All right, I'm whipping up a speedster character. Figured if she's going to run real quick she'll have to think very quickly so that she doesn't end up as a smear against a wall. So, I did some calculations to determine how fast she'll need to think in order to run and I came up with a decent conversion. Anything that can be done normally in a single day, she can do in a second. In essence, she perceives a single second as 24 hours. It's here that I have a problem. Given the radically different perception of time, how would this affect the speedster's ability to function outside of costume?

*In responce to some comments below:

No, she ages normally she just perceives time differently.

I'm handwaving majority of physics and biology in relationship to the actual movement, and focusing on a more psychological angle.

  • $\begingroup$ Comments are not for extended discussion; this conversation has been moved to chat. $\endgroup$
    – L.Dutch
    Commented Sep 1, 2020 at 6:17

13 Answers 13


Yeah, this character might have never actually spoken to another human, depending when the superpower is activated. They are just too slow to meaningful interest with. Heck, most people probably couldn't interact with her because standing still long enough to be registered by the human eye would require a twelve hour nap on her part.

If anything, areas which this character protects would basically appear haunted. A crazy blur is always happening, food and water constantly goes missing, objects move around, and beneficial things (people getting saves, bullets vanishing from criminals guns, homeless people suddenly acquire coats) happen almost at random. Unless your character leaves notes, it would take people a while to figure out what's happening.

If her metabolism is three meals a second, she would be able to eat an entire grocery store in a month. And I hope she has good planning skills, cause otherwise she wouldn't be able to actually cook anything. If she can manage having a house with that kind of diet, she might appreciate hummingbirds, who STILL are crazy slow compared to her.

That all sounds like an awesome concept to me, but there is a problem that does need to be solved for this plot to work:

The average person lives for 27.000-ish days. That means your character's entire lifespan would be 450 minutes, or seven and a half hours. That's a heck of a short superhero career. But hey, it could be an absolutely world changing glorious seven hours.

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    $\begingroup$ "...world changing glorious seven hours" * i.imgur.com/XtNgN61.gif $\endgroup$
    – Martijn
    Commented May 16, 2018 at 13:15
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    $\begingroup$ The average person lives for 27.000-ish days. That means your character's entire lifespan would be 450 minutes, or seven and a half hours. It's the other way around. Every 450 minutes, this character would mentally have aged an entire human's cognitive lifespan. I see no mention of OP assuming that she "burns through" life at the same increased rate, so it seems unwarranted to assume so. If you're really going to assume the same increased physical speed for her entire metabolism, then the speed of breathing alone would be already be an issue of physical limitations. $\endgroup$
    – Flater
    Commented May 16, 2018 at 14:15
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    $\begingroup$ Chances are communication via sound is not even possible. Even speaking with a frequency at the lower end of the spectrum for male voices (100Hz) would not be audible to humans (8640 kHz >> 20 kHz). Lacking special ears she won't be able to hear other people either: Upper end of the voice spectrum for humans 3kHz dividing by 86400 yields < 0.35 Hz << 20 Hz... $\endgroup$
    – fabian
    Commented May 16, 2018 at 14:50
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    $\begingroup$ @Martijn Maybe they didn't start their superhero career until they were (subjectively) 5 years old. That's still a pretty early start for a world-saving career but it would consume about 30 minutes. $\endgroup$ Commented May 16, 2018 at 15:17
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    $\begingroup$ And if by some chance she did stand still long enough to be noticed by someone, they might just notice her aging, furthering the "haunted" vibe. $\endgroup$ Commented May 16, 2018 at 16:07

...how would this affect the speedster's ability to function outside of costume?

Supposing she gets the power out of the blue someday, she will crack (mentally) within under a minute.

For starters, the world will be a much darker place. Her flicker rate being 86400 faster than ours, she will have only $\frac{1}{86400}$ of the ambient light available for each frame of her visual cortex processing. On the other hand, if her flicker rate is not different from ours, she is as blind as a jellyfish.

Also imagine going to the bathroom. She will have to go at least once in the first couple seconds. As she does number two, the... It falls 86400x slower. She will have to pull it out with her hands or wait what would seem like a few days. And when she tries to clean herself with toilet paper, the friction of cellulosis being rubbed against human skin at hypersonic speed will literally set her ass on fire.

