Today was a particularly well balanced day.  It was the equinox.  On top of that, I got to teach some nice topics such as atomic theory.  It is always a joy to reveal, to students, how it was that mankind discovered an element on the sun before it was discovered on earth.  It was all discovered in a time before space travel and before computers.  These are not the things that discover truths, ideas are.

The A-level students are ready for the discovery of Helium (named in honour of the sun, Helios, where it was discovered), their minds are prepared.  A junior class are not as prepared but they are ready for the seeds of scientific strangeness to be planted.  I told them how time travel forwards in time is an aspect of Einstein’s theory of special relativity.  Of course they refuse to believe, and this is the bit I love.  I then tell them that it is true and proven.  I tell them that there are satellites with clocks on board travelling at speed around our earth.  They are travelling fast enough for time to slow down on board the satellites and the clocks now all out of sync.  I then tell them that, if they desire, they can walk down the street and buy a device that listens to all these clocks that are wrong.  It listens and thinks.  It realises that the wrong time of a satellite is due to its fast speed and it listens some more.  After pondering the problem for a moment it compares all the wrong times and figures out where it is on the planet.  Without this time travel effect GPS would simply not work.

After all this I arrive home on the autumnal equinox as the leaves are falling on the roads.  I arrive home and find the little man.  He is close to that time, close to completing his first orbit around the sun.  Tempus fugit.  Fugit irreparabile tempus

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