New study may shed light on what happened to Amelia Earhart
The disappearance of American pilot Amelia Earhart is one of unsolved mysteries of the 20th century. Her plane went missing Central Pacific in 1937. In 1991 on an island located near that place was found aluminum panel, presumably from an aircraft. But only now scientists with the help of new research methods have found letters and numbers on this panel. 
Perhaps now the researchers are one step closer to solving the problem. what happened to Amelia Earhart. Scientific analysis revealed on the panel once engraved letters and numbers "D24", "XRO" and either "335" or "385", which were not visible to the human eye. The experts believe that it could be production code. 
One theory is that the panel found on the island Nikumaroro in the Western Pacific in 1991, actually is a metal patch that was added to the aircraft Earhart during renovations. 
In 1937, Amelia Earhart set herself the task of becoming the first woman to fly around the world. She took to the sky 1 June 1937. But a few weeks later, the plane disappeared next to Howland Island in the Pacific Ocean, and despite the ongoing search 17 days, its wreckage was never found. It is generally accepted that the plane ran out of fuel and fell into the sea, but not all of it agree.
Model aircraft Amelia Earhart Lockheed Electra 
There are several main theories:
1. Amelia Earhart and her navigator Fred Noonan fall into the ocean at several kilometers from the destination due to visibility problems and fuel, and instantly die.
2. Earhart and Noonan crash on Nikumaroro Island, where they later die as a result of attacks by coconut crabs that prey on food at night and grow up to a meter in length. The name of these crabs comes from their ability to open hard shells with their claws coconuts.
3. Earhart and Noonan veer off course and crash landing near Mili Atoll in the Marshall Islands. they are rescued, but soon the Japanese take them prisoner and send them to a camp on Saipan. Noonan beheaded, and Earhart dies in 1939 of malaria or dysentery.
4. Earhart and Noonan make it to Howland Island as planned and are eaten by cannibals.
5. Earhart was an American spy sent to gather information about the Japanese before World War II.
6. Earhart and Noonan can't find Howland Island and try to implement a contingency plan. After ten hours' journey back to where they came from, they endure wreck in the jungle of the island of East New Britain, which is now known as Papua New Guinea.
As you can see, there are a lot of theories: from death in a crash to capture and being held hostage by the Japanese. There are even theories that she returned to the US under a false name. The latter is based on archival photograph of Earhart and her navigator Fred Noonan alive and in dock in the Marshall Islands, hundreds of miles from Howland. 
And there is only one piece of evidence that can shed light on the fact that actually happened is an aluminum patch that was recently subjected to scientific analysis using new methods criminalistics.
These letters and numbers, invisible to the human eye, according to experts, can be linked to the production code. Criminologists working feverishly to see if they can trace the origin of the code and understand if the metal panel belonged Earhart aircraft or not.
This data may at least reinforce some theories and rule out others entirely.
Amelia Earhart and Fred Noonan 
Researchers are testing the hypothesis that Earhart and her navigator Fred Noonan landed and ended up dying on Gardner Island, which is now called Nikumaroro.
If they can definitively determine what the discovered tags, such as a serial number, this can either confirm that the panel belongs to the Earhart aircraft, or definitively exclude such opportunity.
To discover the hidden text, the researchers used non-destructive imaging technique called neutron radiography, with with which you can find the smallest clues.
Neutron radiography involves irradiating a sample—in this in the case of a panel, by neutrons. Neutrons pass through heavier particles and interact with some nuclei of lighter particles in sample.
Digital photographic plate captures contrasts as neutrons escape from the sample on the other side, creating a screen printed image sample, including information invisible to the naked eye.
