Giant-impact hypothesis
Videos
The giant-impact hypothesis, sometimes called the Theia Impact, is an astrogeology hypothesis for the formation of the Moon first proposed in 1946 by Canadian geologist Reginald Daly. The hypothesis s
Artist's depiction of a collision between two planetary bodies. Such an impact between Earth and a Mars-sized object likely formed the Moon.
Ancient rift valleys – context
Ancient rift valleys – closeup (artist's concept)
Full Moon 2010
Early Earth
Videos
Early Earth, also known as Proto-Earth, is loosely defined as Earth in the first one billion years — or gigayear — of its geological history, from its initial formation in the young Solar System at ab
Giant-impact hypothesis
…an astrogeology hypothesis for the formation of the Moon first proposed in 1946 by Canadian geologist Reginald Daly. The hypothesis suggests that the Proto-Earth collided with a Mars-sized co-orbital protoplanet likely from the L4 or L5 Lagrange points of the Earth's orbit approximately 4.5 billion years ago in…
Artist impression of the Early Earth as a lava planet during the Hadean eon
Artist's impression of Archean Earth, showing an orange atmospheric haze, leading to the alternative description of the planet in that stage of its development as a "pale orange dot"