If a person passes near me at Mach 2 speed would I see him?

In summary, the conversation discusses the concept of seeing a person moving at Mach2 (1522 mph/h, 2469.6 km/h) and the factors that affect visibility at such high speeds. The answer to whether a person would be visible at this speed depends on the rate at which the visual cortex of the brain processes signals from the optic nerves, the size of the object, and the individual's ability to notice supersonic objects. It is impossible to see a bullet in flight, but an aircraft traveling at the same speed would be visible. The conversation also brings up the scenario of a person stealing a wallet at Mach2 speed, which would only be visible for a fraction of a second due to the speed involved.
  • #1
genu6
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If a person is moving at Mach2 (1522 mph/h , 2469.6 km/h) and he passes close by me in a radius of 2-3 meters, would I be able to see him? Please for the sake of the question, ignore sound effects, sound barrier details etc. I'm only interested in the speed and the visual part. IF yes, what exactly am I going to see? A short term blur with very little details or more like everything?

Also, if I see him at that speed, what speed do you think he's going to need to be moving at in order for me not to see him at all? (e.g. bullet)
 
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  • #2
The answer to this will be mostly determined by the rate at which the visual cortex of the brain is able process signals incoming from the optic nerves, and the speed + amount (bandwidth?), of signals that the optic nerves themselves are capable of.
I would think this could vary between different individuals, (well maybe not the signal transmission rate).
The size of the passing object makes a difference too.
It is as you say impossible to see a bullet in flight, but an aircraft traveling at the same speed would be visible.

My guess is that you would see an object the size of a person approaching, but wouldn't really register much detail at the stage of it passing by.
Our visual systems have not evolved in an environment whereby there would be an advantage in noticing supersonic objects.
However they DID evolve in an environment whereby minute movements of objects are readily seen, and that certainly would have an advantage.
 
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  • #3
Thank you, that's very informative! :)

Imagine however you are standing at the beginning of a 50 meter long street, the person travels 50 meters, steals your wallet and goes back 50 meters to exit the street, this is all happening at Mach 2, what do you think you would you see in this scenario?
 
  • #4
Mach 2 is 686 meters per second, I think 50 meters would take 7.28 centiseconds. You would observe a total of 15-16 centiseconds. Jeez, I just realized how fast that is. Guess I answered my own question.
 

Related to If a person passes near me at Mach 2 speed would I see him?

1. Would I be able to see the person passing near me at Mach 2 speed?

Yes, it is possible to see a person passing near you at Mach 2 speed, but it would depend on various factors such as distance, lighting conditions, and the person's size and clothing color.

2. How far away would the person need to be for me to see them?

The person would need to be within a certain distance in order for you to see them at Mach 2 speed. This distance would depend on the factors mentioned above, but generally, the person would need to be within a few hundred meters for you to see them.

3. Would the person appear blurred or distorted at Mach 2 speed?

Yes, the person would appear blurred or distorted due to the high speed they are traveling at. This is known as the "Doppler effect" and is caused by the change in wavelength of light as an object moves towards or away from an observer at high speeds.

4. What would the person's appearance be like as they pass by at Mach 2 speed?

The person's appearance would be affected by the Doppler effect, as mentioned before. Additionally, they may appear to have a "shock wave" surrounding them due to the air being compressed and heated as they travel at high speeds.

5. Would there be any other effects on the person passing near me at Mach 2 speed?

Yes, there could be other effects on the person passing near you at Mach 2 speed. These could include changes in air pressure and temperature, as well as potential physical effects on the person's body due to the extreme forces they would experience during such high-speed travel.

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