What does the earth system include?

What is the ultimate source of energy for the earth?

For which of the following astronomical motions is the amount of rotational energy the greatest: the Earth's rotation about its axis or the Moon's revolution about the Earth? The mass of the Earth and Moon are $6.0 \times 10^{24} \mathrm{~kg}$ and $7.3 \times 10^{22} \mathrm{~kg}$, respectively. The radius of the Earth is $6.4 \times 10^6 \mathrm{~m}$. The Moon's orbital radius is $3.9 \times 10^8 \mathrm{~m}$. (Assume that the Moon completes one revolution every 28 Earth days and that the Earth is a solid sphere of uniform density.)

Imagine an Earth-Moon-Sun system in which the Moon was much smaller than the present Moon. How would this affect solar eclipses as seen on Earth?

diatomaceous earth , red tide, bioluminescence

In what ways does Earth move?

In the approximation that the Earth is a sphere of uniform density, it can be shown that the gravitational force it exerts on a mass m inside the Earth at a distance r from the center is $mg(r/R)$ , where R is the radius of the Earth. (Note that at the surface, the force is indeed mg, and at the center it is zero). Suppose that there were a hole drilled along a diameter straight through the Earth, and the air were pumped out of the hole. If an object is released from one end of the hole, how long will it take to reach the other side of the Earth? Include a numerical result.

How does the planet Mars compare with Earth? (1) Mars is about equal to the diameter of Earth, twice as far from the sun and has a much shorter day. (2) Mars is about twice the diameter of Earth, twice as far from the sun and has twice the day length. (3) Mars is about half the diameter of Earth, twice as far from the sun and has a shorter day length. (4) Mars is about half the diameter of Earth, twice as far from the sun and has a similar day length

The mean distance from the Earth to the Sun is $1.50 \times 10^{11} \mathrm{~m}$. How long does it take for light to travel from the Sun to the Earth?

What percentage of the earth is covered by water?

Why is Earth called "the blue planet"?

Two atomic clocks are synchronized. One is put aboard a spaceship mat leaves Earth at t=0 at a speed of 0.750c. (a) When the spaceship has been traveling for 48.0 h (according to the atomic clock on board), it sends a radio signal back to Earth. When would the signal be received on Earth, according to the atomic clock on Earth (b) When the Earth lock says that the spaceship has been gone for 48.0 h, it sends a radio signal to the spaceship. At what time (according to the spaceship's clock) does the spaceship receive the signal?

Is the amount of energy required to get a spacecraft from the Earth to the Moon greater than, less than, or equal to the energy required to get the same spacecraft from the Moon to the Earth? Choose the best explanation from among the following: $I$. The escape speed of the Moon is less than that of the Earth; therefore, less energy is required to leave the Moon. $II$. The situation is symmetric, and hence the same amount of energy is required to travel in either direction. $III$. It takes more energy to go from the Moon to the Earth because the Moon is orbiting the Earth.

What causes the Earth to orbit the Sun?