Grunt Productions 2005

What makes What makes Earth the Earth the “Blue “Blue Planet”?Planet”?

A Brief By Lance Grindley

Grunt Productions 2005

== x 100 x 100

≈≈ 70.9% of Earth’s surface70.9% of Earth’s surface

361.8x10361.8x1066 km km22

510.1x10510.1x1066 km km22

Earth’s total surface Earth’s total surface area = 510x10area = 510x1066 km km22 (= 4(= 4ππRR22, where R = , where R = Earth’s radius = 6371 Earth’s radius = 6371 km and km and ππ = 3.14) = 3.14)

∴∴ Ocean surface Ocean surface areaarea

Earth is called the Earth is called the “Blue Planet” because “Blue Planet” because water covers water covers >>70% 70% of Earth’s surfaceof Earth’s surface

Ocean surface= 361.8

x106 km2

Earth’s surface

Land surface= 148.3

x106 km2

106≈ 510 x

km2

Grunt Productions 2005

... and water is blue because... and water is blue because i ts absorption its absorption bands extend through the red part of the bands extend through the red part of the visible spectrum (red l ight absorbs 100 timesvisible spectrum (red l ight absorbs 100 times

1010 44

1010 22

11

1010 -2-2

1010 -4-4

Abs

orpt

ion

coef

ficie

nt (

cmA

bsor

ptio

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effic

ient

(cm

-1-1))

100 nm100 nm 1 1 μμ mm 10 10 μμ mm

WavelengthWavelength

more than blue more than blue l ight).l ight).

Together with the Together with the five-times greater f ive-times greater scattering of blue scattering of blue l ight over red l ight,l ight over red l ight, t his absorption his absorption spectrum of water spectrum of water contributes to the contributes to the blue color of lake, blue color of lake, river and ocean river and ocean waters.waters.http://www.lsbu.ac.uk/water/vibrat.html

Grunt Productions 2005

Water is a chemical compound, HWater is a chemical compound, H 22O, O, that …that …

forms from the joining of forms from the joining of one oxygen and two hydrogen one oxygen and two hydrogen atoms, i.e., atoms, i.e., 2H2H 22 + O + O 22 2H 2H 22OO

andand

survives between 0ºC survives between 0ºC and 100ºC temperatures.and 100ºC temperatures.

We should therefore f ind water We should therefore f ind water at al l the locations having adequate at al l the locations having adequate quantit ies of hydrogenquantit ies of hydrogen and oxygen and oxygen and 0ºC ― 100ºCand 0ºC ― 100ºC temperatures.temperatures.

HydrogenHydrogenOxygenOxygen

Grunt Productions 200500 2020 4040 6060 8080 100100

1010 1212

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ndan

ce r

elat

ive

to S

i = 1

0A

bund

ance

rel

ativ

e to

Si =

1066

Atomic Number (Z)Atomic Number (Z)

Judging from chemistry, Judging from chemistry, water should abound all water should abound all

over the universe.over the universe.HydrogenHydrogen

HeliumHelium

OxygenOxygenCarbonCarbon

NitrogenNitrogen

SiliconSiliconNeonNeon

MagnesiumMagnesiumIronIron

SulphurSulphurAluminumAluminum

CalciumCalciumNickelNickel

SodiumSodiumArgonArgon

ChromiumChromiumPhosphorousPhosphorous

ManganeseManganeseChlorineChlorine

PotassiumPotassium

HHHeHe

OOCCNN

SiSiNeNeMgMgFeFeSSAlAlCaCaNiNiNaNaArArCrCrPPMnMnClClKK

74.50074.50023.84023.840

0.82000.82000.37500.37500.09100.0910

0.08300.08300.05500.05500.05700.05700.10400.10400.03800.03800.00660.00660.00740.00740.00920.00920.00330.00330.00300.00300.00320.00320.00090.00090.00110.00110.00060.00060.00030.0003

Composition of the UniverseComposition of the Universe

Grunt Productions 2005A conceptual look at the hydrological cycle

Run-off also erodes rock materials from land and piles them as sediments on the continental margins

