Interstellar scale

The scale of planets, stars, and galaxies is very hard to grasp; here are some models that will help. Distances are rounded off for easy visualization.

To visualize the solar system we can use a scale of one billionth, the nano scale.

At the nano (one billionth) scale:

• The Earth is half an inch across.
• The moon is 1/8 inch across and a foot from the Earth.
• The Sun is five feet across and 500 feet from Earth.
• Jupiter is six inches across and half a mile from the Sun.
• Pluto is four miles from the Sun.
• The nearest star, Alpha Centauri, is as far away as once around the earth.
• The speed of light is one foot per second.

This is still too large a scale for interstellar space but we can use a scale of one billionth times one billionth, the nano-nano scale.

At the nano-nano (one billionth times one billionth) scale:

• The earth is as small as an atom.
• The solar system is too small to see.
• The speed of light is 3/8 inch per year, three feet per century, or six miles per million years.
• The nearest star, Alpha Centauri, is one and a half inches away.
• The brightest star, Sirius, is three inches away.
• The stars in the Big Dipper range from two to four feet away.
• The North Star, Polaris, is thirteen feet away.
• The Milky Way, our galaxy, is half a mile wide and has 150 billion stars.
• The nearest galaxy, Andromeda, is a mile wide and seventeen miles away.
• The next nearest galaxies are six in a group named Sculptor, 60 miles away.
• There are 50-100 billion galaxies within a distance of 3-4 times around the Earth.
• Light from this far away has been traveling since the big bang.

Here is a description of a one billionth scale model of our solar system that would attract tourists to a community.

It is built by putting a scale model of the sun outdoors in a highly visible location and putting scale models of the planets indoors in businesses at the correct distances. Each model planet is mounted on a plaque describing it and giving the locations of all the others. The model only costs a few thousand dollars.

It attracts customers to the businesses and visitors to the area as well as providing a real science education experience. Customers at any of the businesses see one of the plaques and learn about the model. They may then visit the rest of the businesses to see the other plaques. The model can be toured by science classes and mentioned in tourist brochures.

The relative sizes and distances of objects in our solar system are hard to grasp; the model gives visitors an experience of their true scale. The distance to the nearest star is the distance completely around the Earth and the speed of light is about one foot per second.

Object                Diameter            Distance from sun

Sun            4 feet 7 inches 
Mercury             0.2 inches               190 feet
Venus               0.5 inches               350 feet
Earth               0.5 inches               490 feet
Earth's moon        0.14 inches               15 inches from Earth
Mars                0.3 inches               750 feet
Jupiter             5.5 inches               0.5 mile
Saturn              4.7 inches               0.9 mile
Uranus              2.0 inches               1.9 miles
Neptune             2.0 inches               2.8 miles
Pluto               0.1 inches               3.7 miles
Nearest star                               25,000 miles