I was reading an article recently (and I don't remember where! but if I do, I'll edit this post to put a link) about the star Canis Majoris. This is the largest star currently known to exist. How big is it? Well, this star is located in the constellation Canis Major (the Big Dog), if you want to see it for yourself. But according to what I'm reading, it is 1.7 billion miles in diameter.
The problem with numbers like that, though, is that they're just meaningless to the human brain. We can't visualize distances of that magnitude, and remember, when talking about distances in space, that is still a tiny number in comparison to something really big, like, say, the diameter of the Milky Way Galaxy. So this is where we have to come up with little visualizations in order to conceptualize these distances. Here's a picture that tries to help:
That kind of helps, but I wanted an even better way to try to conceptualize the relationship of size here. Well, I was bored the other day, so I came up with one! Huzzah! Here's how it goes.
Imagine the Earth as a sphere that is one inch in diameter. Got it? Earth, a little smaller than a golf ball. Maybe a little bigger than a big marble. One inch in diameter. That means that in our scale here, one inch equals about 8,000 miles.
Now, after a bit of Googling, I find that the diameter of our Sun is approximately 864,000 miles. Doing a bit of division, we now can figure that if the Earth is a ball one inch in diameter, then our Sun is a ball 108 inches, or 9 feet, in diameter. Now I find that a little surprising in itself. We all know that the Sun is a lot bigger than Earth, but the jump in relative sizes proportionally takes us from a one-inch Earth to a nine-foot Sun!
And now we do the math for Canis Majoris, which is, as noted above, 1.7 billion miles in diameter. That's 1,700,000,000 miles. Dividing that by our 8,000 miles for one inch, we find that a ball in this scale representing Canis Majoris would be 212,500 inches in diameter. Of course, we have a hard time conceptualizing that number of inches too, so dividing that by 12, we find that our Canis Majoris ball is 17,708 point something feet in diameter. But that's still hard to see, so divide that by 5,280, and we find that if one inch equals the diameter of the Earth, then Canis Majoris is a ball just over 3 and one third miles in diameter.
My point here is simply this: Whoa.