EvaporationEvaporation320,000 km320,000 km33

EvaporationEvaporation60,000 km60,000 km33

Ocean storage1,370,000,000 km3

Precipitation285,000 km3

Precipitation95,000 km3

Run-off: 35,000 km3

Grunt Productions 2005

Grunt Productions 2005

As this map shows, the relative youth of ocean floor is a As this map shows, the relative youth of ocean floor is a peculiarity of the world geological map.peculiarity of the world geological map.00 55 6565 135135 185185 6565

Grunt Productions 2005

The older sea The older sea floor tends to floor tends to

be farther be farther from the from the

ridge axisridge axis

0.0

0.0

9.6

9.6

20.2

20.2

33.0

33.0

40.2

40.2

47.9

47.9

56.0

56.0

68.7

68.7

83.0

83.0

118.

011

8.0

126.

512

6.5

131.

713

1.7

141.

914

1.9

149.

914

9.9

156

.615

6.6

180.

018

0.0

Age of the sea floor (Ma BP)Age of the sea floor (Ma BP)

Grunt Productions 2005http://www2.nature.nps.gov/geology/usgsnps/animate/A08.gif

This animation of Alfred Wegner’s PANGEA, a supercontinent that existed

~250 Ma ago, shows how Atlantic andIndian oceans

formed from PANGEA’s dispersal, a

process that also created

the Himalayas, Andes and

Alps.

Grunt Productions 2005

The spreading seafloor records the The spreading seafloor records the geomagnetic polarity reversals that occur geomagnetic polarity reversals that occur as the basaltic seafloor forms.as the basaltic seafloor forms.

Grunt Productions 2005

H

OH

2H2

+O2

2H2O

Grunt Productions 2005

Water is a chemical compound Water is a chemical compound that forms from the joining of that forms from the joining of

one oxygen andone oxygen and two hydrogentwo hydrogen

atoms, i.e.,atoms, i.e.,

2H2H 22 + O + O 22 2H 2H 22OO

HydrogenHydrogenOxygenOxygen

Grunt Productions 2005

2H2H 22 + O + O 2 2 2H 2H 22OO

HOO

H

OOH

H

HOO

H

HOO

H

Grunt Productions 200500 2020 4040 6060 8080 100100

1010 1212

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ndan

ce r

elat

ive

to S

i = 1

0A

bund

ance

rel

ativ

e to

Si =

1066

Atomic Number (Z)Atomic Number (Z)

HydrogenHydrogenHeliumHelium

OxygenOxygenCarbonCarbon

NitrogenNitrogen

SiliconSiliconNeonNeon

MagnesiumMagnesiumIronIron

SulphurSulphurAluminumAluminumCalciumCalciumNickelNickel

SodiumSodiumArgonArgon

ChromiumChromiumPhosphorousPhosphorousManganeseManganese

ChlorineChlorinePotassiumPotassium

Other elementsOther elements

HHHeHe

OOCCNN

SiSiNeNeMgMgFeFeSSAlAlCaCaNiNiNaNaArArCrCrPPMnMnClClKK

EarthEarth

29.829.8

15.615.6

13.913.933.333.3

1.51.51.81.82.02.00.20.2

1.91.9

74.50074.50023.84023.840

0.82000.82000.37500.37500.09100.0910

0.08300.08300.05500.05500.05700.05700.10400.10400.03800.03800.00660.00660.00740.00740.00920.00920.00330.00330.00300.00300.00320.00320.00090.00090.00110.00110.00060.00060.00030.0003

UniverseUniverse

Note that chemistry is not the reason Note that chemistry is not the reason why water shouldwhy water should

occur al l over theoccur al l over the universe.universe.

Grunt Productions 2005

OEC

A

7N

(%8

0.)

L

(

AN

D

%29.2

)

Oceanridges(22.1%)Continental

platforms(18.9%)

Oceanbasin floors(29.8%)

Continental shelf and slope (11.4%)

Island arcs, trenches, guyots etc. (3.7%)

Continental rise (3.8%)

Conti-nentalmountains(10.3%)

Grunt Productions 2005

Grunt Productions 2005