Earth: Facts and Formation

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Questions and Answers

According to the Planetesimal Hypothesis, what was the primary cause of matter being ejected from the sun to form planets?

The gravitational pull of other stars in the galaxy.
A collision between the sun and a comet. (correct)
The natural cooling and contraction of the sun's core.
A gradual process of solar flares and eruptions over millions of years.

The Earth and humans evolved simultaneously, making it easy to pinpoint the exact origin of the Earth.

False (B)

What is the approximate surface area of the Earth, in square kilometers?

509,700,000

The Planetesimal Hypothesis was proposed by George Wofan in ______.

<p>1749 A.D.</p> Signup and view all the answers

Match the following Earth characteristic with its corresponding value:

<p>Estimated age = 4.5 billion years Area of Lithosphere = $148,400,000 km^2$ Average density = $5.5 g/cm^3$ Number of satellites = 1 (moon)</p> Signup and view all the answers

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Flashcards

What is Earth?

A planet in the solar system, revolving around the sun.

Estimated age of the Earth?

Approximately 4.5 billion years.

What is the Lithosphere?

The solid outer section of Earth, including the crust and upper mantle.

What is the Hydrosphere?

The total amount of water on a planet.

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What is Planetesimal Hypothesis?

A theory suggesting planets formed from matter ejected from the sun after a collision with a comet.

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Study Notes

Earth is a planet in the solar system that revolves around the sun.
Human beings and the Earth did not evolve at the same time.

Earth Facts

Estimated age is 4.5 billion years
Surface area is 509,700,000 km²
Lithosphere area is 148,400,000 km²
Hydrosphere area is 361,300,000 km²
Diameter along the equator is 12756.3 km
Mass is 6 x 10^24 kg
Average density is 5.5 g/cm³
The Earth has one satellite: the moon.

Planetisimal Hypothesis

Proposed by French philosopher George Wofan in 1749 A.D.
A comet collided with the sun, causing matter to be thrown out.
The thrown out matter cooled and formed planets, including Earth and satellites.