The word comet derives from the Old English cometa from the Latin comēta or comētēs. That, in turn, is a latinisation of the Greek κομ?τη? ("wearing long hair"), and the Oxford English Dicti ...
Protoplanets are large planetary embryos that originate within protoplanetary discs and have undergone internal melting to produce differentiated interiors. They are believed to form out of kilometer- ...
Some of the most likely contributory factors to the origin of the Earth's oceans are as follows:The cooling down of the primordial world to the point where the outgassed volatile components were held ...
Further information: Atmosphere of EarthFurther information: Extraterrestrial liquid waterWater vapor is a significant component of the Earth's atmosphere and a greenhouse gas. It is also common in th ...
Outgassing is a challenge to creating and maintaining clean high-vacuum environments. NASA and ESA maintains a list of low-outgassing materials to be used for spacecraft, as outgassing products can co ...
The main piece of evidence for a lunar cataclysm comes from the radiometric ages of impact melt rocks that were collected during the Apollo missions. The majority of these impact melts are believed to ...
Many asteroids have been placed in groups and families based on their orbital characteristics. Apart from the broadest divisions, it is customary to name a group of asteroids after the first member of ...
Trojan asteroids are a population that share an orbit with a larger planet or moon, but do not collide with it because they orbit in one of the two Lagrangian points of stability, L4 and L5, which lie ...
A newly discovered asteroid is given a provisional designation (such as 2002 AT4) consisting of the year of discovery and an alphanumeric code indicating the half-month of discovery and the sequence w ...
In 1898, George Darwin made the suggestion that the Earth and Moon had once been one body. Darwin's hypothesis was that a molten Moon had been spun from the Earth because of centrifugal forces, and th ...
Theia was thought to have orbited in the L4 or L5 spots in the Earth's orbit. It grew to a Mars-like size and, through Gravitational perturbation from Venus, was moved around and eventually set on a c ...
Use of the phrase "working hypothesis" goes back at least two centuries.Charles Sanders Peirce came to hold that an explanatory hypothesis is not only justifiable as a tentative conclusion by its plau ...
Cohesion is the component of shear strength of a rock or soil that is independent of interparticle friction.In soils, true cohesion is caused by following:Electrostatic forces in stiff overconsolidate ...
If the granular material is driven harder such that contacts between the grains become highly infrequent, the material enters a gaseous state. Correspondingly, one can define a granular temperature eq ...
The word planetesimal comes from the mathematical concept infinitesimal and literally means an ultimately small fraction of a planet.While the name is always applied to small bodies during the process ...