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    $\begingroup$ Imagine going to a public bathroom and having to purposely slow your poop speed to a near pause so your not shooting pieces of crap faster than the speed of sound $\endgroup$
    – Shadowzee
    Commented May 16, 2018 at 4:02
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    $\begingroup$ Surely going to the bathroom is something that would occur once every day in the speedster's time, or once every 86,400 days in normal time. Not once per day in normal time and once every second in the speedster's time. Annoying and gross still, but if you gained the powers suddenly the instant you finished on the throne, it would be the year 2250 before it came up. $\endgroup$
    – Scott
    Commented May 16, 2018 at 6:26
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    $\begingroup$ @Scott you've got your conversion backwards, I think. $\endgroup$
    – Soron
    Commented May 16, 2018 at 7:10
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    $\begingroup$ The sun is 400,000x brighter than the full moon. At 90,000x dimmer, you'd still be able to read text under the light of the sun. (our sensitivity to light is logarithmic) $\endgroup$
    – Yakk
    Commented May 18, 2018 at 18:32

Anything that can be done normally in a single day, she can do in a second.

You're talking about a speed-up factor of 86,400 times faster.

An average human walks at about 5 km/hr.

Your speedster walks at 432,000 km/hr.

The speed of sound in air is about $\frac 1 {400}$th that speed.

How fast is "realistic" ?

Well you'll need to drop those numbers down a lot.

Energy requirements to travel fast are proportional to the square of velocity. So traveling 86,400 times faster requires over 7 Billion times more energy to reach that velocity.

That's not remotely realistic.

Also keep in mind that you're moving through air and as you start approaching the speed of sound it will become hard to shift out of the way. The technical term you need to be aware of is compressibility.

The practical limit for a speedster is probably in the region of sub-sonic, maybe in the 500 km/hr region. Going super-sonic is doable, but your speedster will be leaving sonic booms in their wake and rapidly draw attention from angry mobs and the authorities.

My Brain Hurts.

Alas even that 500 km/hr may be impractical.

You've a brain and nervous system that operates at electrochemical speeds, which is regrettably slow. This page from Wikipedia on Nerve Conduction Velocity tells us that the faster speed would be about $120$ m/s or about $430$ km/hr.

Remember those speed limits posted on roads and all that stuff your driver instructor told you about vehicle separation ? That's for a good reason : people can't react that quickly. The limit is how your brain and nervous system works. Your speedster racing through the streets at 500 km/hr can't (if they have a human nervous system) react fast enough to avoid collisions.

So your speedster is really not human at all - no human brain or nervous system, no human anatomy because that can't support such rapid movement.

Now humans do drive cars and other vehicles fast, but keep in mind the context that is done is. Driving at 100 km/hr on the motorway is different from trying that on the street - the distances between potential problems is larger giving you more reaction time. Likewise other forms of high speed transport.

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    $\begingroup$ "realistic" is a important point, it's not about how she can achieve that speed but how you make anything work around her. Imagine trying to open door, either you walk normaly to the door and stop at 5 cm and look at the door shatter around you. Or you spend the next 30 hour trying to leave your house without destroying it. It's ok, take this glass of watter.. oh shit! $\endgroup$ Commented May 16, 2018 at 8:55
  • $\begingroup$ @DragandDrop I think this comes down to the OP's view of how much time they spend at this accelerated pace. But "reality check" is not a great idea anyway when we're talking about any superheros, IMO. $\endgroup$ Commented May 16, 2018 at 9:57
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    $\begingroup$ Regarding reaction speed: Isn't that entirely the point of the question? If we assume the speedster is capable at moving those speeds, it's no less reasonable to assume they process faster, too. $\endgroup$
    – Bobson
    Commented May 16, 2018 at 15:51
  • $\begingroup$ @Bobson It's a "reality check " tag so we must work with reality and brains don't function faster just because we go faster. They're governed by electrochemical activity and it's speed is what it is. What I'm drawing attention to is that if we stick with a reality-check then this speedster won't be biologically human in any way except may rough shape. Every aspect of the being would need to be quite different. Until the OP responds to comments we're stuck with the question asked. $\endgroup$ Commented May 16, 2018 at 20:10

Ignoring the physics and just assuming you literally fast forwarded your character, your character won't be able to function in real life. Your hero is operating 86400 times faster than a normal person or everything is 86400 times slower. Nothing would appear to move to her and her memory and understanding of speech and sounds would be vastly different and she would basically need a perfect memory to be able to say hello at a normal persons speed, let alone have a decent conversation.

