From left to right:

Mercury, Venus, Earth (and our moon), Mars, and … Uungh?  That’s Ceres – a planetoid in the asteroid belt that’s probably the biggest remnant of the planet that originally occupied that orbital slot.  If you zoom into the picture, you can probably see a bunch of little gray flecks that are supposed to be asteroids around it.  There are also specks for stars, and blue, gray, and purple variations in color in space, but I think they’re too “subtle” to come across in this photo.

Next stop – Jupiter!

(In case you were wondering, the sizing of the planets aren’t entirely random, though they’re clearly not to a linear scale.  Since I wanted to convey something of the proportional sizes without having to render the sun as the side of our house or Mercury as a speck, I took the average of the logarithmic distillation of the radius and the square root.  The actual formula I plugged into Excel is:

(log2(0.01 * R) + √(0.01 * R))/500000

The initial multiplier of 0.01 is in place as a kind of sorting mechanism – any object with a radius of less than 100 kilometers ends up with a negative logarithmic value, so unless averaging it with the square root brings it back above zero, I can’t draw it.  I think the smallest radius I plan to draw is about 80km, which cuts the scores of moons around Jupiter and Saturn down into the manageable 8-12 range.  The 500000 dividing out the function converts kilometers to centimeters and adds an additional scalar to make sure Jupiter fits entirely in the 8″ available in the canvas.)