Suppose that a human body in its entirety were exposed to something like 1 million degrees Celsius for a millionth of a second (if such a thing were technologically possible.) Would the outcome be a merely-singed body, or a much more serious burn, even death?
We could treat this as two sliding scales of temperature and time. What if it were a thousand degrees Celsius for a hundredth of a second? Etc. etc.
It’s been done, at Hiroshima and Nagasaki.
But that lasted much longer than a millionth of a second. The fireball and its intense heat was present, and radiating, for a far longer time.
Think about what temperature is, and how it differs from energy. It all depends on how you’re exposing the body to that temperature, and if you want it to be super brief you are going to run into the issues of defining the difference between a brief exposure to 1 million degrees, by a front of particle radiation. (Sort of … what’s the average speed of nitrogen at 1 million degrees?)
If this exposure is to be through being hit by “very hot air”, you’re looking at nitrogen molecules moving at an average speed of 3900 m/s. The effect on the human body would depend on how you’re managing to engineer the exposure. A brief drop through a chamber with rarefied hot air is going to be different from … however you’ll engineer a brief exposure to high pressure.
I’d assume similar to being struck by lightning.
I once asked What would happen if you fell into a volcano?
running_coach posted a link to this video: Disposal of organic waste in Erta Ale Volcano lava lake causes violent eruption
Water turns to steam surprisingly fast, and causes a surprisingly violent explosion.
What if you dunk yourself in water first?
To a first approximation, it’s going to come down to the amount of energy transmitted to you. If it’s a small amount, there’s basically no way it can cause damage–depending on the characteristics, maybe it vaporizes your top level of skin cells, or maybe it penetrates more and heats your skin by some amount, but if the duration is short enough it shouldn’t matter what the temperature is.
That said, an object at a million degrees is radiating energy at an immense rate (proportional to temperature to the fourth power). Depending on the size of the object and how close it is, a millionth of a second might not be short enough.
Lasers can be designed with very short duration pulses, but very high peak power. Take a peek at the table on page 41 here. One of their lasers has a peak power of 16.5 gigawatts. If that were continuous, it would vaporize a person instantly. But the pulse time is under a picosecond and the energy per pulse is just 15 millijoules. You can’t do significant damage with that little energy.
The corona of the Sun is at a temperature of millions of degrees, but if you were in the corona, but shaded from the photosphere (the “surface” that’s glowing brightly), you’d freeze to death, because you’d lose energy to distant space more quickly than you could gain it from the very hot but very diffuse gas.
I think this is one of those questions where there are enough variables that you could get whatever answer you like.
e.g. What is transmitting that energy to you? If it’s air, what pressure is the air at? Are you wearing clothing? How sweaty is the skin? All these things would matter a lot for calculating the effect of E huge energy over T tiny time.
Aha! I hadn’t thought of it this way. I always assumed that disposal of the One Ring Of Power caused Mt. Doom to erupt, but this suggests that it was actually the disposal of Gollum that did it.
Does anyone understand why the ‘citation needed’ text about 2/3 down that page links to a search on Gibson guitars? An inside xkcd joke I assume?
The Sun’s surface is relatively cool. It’s hotter than, like, Phoenix,[ citation needed ] but compared to the interior, it’s downright chilly. The surface is a few thousand degrees, but the interior is a few million degrees.[4] What if you spent a nanosecond there?
Nobody liked Gollum. Not even Mt Doom. Sad.
Randall often uses the “citation required” note as a joke at XKCD and What-if. In this case, he’s imaging a Wiki-editor demanding a citation that the Sun’s surface is hotter than Phoenix (a notoriously hot location in the US).
And now I see that the “citation required” goes to a link for pictures of a “Gibson Citation” guitar, which means “citation required” means “Give me a Gibson Citation!”
I have to pay more attention - I totally missed your point. Sorry about that.
You can run your finger through a candle flame quite painlessly, also a gas stove flame. I’d be hesitant to try that with an oxyacetylene welding torch. Here’s a big argument on the temperature of static electricity. Since I can see ionized gas in the spark, I expect T must be quite high.