You really need to scale perception and thought speed along with movement speed, otherwise your character won't be able to operate properly because they interactions will take place over what is effectively a life time.

For a comparison here is the entire bee movie, 2 times as fast but it speeds up by 15% everytime the word bee is mentioned its a 1.5 Hours movie in 5 minutes, Roughly 18x faster. Still 4800 slower than how fast your hero perceives things https://www.youtube.com/watch?v=JMG1Nl7uWko

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    $\begingroup$ "For a comparison here is the entire bee movie" usually what I expect to hear in a discussion about physics and human biology $\endgroup$
    – Gramatik
    Commented May 17, 2018 at 19:59
  • $\begingroup$ Now do the bee movie where it gets 15% slower every time someone mentions bee. $\endgroup$
    – Yakk
    Commented May 18, 2018 at 18:35

If you want to focus more on the psychology of having the speed power, your speedster should be able to use the power (both movement/speed perception) in a similar way that you use your muscles.

Anything that can be done normally in a single day, she can do in a second.

As your speedster is activating powers 0(human)-100%(86400x), just slow down time by that much. You don't need to slam your fingers as hard as you possibly can while typing. I don't see any reason why this power would be treated any differently than using a muscle. Now that is not to say that using the speed muscle exerts effort (my heart is pumping blood and that costs me no effort). With that being said, some psychological effects of such a power would be...

  1. You always win!: Your speedster can play almost any skill game and either be amazing (playing FPS/ any traditional sport/martial arts) or cheat to victory (playing poker and peeking at opponents hands/move an opponents darts midair if playing darts/get the answers to test by running around a room) etc... This might contribute to confidence in many social events such as bars, carnivals, street pickup games allowing your speedster to shine in many areas while putting in a lot less effort than normal folk.

  2. Ring of Gyges: There is an argument to be made that your speedster might have to deal with a lot of moral issues. Assuming your speedster is the only one she can steal, kill, commit petty acts such as putting individuals in awkward position (trip/draw on someone's face/undress a coworker at work until they are fired) without impunity. She couldn't even be perceived. Having the speed ability is a burden or a vice.

  3. Dealing with the cost of time: Your speedster can interact with many people face to face with basically no lag time in terms of getting to an individual. Your speedster has also had a life where most of the time she can ask herself "Oh if I want X task to be done, I'll just do it really quickly and I still have my whole day ahead of me". Cleaning/traveling/maintenance/possibly her job can all be optimized by going faster. It might be frustrating that hanging out with people consumes so much of her time when she can be doing other things. Consider going out on a date to the movies. She is probably accustomed to speeding up all movies and then perceives everything normally at relative speed so she can watch an entire movie in seconds. NOW when she goes on a date to the movies it's a huge time sink. In this way the power makes her very selective of the people/places/events she interacts with and perhaps even a bit impatient. Even hanging out with someone that speaks to slow can be a huge burden of time on the speedster.
  4. Anxiety/Guilt: Just because she can think faster does not make her think better. There may be some circumstances where she sees a problem, but is helpless to solve it. Panicking while the world is in slow motion. Worse yet, a circumstance where she could have solved the problem but only thought of the way in hindsight. For instance, if in the speedster's past a helicopter fell nearby her and only after it fell to the ground exploding she realizes she could have spun her hands real fast and lowered the helicopter to the ground slowly. Or perhaps some sort of Gwen Stacy situation
  5. Food: OK so here's how she should eat. She will typically eat a cheeseburger when she is hungry 3 * a day (cheeseburger is example, substitute for meals). So that is 1 cheeseburger every 28800 seconds. Every day she goes into super speed mode, run the following calculation (keep adding while doing it per day)=> **(relative seconds spent in speed * power level (0%-100%) * 86400) ** Whenever she breaks 28800 that's another cheeseburger she needs to eat. example 60 seconds * 100% power * 86400 = 5184000 => 5184000/28800 = 180 cheeseburgers consumed that day. She may need to eat a lot depending on power usage. There could be some social pressure to not eat around others. Your speedster could be seen to pig out all the time yet never gain any weight. Might cause suspicion rumors or contempt to arise.
  6. Self taught: Literally no one can keep up with your speedster. Even if the person knows a wealth of knowledge, the best thing a teacher can do is to just throw books at your speedster. Your speedster probably knows an insane amount of information at subjects she is interested in. The rate of speed that she can acquire info will quickly allow her to become a specialist in any field she desires.

