I enjoyed Chris Stewart's sortie into the realms of Relativity in his article "How can you see matter moving faster than light?" in Canopus of April 1999. Actually my head started spinning and I got quite dizzy at his mentioning guzzies buzzing at 199 and 200 kilometres per hour. (What are guzzies?). And I must object at his spelling of koeksusters -- they have nothing to do with female siblings but every- thing to do with the sissling sound of cold doughy plaits being plunged into hot oil -- that's why they are called koeksisters from the sissling sound they make!

But to get to his quasar which emits a jet of matter at a speed greater than the speed of light: The quasar recedes from Earth at the speed v and covers the distance QA = v in 1 second. While the quasar travels over this distance, its emitted jet of matter travels from Q to B = c in 1 second, this being the speed of light. We see the jet as travelling the distance AB. How long is AB? Let's call the length AB, x. In 550 BC Pythagoras proved that the sum of the squares on the right angle sides of a right angled triangle is equal to the square on the hypotenuse.

i.e. \ or \ Thus i.e.

This is always less than c because is less than 1 and the square root of is also less than 1.

Now is the distance we see the jet travelling in 1 second but its actual distance is c in 1 second. Therefore the speed of the jet = . Since is always less than c, AB must be more than c, the speed of light.

Nobody schooled in Relativity would fall into this trap, but it does seem as if the speed of the jet is more than the speed of Light., whereas the speed of the jet is

Remember Alf and Ben in their boats on the river flowing at a speed of v?