So secret, its 存在 is not even 定評のある: Futuristic 'Aurora' 秘かに調査する 計画（する） that travels at SIX TIMES the 速度(を上げる） of sound is 非難するd for mysterious にわか景気s heard at the 週末

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The origin of the mysterious bangs heard across the UK and New York at the 週末 are yet to be 公式に identified.

But a 主要な theory is that they were created by an 航空機?かもしれない?travelling?at supersonic or hypersonic 速度(を上げる）s above the 大西洋.

This has led 共謀 理論家s to せいにする the にわか景気s to a 秘かに調査する 計画（する） rumoured to be under 開発 by the US 軍の, under the codename Aurora.

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Aurora is rumoured to be a 最高の，を越す secret 航空機 that has been in 開発 since 1989.?These （人命などを）奪う，主張するs 起こる／始まるd in 航空 Week and Space 科学（工学）技術 magazine in 19 89. In November 2013, Lockheed ツバメ 発表するd it was developing a 類似の SR-72 秘かに調査する 計画（する） (illustrated) said to be able to 加速する up to Mach 6

Dr Bhupendra Khandelwal, an 工学 研究 associate from Sheffield, （人命などを）奪う，主張するs the loud bangs were created by a type of 実験の jet engine called a pulse detonation engine.??

Claudia Angiletta, a 居住（者） from Croydon, South London, 記録，記録的な／記録するd the sounds as she was watching TV at home at around 10pm GMT on Saturday.

Within minutes, Twitter 使用者s had started spreading hashtags - from the straightforward #loudbangs to the somewhat melodramatic #omgwereallgoingtodie.

At around the same time, 居住（者）s in 場所s 含むing Buffalo, Cheektowaga, Clarence and as far north as Niagara 落ちるs on the east coast of the US also took to social マスコミ to 報告（する）／憶測 the unusual noises.?

Twitter 使用者 Brailsford believes the noises were created by hypersonic にわか景気s (tweets pictured above). He 追加するd that the continuous and 半端物 sound could be explained by reverberations around the 成層圏??

熱中している人s （人命などを）奪う，主張する that such a supersonic or hypersonic 計画（する）s could be what 原因（となる）d the strange noises at the 週末. In particular, an 専門家 said the sound is 類似の to that created by pulse detonation engines. An artist's illustration of what the Aurora 計画（する） could look like is pictured

People 述べるd it as loud enough to shake their homes and 動揺させる windows.

This has led 共謀 理論家s to （人命などを）奪う，主張する the 力／強力にする source could be behind a hypersonic US 秘かに調査する 計画（する）, dubbed Aurora.

Aurora is rumoured to be an ultra 最高の，を越す secret 航空機 that has been in 開発 since 1989.

It could be a 後継者 to the Mach 3.35 Lockheed ツバメ SR-71 Blackbird （手先の）技術 that was retired in 1998.?

By comparison, extreme 報告（する）／憶測s （人命などを）奪う，主張する the Aurora could 攻撃する，衝突する up to Mach 11.8.?

These （人命などを）奪う，主張するs 起こる／始まるd in 航空 Week and Space 科学（工学）技術 magazine, which ran an article in 1989 about a mysterious 入ること／参加（者） in the 1985 US 予算.?

The 入ること／参加（者） said $445 million was せいにするd to '黒人／ボイコット 航空機 生産／産物' under the 指名する Aurora.

These 報告（する）／憶測s did not 言及／関連 a 選び出す／独身 （手先の）技術, instead they discussed a 一連の 計画（する）s.

Other 報告（する）／憶測s 示唆する the Aurora programme kicked off at Lockheed ツバメ's Skunkworks in 1987.?

The 会社／堅い was said to be looking into 取って代わるing its SR-71 Blackbird, which was later retired in 1998.

However, the former 長，率いる of Lockheed's Skunkw orks 分割, Ben Rich, said Aurora was a codename for the stealth 事業／計画（する） which 結局 led to the B-2 Spirit.

But, in November 2013, Lockheed ツバメ 発表するd it was developing a 秘かに調査する 計画（する） with 類似の 科学（工学）技術s called SR-72.

The 会社／堅い said the 計画（する） can 加速する up to Mach 6, or 4,567mph (7,349km/h) - three times faster than Concorde.?

