by Diane Harrison & Robert Frola
Guyra's Sonic Disturbance
Most of the information relating to the Guyra incident is reliant on the recording of a sonic disturbance which was recorded on the night of the 7th December 1999 at 8.12pm at Armidale's New England University.
Many people wonder what objects can cause a sonic disturbance. A number of things can e.g: Lightning, a bull whip, even the Space Shuttle which is well known to cause a double sonic booms, and planes etc. Here is an example of what a sonic booms looks like (right).
As an airplane or meteor flies faster than the speed of sound, it "pushes" on the sound waves in front of it. But, sound waves obey the speed limit - they can't travel faster than the speed of sound. So, the waves pile up against each other as they are created. These "piled up" waves are called 'Shock Waves'. The greatest shock waves are at the tip and tail of the plane. This NASA photograph shows the shock waves created by a plane in flight, (the "rings" in the photographs are camera artifacts and are not part of the shock waves).
Sonic booms are an impulsive noise similar to thunder. It is caused by an object moving faster than sound - about 750 miles per hour at sea level. An aircraft travelling through the atmosphere continuously produces air pressure waves similar to the water waves caused by a ship's bow. When the aircraft exceeds the speed of sound, these pressure waves combine and form shock waves which travel forward from the generation or "release" point.
As an aircraft flies at supersonic speeds it is continually generating shock waves, dropping sonic booms along its flight path, similar to someone dropping objects from a moving vehicle. From the perspective of the aircraft, the booms appears to be swept backwards as it travels away from the aircraft. If the plane makes a sharp turn or pulls up, the booms will hit the ground in front of the aircraft.
The sound heard on the ground as a "sonic booms" is the sudden onset and release of pressure after the buildup by the shock wave or "peak overpressure". The change in pressure caused by sonic booms is only a few pounds per square foot - about the same pressure change we experience on an elevator as it descends two or three floors - in a much shorter time period. It is the magnitude of this peak overpressure that describes a sonic boom.
Meteors with sounds
Sounds associated with meteors is a topic which has received its share of attention. The sounds in this case are not the usual delayed rumbles and ticks associated with the passage of a bolide, but sounds which are heard simultaneously with the passage of the meteor across the sky! Sounds heard at the same time the meteor is visible are very controversial for a few very good reasons:
1. Sound travels much slower than light and as a result the meteor would, under normal circumstances, be gone before the sound was heard.
2. Very little of the meteor's energy is converted to acoustic energy. By the time the sound has been attenuated by the atmosphere between the meteor and the observer the sound should be barely audible, if able to be heard at all! Even with all these facts in mind, observers remain adamant that they observed these effects. Usually the effects are heard from a remote and quiet site where faint sounds can be heard better.
The best theory put forward so far is that energy from the meteor is propagated electromagnetically and is amplified and 're-transmitted' by a suitable nearby source such as metal fence, wires or a metal shed roof, even empty metal water tanks. This theory has not been proven though, but remains a possible solution to the problem.
Many meteor professionals are skeptical about this. It is felt that it is equally possible that years of watching rockets and fireworks has conditioned us to expect sounds from rapidly moving lights in the sky. It is also possible that the location of the observer isn't as quiet as the observer has been led to believe.
The Guyra meteorite was said to have come from the north east between Monday night and Wednesday morning, quoted by Mr Simon Benson of Guyra in his e-mail report to PRA.
TRUE or FALSE!
Media states that a sonic boom was heard on Tuesday night, indicating that an object impacted in the area
"We believe that the seismograph has detected the sonic booms of the meteorite as it "passed by", rather than the actual impact of the meteorite into the ground".
After speaking to Professor Peter Flood of Armidales New England University he said he had been misquoted and the information he gave to the media was misconstrued due to the media wanting to rap the story up by as early as Friday afternoon.
After speaking to Dr Kevin McCue his first thoughts when he saw the readout was that of a plane losing a part of something. His second thought was that of a meteorite.
When asked what he thought of the meteorite theory he said "It could have been one but the sonic booms reading points to something passing over, not hitting the ground." He also pointed out the reading was of an object travelling East to West on Tuesday at 8.12pm for around 14 seconds. From: Home Page of the Astronomical Society of Victoria Meteor Section http://axis.jeack.com.au/~armarsh/index.html
TRUE or FALSE!
Media shows video footage of an object streaking across the twilight sky as the same object that may have impacted in the guyra area
All of you can remember seeing the incredible footage of a meteorite streaking across a late afternoon sky taken by two young men from Orange, NSW with their camcorder. What the media didn't tell you is that this footage was taken a week prior to the Guyra event, and was filmed in another location in central NSW. If you look closely, the object was travelling from the north to the south, opposite to what they say impacted into the dam (from the east or northeast, based from educated guesses).
