Warning: This post contains spoilers for season seven of Game of Thrones.
The famed astrophysicist took to Twitter Sunday to drop some thermal physics knowledge on fans still wondering about the difference between regular and blue dragon fire following the climactic finale of Thrones' seventh season. "Intriguing Thermal Physics in
#GameOfThrones," he wrote. "Blue Dragon breath would be at least a factor of 3X hotter than Red Dragon breath."
In George R.R. Martin's A Song of Ice and Fire series, ice dragons are described as breathing cold rather than fire. However, wight Viserion was blasting the Wall with blue flames — a detail that the finale's director, Jeremy Podeswa, confirmed in an interview.
"It’s funny because people really accepted the green fire [of wildfire], which burned down the Sept [of Baelor] and the sea battle in the earlier season," he told Winter Is Coming. "I think that fire can have many different manifestations. I think that the ice dragon fire is clearly still fire because it does melt the Wall and tear it down, but it had a particular quality because it’s coming from an undead dragon. So what the chemical nature of that is and the chemical nature of fire would actually be different coming from a non-sentient being...But obviously, an ice dragon is going to have an icy kind of fire but it’s still fire."
Looks like we can put this Thrones mystery to bed.