How fast does a human sized object need to move so I won’t see it?

[gen66]

Summary:: How fast does a human sized object(or a human) need move so I won’t be able to see it at all if it passes right next to me?

Im trying to figure out something in regards to the Flash movies/Flash series but I’m super bad at calculations and math :(
Do you think that mach 2 speed(2469km per hour) is enough for me to not see at all a human sized object passing right next to me?

 

[Ibix]

The Flash travels at the speed of plot, I'm afraid. He, along with many fictional characters, exists in a universe that does not have a coherent physical law because the writers don't have a coherent physical model in mind when writing.

 

[anorlunda]

I thought the question was about the Flash video format.

 

[hutchphd]

Do you think that mach 2 speed(2469km per hour) is enough for me to not see at all a human sized object passing right next to me?

What about the supersonic shock wave? That might get your attention. As previously mentioned, fantasy is fantasy.

 

[berkeman]

Do you think that mach 2 speed(2469km per hour) is enough for me to not see at all a human sized object passing right next to me?

That should work, since you will be knocked unconscious by the shock wave, so you won't be seeing anything until you (hopefully) wake up in the ICU...

 

[hutchphd]

beat you...

 

[gen66]

Ah, still no serious answer :( Ok, please ignore the shockwave the object will create and let's focus only on visibility, how fast it would need to move to be undetectable by humans eyes, e.g. distance 1 to 10 meters away from the eyes.

 

[A.T.]

Do you think that mach 2 speed(2469km per hour) is enough for me to not see at all a human sized object passing right next to me?

Depends the viewing angle, light conditions, and your concentration. I sometimes don't notice people passing me at normal walking speeds.

 

[gen66]

Depends the viewing angle, light conditions, and your concentration. I sometimes don't notice people passing me at normal walking speeds.

If I give you all these, would you try to answer the question or you would just ask for more specific details and variables?
Just a normal viewing angle right in front of you, at eye height or a little bit lower. Light is bright day at 13pm, no clouds. Concentration level is medium, you're just gazing in front of you, it's enough concentration to see an incoming fly/insect in proximity.

 

[A.T.]

Just a normal viewing angle right in front of you, ...

The key is: Are you looking exactly perpendicular to the object's path, or at some oblique angle? That affects how long the object stays in your field of view, and its angular speed across your field of view. This is more a biology question about human perception limits, rather than about physics.

 

[pinball1970]

Ah, still no serious answer :( Ok, please ignore the shockwave the object will create and let's focus only on visibility, how fast it would need to move to be undetectable by humans eyes, e.g. distance 1 to 10 meters away from the eyes.

You may see it but your brain would probably be unable to process the data.
Subliminal cuts in movies are in front of your eyes for a fraction of a second but tend not to notice them.

 

[gen66]

The key is: Are you looking exactly perpendicular to the object's path, or at some oblique angle? That affects how long the object stays in your field of view, and its angular speed across your field of view. This is more a biology question about human perception limits, rather than about physics.

It's perpendicular, question is about physics, it's definitely not a biology question. I'm asking about speed, the answer contains speed, where is the biology in speed? No matter what information you get, you just won't answer the question. Just say it's a difficult one and you don't know and that's it.

 

[gen66]

You may see it but your brain would probably be unable to process the data.
Subliminal cuts in movies are in front of your eyes for a fraction of a second but tend not to notice them.

thank you for the answer. It doesn't contain any numbers unfortunately. Question was about the necessary speed needed.

 

[hutchphd]

47

 

[gen66]

47

aha, if there were less trolls around these forums It would be amazing :)

 

[hutchphd]

This answer has the same level of specificity as the question. You asked for a meaningless number, and I gave you one.

 

[A.T.]

it's definitely not a biology question.

You are asking what a human can see. This is determined by human biology.

 

[berkeman]

aha, if there were less trolls around these forums It would be amazing :)

There's an old saying, "It takes one to know one."

Thread is done.