I remember the exact moment that I knew absolutely everything, beyond the obvious, had changed after September 11, 2001.

I was alone with a new baby and my husband was across the world, deployed with the Navy. I had a lot of time on my hands to obsessively watch the news, and admittedly, I saw too much of it. Soon after the buildings fell, the cable news networks, overwhelmed by the volume of news to cover, started using a ticker across the bottom of the screen to keep up with it all. The anchor might have been discussing the clean-up at Ground Zero, but the silent ticker below was updating viewers about everything else: the Pentagon, Shanksville, and, later, anthrax scares in the U.S. Postal Service. That’s how much horrific news there was to share.

The idea of a news ticker was not new in 2001. It had been used in the past to draw viewers’ attention to urgent situations — weather, elections, etc. — that needed continuous updates. But until September 11, 2001, the ticker was never a permanent feature on the news.

According to James Poniewozik, writing for TIME in 2010, the first channel to use the ticker was Fox News, but CNN and MSNBC soon followed.

“After the shock wore off and the smoke cleared, the ticker remained,” Poniewozik wrote. “It became not just a tool but a symbol. It was a message in itself, a constant prod, an emblem of a media era of constant crisis mode … the data stream onscreen seemed to say, the emergency was permanent; the warning lights were always flashing.”

There is plenty to debate about what the news ticker represents today, among them how displaying constant news benefits cable news financially, but from the viewpoint of my 24-year-old-self back then, the ticker only represented one thing: American life would never be the same.

By November 2001, when the ticker was still ticking, I remember watching television with a fellow military-wife friend and saying, “Well, I guess that ticker is a thing now.” What I didn’t understand — what I couldn’t understand — then was that not just the ticker, but terror itself, had become a “thing” now, too. The terror and the ticker would not stop.

At 24 years old and with a baby on my hip, I thought about anthrax — anthrax! — when I went to the mailbox each afternoon to get my mail. I never imagined that. A few years later, after a mall shooting, for the first time in my life, I walked into a mall to do holiday shopping and considered how I might escape if someone opened fire.

One by one, with each new attack, places that had never seemed unsafe, suddenly gave me pause: movie theaters, colleges, grocery stores, and, eventually, even military bases, which had always seemed like the safest place to be. But the worst by far, and the most unspeakable for me, the one I will not get out of my mind, was the mass shooting at Sandy Hook Elementary. Even in the immediate years following 9/11, when the world seemed upended, I never thought twice about sending my children to an elementary school. But suddenly, school, too, had the potential to be unsafe.

My oldest son, Ford, who was the baby with me on the morning of 9/11, is almost 17. He has never lived in an America without a news ticker. Neither have his two younger brothers. They have grown-up in a world that is completely unlike the one I knew before 9/11. That might be an exaggeration (surely the fabric of American life is the same), but not by much.

I have never taken my children to a movie and not thought about what could happen. We have never gone to a professional sports game without me silently considering all the horrific possibilities in my mind. My boys don’t know a world where “active shooter drills” are not the norm, like a fire drill would be, at school.

And then this week, we woke up and saw that even an outdoor concert can bring tragedy. It is telling that aside from our obvious grief and anger, none of us are really that surprised anymore. Terror has become a steady hum, almost unheard, like the silent presence of a news ticker at the bottom of the screen.

In 2010, Poniewozik wrote that the 9/11 news ticker had not stopped nine years later: “To remove the ticker, after all, would be to say life had gone back to normal, to reject the national shibboleth that everything had changed. Who wanted to be the first to do that?”

What does it say about us that now, in 2017, 16 years later, we still have a need for the ticker?

— Sarah Smiley is a syndicated columnist. Contact her at sarahrsmiley@gmail.com