What is the "greatest sound in the world" that made three rounds of the earth?

ByGhazaleh Ghazanfari

"sound"Is vibrated by molecules in the air, which is recognized by being transmitted to the eardrum. Although it may be hit by noise even in everyday life, the "recorded on the earth"The biggest soundWhat is "What is" limit of sound "and what is it,NautilusIt is summarized.

The Sound So Loud That It Circled the Earth Four Times - Facts So Romantic - Nautilus
http://nautil.us/blog/the-sound-so-loud-that-it-circled-the-earth-four-times

Among the records recorded so far, the biggest sound occurred in 1883KrakatoaWhen a large eruption occurred. Although Krakatoa is an island located between Java island of Indonesia and Sumatra island, it was recorded in Andaman and Nicobar Islands 2000 km from Krakatoa, "It sounds exceptionally loud as a gunshot," he was 3200 km away In New Guinea and western Australia, it was said that they heard "a lot of loud sounds like cannon sounds from the direction of the northwest", and even on Rodrigues Island about 4800 km apart "I heard a gunshot sound far from the east" It was reported that the sound of the volcanic eruption was recorded in 50 locations around the world. The explosion sound at this time is the longest distance record which the human listened directly to the sound generated at a place far away.

ByWikipedia

A tsunami with a height of 30 m was generated by a large eruption so that the shape of the island itself changed, and 165 villages along the coast were destroyed. According to the data issued by the Netherlands, there are 36,417 deceased people, but there are also theories that more than 120,000 people died.

Sounds are caused by changes in atmospheric pressure, but according to the records of the Batavia Gas Production Center located 100 miles from Krakatoa, the pressure generated at this time is 2.5 inches of mercury, and when converted to sound pressure 172 It was over db. As I go up by 10 decibels, most humans feel that the sound has doubled. The limit that human hearing can withstand safely is about 130 decibels, and the sound pressure near the engine of the jet aircraft is about 120 decibels, so it is clear how big the sound was. Then, where is the limit of the sound that can resonate on the earth?

ByStuart Cunningham

By emitting words and singing songs, a person rocks molecules in the air about several hundred times per second. The larger the sound, the greater the vibration of the molecule, but there is a limit to the size of the sound. The limit of the sound in the Earth's atmosphere is 194 decibels, and further sound pressure can not pass through the air. The sound of 194 decibels or moreshock waveIt pushes out high pressure air explosively.

What happened in Krakatoa was very close to this. Air in high pressure creates a blast, breaks the eardrum of the sailor, which was 40 miles away, and travels all over the world. The sound suddenly weakened after Rodrigues Island, which is 4,800 kilometers from the volcano, but still continued to move forward, it revived on the earth for days.

There were towns where seven spike waveforms were observed due to the air pressure coming from multiple directions, and it was said that "sound made seven orbits of the earth", but according to records of observation stations in various parts of the world, the Kalakatoa It is thought that the compression wave born in 3 to 4 rounds on the earth. In addition, it is said that in the place observing the tidal fluctuations, we observed waves as well as pressure waves. In the past it has never been influenced by the sound by "sound", it can be said that the moment the sound physically moved the world.

ByNASA Goddard Space Flight Center

In addition, how the compression wave is caused by the volcanic eruption is smaller than that of Krakatoa, but the scale is smaller, but you can understand well by looking at the following movie.

Volcano Eruption in Papua New Guinea - YouTube


Tourists shooting volcanoes from above the boat.


......, the volcano suddenly erupted.


Pressure is applied to the air, and clouds are born above the volcano.


People photographing the movie are away from the volcano, but the compression wave reaches the boat, and about 13 seconds after the eruption has occurred a large sound like a gunshot is recorded.