Expert on Amelia Earhart’s disappearance reveals what he thinks really happened as scientists 'finally discover' lost plane

An expert who has spent 20 years investigating the disappearance of Amelia Earhart has revealed what he thinks happened to the pilot.

Almost 90 years ago, Earhart disappeared, while flying across the Pacific Ocean in a Lockheed Electra.

She had been travelling across the globe alongside navigator, Fred Noonan, when the pair vanished.

Earhart and Noonan began by flying across the United States before going on to make numerous stops in South America, Africa, Asia and Australia.

At the end of June, the pair landed in Lae, New Guinea and had just 7,000 miles (11,000 km) of their journey left to go, all of which would be over the Pacific Ocean.

However, after they set off from Lae on 2 July 1937, they were never heard from again.

There are a number of theories about what happened to Earhart (Library of Congress/Getty Images)

The pair had planned on stopping at Howland Island to refuel, but they never made it.

There's no conclusive evidence of exactly what happened, but there are a number of theories - some more plausible than others.

Many believe the most likely explanation was that they ran out of fuel and crashed into the Pacific Ocean.

Final radio transmissions back this up, with Earhart warning about poor weather conditions and the aircraft being low on fuel.

"We must be on you, but we cannot see you," Earhart told the nearby USS Itasca (via docsteach). "Fuel is running low. Been unable to reach you by radio. We are flying at 1,000 feet."

At 8:43 am Earhart added: "We are on the line 157-337, flying north and south," which indicated they were flying towards Howland Island.

The pair never made it to Howland Island (Topical Press Agency/Getty Images)

One expert on the case, Chris Williamson, has spent the last two decades investigating what happened.

In a Reddit 'Ask Me Anything' Chris - who hosts the Chasing Earhart podcast - was asked for his own personal opinion on what happened all those years ago.

Chris explained: "I think it’s hard to ignore the Itasca logs and what she said that morning. Anyone who attempts to prove anything else, has to deal with that.

"I think it’s possible that the aircraft out at Buka is hers. Or at the least, a missing Electra. The kicker to that is, there’s only one known missing Electra in the world and that’s hers. Snavely has an aircraft and the site is screaming at us to go look.

"So while they continue deep ocean searches we’re gonna do that. The more we can cross off the table theory wise, the better.

"I think the evidence is strong that the aircraft lies somewhere near Howland, but until someone provides that concrete proof, the entire case is up in the air as far as I’m concerned."

Another theory is that the pair were taken prisoner by Japanese forces, while some believe Earhart survived the crash and lived the rest of her life on Nikumaroro Island.

This particular theory has been popular over the years, due to a number of items that have been recovered, such as a shoe heel - however, this was found to be a size nine and therefore too big for Earhart.

Meanwhile, in 1940, human remains were recovered on the island, which many believe are Earhart's - although this has been disputed.

Purdue University has recently confirmed they are launching a new investigation following satellite images taken in 2015, which appeared to show Earhart's missing plane on Nikumaroro.

A research team are heading out in November, with Steve Schultz, Purdue’s general counsel, telling NBC News: "We believe we owe it to Amelia and her legacy at Purdue to fulfil her wishes, if possible, to bring the Electra back to Purdue."