Hot-Donut Earth? Planet May Once Have Taken on Odd ‘Synestia’ Form The structure of a planet, a planet with a disk and a synestia, all of the same mass. Credit: Simon Lock and Sarah Stewart Earth probably became a “synestia” for a brief period about 4.5 billion years ago, according to a new study. 最新の研究によれば、約45億年前、地球はおそらく短い間「シネスティア構造」になっていた。 brief period - 短期間。 That’s the term for a newly proposed