Everyone is assuming the speed up is reliant on normal physics. But this speed up is impossible by our understanding of how normal physics works, so why does it have to act by those rules?

First of all, assuming you are not worried about her ability to physically survive with the speed up and only considering the mental, you can solve the interaction problem by changing the power a bit. Rather than perceiving as we do at a massively increased rate, the character could simply be able to react to stimuli at that rate while still have regular thoughts or perception. Then she can interact with people like anyone else, but move as fast as she needs to when the time comes.

Secondly, if you are worried about making the speed increase operate "believably" in regards to bodily needs and such, that's probably not possible. Speed increase is such a crazy thing that I'm actually kind of a fan of how the Flash does it. Just saying "speed force" if anything sounds impossible and being done with it. Otherwise, you have to come with ways that the power affects so so many things about the speed and its effect on the environment. Trying to consider super speed as if it was truly the same as moving at that speed makes it less like a super power and mainly just deadly and destructive, either to the user or those around them.

  • $\begingroup$ Welcome to WorldBuilding, Kadill! If you have a moment please take the tour and visit the help center to learn more about the site. You may also find Worldbuilding Meta and The Sandbox (both of which require 5 rep to post on) useful. Have fun! $\endgroup$ Commented May 16, 2018 at 13:08

If it really was permanent then I imagine she'd be bored most of the time. Originally I thought she might act like a disinterested teen that was bored with everything, but the 1 day to 1 second ratio is so extreme that even this would be hard to pull off.

Having studied the current unchanging environment for the equivalent of several weeks without moving (30 seconds our time), she might see something begin to happen.

I think she'd need to be able to go into a deep meditative state for 99% of each millisecond, to avoid death by boredom, waking to keep track of what reality was doing. She would have the time to be deeply spiritual, if that is her thing. Or develop fancy maths to solve in her head and be a super Einstein.

Of course, she'd never drop anything, and would always know where to be at the right time, which could appear freaky to her friends even if she hid the super power. Listening to conversation would be difficult as she'd literally be sleeping for weeks during each sentence spoken. Speaking would be even harder. Imagine forming individual words over a period of days.

There are some problems to overcome. How does she breathe? If I breathe once per two seconds, does she breathe at the same rate even though it appears like once every 2 days to her? How about when she is being fast, does the breathing speed up then to match her metabolism?

If in fact her metabolism does change rate to match her speed then maybe when at slow speed she perceives reality at the same rate that we do and your problem is gone?


Why do they need to think faster?

I'm sure we've all had the experience of seeing something and simply being unable to move fast enough to react. If we could move that bit faster, we could get to that ball, or catch the plate before it falls, or whatever. We already know where it's going, we just can't get there. If your speedster is running down a straight road, they can go the same speed as a car.

More interestingly though, some regular humans are already able to slow down their experience of the world to react to it. http://www.bbc.co.uk/news/science-environment-19477623

I wouldn't really believe this, except that I have personally experienced this once, and I'm far from an elite athlete. This was a pedal bike accident, where a brake lever fell off and jammed my front wheel. In the time for a half rotation of the bike wheel at 20mph and the subsequent quarter-rotation of me and the bike, I had time to: work out what had come off, what had happened to it, analyse my options, feel the lever hit the frame, realise I was going to go over the handlebars, adjust my foot positions to allow a clean launch out of the toe clips, and adjust my arm positions to ensure I would travel on a breakfall trajectory to roll off a shoulder and protect my head. The time it takes you to read that out loud is how much time it felt like I had. I've just done the sums, and 3/4 of a revolution with a 2cm tyre on a 27" wheel at 20mph is 0.18s. I reckon I must have experienced something between a 20x to 50x subjective processing speed-up.

So do your speedsters need extra thinking power? Not really. What I did once, what John McEnroe does as a matter of course, they simply have switched on all the time.


I love ripping on speedsters for their outrageous abuse of physics, but in this case, there may be an interesting alternative.

It appears that you assumed that everything the speedster does got scaled up to higher rates of speed. However, what if that isn't so? What if the core of their being moves slow, and it's only the extreme peripheries that are fast. Such a speedster would see a greater dynamic range, but would still think on human scales, so would be able to relate to you or I.

There's plenty of biology to back this up. If you look at how the body works, from local reactions to reflexes to pattern generation networks all the way up to conscious thought, we already exhibit a tremendous amount of "fast" processing that happens at a subconscious level. Nobody says a speedster has to process conscious thought quicker. It might be more desirable to be able to relate to you or I.

