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By 10 million years, gas in the protoplanetary disc has been blown away, and outer planet formation is likely complete. [38] 10 million – 100 million years 4.5–4.6 bya: Terrestrial planets and the Moon form. Giant impacts occur. Water delivered to Earth. [2] Main sequence 50 million years 4.5 bya: Sun becomes a main-sequence star. [32] 200 ...
Iwan P. Williams and Alan William Cremin [4] split the models between two categories: those that regard the origin and formation of the planets as being essentially related to the Sun, with the two formation processes taking place concurrently or consecutively, and those that regard the formation of the planets as being independent of the ...
As a result, astronomers largely abandoned this theory of planet formation at the beginning of the 20th century. According to some, a major critique came during the 19th century from James Clerk Maxwell (1831–1879), who in some sources is claimed to have maintained that different rotation between the inner and outer parts of a ring could not ...
The "Mars problem" is a conflict between some simulations of the formation of the terrestrial planets which end with a 0.5–1.0 M E planet in its region, much larger than the actual mass of Mars: 0.107 M E, when begun with planetesimals distributed throughout the inner Solar System. Jupiter's grand tack resolves the Mars problem by limiting ...
Viktor Sergeevich Safronov (Russian: Ви́ктор Серге́евич Сафро́нов) (born Velikie Luki; 11 October 1917 in Russia – 18 September 1999 in Moscow, Russia) was a Soviet astronomer who put forward the low-mass-nebula model of planet formation, a consistent picture of how the planets formed from a disk of gas and dust around the Sun.
A planet's year depends on its distance from its star; the farther a planet is from its star, the longer the distance it must travel and the slower its speed, since it is less affected by its star's gravity. No planet's orbit is perfectly circular, and hence the distance of each from the host star varies over the course of its year.
Từ điển bách khoa toàn thư Việt Nam (Encyclopedia of Vietnam), a state-sponsored encyclopedia which was published in 2005. Vietnamese Wikipedia, a project of the Wikimedia Foundation. Vietnam War encyclopedias. Encyclopedic works and encyclopedias focused on Vietnam War-related topics.
Nonetheless, formation via planetesimal collisions can be accomplished within the typical lifetime of a protoplanetary disc. [ 14 ] [ 15 ] The largest planetesimals can grow much faster via pebble accretion, [ 10 ] but if the formation or delivery of pebbles is rapid numerous Earth-mass planets form instead of a few giant planet cores. [ 16 ]