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Timescale Artist's impression of the Moon during the Late Heavy Bombardment (above) and today (below). The Late Heavy Bombardment (LHB), or lunar cataclysm, is a hypothesized astronomical event thought to have occurred approximately 4.1 to 3.8 billion years (Ga) ago, [1] at a time corresponding to the Neohadean and Eoarchean eras on Earth.
After 500–600 million years (about 4 billion years ago) Jupiter and Saturn fell into a 2:1 resonance: Saturn orbited the Sun once for every two Jupiter orbits. [3] This resonance created a gravitational push against the outer planets, possibly causing Neptune to surge past Uranus and plough into the ancient Kuiper belt. [ 69 ]
This model posits that, 4.6 billion years ago, the Solar System was formed by the gravitational collapse of a giant molecular cloud spanning several light-years. Many stars, including the Sun, were formed within this collapsing cloud. The gas that formed the Solar System was slightly more massive than the Sun itself.
The average distance between Neptune and the Sun is 4.5 billion km (about 30.1 astronomical units (AU), the mean distance from the Earth to the Sun), and it completes an orbit on average every 164.79 years, subject to a variability of around ±0.1 years. The perihelion distance is 29.81 AU, and the aphelion distance is 30.33 AU.
Researchers aren’t entirely sure when the impact occurred, but it likely happened about 4 billion years ago, early on in the history of the solar system, which is estimated to be 4.6 billion ...
Studies since the mid-1990s have shown that the belt is dynamically stable and that comets' true place of origin is the scattered disc, a dynamically active zone created by the outward motion of Neptune 4.5 billion years ago; [18] scattered disc objects such as Eris have extremely eccentric orbits that take them as far as 100 AU from the Sun. [a]
The Hadean Eon, from 4.5 billion to 4 billion years ago, is the earliest chapter in Earth’s history and a geological dark age that’s little understood because geologists simply don’t have ...
The Noachian period occurred from 4.1 to 3.7 billion years ago, and little is known from direct measurements dating to the pre-Noachian period on Mars, between 4.5 billion and 4.1 billion years ...