Moab Scale Model Solar System The distance between the planets of our solar system is hard to comprehend. By human standards the distances are enormous and yet, when compared to distances between stars in our galaxy, the distance between planets seems small.

You’ve probably seen a model like this one You’ve probably seen a model like this one. This model of the Solar system is fun to look at and it shows you the order of the planets, but it has a big problem. It is not to scale.

The planets are bigger than they should be and they are too close together. If this model was to scale and the sun was the same size, the earth would be about the size of a pin head.

Even the largest planet, Jupiter, would be smaller than a gumball Even the largest planet, Jupiter, would be smaller than a gumball. The planets should also be much farther away from the sun. For example, Earth should be 35 feet away from the sun.

This scale model solar system is designed to better convey the enormous distances between the planets compared to their relatively small proportional sizes. Moab’s scale model of the solar system allows you to take a stroll from one planet to the other. Although each of the four inner planets (Mercury, Venus, Earth, and Mars) can be walked to with relative ease, getting to Pluto would involve a one-way hike of 9.5 miles!

According to project designer Sam Allen, the display is meant to continue the theme started on East Center Street with Star Hall, Sun Court and Moon Stone Gallery. “I got the idea from the scale model solar system that was on display in the stores along Main Street a few years ago. The concept was fascinating to me.” said Allen. Solar system project designer Sam Allen stands at the center of Moab’s Sun Court on the disk representing the Sun, while holding scale-model cutouts representing Earth and Saturn.

The Moab City Council approved the project and planning and community development director David Olsen was instrumental in getting it done, Allen said, adding that special thanks are also due to Rob Morris of the Clark Planetarium for help with the scale calculations and NASA for the images used on the plaques.

The Sun is represented by a 142-inch diameter yellow disc at the center of the Sun Court, an outdoor basketball court just east of the historic Star Hall building. All of the distances and planet sizes are scaled accordingly (1 inch equals approximately 10,000 kilometers). <-- Sun

The locations of the inner planets are marked with plaques around town and along the Mill Creek Parkway. A map is available at the Grand County Public Library, where the plaque for Mercury also is located.

Even at this small scale, the solar system is too big to fit inside Moab City limits. The final plaque on the Mill Creek Parkway represents Mars. The outer five planets are not represented by plaques, but are denoted by their approximate locations along Highway 191 south of town.

The relative sizes of the planets seem miniscule in light of the sizable distances between them, Allen said, adding that the Earth is only the size of a large marble or jawbreaker 1.3 inches in diameter. Saturn is about the size of a basketball, and Jupiter slightly larger than that. Uranus and Neptune are each about the size of a softball or a large grapefruit. Tiny Pluto – demoted to “dwarf planet” status last year - is nothing more than a pebble less than a quarter of an inch across.

Sun Start the tour at the Sun Court. The Yellow disc in the center of the basketball court represents the sun. The Sun is the closest star to Earth, at a mean distance from our planet of 149.60 million kilometers (92.96 million miles). This distance is known as an astronomical unit (abbreviated AU), and sets the scale for measuring distances all across the solar system. The Sun, a huge sphere of mostly ionized gas, supports life on Earth.

Walk to the Library.

Mercury The scale size of the planet Mercury is represented by a small marble. The small and rocky planet Mercury is the closest planet to the Sun; it speeds around the Sun in a wildly elliptical (non-circular) orbit that takes it as close as 47 million km and as far as 70 million km from the Sun. Mercury completes a trip around the Sun every 88 days, speeding through space at nearly 50 km per second, faster than any other planet. Because it is so close to the Sun, temperatures on its surface can reach a scorching 467 degrees Celsius. But because the planet has hardly any atmosphere to keep it warm, nighttime temperatures can drop to a frigid -170 degrees Celsius.

Next walk to the location of Venus.

Venus It is at the southeast corner of the ball park, 300 E. 100 S Venus It is at the southeast corner of the ball park, 300 E. 100 S. The scale size of Venus is about the size of a quarter. Venus and Earth are similar in size, mass, composition, and distance from the Sun but, Venus has no ocean. Venus is covered by thick, rapidly spinning clouds that trap surface heat, creating a scorched greenhouse-like world with temperatures hot enough to melt lead and pressure so intense that standing on Venus would feel like the pressure felt 900 meters deep in Earth's oceans. These clouds reflect sunlight in addition to trapping heat. Because Venus reflects so much sunlight, it is usually the brightest planet in the sky.

