*From: C. Allen Doudna
Location: Grand Island, Nebraska
Date: 04/13/2010*

As we all know, aliens are going to speak English and use the Metric System, the meter being originally 0.0000001 the distance from Earth's North Pole to Earth's Equator and calculated by multiples of 10 because that is how most human languages count.

Astronomers have proposed using the wavelength of hydrogen--21 centimeters or 8 inches--as the standard unit of measure in attempts at communicating with ET because that wavelength would be universally well-known--but what to multiply it by? Base 2 would likewise be universal--but so awkward why bother at all. Enter Base 8.

For some reason Base 2 and Base 8 translate directly into each other. Take a string of 1s and 0s and break them down into periods of 3 as we do Base 10: 111,110,101,100,011,010,001,000. Now write down the Base 10 (or whatever Base you use) equivilant of each of those periods and voila: you have that long string of 1s and 0s in Base 8!

Multiplying 8 inches (21 centimeters) by 8 gives us some interesting results:

8 x 8 = 64: About the right size for an intelligent creature. Much smaller and there would not be enough brain; much larger and it would be so busy eating it wouldn't have time to think.

64 x 8 = 42 ft 8 inches: About the area such a creature would consider its home--dwelling and a little space for privacy.

42 ft 8 inches x 8 = 341 feet: About the right size for a city block of such homes; much larger and there would not be enough streets for traffick.

341 x 8 = half a mile: A useful unit of measure.

1/2 mile x 8 = 4 miles: As a square the size of a city large enough to be practical but small enough to be friendly.

4 miles x 8 = 33 miles (there was some rounding and these are only approximate figures): About the size of a county or a city state where we would live most of our lives and have most of our government.

33 x 8 = 264 miles: About the size of a typical country, the limit over which a unified culture, language, and government could be maintained through all the thousands of years of horse-drawn transport or its equivilant.

264 x 8 = 2,112: A continant about the size of Australia.

2,112 x 8 = 17,000 miles: The equitorial circumfrence of a planet smaller than Earth but larger than Mars and a surface gravity about 90% that of Earth.

17,000 x 8 = 136,000 miles: Can't think of anything.

136,000 x 8 = 1 million miles: Considered the beginning of Interplanetary Space?

1 million x 8 = 8 million miles: About halfway to the nearest planet.

8 million x 8 = 64 million: About the orbit of Venus. Since most stars are smaller than our sun this would probably be the common orbit for a habitable planet.

64 million x 8 = 512 million miles: About the size of a sunlike star.

512 million x 8 = a billion: About the orbit of Pluto.

**From: Greg Bear**

Date: 05/07/2010

The Sumerians, as I recall, preferred basic 60! That yields many interesting results for navigational calculations on today's globes...

*From: Al Brady
Location: st neots
Date: 06/08/2010*

Is there a lower limit to how small you can subdivide space? I read that at something like 10x10-31metres it might be granular or a foam. (I feel vaguely privildeged to have been born at a time when at least some kind of asnwer to that exists incidentally) If that pixel resolution was smooth I might measure distance as multiples of that basic length. Thats probably be simplstic though, maybe you could divide together the 'addresses' of two places somehow and the resulting 'number' would be a relative coordinate set. That seems more flexible like. Boy I wish I could download current physics and maths to a reasonable level with some tools for integrating them, that would be such a ride.

**From: Greg Bear**

Date: 06/14/2010

Some time back, the Planck-Wheeler length was described, below which space becomes unpredictable as to metric and quality--foamlike is a good word, but without defining what fills the void in the foam. Or possibly what the foam is made of! I recall that was about 10E-33 cm.

*From: CAllenDoudna
Location: Grand Island, Nebraska
Date: 06/15/2010*

"4 miles x 8 = 33 miles (there was some rounding and these are only approximate figures): About the size of a county or a city state where we would live most of our lives and have most of our government."

If I might add: A glass jar about 33 miles in diameter to get Earth-normal gravity would rotate once every 24 hours. Slightly less than half the sides of the jar would be covered with dirt to form a great valley about the size of New Jersey and slightly over half the jar would be a window. With 33 miles of atmosphere the sky would be blue. The sun would rise over the eastern edge of the valley, travel across a very normal-appearing daytime sky and set over the western edge of the valley 14 hours later. There would then follow 10 hours of night as the valley rated to block the sun and the window rotated out to face the stars.

Arrange a few dozen of these in a circle and place an artificial sun in the center--like wagons around a camprire--and place a large sheet of aluminum foil ahead as a sail. The light radiating equitorially from the artificial sun would provide daylight for the wagons. The light radiating in polar directions would propell the wagon train through intersteller space either directly or by being reflected from the sail. The build-up of speed would be slow and the first couple of generations could still make it back to Grandma's house for the holidays. After that nobody would care because you wouldn't know your cousins anyway, although you could beam video letters back and forth.

In theory you could reach the speed of light, but there are rocks out there and these would impact with the force of a nuclear explosion at greater than 1% of the speed of light. But you've got several New Jerseys to live in and about every hundred years you'd come across a solar system orbiting a planet like Jupiter--probably five times more numerous than those orbiting stars.