Just how large are the planets in our Solar System relative to one another and the Sun? And how far apart are their orbits relative to their respective sizes?
I’ve casual pondered that question ever since I came across my first model of the Solar System (example) – a relatively small collection of rings representing the orbits of planets which were as close to one another in size as the change in your pocket. Even then I sensed they were grossly disproportionate, but it being only a casual interest I neglected to investigate further. That changed recently when I came across an impressively constructed CSS3 map of the Solar System complete with proportionate planets and orbits, the latter relative to the display area. This reignited my interest so I decided to search out the data and create a diagram to display the size accurately (and satisfy a recent urge to design some minimalist desktop wallpaper).
Wallpaper : Expanse, by Coswyn
My first step was to set a point of reference: the Sun, which I set to 1200×1200 pixels, given that the wallpaper would be for a 1920×1200-pixel maximum resolution. The Sun being approximately 1,391,000 kilometers in diameter, I arrived at a ratio of approximately 1160:1. Following this, I determined that the Earth, which is approximately 12,756 kilometers in diameter, would be displayed at 11×11 pixels. The remaining planets were subject to the same ratio for their respective dimensions and I was able to arrive at a model with sizes displayed accurately to scale.
Below is a set of [wallpaper-sized] diagrams depicting my findings…
Size of the Solar System
I considered taking it a step further and displaying the planets in their fully proportionate orbits, but I overlooked one technicality: the Solar System has a diameter of approximately 11,827,040,000 kilometers. At 1160:1 it would set the wallpaper at 10,195,724×1200 pixels, which would require approximately 5,310 24″ monitors set side-by-side to fully display (a line that would stretch nearly 1.85 miles). I was so impressed by this scale that I started investigating alternative solutions to display it in a reasonable space, but I overlooked another technicality: Pluto is approximately 2×2 pixels already (imagine trying to spot that from close to two miles away), so if scaled down to fit in a 25-foot long space the dwarf planet would live up to its classification and be literally microscopic (1/670th of a millimeter (smaller than a single bacterium), or a 0.0054 pixel equivalent, to be exact – that’s like fitting nearly 185 instances of it into a single pixel).
Below is a map of our Solar System with planets and orbits drawn to scale. Notice, however, that no planets are displayed. The reason for this is that the Sun takes up a single pixel at that scale, which results in sub-pixel (in other words, sizes not able to be displayed on a monitor) planets – the Earth, for example, is 1/109th of a pixel…
Size of the Milky Way Galaxy
If these scales are not impressive enough consider the size of our Solar System’s container, the Milky Way Galaxy: it has an approximate diameter of 100,000 light years. 100,000 is not a large number compared to the ones arrived at so far, but 1 light year is 9,460,800,000,000 kilometers. Yes, nearly 9.5 trillion kilometers across, which introduces a new ratio: 800:1 – that is, 800 instances of our Solar System per light year. At its widest known point, the Milky Way can fit 80 billion instances of our Solar System. That’s 900,460,800,000,000,000 kilometers, to be exact – 900 quadrillion (the successor of trillion and, at that size, near predecessor of quintillion), for short.
Size of the Universe
If these numbers do not have your head spinning yet, consider the seemingly incognizable magnitude of the observable universe: 93 billion light years, or approximately 879,854,400,000,000,000,000,000 kilometers, in diameter – that’s nearly 880 sextillion (sextillion > quintillion > quadrillion > trillion). That equals the span of 977,116 Milky Way Galaxies, and that is only what is observable from our spec of a planet, which when compared to the width of a cell membrane sets the universe at close to the size of our Solar System.
From the smallest to the largest point, the known universe is virtually inconceivable in size except by number. We are simply unable to perceive with our eyes the proportion of this great expanse from our small corner of creation, though humility should not be hard to come by as we attempt to imagine the space in which we are suspended and the source and purpose of it all.
Bonus : Videos
Below are several videos which further illustrate the size of our local and extended cosmos…