I love the Internet. Full of brilliant people asking brilliant questions, and brilliant people giving the most amazing answers. On Reddit, user Chalkup asked, “If you could compress a lifetime worth of farts into a single fart, how far would the thrust propel you into the air? (if at all)” The answer (courtesy of Brisco_County_III), as it turns out:
Estimated total volume of farts per day: Call it around a cup, or 250mL since I’m doing the math metric.
Estimated duration of the fart we’re compressing this into: Around two seconds. That’s actually a damn long fart, if we assumed it were shorter you’d get more energy out of it. Estimated size of asshole: We’ll call it 1cm radius.
So let’s start with 40 years’ worth of farts, for the sake of simplicity. That’s 3650 liters of fart (or about 1000 gallons), or 3.65 cubic meters.
So we’re going to jam that lifetime of farts into 2 seconds. Now, I’m going by volume here, not by energy; if I were going by energy, this would be a lot more boring, because it doesn’t add up anywhere near as spectacularly. Regardless, let’s treat this as a rocket problem, where the only major factor is how fast the reaction mass (your fart) is leaving, rather than any resistance of the air to passage of the fart, nothing fancy.
Now, you need to get all of that gas out of your asshole in two seconds, through a 2cm-diameter hole. This is the same as figuring out how long a column of air of 2cm diameter would have to be to contain 3650 liters. That circle has an area of pi cm2, which converts to 0.000314 square meters. You need to get 3.65 cubic meters through that hole in 2 seconds. So… you see where I’m going with this? That gas is going to be shooting out of you real, REAL fast. How fast?
That column of air would have to be 11,618 meters long, which means that it would have to be traveling at 5.8 kilometers per second .
Aside from blowing your asshole apart like a hot dog with an air compressor nozzle stuffed in it, this is a lot of energy. We’ll assume your asshole can take it. This means the total impulse it will transfer to you as it leaves is fucking big. Let’s say you weight 100kg, because it takes a big man for a big fart. How much does this transfer to you? Well, 4.5kg of air, moving at 5.8km/s, will transfer 26,000 Newton-seconds of impulse to you, which divided by your weight…
You will be traveling at 130 meters per second after this fart, or about 300 miles per hour.
How high does that get you? About 1300m in the air. Long story short? Assuming you’re talking about volume, that fart would shoot you a fucking mile into the air.
(Header image from Reddit user gary_mthafkn_oak)