Part 3 — Wildflower Planet

In a dream you are drifting unhurriedly over the surface of a grassy planet thick with thistle and wildflowers. It's like floating in calm water over a colorful coral reef. You are in orbit but your speed is slow as sleepwalk — you have plenty of time to look down at each flower and try to think of its name. Dream-air, which lets you breathe without interfering with motion, also lets you smell the heat in the grass.

The people on this planet have the same custom as the others did of posting radar speed signs. There is one a little way off. "Skimspeed here is one cent. Your speed is ___ ." As you approach it registers your speed and numerals flash in the window telling you that your speed is 1 cent. That is reassuring because it means you will stay in orbit close to the surface.

In Earth terms you are are traveling some ten paces a minute and it will take ten minutes to go the length of a city block. Slow, but the sun is bright and there is plenty to look at; so you don't need to feel impatient — idle drifting is fine. Other people are coasting along in other directions; sometimes paths cross but you rarely collide. Those in ground-level orbits like yours are all going the same speed as you — the skimspeed comes with the planet — so even when you do collide it doesn't hurt. Everything's in slow motion — you even have time for an exchange of courtesies.

A large billboard declares:

Skimspeed here is 1 cent.
Square skimspeed is 1 square cent.
Rumpus on this planet is 1 quartic cent.
This planet weighs ten thousand tons.

That is the force it would weigh in its own surface gravity — if a thousanth of the planet's mass could be scooped up and placed on scales at the planet's surface it would weigh ten tons. A planet's weight is what it thinks it weighs.

We already met the universal ratio of rumpus to weight. A quartic cent corresponds to ten thousand tons of planet weight. There is a constant proportion called G which in these terms equals 1 cent⁴/tenthousand tons. If you like the look better you are welcome to put the 10⁴ in the denominator out in front as a tenthousandth, writing G as 10^-4 cent⁴/ton.