io9 examines, at surprising length, the weighty question, Could Luke Skywalker have really survived a Hoth snowstorm warmed only by tauntaun innards? From the piece:
Using Newton's Law of Cooling, we can estimate the time it takes for the tauntaun's body temperature to reach levels detrimental to Luke's survival. Luke is swimming in a sea of blood, bodily fluids, and organs during his time inside the tauntaun.
This is essentially a liquid-like environment, one that will transmit the body temperature of the tauntaun well. To best model this scenario, merging Luke's body with the tauntaun becomes necessary, creating a one body system.
Forensics teams use Newton's Law of Cooling to estimate the time of death of a newly discovered body. Dead bodies will acclimate to the surrounding temperature of the room as the bodies no longer metabolize nutrients or generate heat. By measuring the rectal temperature of the cadaver and temperature of the room, the time since blood circulation ceased (i.e., death) can be calculated. Let's just let the idea of obtaining a Tauntaun's rectal temperature sit with you a moment.
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