Wikipedia:Main Page history/2019 April 9
From today's featured articlePlanet Nine is a hypothetical planet in the outer region of the Solar System. Its gravitational effects could explain the unlikely clustering of orbits for a group of extreme trans-Neptunian objects, bodies with average distances from the Sun that are more than 250 times that of Earth. These objects tend to make their closest approaches to the Sun in one sector, and their orbits are similarly tilted. Their improbable alignments suggest that an undiscovered planet may be shepherding the orbits of the most distant known Solar System objects. Planet Nine would have a predicted mass five to ten times that of Earth, and an elongated orbit extending 400 to 800 times as far from the Sun as the Earth's. It may have been ejected from its original orbit by Jupiter during the genesis of the Solar System, wrested from another star, captured as a rogue planet, or pulled into an eccentric orbit by a passing star. (Full article...)
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In the news
On this dayApril 9: Vimy Ridge Day in Canada; Day of National Unity in Georgia (1989)
François Rabelais (d. 1553) · Charles Proteus Steinmetz (b. 1865) · Natascha Engel (b. 1967) |
Today's featured picture
Oath of the Horatii is a large painting by the French artist Jacques-Louis David painted in 1784. It depicts a scene from a Roman legend about a seventh-century BC dispute between two warring cities, Rome and Alba Longa. Instead of the two cities sending their armies to war, they agree to choose three men from each city; the victor in that fight will be the victorious city. From Rome, three brothers from a Roman family, the Horatii, agree to end the war by fighting three brothers from a family of Alba Longa, the Curiatii. The three brothers, all of whom appear willing to sacrifice their lives for the good of Rome, are shown saluting their father, who holds their swords out for them. The principal sources for the story behind David's Oath are the first book of Livy, as elaborated by Dionysius of Halicarnassus. However, the moment depicted in David's painting is his own invention. The painting led to the popularization of the Roman salute and also increased David's fame, allowing him to take on his own students. It is now in the Louvre in Paris. Painting: Jacques-Louis David
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