SOLAR SYSTEM Flashcards
1
Q
Definition of asteroid, comets, meteor and meteorite
A
asteroid - rocky body that orbits sun.
comet - ice and dust
meteorite - asteroid that collides with Earth
meteor - asteroid that burns in Earth’s atmosphere
2
Q
Meteorites
A
- remnants of terrestrial planet that failed to form
- 4.6Ga
3
Q
Types of meteorites
A
stony - 93% of meteorites, similar to Earths mantle
iron - 6% of meteorites, similar to Earth’s core
carbonaceous chondrites - <1% of meteorites, water + organic compounds
4
Q
Impact craters
A
- created by bolides (extraterrestrial impact object)
- small = common, large = rare
5
Q
Characteristics of an impact crater
A
- ejecta (radial pattern)
- inverted strata (older sediment on top)
- shocked quartz (shock waves cause quartz to crumble)
- iridium (not often found on earth, indicate iron meteorite)
6
Q
Solar nebula disc theory
A
- Cloud (nebula) of hydrogen gas
- Nebula starts to collapse and spin (“protoplanetary disc”)
- Nuclear fusion begins in middle - forms a sun
- Heavier elements accrete to rocky lump + gas (“planetismal”)
- Planetismals accrete to form planet
7
Q
Solar system age
A
Solar system - 4.6Ga
Earth - 4.6Ga
Universe - 14Ga