came close.

Megan Thee Stallion and JoJo Siwa also maintained momentum this year. Megan graduated from college, a goal she’d been reiterating for over a year. JoJo Siwa, who came out as pansexual in 2021, became the first contender on “Dancing With the Stars” to dance with a partner of the same gender. She and Jenna Johnson made a great pair.

The fact that JoJo Siwa was a delight on a reality TV dance competition wasn’t surprising. She had, after all, made her showbiz debut as a child on the reality TV show “Dance Moms.”

Maybe it’s the double whammy of something nice actually happening for someone, along with the rareness of that someone seeming like a decent person. We’ve certainly been starved of a lot of nice things for years, and these folks kept us rooting for them.

Literary discourse magnets

What’s that old saying? The pen is mightier than the sword? It seems 2021 proved that to be undeniably true thanks to a handful of authors who seem to exist at the center of a Venn diagram between idol and enemy depending on who you ask.

There was, of course, “Bad Art Friend,” a New York Times Magazine article about two feuding writers that brought Twitter to a standstill.

And of course, Sally Rooney, the hype-fueling author of “Conversations With Friends” and “Normal People.” Her latest novel, “Beautiful World, Where Are You?”, spurred conversation when she declined to sell the rights to her book to an Israeli publisher, citing her support of the Palestinian people. Who writes about the writers that get written about?

Pop culture bad boys

You know who’s got two thumbs, a slender frame, a plethora of tattoos and a famous brunette girlfriend? These guys.

The supposed bad boys of the moment — Machine Gun Kelly, Travis Barker and Pete Davidson — had an above-average year. Machine Gun Kelly and his girlfriend, Megan Fox, are the hottest item on any red carpet. Mr. Barker overcame his nearly 13-year-old fear of flying and is now engaged to Kourtney Kardashian. Mr. Davidson, for his part, is possibly dating Kim Kardashian and continues to reign supreme not only as the King of Staten Island but also of our hearts.

Pop princesses that hurt your feelings with their music

What is it about this year (aside from the pandemic we continue to live through) that made us so sad? Perhaps it was the huge number of albums soaked in the sweet scent of heartbreak from the queens and princesses of pop.

We kicked the year off with Olivia Rodrigo bringing us back to our angsty teen years of love and loss. Then, in November, came Taylor Swift’s rerelease of “Red,” along with her 10-minute version of “All Too Well” and a short film that was painful to watch. (Let’s just say it was a bad week to be Jake Gyllenhaal.)

Finally, Adele drove us home, serenading and letting us in on what it feels like to be alone, but maybe not quite lonely. Thank you to the women who hurt our feelings with their music this year — now please let us rest.

Athletes who defined triumph

Three of the biggest athletes in the world made headlines this year by not competing.

Naomi Osaka withdrew from the French Open, citing concerns for her mental health.

Sha’Carri Richardson, who was heavily favored to win the Olympic gold for the United States team as a sprinter, was suspended from the 100-meter race after a positive marijuana test.

Simone Biles pulled out from the Olympic all-around gymnastics competition while on the floor of the stadium in Tokyo. In the process she introduced the concept of “the twisties” — a sort of disorienting vertigo that gymnasts face — to the masses.

All three women were blasted for their decisions, but each was also heralded as a new type of role model. All three attended this year’s Met Gala.

Quitting is usually considered worse than losing in the world of competitive sports. But for some, the conversations spurred by the absence of these women made a greater impact than any victory could have.

Of course, there’s still glory in not quitting. Stephen Curry broke the record for most regular-season 3-pointers on Tuesday and garnered a bevy of accolades, including a crowd chanting “M.V.P.” and Spike Lee, clad head to toe in orange, contorting himself on the floor to capture the moment on his phone.

Revisionist rescue missions

It’s easy to forget just how differently we were thinking of Britney Spears a year ago. There were online rumblings about a conspiracy to control her and a movement to “free” her, but few of us understood the realities of what her life under a conservatorship meant.

The conversation changed significantly after The Times’s “Framing Britney Spears” and “Controlling Britney Spears,” as well as Erin Lee Carr’s Netflix documentary, “Britney vs Spears.”

In a matter of months, people who were unaware or indifferent to Ms. Spears’s personal life were roped in. Ultimately, the pop star’s personal trajectory and her public perception turned around.

She wasn’t alone. This was a year of revisiting, reconsidering — and in some cases, trying to rescue — women who were famous or infamous in the past.

Princess Diana, an object of aggressive international media fascination when she was alive, had a posthumous cultural moment with both a Hollywood movie and a Broadway show — for better or worse — that reconsidered her legacy as a princess, an icon and a human being.

Monica Lewinsky was portrayed with sympathy by Beanie Feldstein on “American Crime Story.” Ms. Lewinsky herself was a producer for the project.

Anita Hill’s press tour for her book about gender violence became an occasion to reconsider the ways she had been written about in the wake of her 1992 testimony against Clarence Thomas.

And Sinead O’Connor, another ’90s punchline for years, wrote a memoir that prompted a fresh look.

Of course, many of the wrongs inflicted on our female celebrities have not been accounted for. But this year was an indication that there may be an appetite to try to get things right.