{"id":155325,"date":"2025-11-27T08:16:10","date_gmt":"2025-11-27T08:16:10","guid":{"rendered":"https:\/\/www.newsbeep.com\/il\/155325\/"},"modified":"2025-11-27T08:16:10","modified_gmt":"2025-11-27T08:16:10","slug":"the-lost-planet-that-gave-birth-to-the-moon-may-have-been-earths-next-door-neighbor","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/il\/155325\/","title":{"rendered":"The Lost Planet That Gave Birth to the Moon May Have Been Earth\u2019s Next-Door Neighbor"},"content":{"rendered":"

\"\" <\/a>Portions of the moon-forming impactor Theia survived throughout Earth\u2019s history in the deep mantle while others went on to form the Moon. Credit: CNN World. <\/p>\n

About 4.5 billion years ago, Earth had a violent neighbor. A young, still-forming planet named Theia slammed into our world with enough force to melt vast portions of its mantle and scatter a huge amount of debris into orbit. This molten debris would eventually coalesce into the Moon we know today. <\/p>\n

Theia itself didn\u2019t survive the impact, but new evidence suggests that it wasn\u2019t some distant wanderer from the outer solar system. It was our next-door neighbor.<\/p>\n

The Cosmic Autopsy<\/p>\n

Researchers from the Max Planck Institute for Solar System Research (MPS) and the University of Chicago have pieced together the most detailed reconstruction yet of Theia\u2019s chemical makeup and origin. Their conclusion: Theia likely formed closer to the sun than Earth did.<\/p>\n

\u201cThe composition of a body archives its entire history of formation, including its place of origin,\u201d said Thorsten Kleine, director at MPS and a co-author of the study.<\/p>\n

The researchers examined the isotopes of certain key metals \u2014 particularly iron, molybdenum, and zirconium \u2014 in both terrestrial and lunar rocks. Isotopes are different versions of an element, distinguished by the number of neutrons in their nuclei. In the early solar system, these isotopes weren\u2019t evenly distributed; they varied depending on how far from the sun a planet formed. That variation makes them a kind of chemical geolocation metatag.<\/p>\n

Using samples from 15 Earth rocks and six moon rocks collected by Apollo astronauts, the team measured isotope ratios with extraordinary precision. They found that the Earth and the moon share nearly identical isotopic compositions. That\u2019s no surprise, as earlier analyses of chromium, calcium, and titanium had hinted at the same thing. <\/p>\n

But it deepens the mystery of the moon\u2019s birth. If the moon formed largely from Theia\u2019s debris, why does it look so chemically identical to Earth?<\/p>\n

Reverse Engineering a Lost Planet<\/p>\n

To find out, the scientists turned to a kind of planetary reverse engineering. By calculating which mixtures of elements could produce today\u2019s isotopic signatures in Earth and the moon, they worked backward to deduce what Theia must have been made of.<\/p>\n

\u201cThese elements have different affinities for metal and therefore partition into planetary mantles in different proportions; this is why gold is so rare and precious!\u201d explained planetary scientist Nicolas Dauphas of the University of Chicago and the University of Hong Kong. \u201cThey give us access to different phases of planetary formation.\u201d<\/p>\n

Earth\u2019s iron core<\/a> formed early, drawing down metals like iron and molybdenum. Yet both elements remain in the mantle today, meaning they must have arrived later \u2014 likely delivered by Theia. The isotopic evidence suggests that Theia was a rocky planet with a metallic core, about 5 to 10 percent of Earth\u2019s mass, formed in the inner solar system.<\/p>\n

\u201cThe most convincing scenario is that most of the building blocks of Earth and Theia originated in the inner solar system. Earth and Theia are likely to have been neighbors,\u201d said Timo Hopp, lead author of the study. <\/p>\n

Theia wasn\u2019t a rogue object from deep space, as previously assumed. It was a sibling world, assembled from the same solar dust and metal-rich debris that built Earth. Then fate \u2014 or better said physics \u2014 brought the two together in a collision that remade them both.<\/p>\n

A Shared Origin, A Divergent Destiny<\/p>\n

The idea of a giant impact forming the moon dates back to the 1970s in order to explain why Earth and the moon\u2019s compositions are nearly indistinguishable. If the moon were mostly made of Theia\u2019s material, it should look different. If it were mostly made of Earth\u2019s mantle, it shouldn\u2019t have enough iron.<\/p>\n

The new study shows that both planets were born from nearly the same region of the solar system, which explains why their chemical signatures match so closely. It also suggests that the moon inherited both Earth\u2019s and Theia\u2019s materials, thoroughly mixed in the fiery aftermath of the collision.<\/p>\n

Thorsten Kleine called the team\u2019s work a \u201creverse engineering of a planet.\u201d By integrating isotope data with meteorite comparisons, the scientists reconstructed Theia\u2019s \u201clist of ingredients\u201d and traced its probable birthplace to a zone even closer to the sun than Mercury and Venus once orbited.<\/p>\n

Back in 2020<\/a>, Kleine\u2019s group showed that celestial bodies forming near the sun tend to be richer in heavy elements like molybdenum. Earth\u2019s mantle, in fact, contains a bit more molybdenum and zirconium than models predict it should. Those excesses, the team now argues, came from Theia.<\/p>\n

Theia\u2019s collision didn\u2019t just sculpt the moon; it reshaped Earth itself. The impact may have altered our planet\u2019s tilt, seeded its mantle with vital metals, and stabilized its orbit. Without that cosmic accident, Earth might not have developed the long-term climate stability that allowed life to evolve.<\/p>\n

The findings were reported in the journal Science<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"Portions of the moon-forming impactor Theia survived throughout Earth\u2019s history in the deep mantle while others went on…\n","protected":false},"author":2,"featured_media":155326,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[23],"tags":[85,46,8245,53062,141,145,48524],"class_list":{"0":"post-155325","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-space","8":"tag-il","9":"tag-israel","10":"tag-moon","11":"tag-moon-formation","12":"tag-science","13":"tag-space","14":"tag-theia"},"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/posts\/155325","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/comments?post=155325"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/posts\/155325\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/media\/155326"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/media?parent=155325"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/categories?post=155325"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/tags?post=155325"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}