People across Devon and Cornwall have inundated police with calls saying they had experienced an earth tremor.
Officers from the region said they received reports of people hearing loud bangs and buildings shaking from about 16:15 BST on Thursday.
Police staff in Devon's Newton Abbot station also said floors shook.
The British Geological Survey said it had no evidence of a tremor, but added it could have been a sonic boom from a meteorite falling to earth.
'Spectacular' noise source Police said the calls were "fairly widespread", coming in from Harrowbarrow in south east Cornwall, as well as the South Hams and Teignbridge areas of south Devon, the Tamar Valley and Dartmoor.
Insp Gareth Twigg, of Devon and Cornwall Police, said: "The first calls reported sounds like an explosion. Further calls also described noise and then objects shaking.
"One lady on Dartmoor who was alive during World War II said it was like a bomb going off.
"In Newton Abbot station, we had windows and the ground shaking, so we were getting it first hand too.
"We checked with the British Geological Survey to ask if it was because of a tremor, but they said it may have been caused by something a little more spectacular - possibly a sonic boom from a meteorite as it caused pressure changes in the atmosphere while falling.
"It appears nothing has struck the earth that has caused any damage or injury ( via bbc.co.uk ).
"We're waiting to hear if we get anything back from local scientists."