Monday, December 5, 2011

Incredible Snapshots of Sonic Booms

Sonic boom adalah istilah bagi gelombang kejut di udara yang dapat ditangkap telinga manusia. Istilah ini umumnya digunakan untuk merujuk kepada kejutan yang disebabkan pesawat-pesawat supersonik. Saat pesawat terbang melebihi kecepatan suara, muncullah gelombang kejut pada bagian tertentu pesawat. Gelombang kejut adalah daerah di udara dimana terjadi perubahan (tekanan udara, temperatur, densitas) secara dadakan. Gelombang kejut ini merambat dalam bentuk kerucut dan bisa sampai ke permukaan tanah, memekakkan telinga dan memecahkan kaca-kaca. Karena itu pesawat supersonik biasanya tidak terbang di atas daerah berpenduduk.


10. Sonic Boom Cloud
In this image it looks frighteningly as if there is an explosion at the back of the plane, but it's just the image of the sound barrier breaking before we hear the sonic boom itself. We have all heard sonic booms even if we haven't realized it or even seen them. This plane here is one of the best examples of both the sight and sound phenomena. One of the most common, however, is thunder, which is produced by lightning. You see the lightning first before you hear the thunder. Another object that creates miniature sonic booms is the bullwhip when it cracks. Then there is the space shuttle, of course, and the object we most associate with sonic booms: aircraft capable of flying faster than the speed of sound.




9. F-14D Tomcat
A stunning image of a sonic boom on a cloudy day, the jet looks like it is wrapped in a halo as it flies over the USS Theodore Roosevelt. We see a sonic boom before we hear it because the speed of light is much faster than the speed of sound. Think of the lightning and thunder example – we see the lightning before we hear the thunder, because of this.




8. B-1B breaking the sound barrier
In southwest Asia, a B-1 Lancer banks left as it breaks the speed of sound just before it does an acrobatic roll over. This happened while the U.S. Air Force, Navy and Royal Marines held an open house to show off their various aircraft. Sonic booms are a fascinating phenomenon that occur when an aircraft (or other object) goes faster than the speed of sound. Shockwaves are created and these build up into an explosion of sound when crossing the sound barrier. Three things are needed for a sonic boom. First, an object moving at supersonic speed (the plane), second, the medium through which that speed can travel (air) and third, shock waves.




7. Airforce F-22 Raptor
This incredible image shows trans sonic vapor forming over the wings of an F-16 fighter jet with what looks like rainbows forming. Just as the way a ship cuts through water and bow waves condense at the point to trail out behind it, when a plane passes through air it creates the same type of pressure.




6. FA-18 breaking sound barrier
The spectacular image here shows a sonic boom starting at the edge of the wings of a plane. A plane is continuously pushing air molecules out of the way as it flies, but when it passes Mach 1 and is flying at about 1,225 km, the air has been compressed into a cone starting at the nose of the plane and merging into a single shock wave.




5. Supersonic aircraft breaking the sound barrier
This stunning shot is just as cinematic as it looks – in fact it was taken for Columbia Picture's visual effects unit, for a sequence in the film 'Stealth' on board USS Carl Vinson (CVN 70). It shows the Commanding Officer of the 'Black Cocks Down' of Marine Fighter Attack Squadron Three One Four (VMFA-314) reaching supersonic speeds off the bow of the nuclear aircraft carrier. How loud a sonic boom sounds depends on how far away it is from the person hearing it. Because planes are pretty far away, it sounds like a deep double boom, but in the case of a bull whip, when it is close, it is a fireworks-type crack. You can imagine that if the planes above were seen as close as they seem to have been, it would have been a pretty deafening noise.




4. FA-18 Faster than sound
Here we see an F/A-18 piloted by Lt. Cmdr. James Montgomery breaking the sound barrier as it does a flyby over the USS Enterprise aircraft carrier. Even though you can see the mini boom right behind the pilot's head here, one interesting thing is that pilots don't hear it. By the time the boom occurs, they are already in front of the sound so can only tell by their instruments that they have passed the speed of sound. You would think there would still be a sound trail considering how close they are - but there isn't.




3. FA-18F Super Hornet
During a flyby on the Philippine Sea, a F/A 18F Super Hornet breaks the sound barrier over the aircraft carrier USS Kitty Hawk. If it were not for Theodore Karman, "the father of Supersonic Flight", the inventor of the math tools needed to design the details of the planes for getting past trans sonic speeds, we would never have seen this image of the F-18 Super Hornet. The pioneers that went before the planes of today truly changed the world as we know it.




2. F-18 Diamond back Blast
The Super Hornet doing a flyby here shows a perfect example of water condensing due to sonic shock in its flyby. For those scientifically minded it is also known as the Prandtl–Glauert singularity. The men and women who first took these planes past the speed of sound were extremely brave heroes all.

Chuck Yeager piloted the first manned aircraft to break the speed of sound in an experimental research rocket plane called the Bell-1. The first production plane to break the sound barrier was piloted by a woman named Jackie Cochran in an F-86 Canadair Sabre in 1953. Yeager was her wingman and a lifelong friend. She was a fascinating woman, and apart from being the first to break the sound barrier was also the first woman to land and take off from an aircraft carrier, the first woman to reach Mach 2, the first woman to pilot a bomber across the North Atlantic (in 1941), the first pilot to make blind (instrument) landing, the only woman to ever be President of the Federation Aeronautique Internationale (1958–1961), the first woman to fly a fixed-wing, jet aircraft across the Atlantic, the first pilot to fly above 20,000 feet with an oxygen mask, and the first woman to enter the Bendix Transcontinental Race. She still holds more distance and speed records than any pilot living or dead, male or female, and remember most of this was done at a time when women were considered incapable of doing the things men did.




1. F-22 Supersonic
Here we see an Air Force F-22 Raptor making a supersonic flyby over the aircraft carrier USS John C. Stennis, which was participating in the joint exercise Northern Edge 2009.

Sonic booms are one of the wonders of the natural world even if they are most famous as being recreated by fighter jets (now that the Concorde no longer flies). Don't forget, though, when you hear thunder it is also a sonic boom, and someone cracking a bull whip is creating one as well. They occur when space shuttles and other rockets take off, and some scientists believe the first time that sonic booms occurred was 150 million years ago, with some dinosaurs whose tails cracked at the speed of sound.


And here is the video of sonic boom



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