Pkt Vocab Meteorites, Asteroids, Comets

Widmanstatten pattern

the patterns of crystals from nickel-iron alloys that have grown larger in the fast cooling of a meteorite

chondrite

stony meteorites

chondrules

rounded bits of glassy rock ranging in size from microscopic to as big as a pea

carbonaceous chondrite

contain both chondrules and volatile compounds; the least altered remains of the solar nebula

achondrites

stony meteorites that contain no chondrules; lack volatiles

meteor shower

a display of meteors that are clearly related in a common origin; must be at least 6-60 per hour

coma

the head of a comet; is a vast cloud of gas and dust up to 100,000 km in diameter

Oort cloud

a spherical cloud of icy bodies believed to extend from 10,000-100,000 AU from the sun; located past the orbit of Pluto

Kuiper Belt

a region of the solar system beyond the orbit of Neptune, believed to contain many comets, asteroids, and other small bodies made largely of ice.

comets

a celestial object consisting of a nucleus of ice and dust and, when near the sun, a "tail" of gas and dust particles pointing away from the sun.

asteroids

irregular rocky metallic objects that orbit the sun but are too small to be considered planets

meteoroids

a small body moving in the solar system that would become a meteor if it entered the earth's atmosphere.

meteorites

A meteoroid that passes through the atmosphere and hits Earth's surface.

C-type asteroids

very dark asteroids that are carbonaceous in composition; about as bright as a chunk of coal; common in the outer belt

M-type asteroids

Brighter, but not red asteroids, probably made out of metal-rich materials; probably iron cores of fragmented asteroids

S-type asteroids

bright reddish color made of sailicates, mixed with metals; common in the inner belt

LONEOS

Lowell Observatory Near Earth Object search; able to survey the entire sky visible 3x a month for research

Oort, Jan

Dutch astronomer proposed that the long-period comets are objects that fall in from the Oort cloud

Gerard Kuiper

Dutch Astronomer proposed that the formation of the solar system should have left behind a belt of small, icy, planetismals beyond Jupiter

Comet Halley

returns to the Sun's vicinity approximately every 76 years in an elliptical orbit; nucleus size 16x8x7 km; will return in 2061

Perseid Meteor Shower

- one of the two best meteor showers each year
- radiant is found in the constellation Perseus
- August

Comet Hale-Bopp

Comet with an usually large nucleus estimated to be 40 km in diameter; that orbits around the sun every 2,537 years

gas tail

the tail of a comet produced by gas blown outward by the solar wind

dust tail

made of rock/dust particles; this tail curves because the particles begin to orbit the Sun; these particles supply the "monthly" meteor showers on Earth