A police sergeant in Portland, Maine was just spending a fairly normal Tuesday night at work when his vehicle's dash cam captured an incredible scene: an inexplicably bright, burning object hurtled through the night sky.

Was it a meteor? Was it an alien spacecraft?

The video, which has since been posted on the Facebook page of Portland Maine Police Department, catches another police officer - whose name is Graham Hults - as he says in astonishment, "Oh my ... God."

Both Hults and Police Sgt. Tim Farris were fortunate enough to watch the cosmic object blaze across the Portland night sky. Farris was on the lookout for over-speeding drivers while parked in front of the central fire station when it occurred.

"You never know what you are going to see on duty," the police department said in its humorous Facebook post.

The fireball, which could have been a meteor or an alien spaceship, was caught on video 50 minutes after midnight on May 17.

After the fireball streaked through the night sky, the American Meteor Society (AMS) said it had received 690 reports of sightings from New Jersey to Quebec in Canada.

New Photo (+ video & map) of the #Fireball caught on May 17 over Northeastern US.. https://t.co/9sl1NJ9fDD #meteor pic.twitter.com/SpJ0cSGwDx

— AMSMETEORS (@amsmeteors) May 17, 2016

Sightings were also reported in other areas including New Hampshire, Massachusetts, New York, New Jersey, Pennsylvania, Connecticut, Rhode Island and Vermont.

According to the AMS, there have been no reports of any damage, but it's also not surprising, as fireballs that hurtle through the night sky are quite usual.

Fireball is a term scientists use to indicate a very bright meteor, including the one seen over Portland. The AMS says thousands of meteors fall into the Earth's atmosphere every day, but they only often fall in uninhabited areas or during daytime when it is too bright to see them.

A resident of New Hampshire described the event as "absolutely amazing."

Another lucky watcher saw the fireball from Ontario and said the object seemed like it was so close as it descended. He said he waited for a minute to see if fire was erupting beyond the end of the lake.

"But [there was] nothing," said the man.

Vermont radio station Star 92.9 posted a series of photos reportedly from a listener who witnessed the fireball.

Watch the video from the Portland Maine Police Department below.

Here is another video, which was captured in the northeast.