Concorde flew no faster than Mach 2, まず第一に／本来 because the 構成要素s weren’t 利用できる in the Sixties that could withstand greater heat.

科学（工学）技術 has 前進するd since then, and the SR-72 will be a いわゆる ‘warm structure’ - it will heat up rather than 反映する the heat using the sort of ceramic tiles that covered the Space 往復（する）.

Concorde wasn’t 許すd to 飛行機で行く supersonic over land because of the ‘sonic にわか景気’ - the sound associated with the shockwaves created by a （手先の）技術 moving faster than the 速度(を上げる） of sound.

Aurora is rumoured to be a 最高の，を越す secret 航空機 that has been in 開発 since 1989. It could be a 後継者 to the Mach 3.35 Lockheed ツバメ SR-71 Blackbird （手先の）技術 that was retired in 1998 (pictured).?These （人命などを）奪う，主張するs 起こる／始まるd in 航空 Week and Space 科学（工学）技術 magazine in 1989

A PDE engine 作品 by using 軍隊 from a 一連の 爆発s, 原因（となる）d by mixing a 燃料 もや and 空気／公表する intake, to thrust itself 今後. It can theoretically 力／強力にする 計画（する）s at five times the 速度(を上げる） of sound.?A PDE can 爆発させる between 60 and 100 times a second and its contrails appear to look like '（犯罪の）一味s on a rope' (pictured), or a spine

によれば 専門家s, 含むing Dr Phillip Atcliffe, 上級の lecturer in aeronautical 工学 at Salford University, if a 乗客 jet flew at Mach 6 at 現在の jet 高度s of around 30,000ft (9,144 metres), the sonic にわか景気 could 損失 buildings.

公式の／役人s routinely 否定する Aurora 存在するs. But that has not 鈍らせるd the spirits of the 理論家s, who point to a sighting of a mysterious triangular 反対する by a North Sea oil engineer in August 1989.?

Dr Khandelwal was keen to distance himself from the world of 共謀 theories, though he 譲歩するd there could always some things unknown to the public.

‘Of course we can’t know for sure if someone else could have the 科学（工学）技術 already,' he said.

Dr Khandelwal, is の中で a team of scientists working on the 科学（工学）技術 behind such types of 'pulse detonation engine'.

'It makes the same 肉親，親類d of pulsing sound as the one on this 音声部の,' he told MailOnline.?

WHAT WOULD AN AURORA PLANE LOOK LIKE?

速度(を上げる）: 速度(を上げる）s are 報告（する）／憶測d to be in the 範囲 of Mach 5 to 8.

Length: 110ft (33.5 metres)

Wingspan: 60ft (18.2 metres) ?

Engine: There are a number of possible engine 科学（工学）技術s that have been linked to the Aurora 事業／計画（する）.?

In November 2013, Lockheed ツバメ 発表するd it was developing for its SR-72 秘かに調査する 計画（する） (pictured) said to be able to 加速する up to Mach 6

One in particular, which Dr Bhupendra Khandelwal?an 工学 研究 associate from Sheffield believes may have 原因（となる）d the にわか景気s heard over the UK and New York, is called a pulse detonation engine (PDE), or pulse detonation wave engine (PDWE).?

At 正規の／正選手 速度(を上げる）s, the （手先の）技術 would be 力／強力にするd by a 伝統的な jet engines built into the lower fuselage.?

Once it 攻撃する，衝突するs supersonic 速度(を上げる）, the PDE takes over.?

A PDE 作品 by sending liquid methane or liquid hydrogen into the engine.?The 燃料 もや is then 点火（する）d.

This detonation is made inside a 特に designed 議会 and occurs when the 航空機 is travelling beyond the 速度(を上げる） of sound.?

At these 速度(を上げる）s, a 'thrust 塀で囲む' is created.?

This is when the （手先の）技術 is travelling so 急速な／放蕩な, 空気／公表する is 押し進めるd 近づく the nose that creates a '塀で囲む'.?

When the detonation occurs, the 航空機's thrust 塀で囲む is 押し進めるd 今後, and this is repeated 非常に／多数の times to 推進する the 航空機 今後.?

Alternatively, pulsejets could compress the 空気／公表する 原因（となる）d as the （手先の）技術 travels 今後 to make it more 簡素化する, while 燃料 is 点火（する）d in a 燃焼 議会.?

