Ships， airplanes， helicopters and men—they have all been sucked into the Bermuda Triangle at some point of time or the other. None of them have ever returned. It is impossible to provide details of the first such disappearance because of erratic record keeping over the years， but it was the US Navy that first brought the Bermuda Triangle mystery into the limelight.

On 5 December 1945， five Avenger torpedo bombers of the US Navy took off from Fort Lauderdale on a routine training flight over the Atlantic. They did not return. A large Mariner flying boat sent to search for the missing aircraft also failed to return. No trace has ever been found of the six planes or the 27 crew members. As a result of this incident， it was discovered that quite a few ships and aircraft had also been lost， apparently without explanation in the triangular area off the southeast coast of the United States bounded by Bermuda， Puerto-Rico and Florida.

Every investigator worth his salt has postulated a number of theories that attempt to satisfactorily explain the mysterious happenings at the Bermuda Triangle. Some of the more bizarre explanations include extra-terrestrials， the presence of a huge magnet， the position of the moon， and the return of the inhabitants of the lost city Atlanta.

One of the more credible theories seems to belong to Dr Richard McIver， who centers his explanation on the presence of methane hydrate. Methane hydrate was first encountered in the 1920s and 1930s in the early days of the American and Soviet gas industries. Natural gases （a mixture of flammable gases found in the Earth’s crust） were being piped across the Atlantic but occasionally the pipes would become mysteriously plugged up.

All gases except for helium， hydrogen and neon can form hydrates if enough gas and water are present， if the pressure is high enough and if the temperature is low enough. These conditions can be found naturally occurring on earth， and methane hydrate has been found to exist in huge quantities in many parts of the sea floor and is concentrated in some places on continental slopes such as the Bermuda Triangle. The structure of the molecule of methane hydrate is such that it facilitates the capturing of a large amount of gas. If this were to break-up， then even a small area could cause a large gas release.

Sediment piles on continental slopes have the tendency to accumulate on the slopes of the edge of continental plates. But it is unstable and can tumble down. When this happens， it can cause the removal of the hydrate layer， releasing the methane gas trapped below. Methane gas bubbling up through the sea will cause an area of decreased density； ships will lie lower in the water and will be swamped by the least wave； also methane gas when mixed with air in the correct proportions is highly explosive. This could account for the mysterious disappearances of both ships and aircraft.

All this activity on the sea bed occurs at the edges of tectonic plates， where there is constant activity as a result of the pressures beneath the earth’s crust； any wreckage sinking to the bottom would be lost forever beneath the moving plates.

The latest myth that is doing the rounds is that there have been disappearances in the Indian and Pacific oceans， this means that the Bermuda Triangle is widening in scope.

船舶、飛機、直升機和人——他們?nèi)慷荚谀硞€時間內(nèi)被吸進了百慕大三角區(qū)，音訊全無。第一次出現(xiàn)這樣的“失蹤”時，由于幾年間不全面的記錄，無法提供更多的細節(jié)信息。是美國海軍第一次把百慕大三角區(qū)之謎帶入眾人的視線。

1945年12月5日，美國海軍的5艘“復仇者”號魚雷轟炸機從勞德代爾堡出發(fā)執(zhí)行飛越大西洋的常規(guī)訓練任務(wù)，他們再沒返回。派出去搜尋失蹤飛機的大型“水手”號飛艇也沒有回來。沒有6架飛機和27位機務(wù)人員的任何蹤跡。因為這起事故，人們發(fā)現(xiàn)在這之前就已有一些船和飛機無緣無故消失在由（英屬）百慕大群島、（美屬）波多黎各和佛羅里達州所構(gòu)成的美國東南海域的三角區(qū)。

每一個名副其實的調(diào)查者都假設(shè)了很多理論，試圖對發(fā)生在百慕大三角區(qū)的神秘事件給出滿意的解釋。其中不乏古怪的解釋，有人認為這些現(xiàn)象和外星人、巨大的磁場、月亮的位置以及迷失之城亞特蘭大的居民的返回有關(guān)。

在這些理論中，理查德·麥基弗博士的理論似乎更可靠，他將原因重點放在甲烷水合物的存在上。人們第一次發(fā)現(xiàn)甲烷水合物是在20世紀20年代和20世紀30年代美國和蘇聯(lián)天然氣工業(yè)早期。天然氣（在地殼中發(fā)現(xiàn)的可燃氣體的混合物）通過管道送過大西洋，但是時不時的管道會神不知鬼不覺地被堵住。

除了氦、氫和氖，所有氣體都可以形成水合物，只要存在足夠的氣體及水，且壓力夠高、溫度夠低。這些情況在地球上自然地發(fā)生著，因此甲烷水合物在許多海床上大量存在，并集中在大陸斜坡上一些地方，如百慕大三角區(qū)。甲烷水合物的分子結(jié)構(gòu)便于俘獲大量氣體。這種分子結(jié)構(gòu)一旦分解，即使很小面積也可能會導致大量氣體的泄露。

在大陸斜坡堆積的泥沙容易在大陸板塊邊緣的坡上積聚起來。但它是不穩(wěn)定的，會滾落下來。當發(fā)生這種情況時，它會引起水合物層的消失，被困在下面的甲烷氣體便釋放出來。噴出海面的甲烷氣體會導致所在海面的海水密度下降；船就會下沉，一個很小的波浪就可將它淹沒；同樣，當甲烷氣體和一定比例的空氣混合時具有高度爆炸性。這可以用來解釋船舶和飛機神秘失蹤的原因。

所有這些活動都發(fā)生在地殼構(gòu)造板塊邊緣的海床，由于地下壓力，那里活動頻繁。任何下沉到海底的殘骸將永遠消失在移動的板塊之下。

最近在印度洋和太平洋也相繼發(fā)生（船舶、飛機）神秘失蹤事件的傳言正迅速傳開，這意味著百慕大三角區(qū)的范圍正在擴大。