Earth might once have resembled a hot, steamy doughnut | Science News

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Earth might once have resembled a hot, steamy doughnut

The newly proposed planetary shape is called a synestia

By
9:00am, July 21, 2017
synestia illustration

PUFFED UP  Early in its development, a rocky planet may turn into a synestia (illustrated), a spinning disk of vaporized rock that looks like a jelly-filled doughnut with a small, solid core (gray).

Synestia
\sin-es-ti-ə \ n.

A large spinning hunk of hot, vaporized rock that forms when rocky, planet-sized objects collide

Earth may have taken on a jelly doughnut shape early in its history. The rocky planet was spinning through space about 4.5 billion years ago when it smacked into a Mars-sized hunk of rotating rock called Theia, according to one theory (SN: 4/15/17, p. 18). That hit may have turned Earth into a synestia, a blob of mostly vaporized rock with an indented center, resembling a slightly squished jelly doughnut, new simulations suggest. This synestia wouldn’t have had much of a solid or liquid surface. And the structure could have spread to about 100,000 kilometers across or more, much larger than its original 13,000 kilo­meters or so. The added girth would have come from rock vaporizing and continuing to spin quickly, which would puff up and

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