In Invincible (The Flash 2014 S02E22), Caitlin hallucinates Zoom appearing in front of her. I think it is a hallucination, but I wonder: Can a speedster move fast enough that they can remain unnoticed by everyone in a room, except select people?

I see several problems:

  • Wind
  • Sound
  • The crackling/sparks from Speed Force lightning

Of course, it's the speed of the speedster that should cause the invisibility, not the conditions in the room. The Flash crouching in a corner behind a flower pot in a poorly-lit auditorium with just a janitor sweeping the floor doesn't count.

I don't think the Flash in the current TV show has shown this ability (or any other speedster in that show), or that anybody in that show has enough control over air and the Speed Force discharges to be able to do so. If one has, it would be great, but if not, an example from any of the DC speedsters would do.

  • 3
    Just what was The Flash doing hiding in that poorly light auditorium with the janitor?
    – Xantec
    May 19, 2016 at 21:17
  • 1
    Unfortunately, I didn't notice him then. :D
    – muru
    May 19, 2016 at 21:18
  • Human eyes have a refresh rate of approximately 60 fps. Anything that can move in and out of the line of sight within that time is unnoticeable.
    – user40790
    May 19, 2016 at 21:23
  • 2
    @Axelrod sure, but there's wind. A lot of scenes involve people reacting to the wind from a hero moving too fast, or to objects moving due to the wind (paper, for example).
    – muru
    May 19, 2016 at 21:24
  • As speed increases, air caught by a body increases. Wind should always be a factor.
    – user40790
    May 19, 2016 at 21:26

4 Answers 4


It depends on whether you are watching the televised Flash or the comic Flash to determine the special effects of the Flash's Speed Force-derived abilities. Each has different requirements based on the media and as such will appear differently.

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In the Televised Series

  • In the modern Flash depiction, he is shown having the ability to move at speeds beyond human visual awareness. He can appear and disappear in the blink of an eye. Timed properly, he can move past someone and they never know he was there.

  • At his top speeds, no one will notice him except by the very limited atmospheric effects he creates as a side effect of his speed. I say limited because if true physics were in action, he would make much more of a physical disturbance.

  • Given real world physics, the Flash should have quite the atmospheric effect, particularly when he reaches the speed of sound, but thanks to the physics distortion built into the Speed Force, he does not generate the powerful bow shock and sonic disturbances associated with his rate of speed. Nor does he disturb the air around him at anywhere near the levels he should.

  • The question says can he move without being seen? Yes. We have seen him move without generating any special effects. Normally the Flash does not generate the lightning effects unless he wants to. We know he can control their visibility because he uses his lightning to obscure the vision of two law breakers (when he had lost his powers and was using holograms to simulate the Flash still being active.)

Zoom, on the other hand does not suppress his powers, using the blue lightning around him as a sign of his power and his greater speed to intimidate others.

Can he move through a scene without being seen or noticed? It should be possible, otherwise scenes, such as the episode Invincible, where he is talking to his boss as the Flash, zips out and then suddenly reappears as Barry (without the corresponding swooshing and lightning) would not be possible. Strangely enough, most of the time it is the leaving of the scene where papers fly about, not the arrivals. Both should have the same amount of atmospheric disturbance.

  • Because television is a visual medium, the tell-tale swooshing sound effect, the yellow lightning and the flying papers are all signs that the Flash has entered or left the scene. This is done for the viewer visual edification, showing how fast the Flash appears to be; a form of eye candy for the viewer.

  • This eye candy as I call it can be traced back to the comic depictions made famous by Carmine Infantimo who is the iconic artist who produced the most dynamic depictions of the Flash using his powers during the Silver Age.

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In the Comics

In the comics, the Flash has show he has complete control of his atomic structure. So much so he can manipulate his molecules for a number of feats the televised Flash is still learning to do.

