This summer we're going to see Channing Tatum save the president's residence in White House Down, just a few months after Gerard Butler did the same thing in Olympus Has Fallen. This brings up two good points: the White House needs a new alarm system, and Hollywood has a tendency to release pairs of similar movies right next to each other.

Fifteen years ago this week, moviegoers flocked to see a comet hurtle toward Earth in Deep Impact. Eight weeks later, we did it all over again for Armageddon, except this time it was an asteroid and somehow Aerosmith was involved. The previous year had seen Dante's Peak and Volcano released 11 weeks apart (neither one in the summertime, strangely). Later in 1998, there would be a face-off between talking-insect cartoons Antz (October 2) and A Bug's Life (November 14).

Since that time, it has been a matter of conventional wisdom that Deep Impact was "smarter" or "better" than Armageddon, while Armageddon was "more entertaining" and "more lucrative." (That last part is definitely true: $554 million worldwide versus Deep Impact's $350 million.) Certainly Deep Impact focuses more on the human reaction to impending doom than does Armageddon, which is primarily interested in blowing things up and using animal crackers for sexual purposes. But neither film got many positive reviews: 47% at Rotten Tomatoes for Deep Impact, 39% for Armageddon. Watching them both now, it's interesting to see how alike and different they are, and how they're both not very good, but for different reasons.

As you'd expect from a Michael Bay movie (this was only his third!), Armageddon is in every way BIGGER than Deep Impact. It's a half hour longer, and it cost almost twice as much to make. Deep Impact's comet is seven miles wide and will strike in a year; Armageddon's asteroid is "the size of Texas" and will be here in 18 days. The comet threatens to create a cloud of dust that will block out the sun for two years; with the asteroid, it'd be more like a THOUSAND years. Deep Impact calls it an "extinction-level event" (the same term was used in Oblivion); in Armageddon, it's a more straightforward "global killer."

There's also quite a bit more destruction in Armageddon. Deep Impact is set up so that nothing catastrophic happens until the comet actually hits the Earth, 10 minutes before the final credits roll. Over in Armageddon town, things are different. The title itself explodes after appearing on the screen. The asteroid is discovered because it BLOWS UP THE SPACE SHUTTLE!! (The comet in the other movie was peacefully discovered by young astronomers.) What's more, bits of the asteroid start hitting the Earth immediately -- New York is struck before the 10-minute mark -- and until Bruce Willis and company can blow up the asteroid, our planet is essentially "in a shooting gallery." In other words, anytime the story slows down, we can spice it up with an asteroid attack.

People who know about such things say the science in Deep Impact is less preposterous than the science in Armageddon. That's one of the reasons Mimi Leder's film is more "respected" than Michael Bay's. What we tend to forget is how terrible Tea Leoni is. She plays a TV journalist in Deep Impact who uncovers the government's knowledge of the comet's impending arrival. She could scarcely be a duller screen presence. Her character is promoted to news anchor for this story -- literally the biggest news story in the history of mankind -- and she goes on TV like she's half asleep. By my calculations, Deep Impact would be approximately 35 percent better if it had a more dynamic lead actress.

Today, of course, Armageddon is revered as a top-notch popcorn flick (it got a Criterion Collection release, for crying out loud) while Deep Impact is more or less forgotten. I'd be more OK with that situation if Armageddon -- for all its watchable, energetic mayhem -- weren't also such a dumb, dumb movie. It's a half hour longer than Deep Impact, and probably 40 decibels louder, but it's not a lot better. I suppose the lesson is this: when two mediocre film compete, the mediocre film that offers more spectacle and less Tea Leoni will be the winner.

When Deep Impact was released, on May 8, 1998:

- It easily took first place at the box office with $41.2 million, the ninth best opening weekend of all time at that point. (As of today, it is the 194th best opening weekend.) The other new semiwide release that weekend, the Jada Pinkett Smith rom-com Woo, landed in seventh place. Among the other films in the top 10 that weekend: City of Angels, He Got Game, Les Miserables, The Object of My Affection and Titanic (in its 21st week of release).

- The most popular shows on TV were Seinfeld (which was six days away from its final episode), ER, Veronica's Closet, Friends and Touched by an Angel. Murphy Brown, Unsolved Mysteries and The Larry Sanders Show were all about to air their last episodes, while Dawson's Creek and Teletubbies were new, and Sex and the City was a month away from its debut. The year 1998 was a confusing time for everyone.

- Elle Fanning was a month old, and Jaden Smith had two months left in the womb. Speaking of people being born, some people had also recently died. Among them: Eddie Rabbitt, James Earl Ray, Pol Pot and Linda McCartney. Frank Sinatra, Phil Hartman and wrestler Junkyard Dog all had less than a month left on this Earth. (Sinatra died on the same day as the Seinfeld finale, by the way. That's how disappointing it was.)

- In the world of popular music, Dave Navarro had left the Red Hot Chili Peppers a few weeks earlier; Geri Halliwell was about to leave the Spice Girls; and George Michael had recently been arrested for being naughty in a public restroom. "Too Close," by Next was number one on the Billboard Hot 100 chart, having replaced K-Ci & JoJo's "All My Life." Brandy and Monica's "The Boy Is Mine" was about to be the top hit for pretty much the entire summer. I was in college at the time, and I honestly have no memory of any of the songs I just mentioned. But the Wikipedia entry for "Too Close" is enlightening: "The song is about a man who has become aroused by a young woman who is grinding on him at the club and cannot control his erection."

- Speaking of erections, it had been less than six weeks since the FDA approved a new drug called Viagra, and less than a week since the 1,000,000th Viagra joke had been made on a late-night talk show.