1-2. FORMATION & EVOLUTION OF THE EARTH

http://www.astexhibits.com/earth-day-4222013-is-almost-here/

The Physical Characteristics of the Earth

Distance to the SUN: 149,6000,000 km Diameter: 12,756 km Mass: 5.98*1027 g Density: 2-3g /cm3 (Crust), 5.52g/cm3 (Bulk) Elemental abundance:

Bulk: Fe > O > Si > Mg > Ni > Ca > Al > S Crust: O > Si > Al > Fe > Ca > Na > K > Mg Atmosphere: N > O > Ar > C > H

http://www.ucl.ac.uk/EarthSci/people/lidunka/GEOL2014/Geophysics7%20-%20Deep%20Earth/Earth%20Structure.htm

Internal structure of the Earth.

Key Questions

How did it start to aggregate? What were the heat sources for the

reconstitution (to have such an concentric internal structure)?

Where did the atmosphere and water (volatiles) come from?

How did the life begin and bring the changes of the environment?

Formation & Evolution of the Earth

http://ay201b.files.wordpress.com/2011/04/proplyd_concept.jpg

http://sciexplorer.blogspot.kr/2011/03/earth.html

Collison between Theia & Protoearth