Last night, a few of us PopSci editors were invited to an IMAX screening of the new movie Poseidon, the Wolfgang Petersen flick about a cruise ship that’s hit by a huge rogue wave. The film, which opens today, has all the teeth-gritting suspense of The Day After Tomorrow—with the cheesy dialogue slashed by a good 75 percent. As the star, actor Josh Lucas, explained in a Q&A session after our screening, that’s because the actors realized on-set that the script was pathetically absurd and cut out as much of the dialogue as they could get away with.

Lucas also bluntly acknowledged that the reason actors do these films is just for the money and that the filming itself was a painful slog. Literally; two emergency-room visits resulted from injuries he sustained as he struggled through the submerged maze of wires and debris that made up the set.

But enough about the star. How about the 100-foot wall of water that scuttles the ship in the first place? About as absurd as The Day After Tomorrow‘s 24-hour global freeze, right?

Actually, no. It turns out these waves are real, and they actually do sink a number of ships each year. Rogue waves (also called freak waves or monster waves) were long assumed to be just the stuff of mariner legend. Until January 1, 1995, when just such a wave was definitely documented at a North Sea oil platform (in a rare though insignificant case of action flick mimicking reality, the wave also strikes the fictional Poseidon on New Year’s). In 2000, the EU initiated Project MaxWave, which used imagery from European Space Agency satellites to conclude once and for all that rogue waves are real. Scientists are now using the project’s finding to study the root causes of the monster swells. My conclusion: Add rogue waves to the long list of good reasons never to go on a cruise. And check out this link for more on the science behind them. —Kalee Thompson