A rare meteorite examined in 2026 has revealed evidence of a Moon-sized world that orbited the young Sun more than 4.5 billion years ago before vanishing from the solar system. The ancient body existed during the period when Earth was still forming, then disappeared in what scientists believe may have been a catastrophic collision.
The meteorite analysis provides a glimpse into the chaotic early solar system, when planetary bodies were still coalescing and collisions were common. The Moon-sized world would have been comparable to Mars in scale, orbiting among the other developing planets during a period of intense bombardment and gravitational interactions.
Scientists working with the meteorite found chemical signatures that could only have come from a planetary body of substantial size. The evidence suggests this world existed for a period before being destroyed, likely shattered in an impact with another large object during the violent early phase of solar system formation.
The discovery adds to understanding of how the solar system evolved from a disk of gas and dust into the arrangement of planets seen today. During the first several hundred million years after the Sun formed, dozens of planetary bodies competed for space and material. Many of these early worlds collided with each other or were ejected from the solar system entirely through gravitational interactions.
According to researchers at Curtin University, the early solar system was vastly different from what we see now. Earth itself was mostly a water world with few pieces of continental crust, while the Sun would have been dimmer and the Moon closer to our planet. Early life existed in the form of stromatolites, a type of cyanobacteria similar to algae.
During this period known as the Archean eon, meteorite impacts were continuous. Evidence of these collisions remains visible on the Moon's surface, but on Earth they have largely been erased through erosion, subduction and plate tectonics. Finding preserved evidence of these ancient impact events is therefore exceptionally significant for scientists.
The meteorite that preserved evidence of this lost world survived the intervening 4.5 billion years before falling to Earth and being recovered for study. Meteorites serve as time capsules from the early solar system, containing materials and chemical records that predate Earth's oldest rocks.
Associate professor Bruce Schaefer from Macquarie University described the research as "a real detective story," noting that the combination of techniques used to analyse the meteorite was clever and innovative. He emphasized that discovering physical evidence of these ancient events is particularly exciting because while scientists know such impacts must have occurred, actually observing them provides powerful confirmation.
This particular specimen has proven especially valuable for reconstructing the population of bodies that existed in the young solar system but left no other trace of their existence.