This picture of the different configurations in which Jack could’ve fit on the plank Rose rested on at the end of Titanic has been going around Tumblr (I’m not sure the original source) for almost a year now, and Mythbusters finally got around to investigating on last night’s show. James Cameron addressed Jack-could’ve-fit gate himself last month,

The Mythbusters boys and their goatees of absolute authority essentially confirmed James Cameron’s explanation.

It is plausible that Rose and Jack could have both stayed afloat on the board and survived hypothermia just long enough to be rescued — but only if they’d thought to tie Rose’s life jacket underneath the board to help with its buoyancy. Otherwise, the weight of both their bodies would have sunk the board low enough in the freezing water that they both would have died. Let’s break it down further:

• For the hypothermia tests, Cameron said Fifth Officer Harold Lowe, who rescues Rose in the film, began his search about 20 minutes after the ship sank and continued for about 45 minutes, according to survivors. Since Rose is one of the last people to be rescued in the film — the officer hears her whistle right as he’s about to give up — they decided 63 minutes is fair. To test whether a human could have survived that long in freezing conditions, Jamie built ThermoMan, a dummy with gelatin flesh and a water-heated copper cardiovascular system that was rigged to monitor body temperature. Once they had him at 98.6° F, they submerged him in 29° water and timed how long it took him to reach deadly hypothermia. They pronounced Jack dead at 51 minutes because his body temperature dropped to below 85° F, which means he would have experienced loss of motor control and not been able to hold onto the board. So the movie had that right: Jack would have drowned.

In the second hypothermia test, ThermoMan was warmed back up to 98.6°, dressed in his wet clothes, and set hovering above the freezing water in 29° F air. Though the drop of body temperate drop was nearly identical, the difference was, when he reached the temperature that would cause him to become immobile, he was laying safely on top of the board. He wouldn’t have drowned. That bought him more time. As long as he was rescued before his body temperature dropped below 82° F, he could be revived. At 63 minutes, ThermoMan’s core body temp was 82.5° F. So technically, Rose would have been alive to be rescued.

As for whether the board could have supported both Jack and Rose for 63 minutes, Adam first did a small-scale test using dolls and a board made of the same wood used in the film. The board tipped immediately and started to sink. Point for Cameron. Next, “Jack Savage” and “Rose Hyneman” did a full-scale test in the water, scaling up the board’s buoyancy to adjust for their increased mass as stand-ins for the actors — and outfitting “Rose” with a period-accurate life jacket made with the same materials and buoyancy as the one Winslet wears in the movie. It took “Jack” multiple attempts to be able to climb aboard and stabilize the board. But it sunk low enough in the water that drowning after loss of motor control would have been a danger. That’s when they tied Rose’s life jacket underneath the board, which raised it enough that they could position 80 percent of their bodies out of the water while resting on the board without needing to hold on. They made it 63 minutes. “With all we’ve learned, I think Jack’s death was needless,” Hyneman concluded. So yes, it’s plausible that both Jack and Rose could have survived on the board if they’d MacGyvered her life jacket. [EntertainmentWeekly]

Of course they had to increase the board’s buoyancy to account for 2012 people’s mass as opposed to 1912 people’s. I blame the advent of the Taco Bell-introduced “fourth meal.” I’m told another adjustment they had to make was to give “Jack” and “Rose” iPhones in order to pass the time tweeting “trying not to drown, lol” and “the ocean is cold, smh” to keep from dying of boredom. I mean let’s be honest, 63 minutes is a long time to just sit there not being entertained.