Main Mass of NWA 8563 — a Rare Monomict Eucrite Meteorite from Asteroid 4 Vesta : 無料・フリー素材/写真
Main Mass of NWA 8563 — a Rare Monomict Eucrite Meteorite from Asteroid 4 Vesta / jurvetson
| ライセンス | クリエイティブ・コモンズ 表示 2.1 |
|---|---|
| 説明 | I am in awe of its cosmic beauty.From SpaceCom: "Unlike most asteroids, the interior of Vesta is differentiated. Like the terrestrial planets, the asteroid has a crust of cooled lava covering a rocky mantle and an iron and nickel core. This lends credence to the argument for naming Vesta as a protoplanet, rather than as an asteroid.Vesta's core accreted rapidly within the first 10 million years after the formation of the solar system. The basaltic crust of Vesta also formed quickly, over the course of a few million years. Volcanic eruptions on the surface stemmed from the mantle, lasting anywhere from 8 to 60 hours. The lava flows themselves ranged from a few hundred meters to several kilometers, with a thickness between 5 to 20 meters. The lava itself cooled rapidly, only to be buried again by more lava until the crust was complete. Dawn's gravity put its core at about 18 percent of Vesta's mass, or proportionally about two-thirds as massive as Earth's core.In fact, if it weren't for Jupiter, Vesta could have had a good chance at becoming a planet."In the asteroid belt, Jupiter basically stirred things up so much that they weren't able to easily accrete with one another," Dawn scientist David O'Brien, of the Planetary Science Institute in Tucson, Arizona, told reporters in 2012."The velocities in the asteroid belt were really high, and the higher the velocity is, the harder it is for things to merge together under their own gravity," O'Brien added.A massive mountain towers over Vesta's southern pole. The enormous mountain reaches up over 65,000 feet (20 kilometers) in height, making it nearly as tall as Olympus Mons, the largest mountain (and volcano) in the solar system. Olympus Mons soars about 15 miles (24 kilometers) above the surface of Mars.Vesta's unique composition means that it is responsible for an entire group of meteorites. The HED meteorites — made up of howardites, eucrites and diogenites — tell the story of Vesta's early life. Eucrites form from hardened lava, while diogenites come from beneath the surface. Howardites are a combination of the two, formed when a large impact mixed the two sections together. Vesta has been suspected as being the source of the HED meteorites since 1970. Dawn's mapping spectrometer verified that proposition. The Dawn team thinks the HEDs came from an impact basin named Rheasilvia, after an ancient Roman vestal virgin priestess. At 310 miles (500 kilometers) in diameter, Rheasilvia is nearly as large as Vesta itself. It most likely formed from a collision that stripped away most of the southern hemisphere's crust, revealing the asteroid's interior." |
| 撮影日 | 2020-04-04 16:23:07 |
| 撮影者 | jurvetson , Los Altos, USA |
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| カメラ | DSC-RX100M3 , SONY |
| 露出 | 0.01 sec (1/100) |
| 開放F値 | f/1.8 |