Distances of the Planets from the Sun
Lesson notes
Overview
Planetary distances grow roughly geometrically, so a log scale is needed. This topic is rated beginner and is number 30 of 98 in Earth & Space. Core ideas and first intuitions. No prior knowledge needed.
What you are seeing
The panel above shows a bar chart that compares values on one scale, so differences in size are easy to see. The animation is drawn live from the model, so everything you see responds to the sliders. Press Space to pause, use Restart to replay from the start, and change the speed to slow down quick events.
In depth
The planets’ distances from the Sun, measured in astronomical units, where 1 AU is the Earth–Sun distance, grow roughly geometrically: Mercury 0.39, Venus 0.72, Earth 1, Mars 1.52, Jupiter 5.2, Saturn 9.6, Uranus 19.2 and Neptune 30. A log scale is therefore needed to show them all in one picture. Light takes about 8 minutes to reach the Earth and over 4 hours to reach Neptune. The Titius–Bode rule tried to describe the spacing but is not a law.
Reading the relationship
The expression "astronomical units" is a compact summary of the idea. It uses the symbols a, s, t, r, o, n; name what each one stands for before you start. Then use the sliders to see how changing one quantity changes the others.
A guided exploration
1. Run the animation once with the default settings and describe in words what happens. 2. Change one slider at a time and note which quantity responds most. 3. Push each slider to its extreme and decide whether the result still makes sense.
Try this
Start by only moving one slider at a time. Say aloud what you expect, then check.
Common pitfalls
Earth and space systems work on very different scales of time and distance. Check which scale a number refers to before comparing it with another.
How it connects
It builds on “Ocean Tides”, the topic before it in Earth & Space. Once you are comfortable, continue with “Surface Gravity of the Planets”.
Why it matters
Earth and space science helps us understand our planet, its climate and the wider universe.
Where you might use it
- Revising “Distances of the Planets from the Sun” before a class, exam or certification
- Forecasting weather and understanding climate records and their uncertainty
- Planning for earthquakes, floods and other natural hazards in cities
- Interpreting satellite images, space missions and the age of rocks and stars
Frequently asked questions
What is Distances of the Planets from the Sun?
Planetary distances grow roughly geometrically, so a log scale is needed. It is a beginner topic in Earth & Space.
How do I use the Distances of the Planets from the Sun simulation?
The panel at the top shows a bar chart that compares values on one scale, so differences in size are easy to see. Move the sliders one at a time, then press Space to pause the animation and look closer.
What does the formula mean?
The expression astronomical units packs the idea into symbols. Name each symbol first, then change one quantity with the sliders and see which others respond.
Who is this topic for?
Core ideas and first intuitions. No prior knowledge needed. If the quiz feels hard, reread the lesson notes and try the previous topic first.
What should I learn before this?
Start with “Ocean Tides”, the previous topic in Earth & Space. Each topic in a subject builds on the ones before it.
How do I track my progress?
Press “Mark as learned” on this page. Progress is stored only in this browser and is never sent anywhere. The Browse page can show topics you have learned or still need to learn.
Quick quiz
More in Earth & Space
See all →Surface Gravity of the Planets
Weight depends on a planet’s mass and radius; Jupiter’s gravity is 2.5 times Earth’s.
Kepler’s Third Law
The square of a planet’s orbital period is proportional to the cube of its distance.
The Habitable Zone
Liquid water is possible where starlight intensity is neither too strong nor too weak.