96 12 15 Mega TeraGiga Peta es of half a micrometre dimensions smaller than this fall into nanoworld territory The wavelength of visible light is approximately 500 nanometres long which is why optical systems fail in the nanoworld and are replaced by electron microscopes UNDERSTANDING ATOMS BY SCATTERING A picometre is 1000 times smaller than a nanometre and opens the door into the microcosm of the atom for us The size of an atom is around 100 pico Here on Earth we give distances in kilometres If we were to start in Biberach in Swabia Australia would be 20 000 kilometres away Spain 2000 kilometres away and Ulm a mere 40 kilometres away Within our own homes we measure distances using a metre stick if necessary to the nearest millimetre Yet when we meas ure shorter distances the physicists methods are needed again If we want to know to the nearest micrometre how rough and therefore how sharp a cutting edge on a milling cutter or drill is we need a microscope Optical microscopes can show small distanc FROM SPACE DOWN TO EARTH Thanks to Hubble and other tele scopes astronomers now know the extent of the universe The diameter of the known universe is roughly 80 billion light years and light takes 100 000 years to travel the length of the Milky Way our own galaxy The closer to Earth we come the less suitable light years are as a measure of distance as light takes just eight minutes to reach our planet from the sun 10 to the power of x metres THE MEASURE OF ALL THINGS FROM THE INNERMOST REACHES OF THE NUCLEUS TO THE FURTHEST GALAXIES THE HUMBLE METRE SCALES BY ROUGHLY 42 ORDE RS OF MAGNITUDE 28 PERSPECTIVES

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