Early Earth: ATMO-310/OCN 310 Overview

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Questions and Answers

What is the approximate age of the Earth?

3.5 billion years old

5 billion years old

4.2 billion years old

4.57 billion years old (correct)

Which phenomenon is responsible for the formation of gas giants in the solar system?

Impact events with asteroids

Solar radiation blowing solid matter away

Radioactive decay of heavy elements

Gravitational forces condensing gases (correct)

What event does the Giant Impact Hypothesis describe?

The collision of Earth with a Mars-sized planet (correct)

The heating of Earth from solar radiation

The formation of the first asteroids

The condensation of gases into liquid

Which of the following factors contributed to the heating and melting of the early Earth's interior?

High-speed collisions transferring kinetic energy Signup and view all the answers

What provided scientists with access to debris from the formation of the solar system?

Meteorites Signup and view all the answers

What primarily contributed to the creation of the Earth's initial atmosphere?

Volcanic out-gassing Signup and view all the answers

Why did helium (He) and hydrogen (H) escape from the Earth's early atmosphere?

Earth's gravity was not strong enough to hold them Signup and view all the answers

Which of the following gases is NOT released during volcanic eruptions?

Oxygen (O2) Signup and view all the answers

How did the oceans on Earth primarily form?

From water vapor released by volcanic eruptions Signup and view all the answers

Which process is described as the creation of a thicker atmosphere over time?

Volatile transfer Signup and view all the answers

What is the density of the continental crust compared to oceanic crust?

Lighter than oceanic crust Signup and view all the answers

What is the earliest evidence of surface water on Earth dated to?

3.8 billion years ago Signup and view all the answers

Which gases contributed to the thick atmosphere by 3.5 billion years ago?

Carbon dioxide, methane, and water vapor Signup and view all the answers

What is the primary theory explaining the formation of the universe?

Big Bang Theory Signup and view all the answers

Which of the following correctly describes a step in the formation of the solar system according to the Nebular Hypothesis?

A large gas cloud begins to condense. Signup and view all the answers

What occurs when the temperature in the Sun reaches one million ºC during its formation?

Thermonuclear fusion begins. Signup and view all the answers

What is the term used for the variations that influence mean circulation patterns in the atmosphere and ocean?

Natural variability Signup and view all the answers

How long after the Big Bang did our solar system begin to form?

10 billion years Signup and view all the answers

Which scientist is associated with the formulation of the Nebular Hypothesis?

Immanuel Kant Signup and view all the answers

What was the condition of all energy and mass in the universe at the moment of the Big Bang?

Existing in an infinitely small point Signup and view all the answers

What is the initial stage of the solar system formation as per the Nebular Hypothesis?

A large gas cloud (nebula) begins to condense. Signup and view all the answers

What was the primary composition of the Earth's early atmosphere?

Hydrogen and Helium Signup and view all the answers

What caused the loss of Earth's first atmosphere?

The impact leading to the origin of the moon Signup and view all the answers

What percentage of water vapor was likely present in Earth's second atmosphere?

Roughly 80% Signup and view all the answers

Which gas was NOT a significant component of the Earth's second atmosphere?

Oxygen (O2) Signup and view all the answers

What was significant about the sun during Earth's cooling period?

It was about 30% weaker than today. Signup and view all the answers

How did oxygen begin to form in the Earth's atmosphere?

By the splitting of water molecules by solar radiation. Signup and view all the answers

What prevented the Earth from freezing over, despite the sun being weaker?

Strong greenhouse effect from CO2. Signup and view all the answers

What effect did the establishment of oxygen have on Earth's atmosphere?

It formed the ozone layer. Signup and view all the answers

What happened to oxygen levels between 2.5 billion years ago and 500 million years ago?

Oxygen levels increased significantly. Signup and view all the answers

What was one consequence of increasing oxygen levels for carbon dioxide levels?

CO2 levels decreased due to photosynthesis and chemical weathering. Signup and view all the answers

What process significantly contributed to the removal of CO2 from the atmosphere?

