The Game of Thrones: The Physics behind Viserion

Winter is coming.

The penultimate episode of the famous series "The Game of Thrones" has given strong and conflicting emotions to the vast international audience interested in the show. Although the audience is accustomed to narrative upheavals in the plot of the story, the death of the dragon Viserion has left a bitter taste in viewers.

For those not following the show, here is a very brief summary. Daenerys, legitimate heir to the Iron Throne, decides to clash with Queen Cersei and the entire Lannister House to claim her role. The Queen of Dragons has, in fact, three enormous dragons capable of spitting out incandescent flames able to incinerate their adversaries.

Suddenly, another fearsome adversary, the Night King, looks out from the northern borders of the known kingdom and terrorizes the inhabitants of the continent. In fact, this warrior is able to bring back to life the fallen in battle and intends to march on Westeros with his massive army of undead. In a desperate rescue mission, however, one of the three dragons remains a victim of the Night Knight and is placed in the ranks of the vast army of the undead. In the final episode, the Night Knight uses Viserion to dissolve, thanks to a powerful blue flame, a significant portion of the Barrier facilitating the entry of his army into the lands of Westeros.

Characters of the famous TV series: The Game of Thrones.

Let's see the Physics behind this scene!

Before being hired by the Night King, Viserion was able to spit yellow and orange flames, not blue. The first hypothesis that can be made is that the transformation of Viserion implied an anatomical transformation of the dragon itself. The blue flames, in fact, unlike the yellow flames have a much higher calorific value. When the fuel (methane probably) and the comburent (oxygen) are mixed effectively they give life to an oxidation reaction which produces a blue flame. The yellow color of the flames is due to the poor mixing efficiency of the two reagents which let "escape" fuel particles emitting an electromagnetic radiation with a wavelength of 590 nanometers (according to the model of the black body emission). The particles that are leaving the flame are easily visible on cold surfaces near the flames; the tarry substance they form is usually called soot.

Viserion, therefore, has an anatomical structure that allows the development of a much more efficient chemical reaction, capable of producing much hotter flames. Perhaps, the anatomical conduit, in which the comburent and the fuel are mixed before the expulsion of the flame, has undergone an increase of its diameter during the transformation.

The undead Viserion is able to spit blue flames. The color indicates that the temperature of the flame reaches 1400 ° C.

Now let's move on to the moment when Viserion melts the cold ice of the Barrier.

We hypothesize that the wall of ice that Viserion melts is 210 meters high, 500 wide and 50 meters thick (according to information given by the writer George R. R. Martin). Assuming, moreover, that the temperature of the ice on the wall is equal to -20 ° C, the energy released by the flames to completely melt the ice is enormous. A two followed by 15 zeros (Joules). This is equal to the kinetic energy possessed by a 100-ton train traveling at a speed of 190 kilometers per second!

The barrier at the northern border of the known kingdom.

To conclude, it is clear that the fantasy genre, by definition, can not be accurately described by a purely scientific interpretation. Therefore, we wait patiently for the arrival of the first episode of the last season of "The Game of Thrones", scheduled for March 10th, 2019.