For his next trick, your cosmic correspondent for the past quarter-century will (try to) retire.

As the day shrinks into its annual darkness, here's what I know about the cosmos -- so far.

For an instant of cosmic time you are the center of the universe, wondering where everybody is going and why, as trillions of galaxies, smudges of light and possibility, recede. You trust that the steady rise and fall of stars heralds order, only to be ambushed by surprise and confusion.

For the last quarter-century, I have been privileged to ride on a vertiginous wave of awe and terror. Armed with the coolest business card in journalism, identifying me as the "cosmic affairs correspondent" of The New York Times, I descended into the bowels of the Large Hadron Collider in Geneva, froze on stormy mountaintops in Mexico and drank in glittery star fields on peaks in Chile and Hawaii. I lectured about Albert Einstein in Hong Kong and Berlin and despaired as I wandered the muddy rubble of the World Trade Center after Sept. 11.

Now, I am retiring from The Times and must relinquish that business card, although not the mission behind it. I will continue to appear in these pages from time to time and work on a book trying to marry the personal and the cosmic.

This gig provided me with a thrilling vista of history and science. Researchers and the rest of us heard black holes colliding, spreading ripples through the fabric of space-time, and saw them staring like smoke rings from the hearts of galaxies -- trap doors into the end of time. After 50 years and $10 billion, physicists finally discovered the Higgs boson (or "God particle"). It was the missing key to physicists' best, but still unsatisfying, theory of nature yet, called the Standard Model.

Astronomers discovered that there are billions of possibly habitable planets in the galaxy. At the same time, they have had to accept that 95 percent of the cosmos consists of invisible "dark matter" that binds stars in galaxies and a "dark energy" that pushes those same galaxies apart ever faster. Nobody knows what this dark stuff is.

In 2015, when I first heard rumors that the twin antennas of the Laser Interferometer Gravitational-Wave Observatory had felt the cosmos quaking from the collision of two black holes deep in space and time, I didn't believe it. What I knew about LIGO had convinced me that it was an outlandishly ambitious experiment bound to fail.

Instead, it turned out to be a listening post to a dark side of the universe. Now I have a phone app that, with a loud chirp, announces every new gravitational wave event. Lately it has been going off once a day, sometimes waking me at night, like the bell in "It's a Wonderful Life" that rings whenever an angel gets its wings.

What angels are those, tapping a fandango across the darkness? Doubtless some are colliding black holes, but there is an additional bestiary of theoretical candidates -- wormholes, cosmic strings -- that would leave a distinct signature in the form of gravitational waves. What fun it would be to detect them.

I came of age in the Sputnik era, when science and space exploration suddenly became a national priority in the United States. We Americans, the reasoning was, had to beat the Soviets to the moon and build better missiles and computers to protect ourselves. Scientists were potential saviors and heroes; everything was possible. Later, giant particle accelerators were built to explore the mysteries of inner space. The Berlin Wall fell. The fruits of innovation flowed: the transistor, the internet, CT scans and MRIs, global positioning systems, Nobel Prizes.

Today, it's fair to say that some of the bloom has come off the rose. With the end of the Cold War, funding for physics and space exploration began to lag. The James Webb Space Telescope is revealing profound vistas of the earliest years of the universe -- but an ambitious effort to fetch rocks from Mars and examine them for signs of life is floundering. The attempt to return humans to the moon after 50 years is mired in delays and cost overruns. The political response to Covid has cast doubt on the very concept of public health; the political response to climate change has cast doubt on the concept of scientific expertise. Artificial intelligence has become frighteningly smart. Silicon Valley has led us to new realms of loneliness, squinting at tiny screens for fragile intimations of community.

"How does it feel," Bob Dylan sang almost 60 years ago, "to be on your own, to be without a home, like a complete unknown, like a rolling stone?"

And yet science, proceeding on skepticism, not certainty, is arguably the most successful human activity of all time. Its truths are temporary; progress, the saying goes, comes only at the funerals of philosophers and cosmologists. The philosopher Lucretius decreed that there was nothing in nature but atoms and void. We're still learning what atoms can do.

Everything that scientists have learned tells us that the universe is dynamic, and so is our knowledge of it. Nothing lasts forever, not even forever itself. Stars are born and they die; their ashes congeal in new generations of flash and crash. And so the show goes, until the last, biggest black hole gasps its last puff of subatomic vapor into the void.

We don't know what wonders await discovery back in the first nanosecond of time or in the yawning eons yet ahead. We don't know why there is something instead of nothing at all. Or why God plays dice, as Einstein put it as he mulled the randomness implicit in quantum mechanics, the house rules of the subatomic realm.

Andrea M. Ghez, who won a Nobel Prize in 2020 for investigating the supermassive black hole at the center of the Milky Way, told me recently that her favorite moments in science were those when she was confused. John Archibald Wheeler, the physicist who pioneered the study of black holes, liked to say, "We will first understand how simple the universe is when we realize how strange it is."

Going forward, my money is on confusion.