Researchers at Ghent University in Belgium have etched a tiny world map (on a scale of 1 to one trillion) onto an optical silicon chip. They reduced the Earth's 40,000 km circumference at the equator down to 40 micrometres, or about half the width of a human hair, to fit it on the chip

show teh ek=length of the earth's circumfrance as represented in the chip in scientific notation