The Red Planet has a bloody history.Newly examined data from NASA's retired InSight lander suggest that there may be giant chunks of rocky material deep inside the mantle of Mars, which were lodged there after a barrage of massive objects slammed into its surface some 4.5 billion years ago. Some of these smithereens are so large, the researchers say, that they're effectively protoplanets — moon-sized objects in the early stages of becoming a planet proper. In other words: Mars could be stuffed with the dead embryos of failed worlds.The work, published as a new study in the journal Science, reveals a picture of the Martian interior that astronomers say is unprecedented for any planet, including our own."We've never seen the inside of a planet in such fine detail and clarity before," study lead author Constantinos Charalambous from Imperial College London said in a NASA statement about the work. "On Earth, features like these may well have been largely erased."Though it's home to the largest volcano in the solar system — Olympus Mons, which towers at twice the height of Mount Everest — Mars has long been considered to be a "dead" planet, showing little signs of contemporary geologic or volcanic activity. Unlike Earth, its crust isn't broken up into tectonic plates; it's just one huge, inert slab. Recent discoveries have shown that Mars is more moribund than actually dead, but it's a still largely inactive world.That said, its interior still houses many secrets and surprises, producing the odd pulse here and there. It's still occasionally rattled by tremors, or marsquakes, and the seismic waves these produce offer a rare opportunity to interrogate what lurks beneath the surface. That's because seismic waves can slow down or speed up depending on the material they pass through. By analyzing how the waves travel, along with other subtle changes to their mechanical properties, scientists can piece together a picture of everything they touched.In data collected by a seismometer on NASA's Insight lander, the researchers found eight marsquakes that contained unusually powerful waves that slowed down deep in the mantle. Initially, "we thought the slowdowns were happening in the Martian crust," coauthor Tom Pike, also from Imperial, said in the statement. "But then we noticed that the farther seismic waves travel through the mantle, the more these high-frequency signals were being delayed."From there, with the help of planet-wide computer simulations, they revealed that these slowdowns were taking place in localized pockets inside the mantle with a different composition to their surroundings — a clear sign, they say, of something embedded in there that came from off the planet.The foreign debris likely got there early on in the solar system, a violent and tumultuous period when huge chunks of wayward material frequently smashed into the newly formed planets. According to the NASA release, the "ancient impacts released enough energy to melt continent-size swaths of the early crust and mantle into vast magma oceans, simultaneously injecting the impactor fragments and Martian debris deep into the planet's interior."Earth was not spared this kind of punishment — a catastrophic collision with a protoplanet is thought to have spawned the Moon, for example — but its scars from this period are long gone. Being an active world, it continuously churned through its upper mantle, pushing old and damaged tectonic plates into its core and replacing it with fresh stretches of crater-and-lump-free skin.All told, the new research builds the case that Mars is a single-plate world, and may gave us a hint of what the interior of the other rocky planets of our solar system are like."What we're seeing is a mantle studded with ancient fragments," Charalambous said of Mars. "Their survival to this day tells us Mars' mantle has evolved sluggishly over billions of years."More on Mars: Why the New York Times Claimed Life Had Been Found on MarsThe post NASA Finds Evidence That Mars Devoured Huge Chunks of Other Planets appeared first on Futurism.