Chemical weathering and marine organisms incorporation into shells. Signup and view all the answers

What climatic change was caused by lower levels of CO2 in the atmosphere?

The earth became more susceptible to ice ages. Signup and view all the answers

What factors caused the cooling of the earth around 750-550 million years ago?

Orbital variations decreasing solar radiation leading to severe glaciation. Signup and view all the answers

How did volcanic activity impact the atmospheric CO2 levels post-glaciation?

It contributed to the increase of CO2 levels due to reduced weathering. Signup and view all the answers

What major climate shifts have occurred over the last 700 million years?

Warm periods occasionally interrupted by ice ages. Signup and view all the answers

Which cycle is associated with long-term climate variability based on Earth's orbital characteristics?

Milankovitch cycles. Signup and view all the answers

Study Notes

Formation of the Universe and Solar System

The universe originated approximately 14.4 billion years ago with the Big Bang, leading to the creation of stars and galaxies.
The Nebular Hypothesis describes solar system formation from a large gas cloud (nebula) condensing under gravity, culminating in the formation of our sun and planets.

Formation of Planets

Inner planets accumulated solid materials due to gravitational forces, incorporating both light and heavy atoms.
Solar radiation expelled lighter gases (hydrogen and helium) from the inner planets, leading to the formation of gas giants like Jupiter and Saturn.
Beyond Neptune, icy bodies composed of frozen gases formed Pluto, Sedna, and the Kuiper Belt Objects, while leftover debris created comets and asteroids.

Age and Early History of Earth

Earth is estimated to be around 4.57 billion years old, based on the dating of meteorites using radioactive isotopes.
The early Earth's surface faced constant impacts from asteroids and comets for about 500 million years.

Moon Formation

The Giant Impact Hypothesis suggests a Mars-sized body collided with Earth, forming the moon approximately 50 million years post-Earth's creation.
This hypothesis gained credibility through modern computer simulations.

Heating of Early Earth

Three main factors contributed to the heating of early Earth: kinetic energy from collisions, compression from gravitational forces, and refinement through radioactive decay.
Continents formed from solidified magma rising from the mantle; oceans and atmosphere developed via volcanic outgassing.

Earth's Atmosphere Evolution

Initially, Earth's atmosphere comprised helium and hydrogen, which escaped into space due to weak gravity.
Volcanic outgassing over millions of years created a thicker atmosphere rich in water vapor, carbon dioxide, and other gases, but virtually lacking in oxygen.

Formation of Oceans

Oceans likely formed from water vapor released during volcanic activity and potentially from comet impacts.
The earliest evidence of surface water is approximately 3.8 billion years old.

Continental Formation

By 2.5 billion years ago, continents emerged with a density of 2800 kg/m³, floating above denser oceanic crust at 3200 kg/m³.
The Earth's atmosphere by this time was thick with CO2, methane, and water vapor, and had no significant levels of oxygen.

Development of Earth's Atmospheres

Earth's second atmosphere arose from volcanic outgassing and was largely devoid of oxygen, allowing high UV radiation to penetrate the surface.
Significant oxygen accumulation occurred due to photosynthesis, primarily from cyanobacteria, marking the transition to the third atmosphere.

Chemical Weathering and Climate Change

CO2 levels declined due to photosynthesis and chemical weathering, leading to increased susceptibility to ice ages as Earth cooled.
Between 750-550 million years ago, Earth experienced extreme glaciation, influenced by decreased solar radiation and changing orbital characteristics.

Recent Geological History

The last 700 million years featured fluctuating climates, with warm interglacial periods interrupted by ice ages, primarily driven by Milankovitch cycles and volcanic eruptions affecting CO2 levels.

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Description

Explore the early Earth system in this quiz, covering its history, atmospheric and oceanic circulation patterns, and natural variability. Delve into past climates and understand how these factors influence the Earth's system. This overview is essential for students of ATMO-310 and OCN 310.