A supersonic jet when you are stood under as it flies by. makes you jump as well.

a earth sized meter impacting the earth, only no one would hear it !

I believe that the eruption of Krakatoa is regarded by scientists as producing the loudest noise since the arrival of humankind on our planet to date. Interesting question : )

Apparently, violent volcanic eruptions produce the loudest noise ever observed: "The loudest noise ever known was produced by a volcanic eruption at Krakatoa, near Java, in 1883. The sound was heard in Australia, 5000 km away." (from www.thatsweird.net) Another source stated that volcanoes have been known to produce sounds of 272 dB SPL Just to give some perspective, a loud rock band like Spinal Tap will play at about 130 dB SPL. But the decibel scale is logarithmic, so a 10dB change equates to 10 times as much sound energy. That means that Krakatoa was 100 QUADRILLION times more intense than a Spinal Tap concert. Of course, Nigel Tufnel won't let this situation stand....;-D... . . .

The loudest noise in the world is said to have been the eruption of the volcanic island of Krakatoa in Indonesia near Sumatra. When this exploded in August 1883 the sound was destinclively heard as far away as Perth West Australia (approx 1930 miles or 3100km) and in the Mauritius (approx 3000miles or 4800km).

Engineers at NASA claim to have made the loudest noise ever: of 210 decibels. This is so loud that it can make holes in solid materials.

thanks to all who answered this question, very interesting answers. cheers! (i would comment if i could...)

Angry female, no competition known to mankind.

apparently Krakatoa did.

No , my husband when he stuffs my head under the doona and farts!!

1) "- 302?(n) Tungusta Siberia meteor, blew down houses 600 miles away -ref.1.3. 1989 - 302.0488 db(q) = dynamic pressure from a 100000 atmospheres overpressure - 310 (n)Krakatoa volcano eruption-1883 a.d., cracked one foot thick concrete at 300 miles, created a 3000 foot tidal wave, heard 3100 miles away, sound pressure caused barometers to fluctuate wildly at 100 miles indicating levels of at least 170-190 db (p) at this distance of 100 miles even when shouting in someones ear, could not be heard at 100 miles caused fog to appear and disappear instantly at hundreds of miles rocks were thrown to a height of 34 miles. Dust and debris fell continously for 10 days after blast. produced very colorful sunsets for one year, ejected 4 cubic miles of the earth. created anti-node of negative pressure at the exact opposite side of the earth. Sound covered 1 / 10 of the worlds surface, shock (sound) waves “echoed” around the earth 36 times and lasted for about a month! -ref.19. - 316 (n)volcano eruption Sorantini, Italy,1470 b.c. although more energy than Krakatoa, it blew up over a longer period of days and not as violently, hence the instant peak pressure is believed to be lower -ref.1.3. than krakatoa. 15 cubic miles ejected, created tidal wave 165 feet high at a distance of 80 miles -ref.3. - 320 (n)volcano eruption, Tambora Indonesia,1815, ejected 36 cubic miles.approximately equal to 14,000 megaton nuclear bombs or a 14 gigaton bomb based on ejected volume,change in megatons times 1.345 equals volume ejected change.if was a nuclear bomb it would create a crater about 12.4 miles wide and 1.33 miles deep.internal pressure is believed to be about 47 million p.s.i. = 347 db (p) -ref.1.3." Source and further information: http://www.makeitlouder.com/Decibel%20Level%20Chart.txt 2) "Top 10 Loudest Noises" "5. The Blue Whale Blue whales mostly emit very loud, highly structured, repetitive low-frequency rumbling sounds that can travel for many miles underwater. These songs may be used for communicating with other blue whales, especially in order to attract and find mates. The call of the blue whale reaches levels up to 188 decibels. This extraordinarily loud whistle can be heard for hundreds of miles underwater. The whale is the loudest, and, the largest animal on earth. 4. Volcano - Krakatoa The 1883 the Krakatoa eruption ejected more than 25 cubic kilometres of rock, ash, and pumice and generated the loudest sound historically reported at 180 Decibels: the cataclysmic explosion was distinctly heard as far away as Perth in Australia approx. 1,930 miles (3,110 km), and the island of Rodrigues near Mauritius approx. 3,000 miles (5,000 km). 3. 1-Ton TNT Bomb Standing as close as 250 feet away from the impact, the resulting explosion from a 1 ton bomb creates a decibel count of 210. Without sufficient hearing protection, not to mention a complete sound-resistant bunker surrounding you, you could quite literally die from the intense vibrations that would literally shake you apart. Unless, of course, you were under the bomb. 2. 5.0 Richter Earth Quake A sufficient enough quake to rend the ground in twain and destroy buildings, whole rock, and human life reaches a decibel level of 235. If you are caught in the epicenter and are unlucky enough to not be above the ground in a plane or helicopter, the intense noise and vibrations could kill you long before death by any falling object." "1. Tunguska Meteor The Tunguska event was a massive explosion that occurred near the Podkamennaya (Under Rock) Tunguska River in what is now Krasnoyarsk Krai of Russia, at 7:40 AM on June 30, 1908. The explosion was most likely caused by the air burst of a large meteoroid or comet fragment at an altitude of 5 to 10 kilometers (3–6 mi) above Earth’s surface. It was measured with the similar impact of a 1000-Mega-ton bomb with a decibel rating 300-315. This is often considered to be the loudest single-event in history." "[Posting] You should add the loudest theoretical possibly sound: 358 dB. At this Level the airparticles that conduct sound had to be as fast as light. As this is impossible, 358 dB is the maximum for air. db SPL = 20*log(p1/p0) p0=0,00002 Pa (this is the usual reference) p1=Z*V Z=41,5 g/cm²/s (in german “impedanz”) V=300.000.000 m/s (lightspeed)" Source and further information: http://listverse.com/science/top-10-loudest-noises/ 3) "Source of sound Sound pressure Sound pressure level pascal dB re 20 μPa Theoretical limit for undistorted sound at 1 atmosphere environmental pressure 101,325 Pa 194.0937 dB Krakatoa explosion at 100 miles (160 km) in air 20,000 Pa 180 dB Simple open-ended thermoacoustic device 12,000 Pa 176 dB M1 Garand being fired at 1 m 5,000 Pa 168 dB Jet engine at 30 m 630 Pa 150 dB " Source and further information: http://en.wikipedia.org/wiki/Sound_pressure 4) The above was about events on Earth. A supernova explosion would probably release much more energy, but who is going to hear this? "Engineers at NASA claim to have made the loudest noise ever: of 210 decibels. This is so loud that it can make holes in solid materials. " "A supernova is the most energetic single event known in the Universe. Material is exploded into space at about 10,000 kilometres per second. All the stars in our galaxy (about 100,000,000,000) would have to shine for six months to produce the amount of energy released by just one supernova." Source and further information: http://www.einsteinyear.org/facts/physicsFacts/ Further information: http://www.bautforum.com/archive/index.php/t-13378.html http://ask.metafilter.com/29223/what-is-the-loudest-possible-way-to-play-back-a-sound-recording http://cosmology.tamu.edu/talks/Wheeler.ppt http://en.wikipedia.org/wiki/Supernova 5) "Hotblack Desiato is the ajuitar keyboard player of the rock group Disaster Area, claimed to be the loudest band in the universe, and in fact the loudest sound of any kind, anywhere. So loud is this band that the audience usually listens from the safe distance of thirty seven miles away in a well-built concrete bunker. Disaster Area's lavish performances went so far as to crash a space ship into the sun to create a solar flare." Source and further information: http://en.wikipedia.org/wiki/Disaster_Area#Hotblack_Desiato