Question

directions: answer the following questions. 1. how does the structure of our solar system make planets movement change direction? 2. what factors determine if a planet is visible in the night sky without a telescope? 3. describe the differences between the four inner and four outer planets. 4. how did a nebula of gases and dust form our solar system? 5. turn back to page 5. review your answer to the question, \why might astronomers have thought both of these were accurate models at different points in history?\ revise your answer using evidence from the lesson.

Explanation:

Step1: Gravitational forces

The sun's gravity is the dominant force in the solar - system. Planets move in elliptical orbits around the sun. The gravitational pull from the sun and other planets can cause a change in a planet's direction of motion. For example, when a planet is near a massive object like Jupiter, the gravitational interaction can perturb its orbit and change its direction.

Step2: Orbital mechanics

According to Newton's laws of motion and universal gravitation, the combination of a planet's initial velocity and the gravitational forces acting on it result in its orbital path. The structure of the solar - system with its distribution of mass (sun and planets) determines the net gravitational force on each planet, which in turn affects its direction of movement.

Step1: Distance from Earth

The closer a planet is to Earth, the more likely it is to be visible without a telescope. For example, Venus is relatively close to Earth at certain times and is very bright in the night - sky.

Step2: Size of the planet

Larger planets reflect more sunlight. Jupiter, being the largest planet in the solar - system, is easily visible without a telescope due to its large size and the amount of sunlight it reflects.

Step3: Albedo

Albedo is the measure of how much light a planet reflects. Planets with high albedo, like Venus with its thick, reflective atmosphere, are more visible.

Step4: Position relative to the sun

A planet's position in its orbit relative to the sun and Earth affects its visibility. When a planet is in a position where it is well - illuminated by the sun and is in a favorable position in the sky from Earth's perspective, it is more likely to be visible.

Step1: Composition

Inner planets (Mercury, Venus, Earth, Mars) are rocky and have a solid surface. Outer planets (Jupiter, Saturn, Uranus, Neptune) are gas giants or ice giants. Jupiter and Saturn are mainly composed of hydrogen and helium, while Uranus and Neptune have a significant amount of ice in their composition.

Step2: Size

Inner planets are much smaller than outer planets. For example, Earth is much smaller than Jupiter.

Step3: Orbit

Inner planets have shorter orbital periods around the sun as they are closer to the sun. Outer planets have longer orbital periods. Mercury has an orbital period of about 88 Earth days, while Neptune has an orbital period of about 165 Earth years.

Step4: Moons

Inner planets have few or no moons. Mercury and Venus have no moons, while Earth has one moon and Mars has two small moons. Outer planets have numerous moons. Jupiter has over 79 known moons and Saturn has over 82.

Step1: Nebular hypothesis

The solar - system formed from a large cloud of gas and dust called a nebula.

Step2: Gravitational collapse

Gravity caused the nebula to collapse. As it collapsed, it started to spin faster due to the conservation of angular momentum.

Step3: Formation of the protosun

The central part of the collapsing nebula became denser and hotter, forming the protosun.

Step4: Planet formation

In the surrounding disk of gas and dust, small particles collided and stuck together through a process called accretion. These particles grew larger over time to form planetesimals, which then combined to form planets.

Answer:

The sun's gravity and the gravitational forces from other planets in the solar - system, as described by Newton's laws of motion and universal gravitation, cause changes in a planet's direction of motion.