Search results
Results From The WOW.Com Content Network
A meteorite is a portion of a meteoroid or asteroid that survives its passage through the atmosphere and hits the ground without being destroyed. [22] Meteorites are sometimes, but not always, found in association with hypervelocity impact craters; during energetic collisions, the entire impactor may be vaporized, leaving no meteorites.
The traditional way of subdividing meteorites (see Meteorites classification) is into irons, stony-irons, and two major groups of stony meteorites, chondrites and achondrites. For some of the less-studied stony meteorite falls, it is not known whether the object is chondritic; thus the number of meteorites that can be so grouped is 4% lower ...
This is a list of largest meteorites on Earth. Size can be assessed by the largest fragment of a given meteorite or the total amount of material coming from the same meteorite fall: often a single meteoroid during atmospheric entry tends to fragment into more pieces. The table lists the largest meteorites found on the Earth's surface.
The 60-tonne, 2.7 m-long (8.9 ft) Hoba meteorite in Namibia is the largest known intact meteorite.[1]A meteorite is a rock that originated in outer space and has fallen to the surface of a planet or moon.
Sizes can be estimated by timing the lengths of star occultations (when an asteroid passes directly in front of a star). Radar imaging can yield good information about asteroid shapes and orbital and rotational parameters, especially for near-Earth asteroids. Spacecraft flybys can provide much more data than any ground or space-based ...
Image of the M-type asteroid 21 Lutetia taken by the ESA Rosetta Spacecraft during a flyby in 2010. M-type (metallic-type, aka M-class) asteroids are a spectral class of asteroids which appear to contain higher concentrations of metal phases (e.g. iron-nickel) than other asteroid classes, [1] and are widely thought to be the source of iron meteorites.
Gas-rich meteorites are meteorites with high levels of primordial gases, such as helium, neon, argon, krypton, xenon and sometimes other elements. [1] Though these gases are present "in virtually all meteorites," [ 2 ] the Fayetteville meteorite has ~2,000,000 x10 −8 cc STP / g helium, [ 3 ] or ~2% helium by volume equivalent.
Metallic core formation and cooling can be dated by applying the 187 Re/ 187 Os method to iron meteorites. [12] [13] Large scale impact events or even the destruction of the parent body can be dated using the 39 Ar/ 40 Ar method and the 244 Pu fission track method. [14] After breakup of the parent body meteoroids are exposed to cosmic radiation.