# Why doesn’t Quicksilver’s speed cause a sonic boom, lethal to anyone around him? [duplicate]

In X-Men: Days of the Future Past movie, Quicksilver played speed god in Pentagon kitchen to save his new friends (this looked much much faster than his speed demo at home).

Due to that speed, shouldn't there be super sonic boom to kill everyone except Wolverine? How exactly does Quicksilver's power work to avoid sonic boom?

You're free to use comics and physics.

• I think physics explanations are off topic – Shevliaskovic Sep 28 '14 at 17:42
• @Shevliaskovic Physics calculations under the domain of Canon shouldn't be off-topic. I have seen such things here. – Umbrella Corporation Sep 28 '14 at 17:44
• I am not a physicist, but the numbers here sound vaguely plausible: reddit.com/r/AskScienceFiction/comments/26bzw2/… – alexwlchan Sep 28 '14 at 17:53
• The question is blocked, but some facts: The wards fire after Magneto explodes the kitchen and only then Quicksilver moves. Standard bullets move with approximately Mach 0.8-1 and the wards are definitely less than 5m/5.5 yds away. So the whole scene must happen in a timeframe of max 0.02 seconds. The room has a diameter of approx. 6-7 m which means Quicksilver must move with (d*pi/t)=1100 m/s which is Mach 3. If I would describe what would really happen with the wards, it only gets uglier. – Thorsten S. Sep 29 '14 at 19:48
• Well, for one, a sonic boom is not lethal. – Robert Nov 24 '14 at 19:44

### The simplest reason is he does not reach the speed of sound.

• Superspeed depictions in comics and movies often fail to show how little speed is necessary for most speedsters to perform their superfeats. At a mere 90 MPH he is effectively able to cover 132 feet per second!

• Comics don't often show the environmental effects of super-speedsters movements. The wakes caused by their movement through the air are often shown as much smaller. The displacement of air at their highest speeds are never as large as physics should allow.

• In the DC Universe, they get around this (at least for the Flash) by talking about his frictionless speed aura which allows him to use his powers without deleterious effects such as wind or unwanted sonic booms. (The Flash can decide he wants a sonic boom too...)

• In a space that small, Quicksilver does not need to be moving more than about three hundred miles an hour to reach everyone in that room in the timespan displayed. No sonic boom is the result. Particularly since he can go from zero to incredible speeds in microseconds.

Most importantly sonic booms aren't inherently dangerous to living people. The energy involved, particularly with a man-sized object not generating a significant sonic wake (like an airplane with lots of engines might) isn't truly capable of harming anyone; knock you off your feet? Perhaps. Kill you? Probably not.

• Bullets do generally travel faster than sound, and Quicksilver was clearly moving faster than a bullet. He was certainly moving much faster than 90mph. He must have been at least been traveling 1000-1500 mph. – Shamshiel Sep 28 '14 at 21:39
• Consider his speed if he were moving that fast in such a small space. He could circle the room hundreds of times in a single second. Was he really moving THAT fast? – Thaddeus Howze Sep 28 '14 at 22:27
• Since he moved much faster than the bullets, yes, without a doubt. I would guess the screenwriters were more concerned about the Rule of Cool than exactly how fast Quicksilver was moving and whether it made sense, though. Since he was much faster than the bullets (I don't know what kind of gun that was specifically) it's likely he was moving more like 4000-5000mph. 1000-1500 is the bare minimum that's almost certainly too low. – Shamshiel Sep 28 '14 at 22:43