Back-of-the-Envelope Calculations: Comparing Jupiter with Earth
Below, you'll see a drawing of Jupiter showing the Great Red Spot, as well as several of the dark scars, like enormous black eyes, left as a result of the impact of fragments of the comet Shoemaker-Levy in 1994. If you were to cut out a circle that represented the Earth at the same scale, how big would you make the circle?
The Earth fits very nicely within the Great Red Spot, kind of like a blue iris in a gigantic blood-shot eye. This puts into perspective the size of the impact blemishes left by Shoemaker-Levy!
References and Resources
This SERC page describes the use of Back of the Envelope Calculations
The Back of the Envelope : This page outlines one of the essays in the book "Programming Pearls" (ISBN 0-201-65788-0). The book is written for computer science faculty and students, but this portion speaks very well to back of the envelope calculations in general.