these compounds. It is known that the tails and the cores of comets traveling in
space are formed of frozen ice and rock debris. During the formation of our solar
system from extragalactic clouds, the condensation and differentiation of interstellar matter made up of gas, mostly ice-water, and solid dust took place in the
solar nebula. During a gravitational collapse and heating of a solar nebula, water
could be formed from the reaction of hydrogen and oxygen. Eventually the
increasing concentration and agglomeration of the solid dust made up of silicates
and iron must have initiated the accretion of the planets.
Thus, from the extraterrestrial hypothesis, it is possible to explain the concentric layering of matter forming the atmosphere, hydrosphere and solid Earth.
(2) Another hypothesis for the origin of the seawater is the slow release of water
trapped in the solid Earth over geological time. Water was trapped in the solidEarth during the early formation of our planet. Even if the solid interior of the
Earth’s mantle has in average of \2 % water trapped in its different mineral
phases, because of its volume ([40 % of the total Earth) the mantle remains the
most important reservoir of water. The Earth’s mantle contains more than 5 times
the amount of water found in the oceans. The fragments of meteorites, mainly the
carbonaceous chondrites found on earth, contain water in their minerals such as
clay, hydrated silicate and carbon oxides forming organic compounds. These
meteorites have a close composition to that of the Earth’s mantle. If such material
was heated during the early formation of our planet, water would have been
released. During episodic geological events due to radioactive heating and or
gravitational forces generating heat, water could be released from the lattice of the
silicate minerals and from other compounds of iron bearing phases in addition to
forming the raw material for our air, our oceans and life (Turikian 1968).
A study of zircons has found that liquid water must have existed as long ago as
4.4 billion years, very soon after the formation of the Earth. This requires the
presence of an atmosphere.
Why Seawater is Salty
The main salt compounds found in seawater have originated from the slow
alteration and decomposition of rocks. Rivers running into the ocean carry some of
the constituents such as sodium, potassium and silica. Other elements such chlorine (hydrochloric acid) and magnesium are likely to be of volcanic origin. The
fact that its salinity and seawater’s composition has not changed considerably over
time is due to the balance of material entering the ocean with that which is
precipitating into sediment or is ingested by various organisms. Excess sodium
will form zeolite and clay minerals in sediment. Chlorine forms complexes with
silica and other nutrients (potassium, nitrogen, carbon) that are essential for life
and can be ingested by organisms. Chlorine forms chlorite-bearing minerals such
as apatite and sodalite, which are found in sedimentary rocks containing organic
material as well as in volcanic rocks.
34
2 Our Haven, Planet Earth
space are formed of frozen ice and rock debris. During the formation of our solar
system from extragalactic clouds, the condensation and differentiation of interstellar matter made up of gas, mostly ice-water, and solid dust took place in the
solar nebula. During a gravitational collapse and heating of a solar nebula, water
could be formed from the reaction of hydrogen and oxygen. Eventually the
increasing concentration and agglomeration of the solid dust made up of silicates
and iron must have initiated the accretion of the planets.
Thus, from the extraterrestrial hypothesis, it is possible to explain the concentric layering of matter forming the atmosphere, hydrosphere and solid Earth.
(2) Another hypothesis for the origin of the seawater is the slow release of water
trapped in the solid Earth over geological time. Water was trapped in the solidEarth during the early formation of our planet. Even if the solid interior of the
Earth’s mantle has in average of \2 % water trapped in its different mineral
phases, because of its volume ([40 % of the total Earth) the mantle remains the
most important reservoir of water. The Earth’s mantle contains more than 5 times
the amount of water found in the oceans. The fragments of meteorites, mainly the
carbonaceous chondrites found on earth, contain water in their minerals such as
clay, hydrated silicate and carbon oxides forming organic compounds. These
meteorites have a close composition to that of the Earth’s mantle. If such material
was heated during the early formation of our planet, water would have been
released. During episodic geological events due to radioactive heating and or
gravitational forces generating heat, water could be released from the lattice of the
silicate minerals and from other compounds of iron bearing phases in addition to
forming the raw material for our air, our oceans and life (Turikian 1968).
A study of zircons has found that liquid water must have existed as long ago as
4.4 billion years, very soon after the formation of the Earth. This requires the
presence of an atmosphere.
Why Seawater is Salty
The main salt compounds found in seawater have originated from the slow
alteration and decomposition of rocks. Rivers running into the ocean carry some of
the constituents such as sodium, potassium and silica. Other elements such chlorine (hydrochloric acid) and magnesium are likely to be of volcanic origin. The
fact that its salinity and seawater’s composition has not changed considerably over
time is due to the balance of material entering the ocean with that which is
precipitating into sediment or is ingested by various organisms. Excess sodium
will form zeolite and clay minerals in sediment. Chlorine forms complexes with
silica and other nutrients (potassium, nitrogen, carbon) that are essential for life
and can be ingested by organisms. Chlorine forms chlorite-bearing minerals such
as apatite and sodalite, which are found in sedimentary rocks containing organic
material as well as in volcanic rocks.
34
2 Our Haven, Planet Earth