Rumours about an enormous iron meteorite the size of a car lying somewhere on the Nullarbor Plain began circulating in the mid-1940s.

Two expeditions were mounted in the 1960s to find it.

But it was not until 1966 that geologists RB Wilson and AM Cooney found the outer space debris. And it was huge.

The biggest meteorite found in Australia was recovered from the Nullarbor in 1966. ( Supplied: WA Museum )

There were two main pieces, made mainly of iron and nickel, found about 180 metres apart.

Named the Mundrabilla meteorite, the biggest part weighed 12.4 tonnes and it remains the largest meteorite discovered in Australia.

The second piece weighed 5.4 tonnes.

50 years later, another space hunt begins

Now the hunt is on for another possible meteorite, after a fireball lit up the sky and left witnesses across Perth and the Wheatbelt region gobsmacked on Tuesday night.

Scientists are combing the countryside around York, 100 kilometres east of Perth, looking for any alien rocks that may have made it to Earth.

WA Premier Mark McGowan said he hoped this one would not be made of iron.

"If it's made of gold that's great, and will no doubt go to the highest bidder," he joked.

Wherever it is and whatever it is made from, the team from Curtin University's Desert Fireball Network is not expecting to find it at the end of a long furrow cut through a field, like in a Superman movie.

A meteor streaks through the sky over Perth. ( Supplied: Dylan Teede )

Researcher Renae Sayers said meteors travelled about 50,000 kilometres per hour, but then slowed down once they hit the Earth's atmosphere.

"When it hits the ground, it's like somebody's dropped it from a building, or your hand," Ms Sayers said.

"It's travelling at a couple of metres per second. It's slowed down quite a lot."

But a slower speed will not help them find this one.

Cameras used to track location

The team usually relies on the Desert Fireball Network's 52 solar-powered observatories across the country, with high-quality digital cameras in protective boxes mounted on struts, to triangulate the location of meteorites.

In November 2016, four separate cameras captured a meteorite which fell into a field on a farm near Morowa, 370km north of Perth.

Curtin University scientists were able to track the fall line and calculate the landing spot to within 200 metres of where the 1.15 kilogram meteorite was found.

The pristine meteorite sample recovered from Morawa, protected by a non-reactive Teflon bag. ( Supplied: Curtin University )

Ms Sayers said they used the data from each camera as anchor points.

"It's so accurate we can work out where it came down on Earth, and importantly where it came from in space, to work out the orbit," she said.

But this time it is different.

Only one camera, located north-west of Northam, caught the fireball.

An image of the fireball captured in Northam. ( Supplied: Desert Fireball Network, Curtin University )

The others missed it because of poor visibility from cloud cover.

The team is however making use of vision captured on dash cams and security cameras sent in by the public.

The vision shows the fireball start to burn about 80km up in the atmosphere, before possibly breaking into a number of pieces about 20–30km above the ground.

"It appeared in some of the footage that the meteor may have actually broken apart as it was entering the atmosphere, and that means that we will get multiple meteorites," she said.

"That does increase the likelihood that we're going to pick something up.

"We have had fragmented fireballs in the past. The one in 2016, we suspect that was a fragmented piece as well."

A suspected meteor is captured flashing through the sky over Perth. ( Supplied )

Don't expect to cash in on find

And if one is found, you won't get any massive payouts for a piece of interstellar treasure. In fact, it could end up costing you money.

It belongs to the state, under Section 45 of the Museum Act 1969, and ownership is vested to the WA Museum.

The legislation states people cannot move a meteorite, unless it is to give it to the museum.

There can be a reward for providing information that can lead to the recovery of a meteorite that was not known about, but anyone who destroys a meteorite or removes it without authority faces a $1,000 fine.

The Mundrabilla meteorite, for example, now sits in the WA Museum's collections centre in Welshpool.

The WA Museum's meteorite collection is one of the biggest in the southern hemisphere, with about 14,000 specimens from 750 separate meteorites.