In aviation, there is a phenomenon known as the sonic boom when an aircraft is travelling faster than the speed of sound. At subsonic speeds, the sound waves in front of the aircraft travel faster than the plane does, creating the sonic bow wave shown in diagram one. But when the aircraft goes supersonic, it breaks through the so-called “sound barrier,” eliminating the bow wave and causing a massive sonic boom in its wake, shown in diagram three. Even though supersonic flight was first achieved more than 70 years ago, all passenger aircraft today are still subsonic because of the sonic boom problem.
In the cyber realm, this phenomenon is known as a zero-day exploit. This is a vulnerability that was previously unknown (known about for zero days). It is an exploit that is not preceded by an informational bow wave, like a supersonic aircraft. As with the sonic boom, they can be extremely destructive.