For long, scientists have maintained that earth's inner core is a sphere consisting of a solid mass of iron, but a new theory claims there is a Rubik's cube in earth's womb.

According to the theory published in journal Science, Swedish researchers have shown that it is a body-centered cubic crystal structure in the core of earth which forms a cube with atoms in each corner and a further atom in the middle of this cube, making it look like a Rubik's cube.

It is oriented in such a way that its great diagonal is directed along the earth's axis of rotation, which makes it possible for the iron to evince sound propagations with the velocities in seismic observations, the Science Daily reported on Monday.

The findings may be of significance for the understanding of the cooling down of the earth, and of the stability of the earth's magnetic field.

'This study opens new perspectives for our understanding of the earth's past, present, and future,' says researcher Natalia Skorodumova from Uppsala University.

In seismic observations, they found that elastic waves pass more rapidly through this core in directions that are parallel to the earth's axis of rotation than in directions parallel to the equator.

Researchers showed that the body-centered cubic crystal structure at high temperatures­ -- a structure that despite its high degree of symmetry evinces a surprisingly high level elastic properties are contingent on direction.

'We found that the body-centered cubic structure of iron is the only structure that could correspond to the experimental observations,' says researcher B�rje Johansson.