Search results
Results from the WOW.Com Content Network
Pre-Noachian: the interval from the accretion and differentiation of the planet about 4.5 billion years ago to the formation of the Hellas impact basin, between 4.1 and 3.8 Gya. [14] Most of the geologic record of this interval has been erased by subsequent erosion and high impact rates.
Notes (Mars) Eonothem: Eon: not used for Mars Erathem: Era: not used for Mars System: Period: 3 total; 10 8 to 10 9 years in length Series: Epoch: 8 total; 10 7 to 10 8 years in length Stage: Age: not used for Mars Chronozone: Chron: smaller than an age/stage; not used by the ICS timescale
The history of Mars observation is about the recorded history of observation of the planet Mars. Some of the early records of Mars' observation date back to the era of the ancient Egyptian astronomers in the 2nd millennium BCE. Chinese records about the motions of Mars appeared before the founding of the Zhou dynasty (1045 BCE).
The lunar cratering record suggests that the rate of impacts in the Inner Solar System 4000 million years ago was 500 times higher than today. [44] During the Noachian, about one 100-km diameter crater formed on Mars every million years, [3] with the rate of smaller impacts exponentially higher.
However, the largest volcano on the planet, Olympus Mons, is thought to have formed when the plates were not moving. Olympus Mons may have formed just after the plate motion stopped. The mare-like plains on Mars are roughly 3 to 3.5 billion years old. [72] The giant shield volcanoes are younger, formed between 1 and 2 billion years ago.
Astronomers think the collision between Earth and Theia happened at about 4.4 to 4.45 billion years ago ; about 0.1 billion years after the Solar System began to form. [15] [16] In astronomical terms, the impact would have been of moderate velocity. Theia is thought to have struck Earth at an oblique angle when Earth was nearly fully formed.
A 2023 study shows evidence, based on the orbital inclination of Deimos (a small moon of Mars), that Mars may once have had a ring system 3.5 billion years to 4 billion years ago. [32] This ring system may have been formed from a moon, 20 times more massive than Phobos, orbiting Mars billions of years ago; and Phobos would be a remnant of that ...
At least two-thirds of Mars' surface is more than 3.5 billion years old, and it could have been habitable 4.48 billion years ago, 500 million years before the earliest known Earth lifeforms; [4] Mars may thus hold the best record of the prebiotic conditions leading to life, even if life does not or has never existed there. [5] [6]