{
  "id": 2173710,
  "title": "Mystery 'Mega-Planet' 23 Times More Massive Than Earth Baffles Scientists",
  "url": "https://urgent.news/2026/08/20/mystery-mega-planet-23-times-more-massive-than-earth-baffles",
  "topic": "science",
  "section": "Science",
  "published": "2026-08-20T16:29:23.000Z",
  "source": {
    "name": "Newsweek",
    "slug": "newsweek",
    "url": "https://www.newsweek.com/mystery-mega-planet-23-times-more-massive-than-earth-baffles-scientists-12348504"
  },
  "original_language": "en",
  "account": "A massive planet, 23 times more massive than Earth, has baffled scientists due to its lack of atmosphere. Named GJ 523b, the planet is roughly 170 million years old and nearly twice the size of Earth. It is about 60 percent the size of Neptune and weighs approximately 23 times Earth. The University of Wisconsin-Madison researchers describe it as mostly dense rock surrounding a massive core. Lead author Max Kroft expressed surprise at the unexpected find, stating, \"Dense planets like this aren't uncommon, but they're usually small rocky planets similar to Earth or Mercury. This planet is two and a half times bigger than the Earth.\" The planet is classified as a Mega-Earth, an exceptionally large and dense terrestrial planet outside our solar system, more massive than a typical super-Earth. Researchers are now working to better understand GJ 523b and define the Mega-Earth category more clearly. The planet's lack of atmosphere could be due to it having once orbited too close to its star, causing extreme heat to strip away its atmosphere, or it might have formed through a collision between two planets, with the impact heat stripping away the atmosphere.",
  "summary": "“This isn’t what we expected at all,” researchers said of a Mega-Earth that defies planet formation theories.",
  "key_points": [
    "GJ 523b is 23 times more massive than Earth.",
    "Planet lacks atmosphere, baffling scientists.",
    "Researchers studying to understand Mega-Earth category."
  ],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}