How did the Earth Get to Look Like This?

Key points in the formation of the earth:

• Formed via acretion of grains in a 4-step process ( 1. 2. 3. 4. )
• Original Protoearth was molten
• dense material (molten nickel and iron) flowed to the center
• lighter material (molten silicon) flows to the top
• earth cools and solidifies into basic core, mantle and crust structure
• Overall density of the earth is 5.5 grams per cubic centimeter
• The earth has a lot of trapped gasses in its interior

Two significant questions to now ask:

1. Where did the water on the earth come from?

2. This nearby object has a density of 3.3 grams per cubic centimeter. Is this a problem?

The Origin of the Moon:

Until recently, this was not understood. The moon has long been an anamoly because its mass compared to the earth is 1/80 and there is very large for a planetary satellite

Possibilities for Lunar Origin:

• Formed in place by accretion --> NO! its composition is wrong
• Formed someplace else where the average density is 3.5? --> Implies formation near Mars --> how did it get here?
• Fissioned from the earth's mantle (note the density of the earth's mantle is around 3.5) - but by what mechansism?

The above 3 scenarios for lunar formation are all physically implausible so why is the moon there?

Let's imaging the following sequence:

• Shortly after the formation of the earth a leftover planetisimal roughly the size of Mars had either struck the earth or had a close passage to it.
• Here is the Sequence if there was an impact
  • 1. Liberation of Debris
  • 2. Formation of Debris Ring
  • 3. Moon forms via acretion

• Here is the Sequence if it was a close passage
  • Path of Encounter
  • Deformation of Molten Earth
  • Fission
  • Tidal induced debris ring
  • Moon forms via acretion

Outgassing --> Early Formation of the Earth's Atmosphere

Present day composition of volcanoe effluents:

• Water Vapor --> 60%
• Carbon Dioxide --> 24%
• Sulfur --> 13%
• Nitrogen --> 5.7%
• Argon --> 0.3%
• Chlorine --> 0.1%

It is likely that there was NOT enough water released via outgassing to account for the present day oceans

Most of the water was likely delivered to the earth after it formed via collisions with left over planetisimals and cometisimals. The influence of Jupiter on the orbits of leftover cometisimals may well be key.

Tidal forces from a newly formed moon may also be key in promoting first stages of development of life as well.

Hence the earth may need both Jupiter and the Moon if it is to ask a question sometime later.

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The Electronic Universe Project

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