Earth science - unit 4 test: orbital motion.

Answer 1

1. What is orbital motion?
Orbital motion refers to the motion of an object around another object due to gravitational attraction. It occurs when an object is in a stable orbit around a more massive object, such as a planet around the Sun.

2. What is the force responsible for keeping objects in orbit?
The force responsible for keeping objects in orbit is gravity. Gravity pulls the orbiting object towards the more massive object, creating a centripetal force that keeps the object in a stable circular or elliptical orbit.

3. What are Kepler's laws of planetary motion?
Kepler's laws of planetary motion describe the motion of planets around the Sun. They are:
- Kepler's First Law (Law of Ellipses): Planetary orbits are elliptical, with the Sun at one of the foci of the ellipse.
- Kepler's Second Law (Law of Equal Areas): A line connecting a planet to the Sun sweeps out equal areas in equal time intervals. This means that a planet moves faster in its orbit when it is closer to the Sun.
- Kepler's Third Law (Harmonic Law): The square of the orbital period of a planet is directly proportional to the cube of its average distance from the Sun. This law relates the orbital period and the distance of a planet from the Sun.

4. What is the difference between geocentric and heliocentric models of the solar system?
The geocentric model of the solar system is an ancient model where Earth was believed to be at the center of the universe, with the Sun, planets, and other celestial objects revolving around it. The heliocentric model, on the other hand, is a more modern model where the Sun is considered to be at the center of the solar system, with planets, including Earth, orbiting around it.

5. What causes the seasons on Earth?
The seasons on Earth are caused by the tilt of its axis (approximately 23.5 degrees). As Earth orbits the Sun, the angle at which sunlight reaches different parts of the Earth changes. This tilt causes different amounts of sunlight to be spread over different latitudes throughout the year, resulting in the four seasons: spring, summer, autumn, and winter.

6. Explain what happens during a solar eclipse and a lunar eclipse.
During a solar eclipse, the Moon passes between the Earth and the Sun, blocking the Sun's light from reaching the Earth. This can only happen during the new moon phase when the Moon is positioned directly between the Earth and the Sun.

During a lunar eclipse, the Earth passes between the Sun and the Moon, blocking the Sun's light from reaching the Moon. This can only happen during the full moon phase when the Earth, Moon, and Sun are aligned in a straight line.

7. What are comets and asteroids?
Comets are icy bodies that originate from the outer regions of the solar system. They are composed of ice, rock, dust, and other organic compounds. When a comet gets close to the Sun, the heat causes the ice to vaporize, creating a glowing coma (a cloud of gas and dust) surrounding the nucleus, and sometimes also a tail pointing away from the Sun.

Asteroids, on the other hand, are rocky objects that orbit the Sun. Most asteroids are found in the asteroid belt, located between Mars and Jupiter. They are remnants from the early solar system, composed mainly of rock and metal.

8. Describe the differences between meteors, meteoroids, and meteorites.
A meteoroid is a small rocky or metallic object that orbits the Sun. When a meteoroid enters the Earth's atmosphere and burns up due to the friction caused by the air, it is called a meteor. A meteor is often referred to as a shooting star.

If a meteor survives its passage through the atmosphere and lands on Earth's surface, it is called a meteorite. Meteorites are valuable for scientific study as they provide information about the composition and history of the solar system.

9. Explain the process of satellite formation.
Satellites, such as the Moon orbiting the Earth or artificial satellites orbiting Earth, form through a process called accretion. Accretion occurs when dust and gas in a protoplanetary disk begin to clump together due to gravitational attraction, forming larger and larger bodies. Over time, these bodies merge and grow through additional collisions, eventually forming a satellite that orbits a larger celestial body.

10. How does Earth's rotation affect its shape?
Earth's rotation causes a bulge at the equator and flattening at the poles. The centrifugal force resulting from the rotation pushes material away from the axis, causing the equatorial region to bulge. This shape is known as an oblate spheroid or ellipsoid.