Ancient Earth Could Have Been Donut-Shaped 'Synestia' Form, Study Suggests

A new study suggests that the Earth may have been donut-shaped or in a "synestia" form 4.5 billion years ago. The planet could have been a hot, donut-shaped object with vaporized rock as a result of a collision of two planet-sized celestial bodies.

The Earth's ancient history is linked to a collision, potentially with a Mars-sized object called Theia. But this is the first time a study suggested that the Earth could have been donut-shaped due to the impact.

"We looked at the statistics of giant impacts, and we found that they can form a completely new structure," study co-author Sarah Stewart, a planetary scientist at the University of California, Davis, said in a statement.

The donut-shaped or synestia form is proposed as a new type of planetary object. The researchers led by a graduate of Harvard University modeled the scenario that if an Earth-sized object collides with a larger object while moving and spinning really fast, according to Space.com.

These collisions were so violent that the resulting bodies melted and partially vaporized, eventually cooling and solidifying to the nearly spherical planets we know today.

Instead of a debris, their scenario suggested that it will result in a synestia or a weirder donut-sized object. Usually, collisions were believed to be violent causing bodies to melt and vaporize and then cooling and solidifying in nearly spherical shapes creating planets.

But the new ancient Earth theory suggested that it took the form of a donut after the impact called synestia. However, if these planetary objects really do exist, they are short-lived. Based on the paper, the donut-shaped Earth may have only stayed in that phase for about a century. It then lost enough heat to condense back into its form as a solid circular object.

The researchers also suggest that syntesias remain hypothetical at the moment since no one has ever seen it before. But, they are hopeful that mankind may be able to see one in the near future in alien solar systems. The result of the study was published in the Journal of Geophysical Research: Planets.