Myself, I find the pattern to be rather interesting. Such a speedster would have to spend a tremendous amount of time practicing their art, ensuring that once they move up to high speeds, their high-speed-processing parts of their mind are capable of handling any surprises that may come their way, for the slower human-scale parts won't have time to react. Such a speedster might choose to be ultra-moral, because of just how much they can do wrong before their conscious brain catches up and tries to undo the mistakes.

Such a speedster would be able to function completely normally within society, because the core of their mind was still operating at human speeds. They might have some trouble hiding the fact that they are a speedster, if they instinctively do something like catch all of the food when someone gets tripped in the cafeteria and their tray of food goes flying. But after that instinctive save, they'd still want to say "hi" just like everyone else, because the slow part that really matters to them just wants to be part of their community.


Comics writer Peter David described the psychological aspect with the Marvel Comics speedster Quicksilver:

"Have you ever had a day where you are at the ATM and you are in a hurry because you're running late but the person in front of you doesn't know how to use the ATM and they're taking forever? Now imagine what it must be like to spend every day surrounded by people who don't know how to use the ATM."



Our own natural adrenal response "slows time" or appears to. So, if your speedster is only a speedster when the adrenaline kicks in, then their perceptions of normal time / speed things are probably no different from our own so far as normal, everyday stuff.

If the speedster is always a speedster, then everything else is moving in super slow-motion for them. Waiting on a person to complete a sentence - 10 seconds or so for us - is waiting DAYS for the speedster.

It would probably display as the worst case of ADD ever, the speedster constantly doing thousands of little fidgety things while waiting on the molasses-like rate of the non-speedster's words. It could even make them completely unable to communicate with others; they can't slow down their speech enough (literally spending what, to them, is a day of time to say one word) and similarly don't have patience to wait "days" for that sentence to be completed.

  • $\begingroup$ This happened to The Flash once. He was sitting in a theater, watching a movie in the normal way, when he was shot from behind. The bullet contacted his skin instinctively shifted him into super-speed mode, and he used his powers to deal with the situation. $\endgroup$ Commented May 18, 2018 at 22:22

If the speedster cannot turn off his abilities temporarily, he will probably never be able to interact with normal human beings. This would probably drive him mad within seconds (from the outside world). Solitary confinement is one of the worst things we can do to a prisoner.

If he is moving this fast, we will not be able to perceive light in the visual spectrum, but rather shifted one way or the other (I'm not sure which way).

At his speed, he will be moving so fast that a distant obstacle that is out of his range of vision will be too close for even him to avoid.

The guy would never get to enjoy a movie, because all he'd see are pictures that look similar to each other switching at long intervals. Considering the quality of most movies, not a loss.

Modern technology would be ruined by him. Imagine him trying to use a keyboard. The speed of his fingers would break it.

But the big thing is that he would live in a world of unmoving objects. The speed to sound is basically the speed that air can't get out of the way of something (hence the shock wave). He would suffocate in open air because he couldn't move the air in and out of his lungs to support himself. He would go to open a door, and the momentum of the door would be too powerful for him to push it open. A mosquito flying innocently along for him to run into would kill him.

And once he got up to speed, how would he stop? If he suddenly stopped, where would all his momentum go?

One second to 24 hours is much to large a ratio. Even the Flash doesn't move that fast most of the time, and he is one of the most overpowered characters in comic books.

One thing I've considered I call the Flash Paradox. After a battle, the Flash immediately cleans up the scene. From the point of view of the other characters, this is just something that takes no time. On the other hand, the Flash is subjectively doing all this work, so for him it might have taken days (or longer, some of the cleanup that he does are huge projects).


maybe her Source of quickness or speed can be some kind of energy, which will accelerate her mind and body while being used or build kind of field in which time would be warped in order to be accelerated. In that way she would be able to interact with other human beings on a normal level.

If her body is the source of power, her suit might extent the power to her immediate surrounding in order to move through air without trouble.

  • $\begingroup$ Hello HangryDino, and welcome to Worldbuilding. This looks like the core of a good answer, but maybe you could expand on how this "energy" would work. Please visit the help center and take the tour to learn more about how the site works. $\endgroup$
    – Gryphon
    Commented May 17, 2018 at 14:11
  • $\begingroup$ Hello Gryphon, thank you for advice, I will gladly take it. $\endgroup$
    – HangryDino
    Commented May 17, 2018 at 14:13

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