For quite a long time though many researchers thought that going sonic and supersonic, i. Take an aircraft, for example. A plane makes lots of noise, right? The sound waves from an airplane propagate in all directions, ahead of the plane, behind it and sideways. As the plane goes faster, it starts to catch up with its waves.
When the speed of the plane gets close to the speed of the sound waves it emits, the waves start to pile up. That leads to the increased atmospheric pressure and drag and that, in turn, makes further acceleration really difficult. The first human to do just so was American test pilot Chuck Yeager.
He broke the sound barrier in October 14, on Bell X-1 aircraft. These days supersonic airplanes are used for the military and research purposes only.
Until recently there were two commercial supersonic planes, Concorde and Tu , but ever since they retired, we, common people, travel only at subsonic speeds. In some countries, like US, it is against the law for the airplane to fly faster-than-sound because of the sonic boom. Right now scientists are working on the prototype of quiet supersonic aircraft and the US lawmakers are looking into bringing back supersonic passenger flights.
Yes, please! Space rockets go supersonic very early into the flight: within seconds for the unmanned flights and within a minute for the manned flights. Felix Baumgartner , a skydiver from Austria, achieved faster-than-sound speed during his famous supersonic freefall in No abusive material or spam will be published. Does a stronger signal travel faster than a weaker one?
Also, does sound not travel at all in a vacuum? If you were able to stay alive floating in space and witnessed a massive collision of two interplanetary bodies, would you hear absolutely nothing?
A "stronger" signal travels at the same speed, same as light. ColinChambers October 12, AM. The fundamental principle of conservation law of the universe to create order from disorder. Compressed hydrogen is a structure of material with properties -atoms - laws of nature, this study is interesting but it has to includesThermal energy, compounds structures property all have changes close to Kelvin zero.
Thermal energy will no exist. Nibblonian October 12, AM. That said, if you were inside a space suit or space craft filled with air and an energy wave struck, the mechanical barrier could act as a transducer and convert the energy into sound--pretty similar to how a speaker works.
Karmudjun October 12, AM. So our Atlas Rocket only attained one-third of the speed of sound through solid hydrogen during the moon shots. Hard to fathom - but also hard to consider a use for such information. We know aural sound is not propagated in a vacuum from H. But we can detect the 'sound of the Big Bang' with radio telescopes, but that is not an aural wave.
Let's look back a the wave of people in a football stadium. What would make this speed change? Two things could clearly make a difference.
Suppose the stadium wasn't full but instead about every other seat was occupied. This could change the speed of the sound wave. It isn't quite clear if it would make it faster or slower, but I would guess faster since the person would be reacting to the previous person that was farther away.
Another effect could be from the alertness level of the crowd. If people weren't paying much attention, it could cause a longer reaction time and thus a lower wave speed. Actually, now I am curious. I wonder if stadium wave speeds are fairly constant for different stadiums and crowds. My guess is that they would all have similar speed values. Maybe this will be a future blog post. OK, back to sound waves in air. What does this speed depend on?
You could guess a few things. Just like the football crowd wave, the density of particles should matter. And what about the pressure in the air? That should matter too, right? Surprisingly at least for me , a simple model for the speed of sound only varies with air temperature.
Well, as you get higher in the altitude up to a point , the temperature decreases. The pressure and the density of air also decrease. The effects due to pressure and density essentially negate each other.
Like I said, this over simplifies the whole issue. The Wikipedia page on the speed of sound has a lot more detail if you are interested. If you put this together, you can get a plot of the speed of sound as a function of altitude. Oh sure, it will change with weather and stuff, but still you can get a pretty basic model. Here is a plot of the speed of sound at different heights above sea level. Just from this data, you can see that Felix Baumgartner did indeed fall faster than the speed of sound.
However, the question doesn't really make sense. Did he fall faster than the speed of sound at sea level? Was he also going faster than the speed of sound for the altitude he was at? Well, it makes logical sense that if the speed of sound is greatest at sea level and he went faster than the speed of sound he would be going faster than the locals speed of sound. I don't know if "local speed of sound" is an official term, but I like it.
I am using it to mean the speed of sound at the current altitude. Here is a plot of the speed of Felix as he falls along with the plot of the local speed of sound at that same time.
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