TRUE or FALSE!
Media reports local woman witnessed object explode near Guyra
When we arrived in Guyra we tried to contact Barbara Ross to get her side of the story regarding her sighting. According to the Seven Nightly News, it was quite spectatular, with the object exploding near Guyra. Barbara was unfortunately not in, but we did speak to John. He told us that Barbara was quite upset, and that she was grossly misquoted. Barbara phoned Channel Seven asking for a retraction, but they only ignored her request. Below is what Barbara Ross wrote to The Guyra Argus about the whole event, appearing in the Thursday December 16th 1999 edition.
"Some of those smart fellows from the city media certainly know how to make a story out of nothing. Blatant dishonesty does not seem to pose a problem for them.
Last Thursday John and I took French visitors to see the sheep sale in Guyra. We had not heard any news for some days, so were very surprised to learn from John Simpson about all the excitement going at the Guyra Water Supply. There was plenty of speculation at the yards about nature of the mysterious object in the dam, so after the sale we decided to go and have a look for ourselves. Nobody stopped us on the way into the area around the dam, and the media was there in force, so we though it must be OK to wander about. However, after a few minutes a young Policeman politely gave us our marching orders, and we dutifully started to make our way to the gate, laughing and a little ambarrassed. As we were leaving, a reporter from 2UE, together with a reporter and cameraman from Seven Nightly News, stopped us. We were still laughing and completely off guard, so when they started chatting we conversed with them quite openly. That was a mistake! In reply to their question: "What do you think is in the dam?" we said that we were sorry, but we had only just heard about it at the sheep sale, and we didn't have a clue.
After a few minutes, they repeated the question, and we repeated our reply, but I foolishly added that it was probably only a meteorite. Even more foolishly, I went on to say that, if that were the case, it wasn't the only time a meteorite had landed near here recently, as one had come over Black Mountain and exploded into the west a few months ago. They asked me to describe it, which I did, and you can guess the rest of the story! Sure enough, there was I on 2UE and Seven Nightly News describing how we had seen this green light in the sky, etc. etc., as if it were the object in the dam.
Since then, the Australian UFO Research Network has rung home trying unsuccessfully to interview me. They left a message that they will be back in January! I am thinking of leaving town! If it wasn't so hilarious it would be downright infuriating. Give me those honest Argus reporters any day!"
We have tried to contact her on our second visit in May, but time got away from us again. Fortunately, we were able to obtain a copy of her letter.
TRUE or FALSE!
Fragments of the object was recovered. Identified as bits from a meteorite
When we spoke to Guyra's LEOCON Sgt Larry Hoffman, he confirmed to us that no fragment of a meteorite was ever recovered. It hasn't even be confirmed yet that a meteorite did impacted into the dam or that it was responsible for the hole that was discovered earlier on Wednesday 8th December.
Saturday 10.12.99 02:21:28
E-mail: Guyra meteor?
I know someone at the Armidale NSW fire brigade, and while everyone on camera is talking meteorite, everyone at the firestation is talking accidentally dropped ordnance from a military jet which flew over the site earlier.
We at AUFORN feel that the most likely explanation is an accidental dropping of an ordnance from a military jet, most likely a F-111. For years F-111s have used an old abbatoir, not far from the dam for bombing practice. The area around the dam was cordoned off by police and rescue services on Wednesday night. Whatever fell into the dam was removed under the cover of darkness. The following morning, the media was allowed to get quite close to the impact area.
If a 100g meteorite impacting in Germany can cause a crater 20 metres across and 8 metres deep, then a meteorite of roughly the same weight would have caused more damage than a small hole of up to 20 metres deep with the opening around fist size. The reeds would have been blown out of the dam and into the surrounding landscape.
LEOCON Sgt Larry Hoffman of Guyra and a woman Police Officer in Armidale both said they received reports of strange lights seen in the area around 9.00 p.m. that evening. Reports include a truck driver who phoned John Laws about seeing numerous strange lights on that night.
Mr Keith Ridley, a sheep farmer, whose property adjoins the dam told us he heard a "kind of humming sound" which seem to originate high in the sky around 9.00 p.m. on Monday night. He said he is quite familiar with the sounds of an F-111 flying low through the valley, and this sound he has never heard the likes of it before. Other locals, Mr Bruce Sweeney and his wife, also heard an unusual sound on Monday evening.
What did crash into the dam? (i.e. if something did crash into the dam!) Was it space junk, a meteorite or ordnance from a military aircraft? We may never know, but one thing is for certain. Unknown lights and sounds were reported from the Guyra area and beyond over Monday and Tuesday nights. Only time will tell. Until then, the mystery remains.
TO BE CONTINUED - See Issue 17