Now walk by the bridge in the Cross Trails Park Now walk by the bridge in the Cross Trails Park. This is the location of Earth.

Earth Earth is a little larger than Venus, but the scale size is still pretty close to the size of a quarter. Earth, our home planet, is the only planet in our solar system known to harbor life. All of the things we need to survive are provided under a thin layer of atmosphere that separates us from the uninhabitable void of space. Earth is the third planet from the Sun and the fifth largest in the solar system. Earth's diameter is just a few hundred kilometers larger than that of Venus. The four seasons are a result of Earth's axis of rotation being tilted more than 23 degrees.

Follow the path and go through the tunnel under 300 South Street Follow the path and go through the tunnel under 300 South Street. When you get out of the tunnel on the south side you are about to the orbit of Mars.

Mars At this scale Mars is about the size of a dime Mars At this scale Mars is about the size of a dime. Mars is a small rocky body. Its surface has been changed by volcanism, impacts from other bodies, movements of its crust, and atmospheric effects such as dust storms. It has polar ice caps that grow and recede with the change of seasons; areas of layered soils near the Martian poles suggest that the planet's climate has changed more than once, perhaps caused by a regular change in the planet's orbit.

Even at this small scale, the solar system is too big to fit inside Moab City limits. The outer five planets are not represented by plaques, but are denoted by their approximate locations along Highway 191 south of town. For the rest of the tour you will need to ride in a vehicle. Drive South out of town on Highway 191 and look for the small green signs along the side of the road. These are mile markers. They are placed every mile along the highway. The approximate locations of the outer planets are represented by the nearest mile marker.

Jupiter would be at mile marker 124 (near the Farm & City feed store).

Jupiter, mile marker 124. Jupiter is the most massive planet in our solar system. Its scale dimension is about the size of a 14” beach ball. Jupiter resembles a star in composition. In fact, if it had been about eighty times more massive, it would have become a star rather than a planet.

Saturn is close to mile marker 123 (by Grand Rental Center and Moab 4x4 Outpost) Saturn, mile marker 123.

Saturn is surrounded by thin, flat rings Saturn is surrounded by thin, flat rings. Saturn is made mostly of hydrogen and helium. Its volume is 755 times greater than that of Earth. At this scale it is a little larger than a basketball. Winds in the upper atmosphere reach 500 meters per second in the equatorial region. These super-fast winds, combined with heat rising from within the planet's interior, cause the yellow and gold bands visible in the atmosphere.

Uranus is approximately at mile marker 121 near the KOA Kampground and Spanish Trail Arena).

Uranus, mile marker 121. Uranus is a gas giant with no solid surface Uranus, mile marker 121. Uranus is a gas giant with no solid surface. It has some of the brightest clouds in the outer solar system and 11 rings. Its scale size is comparable to a large grapefruit. The first planet found with the aid of a telescope, Uranus was discovered in 1781 by astronomer William Herschel. The seventh planet from the Sun is so distant that it takes 84 years to complete one orbit. Its scale size is about the size of a large grapefruit or a softball.

Neptune is near mile marker 118, by LeGrand Johnson’s.

Neptune, mile marker 118. Neptune was the first planet located through mathematical predictions rather than through regular observations of the sky. Nearly 4.5 billion kilometers from the Sun, Neptune orbits the Sun once every 165 years. It is invisible to the naked eye because of its extreme distance from Earth. It is a little smaller than Uranus, so its scale size is also about the size of a large grapefruit or a softball.

Pluto is close to mile marker 116, about two miles south of Old Airport Road.

Pluto, mile marker 116. Pluto was discovered in 1930 Pluto, mile marker 116. Pluto was discovered in 1930. It was known as the most distant planet from the Sun until August 24, 2006 when the International Astronomical Union (IAU) formally downgraded Pluto to a dwarf planet. Pluto takes 248 years to orbit the Sun. At this scale it is about the size of a pea.

At this same scale, the nearest star in our galaxy, Alpha Centauri, would be 65,044 miles away, too far to represent on any earthly scale (this distance is more than two and a half times around the equator of the Earth).

This PowerPoint Created by John Allen Special Thanks to: NASA Rob Morris, Clark Planetarium