The human body can withstand a set before giving up and dying : fall from second - story windows , years of fevered substance abuse , wolf attacks , etc . We have a fairly good idea of what it ca n’t tolerate , but some style of snuff it in a flash have take in less attention than others , and speed is one of these . We ’ve all seen pictures of people moving at top - speed — but is there a velocity beyond which those blown - back cheeks in reality fly off your face ?
For this week’sGiz Askswe reached out to expert in space locomotion and physiology to see out how tight you’re able to travel before it actually kills you . Technically , it turn out , there ’s no real boundary to that number ; it all depend on the term . Speed can kill you — but it ca n’t do the line alone .
James A. Pawelczyk
Assistant Professor , Kinesiology and Physiology , PennState , who flew aboard the NASA STS-90 Space Shuttle mission as a Payload Specialist
I could be in a re - entering ballistic capsule , and I could be prompt at 25 time the focal ratio of sound . Clearly , that would n’t toss off me — astronauts do that on a regular basis throughout the year . But if I were to stick my psyche out the window , we ’d have an entirely dissimilar story .
If we rephrase the inquiry , then , to “ what is the maximal dynamic pressure a human torso can withstand”—well , I do n’t have a warm number for you , that would have to be calculated , but the consequence becomes that you ca n’t just change by reversal it into a speed , because it depends on the culture medium you ’re move through , which find the dynamic pressing .
Illustration: Jim Cooke (Gizmodo)
If you ’re in the air , that ’s going to dependent on what ALT you ’re at ; if you ’re in pee , it ’s go to be a much slower speed , because the dynamic pressure is run to be greater at the same speed , as it ’s a thicker , more dim metier .
And then there ’s the issue of speedup , which is also an issue of pressure level — the force against the eubstance . Now you ’re trade with how chop-chop you accelerate . And before it kill you , that ’s going to be a social occasion of : what is the acceleration , and what is the rate at which you ’re receive it ? We ’ve seen mankind experience , for a very brief period of time , as much as 40 Gs quickening , which is 40 times the force of gravitation — and they ’ve survived .
Colonel John Stapp ’s amazing self - experimentation in the 1960s on skyrocket sleds are deserving noting here . He was not only the military police detective in charge of those experiments , but the discipline as well .
They were project to test ejection seat engineering , at a time when the US was rise supersonic aircraft . The interrogation they wanted to answer was : what ’s a safe speed that a human can eject from an aircraft ? It calculate on altitude , but also on how rapidly we accelerate away from the aircraft . And indeed we did see human survival at level as corking as 40 Gs . Having said that , if I were to put an unprotected human being on a centrifuge , and to put them even as mellow as 5 or 6 Gs , and were I to then rotate them unendingly , to the point in time that they were to lose cognizance , then continue to rotate them , they would die , ultimately . If I were to take a person and suspend them at one time the force of gravity , and take into account them to hang there in a harness until they elapse out , and continued to leave them there — yes , you could make dying that elbow room , but that would take a issue of many minutes or hours .
John Linder
Professor , Physics and Astronomy , The College of Wooster
It ’s not the speed that kills you , it ’s the speedup , and speeds are relative .
Fifty years ago , Apollo astronauts extend to almost 25 thousand mile per hour comparative to Earth when falling back from the Sun Myung Moon . But just standing on Earth ’s equator , you travel about a thousand mil per minute relative to Earth ’s poles , due to Earth ’s twisting , and 67 thousand mile per hour relative to the sun , due to Earth ’s orbit , and so on .
You could practice mid - sized black trap to gravitationally slingshot crew space vehicle to near wakeful speed , but you ’d need infinite vigor to accelerate a mass to light speeding itself . That 670 - million - miles - per - time of day speed limit is changeless , and tension between the relative pep pill of Newton ’s mechanics and the invariant light pep pill of Maxwell ’s electromagnetism is excellently reconcile by Einstein ’s modification of mechanics near light speed .
Jonathan Clark
Associate Professor of Neurology and Space Medicine at Baylor College of Medicine , who work at NASA from 1997 to 2005 and was a six - clip Space Shuttle work party surgeon
fastness is just a aloofness - per - fourth dimension - unit meter , so the constraints to speed are really dependent on other environmental factors .
The velocity is n’t the issue as much as the change in speed , which is speedup . When you go to space , you have to get enough speed to get out of Earth ’s gravity airfield . To get to depressed orbit , spaceman have to get to 17,500 miles per hr , and to do that they have to change their velocity . They launch such that they ’re taking the gravity from the front of their chest to the back of their chest — that ’s called the G direction . Typically , the beneficial fashion to tolerate it is going from front to back , which is why astronauts launch on a lounge , sit down .
The other constraint of speed is in the atmosphere . John Paul Stapp , when he did hissled run , father up to 46 , 47 Gs , and he was probably going close to 5 or 600 miles an time of day . If you count at his nerve , you would see that it was being blown and heavily distorted , and that his hands were in reality keep on his lap so they would n’t flail around . Speed go through an atmosphere causes what ’s called flowing flail , and that can drink down you . When you ’re in outer space you may go as fast as you want — but you need the protection of a fomite , or a pressure wooing , to keep you from the exposure to the vacuum of space .
We know that humanity have gone 25,000 miles per hr extend to the moon — the speed itself is not an issue , it was in the main the acceleration to get out of the Earth ’s atmosphere that they had to endure .
Once they ’re on their room and speeding up , there ’s no constraints to speed . We ’ll eventually mail humans to mars and they ’ll be go 35,000 miles per hour .
The two programs I was involved with , the Red Bull Stratus and the space dive — the goal was for a man without a vehicle to break the focal ratio of audio , and that was execute because they wear a pressure courting . The reason they did n’t have aerodynamic flail issues was that there ’s very little atmosphere above a hundred thousand foot
you could come upon very gamy speeds — at least ultrasonic ones — as long as you ’re protected , or ( if you ’re free falling from space ) you ’re at an atmospheric concentration that ’s not move to make that flail to uprise .
Do you have a combustion inquiry for Giz Asks ? Email us at[email protected ] .
BiologyGiz AsksScience
Daily Newsletter
Get the best technical school , science , and culture news in your inbox daily .
intelligence from the future , delivered to your nowadays .
You May Also Like
