{"id":458304,"date":"2026-06-03T05:27:32","date_gmt":"2026-06-03T05:27:32","guid":{"rendered":"https:\/\/www.newsbeep.com\/nz\/458304\/"},"modified":"2026-06-03T05:27:32","modified_gmt":"2026-06-03T05:27:32","slug":"meteorite-found-in-africa-preserves-evidence-of-long-lost-massive-protoplanet","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/nz\/458304\/","title":{"rendered":"Meteorite Found in Africa Preserves Evidence of Long-Lost Massive Protoplanet"},"content":{"rendered":"

The Northwest Africa (NWA) 12774<\/a>, an angrite meteorite discovered in the Sahara Desert, likely in Mauritania, appears to be a fragment of a vanished protoplanet, offering the strongest evidence yet that a large planetary body formed and was later destroyed during the Solar System\u2019s chaotic infancy.<\/p>\n

\"This<\/a><\/p>\n

This is an artist impression of the protoplanetary disk around HD 107146. Image credit: A. Angelich \/ NRAO \/ AUI \/ NSF.<\/p>\n

\u201cIt\u2019s incredible to think there was once a world this large,\u201d said University of Colorado Boulder\u2019s Dr. Aaron Bell<\/a>, lead author of the study.<\/p>\n

\u201cWe only know it existed because a few fragments of it happened to land on Earth.\u201d<\/p>\n

\u201cThese meteorites preserved evidence of a completely different pathway through which early planets developed.\u201d<\/p>\n

In the study, Dr. Bell and colleagues analyzed a piece of the NWA 12774 angrite meteorite.<\/p>\n

\u201cAngrites are among the oldest known volcanic rocks in the Solar System, forming within just a few million years after the Solar System began about 4.56 billion years ago,\u201d they said.<\/p>\n

\u201cThey are also exceptionally rare. Out of more than 80,000 meteorites discovered on Earth, only 68 are angrites.\u201d<\/p>\n

\u201cWhat makes angrites especially puzzling is their chemistry. Unlike Earth, Mars and other rocky planets, angrites contain very little silicon dioxide, or silica, which is a major ingredient in nearly every known terrestrial planet in the Solar System.\u201d<\/p>\n

\u201cFor that reason, scientists thought angrites must always come from an asteroid, something with a radius of less than 200 km (124 miles).\u201d<\/p>\n

The researchers found that NWA 12774 contained clinopyroxene, a mineral crystal commonly found in Earth\u2019s crust and mantle.<\/p>\n

In particular, NWA 12774\u2019s clinopyroxene was exceptionally rich in aluminum, a telltale sign that the rock formed under enormous pressure deep underground.<\/p>\n

The scientists then reconstructed the pressure conditions that might have been present for NWA 12774 to form.<\/p>\n

\"The<\/a><\/p>\n

The X-ray image of NWA 12774. Image credit: Aaron Bell \/ CU Boulder.<\/p>\n

To their surprise, the aluminum-rich clinopyroxene needed at least 17.5 kilobars of pressure. For comparison, the crushing pressure at the bottom of the Mariana Trench, the deepest point on Earth, is only around 1 kilobar.<\/p>\n

That level of pressure could not have existed inside a small asteroid.<\/p>\n

Instead, the calculations suggested that the body where angrites came from must have been at least 1,000 km (621 miles) in radius.<\/p>\n

Other clues in the meteorite pointed to an even more striking possibility.<\/p>\n

The crystals inside NWA 12774 still preserved sharp edges and delicate chemical patterns that would have been erased if they formed deep underground.<\/p>\n

This suggested that the crystals likely formed at relatively shallow depths inside the parent body, so the world had to be even larger.<\/p>\n

Under that scenario, the angrite parent body might have stretched beyond 1,800 km (1118 miles) in radius, making it comparable in size to Earth\u2019s moon and possibly approaching a Mars-sized world, which has a radius of 3,300 km (2,050 miles).<\/p>\n

\u201cThere are many meteorites sitting in drawers that haven\u2019t been thoroughly studied, so there were likely more of these protoplanets we don\u2019t know about,\u201d Dr. Bell said.<\/p>\n

\u201cIt remains unclear how the protoplanet met its end. One possibility is that a catastrophic event in the early Solar System shattered it, with its fragments later become the building blocks of other terrestrial planets, including Earth.\u201d<\/p>\n

\u201cThe materials that formed the angrite parent body are fundamentally different from the ingredients of Earth and Mars.\u201d<\/p>\n

\u201cIt points to a distinct and separate evolutionary path in planetary formation in the early history of our Solar System,\u201d Dr. Bell said.<\/p>\n

The study<\/a> was published online April 10 in the journal Earth and Planetary Science Letters.<\/p>\n

_____<\/p>\n

Aaron S. Bell et al. 2026. High-pressure clinopyroxene in Northwest Africa 12774 and new geobarometric evidence for a planetary embryo-sized angrite parent body. Earth and Planetary Science Letters 685: 120029; doi: 10.1016\/j.epsl.2026.120029<\/p>\n","protected":false},"excerpt":{"rendered":"The Northwest Africa (NWA) 12774, an angrite meteorite discovered in the Sahara Desert, likely in Mauritania, appears to…\n","protected":false},"author":2,"featured_media":458305,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[190,19858,232792,232793,17850,3146,110419,20942,51024,111,139,232794,69,19794,98533,36457,170663,147,3145],"class_list":["post-458304","post","type-post","status-publish","format-standard","has-post-thumbnail","category-science","tag-africa","tag-aluminum","tag-angrite","tag-clinopyroxene","tag-early-solar-system","tag-earth","tag-mauritania","tag-meteorite","tag-mineral","tag-new-zealand","tag-newzealand","tag-nwa-12774","tag-nz","tag-planet","tag-planetesimal","tag-protoplanet","tag-sahara","tag-science","tag-solar-system"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts\/458304","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/comments?post=458304"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts\/458304\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/media\/458305"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/media?parent=458304"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/categories?post=458304"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/tags?post=458304"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}