If you looked up the sky at twilight yesterday and thought you saw an all-mighty fireball streaking across the sky - don’t worry, you’re not the only one.

As this footage obtained by 7 News Perth shows, reports of the mysterious and long-lasting flash are right on the money.

One motorist driving on Karrinyup Road said he couldn’t believe his eyes when he saw the strange object heading towards the ocean.

“Must have been a meteor...it went for approximately five minutes,” he said.

“Craziest thing I’ve seen in a long time.”

Exactly what it is this driver - and many others - observed is up for debate.

A meteor is one possible explanation but an aircraft contrail has been offered up as another possible explanation and then there is the chance it’s a man-made object arriving from space.

“Because of its speed it's most likely to be space junk... meteors are moving anywhere from sixteen to thirty kilometres per second,” Perth Observatory’s Matt Woods said.

So far, no evidence has been found on the ground.