Bad Astronomy: Misconceptions and Misuses Revealed, from ...

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Idiom’s Delight: Bad Astronomy
in Everyday Language
LIGHT-YEARS AHEAD
One of the reasons I loved astronomy when I was a kid was because
of the big numbers involved. Even the nearest astronomical
object, the Moon, was 400,000 kilometers away! I would cloister
myself in my room with a pencil and paper, and painstakingly convert
that number into all kinds of different units like feet, inches,
centimeters, and millimeters. It was fun, even though it branded me
as a geek. That’s all changed, of course. As an adult I use a computer
to be a geek a million times faster than I ever could when I
was a kid.
The fun really was in the big numbers. Unfortunately, the numbers
get too big too fast. Venus, the nearest planet to the Earth,
never gets closer than 42 million kilometers from us. The Sun is
150,000,000 (150 million) kilometers away on an average day,
and Pluto is about 6,000,000,000 (6 billion) kilometers away. The
nearest star to the Sun that we know of, Proxima Centauri, is a
whopping 40,000,000,000,000 (40 trillion) kilometers away! Try
converting that to centimeters. You’ll need a lot of zeros.
There is a way around using such unwieldy numbers. Compare
these two measurements: (1) I am 17,780,000,000 Angstroms tall.
(2) I am 1.78 meters tall. Clearly (2) is a much better way to ex-
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