A shocking new discovery made - huge mountains larger than Mt. Everest found 660km under the earth's surface

Scientists have discovered something beneath the earth's surface that could possibly change our understanding about how our planet was formed billions of years ago. They have found massive mountains in earth's mantle.

Generally, we study about three layers of earth in our science classes - crust, mantle and core. Although, it isn't wrong, but technically there are a lot more layers that scientists have identified so far.

According to a study that was published in the Science journal, scientists used data from huge earthquake which took place in Bolivia back in 1994, to find huge mountains in deep earth. These data came from the shockwaves that shook Bolivia with a magnitude of 8.2 - the second largest deep earthquake ever recorded. With the help of these data, scientists were able to find huge mountains and other topography at a depth of 660 km beneath earth's surface that separates the upper and lower mantle. Researchers haven't given it any official name yet, and call it "the 660 km boundary".

Scientists from Princeton University in US and the Institute of Geodesy and Geophysics in China studied the powerful waves that were generated by the massive earthquakes. 

Any earthquake with magnitude 7.0 or higher send shockwaves in all directions which can travel through the earth's core to the other side of the planet. The recorded data is then used by powerful supercomputers to simulate the complicated behaviour of these waves which scatter in the deep earth. The technology used depends upon the fundamental properties of waves - their ability to bounce and bend. For instance, light waves travel straight until and unless an obstacle comes in their path. If there is an opaque surface, it will bounce back (reflect) and if there is a transparent medium like a prism, it will bend (refract). Similarly, the waves from an earthquake travel straight through homogeneous rocks but get reflected or refracted when they encounter a rough or irregular surface.

Since, every surface has some roughness, hence we can observe the scattering of light through them, which carry the information about its roughness - according to Wenbo Wu who was at Princeton at the time of study. Similarly, by studying the scattering of these seismic waves, it was found that there is a layer of rough surface at a depth of 660 km - Wu added. These have stronger topography than the rocky mountains above the earth's surface. This means that their surface has more roughness than the surface we live in, which was surprising for researchers.
Moreover, the geography of these structures is irregular, means their roughness isn't distributed equally - which resembles the structure of surface above earth. Just like earth's surface has irregular distribution with rough high mountains and smooth deep ocean floors, the 660 km boundary also have rough areas and smooth patches. According to a seismologist Christine Houser (an assistant professor at Tokyo Institute of Technology, who wasn't a part of the research), earth's deep layer are as complicated as what we see above the surface.
The researchers also examined a layer 410 km deep - a transition zone at the top of the mid-mantle. However, they didn't observe similar roughness. 

Although, the model doesn't provide any information about precise height determinations, but there are high chances that these things are larger than anything above the earth's surface.
This study will play a major role in further understanding the origin of our planet and how it was formed.