Part 15 — Falling Dream

The trouble with dream air is that you can't use a parachute. You can breathe it but it doesn't slow you down. In your dream you are falling towards a planet. With your arm out-stretched the planet looks about the size of your hand — you must be about five planet radii from center. Tethered to a cloud there is a radar acceleration sign:

Our planet's radius is ten miles. Your acceleration is ___ dimes per minute.

Evidently dime speed (a tenbillionth of the speed of light) carried over from some of the other planets. There it is, a great ball some fifty miles away. Since your distance from center is roughly five times radius, acceleration out here is only one twentyfifth of what it is on the surface — almost nothing by comparison. As you pass, the sign says "Your acceleration is 0.4 dimes a minute." Since out here it's only a twentyfifth what it is at surface, that gives an idea of what your acceleration will be as you hit the surface: 10 dimes a minute.

What ever could have brought you here and given you a starting push towards this planet? Probably something that happened in an earlier dream which you can't remember. The bright sunlight makes you sleepy and, in your dream, you doze off — still falling toward the planet.

When you wake it fills half the sky! You are closing in! The gravity must now be almost the same as on the surface. Already you seem to be going four times your ordinary running speed — judging as best you can you think you might be traveling nearly 400 dimes! (That translates to almost twentyseven miles per hour, enough to make crashing unpleasant.) Soon another billboard appears and as you pass it says "Your acceleration at impact will be 10 dimes per minute." This is it. This is the planet's surface gravity acceleration and for whatever time remains before you hit you will be accelerating at something close to that buck-per-minute rate.

It looks like you have maybe five more minutes of fall left. Assuming that's right, then during those five minutes your speed will increase by about 50 dimes and you will hit the planet going nearly 450 dimes — over thirty miles per hour in earth terms! Already you are beginning to smell the planet into which you are about to crash. It has a warm chocolate aroma, like chocolate pudding. In fact that is what the planet consists of — it was prepared quite some time ago and has been sitting out to cool. At last it's ready for whoever made it to have some.

What a horrible fate, to have to plunge head first into a huge (ten mile radius) ball of chocolate pudding. Perhaps if you imagine very clearly what it would be like to be skimming over the planet's surface your dream will change! You will suddenly be in low circular orbit instead of on a collision course. Well, what would your speed be then? To imagine it clearly you must think of the speed you will be traveling! Fortunately you remember the square root of two — it's 1.4 — and your estimated impact speed of 450 divided by 1.4 comes to a bit under 320 dimes. That's it. You are skimming now. The falling-from-infinity crash speed always turns into the surface skim-speed if you divide by the square root of two.