In the latest episode of Game of Thrones, Jaime Lannister rides his horse, spear in hand, toward the gaping mouth of an angry dragon. While it wasn’t his brightest move, and Tyrion echoed the audience’s sentiments by calling him a “fucking idiot,” Jaime was saved at the last minute by Bronn, who tackled him off his horse and out of harm’s way.
Jaime landed in a nearby body of water, and the episode ends with him slowly sinking farther and farther beneath the surface. Many on the internet are now speculating: Is Jaime dead?
While Bronn, who was conspicuously absent from the shot of Lannister survivors in the preview for Episode 5, could swim down and help lift Jaime or remove his plate armor, simple physics calculations suggest that Jaime can probably swim to land all on his own, especially since he’s right next to the shore. Here, Inverse did the math.
It would still be a tough swim — one that would require a great deal of effort from Jaime. In order to lift himself and his armor, he would have to exert about half as much force as a swimmer setting the world record.
While Jaime’s indestructible plot armor will most likely help him float straight to the surface, far away from the dangers of Daenerys, Drogon, and the khalasar, his real armor does quite the opposite. Plate armor isn’t nearly as heavy as people tend to think, but a full suit of armor from the 12th century still weighs anywhere from 33 to 55 pounds. Not counting Jaime’s golden hand, we can add another three pounds for his sword and another whopping 192 pounds for actor Nikolaj Coster-Waldau’s athletic frame.
That brings us to a total of 228 pounds, or 1,110 Newtons of gravitational force, pulling Jaime Lannister into the deep.
In 1950, the U.S. Navy conducted a series of six experiments to determine the ideal outfit and weight for divers to perform underwater tasks. They concluded that about 20 pounds of added weight would be ideal for divers to be able to navigate underwater. Combined, the data from their six studies shows that adding anywhere from 20 to 40 pounds to a diver will keep them planted squarely on the bottom of a body of water, depending on their outfits. With over 50 pounds of added armor, Jaime would have sunk like a fucking brick.
But buoyant force is Jaime’s saving grace, and the reason is that he only needs to make up for the 50 pounds of gear he’s carrying, not his entire body weight, as well.
Buoyant force is the upwards force that keeps a thing afloat, or at least tries to, depending on how much water that thing displaces. Because humans are about as densely packed as water is — it’s basically a one-to-one tradeoff. That’s why holding your breath and letting all the air out of your lungs often makes the difference between floating and sinking.
As such, an 87-kilogram Nikolaj Coster-Waldau would feel about 853 Newtons of buoyant force pushing him towards the surface. That leaves just 257 Newtons of the original 1,110 Newtons of gravity pulling him down. The remaining weight comes from his dense armor, which adds a lot of weight without displacing water and adding buoyancy.
The swim to the surface, assuming Bronn isn’t around to help Jaime, still won’t be easy, but it’s manageable for someone who’s supposedly one of the strongest knights in Westeros. While his body weight is accounted for, he still needs to lift the remaining 60 pounds of weight from the bottom of that lake up to its surface. And, of course, he would have to do it one-handed.
Season 7 of Game of Thrones will continue, perhaps with or without Jaime Lannister, on Sunday at 9 p.m. on HBO.