This week let’s have ourselves a little awards ceremony. We’ll call them The Solies, awards to planets in our solar system which are at the top of a particular category. Ready? 

In a shocking upset, the Solie for Hottest Planet goes not to Mercury, but to its fellow planet farther out, Venus! One would think Mercury to be the clear winner here, being so close to the sun as it is. But Venus has an extra characteristic that little Mercury does not possess. It has an atmosphere - a thick, nasty, carbon dioxide-filled one which can hold onto heat extremely efficiently. Its average temperature at the surface is a warm 900 degrees Fahrenheit. 

As a consolation prize we’ll give Mercury the Solie for Greatest Day/Night Temperature Difference. Mercury has one heckuva long day. One sunrise to the next lasts about 180 of our days! During its “daytime,” its temp sores to 800 degrees Fahrenheit, but when that same surface turns away from the sun and has months to cool down, it does so with a vengeance, cooling to 280 degrees below zero. Overall difference: over 1000 degrees. Congratulations, Mercury!

The Solie for Most Massive Planet goes to... Jupiter! Now this probably comes as no surprise to you; most people would predict Jupiter the winner here. But what you may not know is that Jupiter is made of more mass - more “stuff” - than all the other planets combined! It is a genuine heavyweight. But wait! Isn’t it only just slightly bigger than Saturn? How can it be so much more massive?

Recall that more mass means more gravity. And recall also that gasses can compress. Jupiter has a lot more mass than Saturn and all the rest combined, but its outer gaseous layers are compressed under that greater gravity. That’s one reason why adding more stuff to Jupiter doesn’t allow it to grow appreciably. 

The Solie for Least Dense Planet goes to... Saturn! But how, if it is so huge! Remember that how dense something is isn’t the same as how big something is. How dense an object is tells us how much stuff is crammed into a certain volume. So something can be huge, like Saturn, but not be made of a whole lot of stuff. So it isn’t too dense. 

In fact, Saturn’s average density is less than that of water, but don’t try floating it in a great ocean to see if it will float. It might stay afloat in your imagination, but in real life, too many physical factors prevent this grade school analogy to work.

Our final Solie was a unanimous choice. This planet is not biggest, smallest, closest, farthest, hottest, coldest, or densest - none of those. But one could write books about the myriad subtle characteristics that make this planet the clear winner for being the one most consistently and artistically designed for life. Our Lifetime Achievement Solie goes to our own home: Earth. 

Congratulations, Earth. May all your inhabitants learn to appreciate just how beautiful you are.