Ch. 1 - Introduction

Question 1

13.8 By

approx age of the universe

Answer 1

13.8 x 10⁹yr

Question 2

approx age of Earth

Answer 2

4.5 x 10⁹yr

Question 3

the beauty part about ♁ distance from ☉ is:

Answer 3

water exists naturally in all 3 phases

Question 4

the “spheres” of Earth

Answer 4

atmosphere, hydrosphere, biosphere, geosphere

Question 5

atmosphere - mass relative to Ô, composition today

Answer 5

< 0.01% M_Ô; 78% N₂, 21% O₂, < 1% other gases

Question 6

water is present as (phase, %):

Answer 6

oceans ~97.2%; ice ~2.15%; groundwater ~0.62%;

soil moisture, vapor in atmosphere, inland lakes, rivers < 1%

Question 7

what is the main sculptor of land masses on Ô

Answer 7

running water; wind is a negligible factor

Question 8

what is the 5th sphere?

Answer 8

the anthroposphere (not yet formalized)