What keeps a planet in orbit around the Sun?

The force of gravity between the Sun and the planet keeps the planet in its orbit.

Do planets have perfectly circular orbits?

No, most planets have slightly elliptical (oval-shaped) orbits, though they are often close to being circular.

What is the difference between a natural and artificial satellite?

A natural satellite is a body like the Moon orbiting a planet, whereas an artificial satellite is a man-made object placed into orbit.

How does distance affect the Sun's gravitational pull?

The further away a planet is from the Sun, the weaker the gravitational pull it experiences.

Why do moons orbit planets instead of the Sun directly?

Moons are held in orbit by the gravitational pull of the planet they are closest to.

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🔭 Knowledge Check: Orbits and Gravity

Test your understanding of how objects move in space and the forces that control them.

1. What is the primary force that keeps planets in orbit around the Sun?

Magnetism
Gravity
Friction

2. Which of these best describes an 'elliptical' orbit?

A perfect circle
An oval shape
A straight line

3. The Moon is considered a natural satellite of Earth because:

It was launched into space by humans.
It orbits the Sun independently.
It is held in orbit by the Earth's gravitational pull.

4. How does the Sun's gravitational pull change as a planet moves further away?

The gravitational pull gets stronger.
The gravitational pull stays the same.
The gravitational pull gets weaker.

5. Which of the following is an example of an artificial satellite?

The ISS (International Space Station)
The Moon
A distant star

Click to Reveal Answers

1. Gravity (This force acts between all objects with mass).
2. An oval shape (Most planets have slightly elliptical orbits).
3. It is held in orbit by the Earth's gravitational pull (Moons orbit planets).
4. The gravitational pull gets weaker (Gravity decreases with distance).
5. The ISS (International Space Station) (Artificial means man-made).

Tags: Solar System, Orbits