Vastness of Space

One of the questions that astronomers are asked is how can they possibly comprehend the vast distances in space, and the answer is usually (if they are honest) that they really can't quite fully grasp it. The human mind has great difficulty in firmly being able to understand the distances between objects in space. If you were to fly around the world, you would go just under 25,000 miles. With cars that keep track of mileage in the hundreds of thousands of miles, the earth's circumference doesn't seem that large. But when you consider that the moon (the closest celestial body to the earth) is around 240,000 miles from the earth, you begin to see that if 240,000 miles is hardly any distance at all, then we will have a hard time understanding millions, billions, and trillions of miles.

The best way to understand how far away things are is to create scale models of sizes we can comprehend. So, here's a little thing for you to try: a scale model of the solar system.

First start by figuring out your scale. If you use a basketball (which is approximately 9.5 inches in diameter) to represent the sun, then you will come up with a scale of approximately 91,000 miles equals an inch. So if that's the case, then how far away would the planets be?

Mercury = 33 feet away and .034 inches in diameter
Venus = 62 feet away  and .083 inches in diameter
Earth = 86 feet away and .088 inches in diameter
Mars = 130 feet away and .047 inches in diameter
(300 feet is 1 football field)
Jupiter = 445 feet away and .983 inches in diameter
(600 feet is 2 football fields)
Saturn = 820 feet away and .828 inches in diameter
(900 feet is 3 football fields)
(1200 feet is 4 football fields)
(1500 feet is 5 football fields)
Uranus = 1645 feet away and .351 inches in diameter
(1800 feet is 6 football fields)
(2100 feet is 7 football fields)
(2400 feet is 8 football fields)
Neptune = 2580 feet away and .337 inches in diameter
(2700 feet is 9 football fields)
(3000 feet is 10 football fields)
(3300 feet is 11 football fields)
Pluto = 3380 feet away and .016 inches in diameter

In case you're curious about the moon, it would be 2.64 inches from the earth in this model, and its diameter would be .024 inches.

But what about father things? Well, in this model, the Oort Cloud would extend out approximately 16 miles from our 9.5 inch sun.

Also, the speed of light is slower: approximately 2 inches a second or 10 feet a minute. This means that it would take nearly 5 hours to reach Pluto. A light year in our model would be approximately 1,000 miles on earth. That means that in our model, one light year would be the distance of St. Louis to Boston.

So what about Proxima Centauri? This is the closest star to our own, and it's about 4.3 light years away. This means that in our model, Proxima Centauri would be over 4300 miles away (or the distance of Boston to Moscow).

To give you one more example, check out the size of the Milky Way galaxy. It is 100,000 light years in diameter. That means that in our example based on our sun being about 9.5 inches in diameter, that means that you would have to have about 100 million miles.

The universe is vast, and even some of the examples don't seem to really help understand the distances involved. But here has been an attempt to help you see how much space is really out there.

Bet you didn't know that!