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Trying to get one's mind around the astronomical numbers (no pun intended) of the universe can be a mind bending experience. One way to
begin to appreciate where we, the planet earth, stand in the solar system, which is part of the Milky Way Galaxy, is to make a scale model.
Sounds simple doesn't it ? However, it turns out a bit bigger than one would think.
Let us start with our solar system that consists of the sun and nine planets. These nine planets, in order from the sun, are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune & Pluto. Below, roughly to scale, are the Sun, Earth, Pluto (the farthest planet), and our nearest star, Alpha Centauri.
Take a 7/8" (22 mm) diameter ball and place it in the centre of Duncan Mall. That will be our sun. Take a pin head and place it 7.75 feet (2.36 m) from "the Sun". That is mother Earth. Now take a grain of sand and place it out in the parking lot some 306 feet (93.29 m) from our "Sun". That represents the farthest planet in our solar system, Pluto. The others are scattered between our "Sun" in the mall and the grain of sand in the parking lot. Are you with me so far? Our nearest star is Alpha Centauri in the southern hemisphere. It is actually a triple star system that appears as one to the naked eye. It is 4.3 light years away. A light year is the distance that light travels in a year, about 5,878,600,000,000 miles or 63,240 times the distance to the sun. It takes a bit more than 8 minutes for the sunlight to reach earth. By the way, that number is over 5 trillion miles; on this continent. You see the Americans and the British have different definitions for billions and trillions. This is one of the reasons why astronomers prefer to use a unit called an ASTRONOMICAL UNIT or a.u. which is the average distance between the sun and earth. It brings these large numbers down to a size that we can, more readily, appreciate. In our scale a light year would be about 93 miles (150 km), the distance from Duncan to Courtney. Let us put Alpha Centauri into our model. To do that we will have to take a 1 1/8" (29 mm) diameter ball and place it 400 miles (644 km) away in Banff, Alberta. We now have a relationship between a pin head (Earth) in the Duncan Mall and a small ball in Banff. Are we talking space? Well, we have started ! Talking of galaxies, we are one of billions in space. Our nearest neighbour is the galaxy Andromeda 2,200,000 light years away. Yes, that is LIGHT YEARS. It is about twice the size of our galaxy and if we wanted to put it into our model we would have to find a disk whose diameter was 1/5th. the distance to the sun and place it in space at a distance from earth more than twice the distance to the sun. So, in our quest to bring our bit of "home space" into model form, we have gone from a pin head in the mall to a distance twice as far away as the sun ...... and we haven't begun to look at deep space! When you look up on a clear night and see all those stars, try and look through a pair of binoculars and you will reveal thousands more in your field of view. As you look at these pinpoints of light realize that the light that you are seeing started out 4, 40, 400, 4,000 or more years ago. The light that you see could well have started out from its source long before Christ was born ! Look up, marvel and enjoy. Ed Boddaert |
