Astronomers Discover a Giant, Rocky 'Mega-Earth' 23 Times More Massive than Our Planet

Astronomers find an ultra-dense mega-Earth 23 times our planet’s mass but only 2.5 times its size

GJ 523b is 2.55 times Earth’s radius but about 23.5 times its mass, making it unusually dense for a planet of its size. Its high density, apparent lack of a thick hydrogen-helium atmosphere and sharply tilted orbit point to an unusual formation history. The team proposes calling planets like this “mega-Earths,” a class defined by large radii and Earth-like or greater densities. GJ 523b is about 2.5 times wider than Earth, yet it packs roughly 23…

Astronomers discover a giant, rocky 'mega-Earth' 23 times more massive than our planet

"This isn't what we expected at all."Astronomers have discovered an unusually massive, dense exoplanet that challenges conventional ideas about how rocky planets form.Called GJ 523b, the exoplanet is about 2.5 times wider than Earth but packs roughly 23 times our planet's mass into that relatively compact size. Worlds this large and dense are sometimes referred to as "mega-Earths," an informal term for unusually massive, predominantly rocky plan…