Taking to social media to tweet about the huge sound, some people said their house “shook” and windows and doors “rattled” from the booming noise on Wednesday morning.
Witnesses said the bang could be heard for miles around for at about 11.45am,, sending “hundreds” of panicked birds up into the air.
One person said: “The sonic boom or whatever it was in Norwich just now literally made my house shake. I too am shooketh.”
Another person who said they live just outside of Norwich said they too “heard and felt a boom which made the windows shake”.
James Lowen, a nature and travel writer in Norfolk, said: “Presumed sonic boom (sudden massive noise) has just sent 500 wood pigeons into the air above our house! Same observed by friends nearby in Norwich too. And further afield? Mad!”
A sonic boom occurs when an aircraft moves at supersonic speed (above 767mph) and breaks the sound barrier, which results in a “thunderous” sound, according to the Royal Air Force.
Flight tracking website FlightRadar24 shows a Boeing KC-135R Stratotanker military refuelling aircraft circled over Mildenhall around the time the sound was heard. However, it remains unclear what caused the sound at this time.