Imagine you want to build a scale model of the solar system.
First, you need to decide on a scale for your model. Let's say we decide we'll use a marble that is 1 cm across to represent the Earth. Then how big would the Sun and the other planets be and where would they go?
To figure out the sizes of the planets and the Sun compared to our Earth marble, you need to multiply the 1 cm size of Earth by the relative sizes of the Sun and the planets. A marble for the Sun would have to be 109 cm across (bigger than a big beach ball), and a marble for Mercury would be about the size of your pencil's eraser.
Next, you need to figure out where to put your model planets. How far are they from the Sun? At this scale, Mercury would be 46 m (151 feet) from the Sun, Earth would be 118 m (387 feet) from the Sun, and Pluto would be more than 5.8 km (3.6 miles) from the Sun!
Imagine you want to build a scale model of the solar system.
First, you need to decide on a scale for your model. Let's say we decide we'll use a marble that is 1 cm across to represent the Earth. Then how big would the Sun and the other planets be and where would they go?
To figure out the sizes of the planets and the Sun compared to our Earth marble, you need to multiply the 1 cm size of Earth by the relative sizes of the Sun and the planets. So a marble for the Sun would have to be 109 cm across (bigger than a big beach ball), and a marble for Mercury would be about the size of your pencil's eraser.
Next, you need to figure out where to put your model planets. How far are they from the Sun? At this scale, Mercury would be 46 m (151 feet) from the Sun, Earth would be 118 m (387 feet) from the Sun, and Pluto would be more than 5.8 km (3.6 miles) from the Sun!
The distances in the solar system are vast. So vast, that it would be difficult to see the planets if they were put at their correct relative distances in the image below (an "artist's rendition" of the solar system). The distance between the Sun and Earth is 149,600,000 km (92,960,000 miles). Astronomers have defined this distance to be 1 astronomical unit (1 AU). The table below shows the distances from the Sun to each of the planets relative in AU.
| Body | Distance from the Sun (in AU) |
|---|---|
| Mercury | .39 |
| Venus | .72 |
| Earth | 1 |
| Mars | 1.52 |
| Jupiter | 5.20 |
| Saturn | 9.54 |
| Uranus | 19.19 |
| Pluto (closest) | 29.6 |
| Neptune | 30.1 |
| Pluto (farthest) | 49.5 |