The 圧力 of the 拡大するing gases in this 議会 then 推進する the jet 今後.

武器s: Rumours （人命などを）奪う，主張する the Aurora may be equipped with 空気／公表する-to-ground 武器s, but this would 追加する 負わせる to the （手先の）技術, 示唆するing it is more likely that the 計画（する） would be used to reach 目的地s and 偵察 使節団s instead. ?

‘When we run a 実験（する） engine it’s a real 産業の noise and you can hear it for miles. We have people coming to us asking to make いっそう少なく noise or keep it to the daytime.'

A PDE engine 作品 by using the 軍隊 from a 一連の 爆発s, 原因（となる）d by mixing a 燃料 もや and 空気／公表する intake, to thrust itself 今後. It can theoretically 力／強力にする 計画（する）s at five times the 速度(を上げる） of sound.

The 科学（工学）技術 builds upon 'pulsejet' 原則s which first 現れるd in the 早期に 1900s and were used in German V-1 飛行機で行くing 爆弾s.

実験（する） fli ghts using the most 最近の forms of the 科学（工学）技術 have lasted only a few seconds, but it is still 名簿（に載せる）／表（にあげる）d by 共謀 理論家s as a possible way of 力／強力にするing the いわゆる Aurora 秘かに調査する jet.

Concorde flew no faster than Mach 2, おもに because the 構成要素s weren’t 利用できる in the Sixties that could withstand greater heat. 科学（工学）技術 has 前進するd, and the SR-72 (engine 詳細（に述べる）s pictured) will be a いわゆる ‘warm structure’ - that will heat up rather than 反映する the heat

Steven Aftergood, a 政府 secrecy 専門家 at the 連合 of American Scientists, said: 'If an 航空機 is responsible, then it’s 価値（がある） 公式文書，認めるing that it may not be 地元の at all.

'Because the sound wave that 原因（となる）s the にわか景気 can be 反映するd by the 成層圏, the source of the event could conceivably be hundreds or thousands of miles away from the place where it is heard on the ground.'??

But Dr Andrew Taylor, a 上級の lecturer in 航空 at Buckinghamshire New University, said the noises did not sound like a normal sonic にわか景気.

WHAT IS HYPERSONIC TRAVEL AND WHAT CAUSES THE SONIC BOOM?

A supersonic 計画（する） is one that 飛行機で行くs faster than the 速度(を上げる） of sound, at Mach 1 or greater, using a jet engine.

Mach 2.5 is about the 速度(を上げる） 限界 for gas-turbine engines. Any faster and the 気温 and 圧力 of 空気／公表する entering the engine is too high for the turbo 機械／機構 inside.?

To 飛行機で行く at hypersonic 速度(を上げる） - Mach 5 and above - 要求するs a different type of engine such as a supersonic-燃焼 ramjet, or scramjet.

These engines have no moving parts. Instead of the 回転／交替ing compressor and turbine in a jet engine, 空気／公表する is compressed and 拡大するd by コンビナート／複合体 systems of shockwaves under the 前線 of the 航空機, inside the inlet and under the fuselage at the 後部.

Travel becomes hypersonic when 気温s get so hot that 空気／公表する 分子s become 安定性のない and begin losing 電子s. At these 速度(を上げる）s the 空気／公表する becomes an electrically-告発（する），告訴（する）／料金d field.

At supersonic 速度(を上げる）s, 空気／公表する moves through a 一連の channels until is slowed 負かす／撃墜する to a point where 燃料 can be more easily 注入するd and 点火（する）d. This 解放（する）s energy and thrust.

At hypersonic 速度(を上げる）, this 空気／公表する moves even faster, which makes it difficult to slow 負かす／撃墜する to the 速度(を上げる） of sound and therefore 要求するs specialist 燃料 and 科学（工学）技術s, as seen in engines 含むing the pulse detonation engine (PDE).?

空気／公表する 反応するs like a fluid to supersonic 反対するs. As 反対するs travel through the 空気／公表する, 分子s are 押し進めるd aside with 広大な／多数の／重要な 軍隊 and this forms a shock wave much like a boat creates a 屈服する wave. The width of the いわゆる にわか景気 'carpet' beneath the 航空機 is around one mile (1.6km) for each 1,000ft (304 metres) of 高度

A PDE can make between 60 and 100 detonations a second.?

