An unexplained incident has concerned Nasa and locals in the area, with some wondering if this could be an alien sighting.

On Monday, residents in Minnesota witnessed a bright object flying across the sky, following a loud bang that rattled their homes.

Investigators have described the phenomenon as the size of a refrigerator that hit the earth at 30,000 to 130,000 miles per hour.

The sonic boom was concluded to be too close to be considered a meteor, according to Beltrami County Emergency Management.

Professor Juan Cabanela, a local physicist, believes that the timing of the boom, also proves that it might not be an asteroid.

"I still don’t know what it was, but I was fairly confident it couldn’t be a meteor," he said in the email, seen by Mail Online.

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