Theia Archives

Artist’s concept of a star and its debris disc against the black background of space. The star is in the background, right of center, and depicted as a small, luminous sphere. Credit: NASA, ESA, CSA, J. Olmsted (STScI)

JWST Studies Of Planet-shattering Collisions

by Keith CowingOctober 2, 2026October 2, 2026

[ESA]. In the early history of our Solar System, a Mars-sized object called Theia smashed into the infant Earth, vapourising massive amounts of rock and blasting it into space. Some […]

The result of 100 successful simulations of the back20 model (the ring at 0.85 au with a 20% background) that produced a good match to all terrestrial planets (as defined in Section 3.1). The black dots show the results of individual simulations with good final planets. The bigger red dots are the real planets. Note that we do not exclude simulations that produced additional bodies with m < 0.05 MEarth in the Mars region (1.2 < a < 1.8 au). Some of these bodies would collide with Mars at t > 200 Myr (these simulations were terminated at 200 Myr). -- astro-ph.EP

Astrogeology, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Impact events, Status Report

Terrestrial Planet Formation From Two Source Reservoirs

by Keith CowingJuly 22, 2025July 22, 2025

This work describes new dynamical simulations of terrestrial planet formation. The simulations started at the protoplanetary disk stage, when planetesimals formed and accreted into protoplanets, and continued past the late […]

Eccentricity and position snapshots over time of a simulation using the mixed scenario where all 4 terrestrial planets fit constraints and the Earth analogue had a final CC embryo impact. Snapshots are shown over time, including the moment after the final giant impact. The initial NC embryos and planetesimals are shown with the embryos in black and the planetesimals in orange, as well as the CC embryos and planetesimals in blue with Jupiter and Saturn in black on the far right. The final snapshot is the real solar system. -- astro-ph.EP

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Extinction events, Impact events, Mars, Mercury, Moon, Status Report, Venus

Dynamical Origin Of Theia, The Last Giant Impactor On Earth

by Keith CowingJuly 4, 2025July 4, 2025

Cosmochemical studies have proposed that Earth accreted roughly 5-10% of its mass from carbonaceous (CC) material, with a large fraction delivered late via its final impactor, Theia (the Moon-forming impactor). […]

Planetary formation -- Grok via Astrobiology.com

Astrogeology, Exoplanets, -moons, -comets, Status Report

Did The Terrestrial Planets Of The Solar System Form By Pebble Accretion?

by Keith CowingNovember 15, 2024November 15, 2024

The dominant accretion process leading to the formation of the terrestrial planets of the Solar System is a subject of intense scientific debate. Two radically different scenarios have been proposed.