The sonic にわか景気 is created when an 航空機 or other type of 乗り物 飛行機で行くs 総計費 faster than the 速度(を上げる） of sound.?

空気／公表する 反応するs like a fluid to supersonic 反対するs. As 反対するs travel through the 空気／公表する, the 空気／公表する 分子s are 押し進めるd aside with 広大な／多数の／重要な 軍隊 and this forms a shock wave much like a boat creates a 屈服する wave. The bigger and heavier the 航空機, the more 空気／公表する it 追い出すs.?

The width of the いわゆる にわか景気 'carpet' beneath the 航空機 is around one mile (1.6km) for every 100ft (30.5 metres) of 高度.

An 航空機, for example, 飛行機で行くing supersonic at 50,000ft (15,240 metres) can produce a sonic にわか景気 反対／詐欺 about 50 miles (80km) wide.?

?'Because the sound wave that 原因（となる）s the にわか景気 can be 反映するd by the 成層圏, the source of the event could conceivably be hundreds or thousands of miles away from the place where it is heard on the ground.'

Steven Aftergood, 連合 of American Scientists

The sonic にわか景気, how ever, doesn't sound the same at each point.

The 最大限 intensity is heard 直接／まっすぐに beneath the 航空機, and this 減少（する）s as the lateral distance from the flight path 増加するs until it 中止するs to 存在する because the shock waves refract away from the ground.

The spread of the sonic にわか景気 depends only upon 高度, 速度(を上げる） and the atmosphere - and is 独立した・無所属 of the 乗り物's 形態／調整, size, and 負わせる.?

Although the 速度(を上げる） at which it was travelling, and its 場所 above the 大西洋 could 減ずる this 高度 and spread.?

Steven Aftergood, a 政府 secrecy 専門家 at the 連合 of American Scientists, said: 'If an 航空機 is responsible, then it’s 価値（がある） 公式文書，認めるing that it may not be 地元の at all.

'Because the sound wave that 原因（となる）s the にわか景気 can be 反映するd by the 成層圏, the source of the event could conceivably be hundreds or thousands of miles away from the place where it is heard on the ground.'?

But Dr Andrew Taylor, a 上級の lecturer in 航空 at Buckinghamshire New University, said the noises did not sound like a normal sonic にわか景気.

一方／合間, Professor Trevor Cox, an acoustic engineer from Salford University told MailOnline: 'To have heard a noise 同時に in New York and the UK, the source of the sound must have been 飛行機で行くing half way between.

'That's an awful long way - about 4,000 miles. You do get 事例／患者s of sounds travelling a long way, for example, in 2005, sound s from the Buncefield 解雇する／砲火／射撃 travelled around 125 miles to Belgium.

'But in this instance, it sounds やめる ありそうもない.'?

'With smaller 闘士，戦闘機 jets just a 選び出す／独身 にわか景気 would be heard, or, as with Concorde, a "二塁打 にわか景気" might be heard from larger 航空機 as both the nose and tail 原因（となる） shock waves,' he said.

'It sounds like 砲火 or other 弾薬／武器, 類似の to what I used to hear as a child growing up in Lincolnshire when the RAF and USAF 航空機 used to do 爆破 runs on the east coast 爆破 範囲s.

'It could be 地質学の or 気象の, but certainly not aeronautical in my opinion.'??

Many Twitter 使用者s 嫌疑者，容疑者／疑うd sonic にわか景気s, 類似の to ones which shook Kent last month when two RAF jets 迎撃するd a Latvian 貨物 計画（する） in British 領空.

But a 省 of Defence 広報担当者 told MailOnline last night she had no 記録，記録的な／記録するs of any jets 存在 緊急発進するd.

Others 示唆するd unusual 天候 条件s might be the source, but the Met Office 解任するd those （人命などを）奪う，主張するs and said there was nothing out of the ordinary.

A 広報担当者 told MailOnline: 'It definitely wasn't 気象の'.?

The 主要都市の Police said there had been a 花火s 陳列する，発揮する in Croydon, but Twitter 使用者s 主張するd that could not explain sounds in Bedfordshire, Glasgow, North Devon, Leicestershire and West Sussex.

At around the same time, a loud にわか景気 was 報告（する）／憶測d by a number of people in the upstate New York areas of Buffalo, Cheektowaga and Clarence more than 3,000 miles away.?