  • He can vibrate and disassociate his molecular structure such that the electromagnetic shells around his atoms no longer interact with normal matter. He is out of phase and can pass through ordinary matter with precise control.

  • He is also capable of vibrating his molecules so that light passes completely through him, rendering him invisible to normal senses. Superhuman senses or other speedsters who may have familiarity with this type of vibration-manipulation based invisibility can become aware of him.

  • Most incarnations of the Flash and other speedsters have far greater control over their Speed Force interactions such that they do not disturb anything in the environment, unless they make a conscious effort to do so. This is how Barry can use sonic booms as a weapon, either as superfast finger-pops or by moving faster than sound and targeting the bow-shockwave he generates to stun opponents.

  • The Flash has had these powers most of his career with his abilities growing more powerful over time. At one point the fastest he could move was the speed of light. (Or so said the Handbook of the DC Universe.)

enter image description here

  • 1
    Comprehensive. About the Invincible scene you talk of, though, I assumed the police just ignore any effects of the Flash's movements as Flash visiting (business as usual) (and Barry is shown as normally jogging up from somewhere).
    – muru
    May 20, 2016 at 0:45
  • From where did he magically appear? He had to slow down enough to be seen, and there were no environmental effects showing his slowing down enough to be noticed AS Barry Allen. His return should have at least some degree of disturbance UNLESS he is able to control it completely. May 20, 2016 at 1:04
  • I'm not sure of the layout of the police station, but there could be a closet or a bathroom on that side of the partition. So he would been seen rushing out from that as Barry Allen. Nobody bats an eye.
    – muru
    May 20, 2016 at 1:07

If the question is, "Can a speedster move through a room unnoticed", then yes. We've seen plenty of cases where speedsters moved through rooms fast enough not to be noticed. As you mention, they have to be careful not to do anything that would get them noticed, such as bumping into things, or creating a draft, but if they are practiced enough they can do it.

But if the question is "Can a speedster move through a room and be selectively noticed?", then probably not. A speedster can go unnoticed by moving faster than the human eye can detect their presence. Think of this similar to how TV works - if the speedster is only in the line of sight "between frames" (e.g. less than about 1/50th of a second or so) then the brain will most likely edit them out as a visual anomaly. But in order to be seen by anyone, they have to slow down long enough for the eye to pick them up -- in which case anyone looking will see them. If they want to be noticed only by specific people, they need to do more than just use their speed. They also need to selectively slow down in places and times when only one person is actually looking -- not much different from someone sneaking around at normal speed.

  • So there are examples where speedsters move fast enough to be unnoticed and managed to control the air around them to prevent gusts? I don't read comic books a lot, so can you suggest an example?
    – muru
    May 19, 2016 at 23:16
  • I thought there were when I wrote the answer, even in the show, but I can't think of one offhand. I will look for a good example.
    – KutuluMike
    May 19, 2016 at 23:17

In response to the flash moving in a crowd unseen, another prime example would be during the current TV version when Barry Allen gets an alert of a metahuman while at jitters. The coffee shop is usually crowded but he doesn't think twice about making a sudden move to take down a criminal and if you notice nobody ever looks up or acknowledges that the flash was present, because they have no knowledge of his presence. Also on behalf of savitar notice that when he runs he immediately enters the speed force which in turn eliminates all side effects e.g. drafts, lightning sound. Once Barry reaches his full potential it is very likely that when he runs he's not even in the same realm as us because of the frequency he moves leaving him undetected.


Yes. In the show, Barry does this to Iris and walks around her while she is "frozen" in timea and she had no idea that it happened.

  • When answering please take the time to 1. only answer if you know and the answer and 2. include evidence to back your answer up. This could be improved with the season/episode number, and a YouTube clip showing it happening. You can edit your answer to include the evidence.
    – TheLethalCarrot
    Aug 9, 2020 at 9:39
  • So did any non-speedster know he was there? If no one did, then this doesn't answer the question.
    – muru
    Aug 9, 2020 at 12:53

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