I really got to thinking about this. The speed of sound is measured at 761.2 MPH at sea level. But how does this number change as air density decreases? The lack of air density is what allowed his terminal velocity to much lower than say a jump at 5k feet high. I am not disputing his maximum velocity (800+ MPH), but did Felix Baumgartner actually produce a sonic boom in the process? I mean, I beleive most people subconsioulsy associate "sonic boom" and "faster than the speed of sound".
[Physics] Did Felix Baumgartner produce a sonic boom during his jump
acousticsaerodynamicsatmospheric sciencefluid dynamics
Related Solutions
According to the American Meteor Society, the sonic boom of an asteroid or meteor (sometimes referred to as a 'fireball') is due to
If a very bright fireball, usually greater than magnitude -8, penetrates to the stratosphere, below an altitude of about 50 km (30 miles), and explodes as a bolide, there is a chance that sonic booms may be heard on the ground below. This is more likely if the bolide occurs at an altitude angle of about 45 degrees or so for the observer, and is less likely if the bolide occurs overhead (although still possible) or near the horizon.
And from CalTech's CoolCosmos page
When an object travels faster than the speed of sound in Earth's atmosphere, a shock wave can be created that can be heard as a sonic boom.
The reason for asteroids causing sonic booms in the lower atmosphere, is according to the article How the Falling Meteor Packed a Sonic Punch (Klotz, 2013) is due to
Because the meteor is supersonic, the waves, which travel at the speed of sound, can’t get out of the way fast enough. The waves build up, compress and eventually become a single shock wave moving at the speed of sound.
Looking a bit further in to what a sonic boom (Using a jet as an example) is and how it occurs is illustrated in the following diagram
So, if a meteor, asteroid is going faster than the speed of sound for particular part of the atmosphere, then a sonic boom will occur. Going back to the American Meteor Society's description of the likely cause of a sonic boom, they stated that if a meteor comes in
below an altitude of about 50 km (30 miles)
then a sonic boom is likely to occur, one of the reasons is that the speed of sound is slower, due to the temperature of the atmosphere at that height and lower. Below is a graph showing the speed of sound plotted against temperature as a function of atmospheric elevation:
If we look at the sonic boom as a $\delta$-function, where we have a really loud sound for a really short time, then it will be able to excite all frequencies at the same way.
You can actually compute this by showing that $$ \delta(t)=\frac{1}{2\pi}\sum_n e^{int},$$ which show how the $\delta$-function is actually composed of all frequencies.
Then it's actually in resonance with any object. However, due to its short lifespan it cannot feed more and more energy into an object (like a window), making the amplitude of the oscillation bigger and bigger until the object breaks.
What most likely will destroy something like a window is the actual pressure front, due to the pressure gradient.
Best Answer
Sonic boom refers to the explosive sound caused by the shock wave from an object traveling faster than the velocity of sound. Yes, It's actually spoken out as breaking the sound barrier.
Felix jumped from an altitude of 39,044 km (which is 128,097 ft.) and reached a peak speed of 833 mph. Yes, He did produce the Sonic boom. Most likely, we use the term Breaking the sound barrier while considering air-crafts like "Concorde" because they could be easily sensed. But in case of Felix, he produced
That "Mach 1.24" reading is comparable to the shock waves produced by Space shuttles...
Velocity variation of Sound: Indeed, Sound varies with Temperature and also with Density. Also, the state of matter (which refers again to density). It travels faster in liquids and even more faster in solids (like 5120 m/s in Iron)
In general, the speed of sound in a gas is given by Laplace correction of Newton's formula. For solids, see Wiki ('cause it's not necessary now...) $$v=\sqrt{\frac{\gamma P}{\rho}}$$
Applying Ideal gas law and using density of air ($\rho=1.293$ $kgm^{-3}$), we could find that the velocity of sound increases by 0.61 per degree celsius rise in temperature in air. Also, the velocity of sound in a gas is inversely proportional to the square root of its density. But, it's independent on Pressure (Don't believe in appearance of the formula). This is because increase in pressure, also increases the density of gas. This could be achieved by using different gas densities (at same volume & pressure).
Also, See the Atmospheric variation of sound's velocity.