People 述べるd it as loud enough to shake their homes and 動揺させる windows.

In the US, in particular, the にわか景気 was せいにするd to a micro-地震.?

But Brian Baptie, 地震学者 at the British 地質学の 調査する told MailOnline: 'Micro 地震s are small.?

'Usually too small for people to feel and it’s 極端に ありそうもない that the noises were 原因（となる）d by this.?

'Even small 地震s some have audible 現象. For example, the Folkestone 地震 of 2007, that had a magnitude of 4.3, had a loud にわか景気ing noise.

'This is because the vibrations travel through the ground, and when this is coupled with the atmosphere it 生成するs sound waves that can be heard over a large distance.

'But, 観察するing this noise across such a large distance, 含むing across countries, is ありそうもない.

Many of the 報告（する）／憶測s were 選ぶd up by Twitter 使用者 事実上の 天文学者 (pictured), who said space 破片 re-entering the earth's atmosphere could have been responsible. He also said he was 納得させるd the noises were created by 航空機 sonic にわか景気s

One possible explanation is that the loud noise and ground shaking could have been a meteorite breaking up in the atmosphere, which would result in a sonic にわか景気 - but this was 解任するd by another 専門家

'It’s a 井戸／弁護士席-known 現象 and happens for big 地震s, but if this was the 事例／患者 it would have been felt 同様に, too, so it is ありそうもない the にわか景気s would just be 負かす／撃墜する to an 地震.'?

Ms Angiletta, who 記録，記録的な／記録するd the sounds told Mail Online: 'I was just at home watching TV when I couldn't hear the program 予定 to the loud noises. It was very distracting as it went on for ages.?

'I went out to look for 花火s but I couldn't see anything in the sky. That's when I 記録，記録的な／記録するd the clip to send to my family to see if they could hear the same thing.'??

The 27-year-old said that her family, who live 概略で seven miles away in Norbury, south London, could also hear the sounds, which lasted for about 30 minutes. She then turned to Twitter to see if anyone could explain what they were.??

Many of the 報告（する）／憶測s were 選ぶd up by Twitter 使用者 事実上の 天文学者, who said space 破片 re-entering the earth's atmosphere could have been responsible.

'Space 破片 such as old 衛星s and things can 原因（となる） sonic にわか景気s heard over very large areas,' he told MailOnline. 'It's the same for big meteors or 激しく揺するs that come in.

'There was very little 勝利，勝つd last night so 条件s were perfect for sound to travel very long distances.'?

Science writer David Dickinson was の中で the 専門家s who 解任するd the meteor theory.?

He told MailOnline that there was one piece of 破片 from ロシアの 衛星 Kosmos 2251 scheduled for re-入ること／参加（者）, but said that the タイミング was 'not a good fit' for it to have been over the UK.?

He 追加するd: 'I do not think it was a meteor or a piece of space-junk, as the noises について言及するd spanned a large segment of time. 加える, unless it was cloudy over the U.K., there would've been visual sightings.??

Theories: There was no 不足 of ideas when it （機の）カム to the possible source of the noises

Dave Reed, who lives in Fareham, Hampshire, said his dogs 'went crazy for a couple of minutes' after 審理，公聴会 what he had assumed were 花火s.

The noises 誘発するd 共謀 theories and 即座の （人命などを）奪う，主張するs of a 'マスコミ 灯火管制／停電'.

Twitter 使用者 Carrie Proctor wrote: 'This is how we'll find our that WW3 has begun. It'll be a Twitter hashtag long before any 公式の／役人 告示!'?

One MailOnline reader heard 類似の noises in Belgium.

Hyacinth Fahsi, who lives in?Grimbergen, 近づく Brussels, said the sound at 11pm 地元の time - the same time as it was heard in Britain - woke his daughter and matched the 記録，記録的な／記録するing in Croydon.

述べるing the sound as 'repetitive 爆発s', he said: 'I first thought it was 花火 but it was different. Maybe 雷鳴, but the sky was （疑いを）晴らす and I didn't see 雷, even far away.

'I wasn't thinking about it until my wife read your article.'?

• Do you have a 記録，記録的な／記録するing of last night's loud bangs? If so, we would like to hear from you. Please email dan.bloom@mailonline.co.uk