The inner core at the center of the Earth, a ball of iron and nickel about 1,500 miles wide, may not be perfectly solid. A new study finds evidence that the inner core’s outer boundary has noticeably changed shape over the past few decades.

The inner core is usually thought to be shaped like a ball, but its edges may actually have deformed by 100m or more in height in places, according to Prof John Vidale who led the research. Earth's core is the beating heart of our planet as it produces a magnetic field that protects life from burning up in the Sun's radiation.