1. Race the inner planets
Which planet will finish first?
Press Play. Count Mercury’s laps while Earth completes one.
What should I notice?
Mercury finishes a little more than four laps. Planets closer to the Sun have shorter years.
Solar System Simulator
Eight planets travel around the Sun. Which one finishes a lap first? Press Play, change the view, and compare their paths. A path around the Sun is called an orbit.
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About this model
The picture is a model. Its scale and timing depend on the selected view.
Planet dots are enlarged. Orbit tilts are exaggerated in angled views. Use View angle 0° to look straight down without that exaggeration.
Distances between orbits use one scale within a view. The date changes the approximate planet positions.
Explore size and distance. NASA/JPL’s position model.
Sat, September 26, 2026
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View angle & playback speed
Moons shown
Planet zoom level
Include:
Planet distances & angles
AU means Earth’s average distance from the Sun. The angle marks a planet’s place around its orbit.
What to look for
Make a guess. Try it. Then check what you noticed.
2. See the gaps
Are the planets evenly spaced?
Look near the Sun. Can you find the four small inner orbits?
What should I notice?
The planets are not evenly spaced. The outer solar system has much larger gaps. The planet dots are enlarged so you can see them.
3. Give Neptune more time
Will Neptune finish a lap in 100 years?
Drag the time slider from left to right. Follow Neptune’s outer ring.
What should I notice?
No. Neptune completes only about three-fifths of its orbit in 100 Earth years. Its full year takes about 165 Earth years.
Questions answered
Which planet finishes an orbit first?
Mercury. Its year lasts about 88 Earth days. In one Earth year, Mercury goes around the Sun a little more than four times.
Why do the outer planets take longer?
They have much larger paths to travel and move more slowly. Neptune takes about 165 Earth years to go around the Sun. See how gravity shapes an orbit.
Why do the inner planets bunch together when I zoom out?
They really are close to the Sun compared with the outer planets. Zooming out shows more space, so their orbits look smaller.
Can I explore a single planet?
Yes. Click a planet in the drawing to open its page, or use the planet guide. Each planet has its own story. Worlds with moons also have closer views of their moon systems.
A closer look
What does AU mean?
AU is a unit for measuring space. One AU is Earth’s average distance from the Sun, about 150 million kilometres. Neptune is about 30 AU away. That is about 30 times farther from the Sun than Earth.
What keeps a planet moving around the Sun?
A planet is already moving. The Sun’s gravity pulls it inward and bends its path. Gravity does not switch off when the planet is far away.
Make a link to a particular view
The date, the zoom, the span, the speed, the layers and any flight path are all in the address bar, so copying the URL shares exactly what is on screen. Set it up above, then take the link — it is the quickest way to hand a class one specific thing to look at.