Northern Lights & Time Zones

As we continue to adjust to the switch over to Daylight Savings Time yesterday, I read a fascinating story this morning on the Universe Today website about how the creation of time zones was motivated in part by the frustrations of a 19th Century astronomer/meteorologist who was studying the aurora borealis (the Northern Lights).  In the 19th century, the aurora were not well understood and scientists of the time tried to study them by timing their fluctuations from many different vantage points to determine their altitude.  In particular, a man named Cleveland Abbe, who founded the US National Weather Service in Cincinnati, OH, set up a far-flung network of about 100 expert and public volunteers to observe simultaneously a particularly active display of aurora on April 7, 1874 and determine the aurora’s altitude.  The data were promptly recorded but Abbe soon discovered that the inaccurate timekeeping by his network of citizen scientists across the US introduced too much error.  To fix this problem, Abbe felt a proposal by a man named Benjamin Pierce to divide the continental US into four time zones had a lot of merit.  Later, Abbe received a letter from Canadian railroad engineer Stanford Fleming, who himself was trying to standardize time to synchronize the trains across Canada, and together Abbe and Fleming lobbied the US Congress to adopt time zones first in 1883.  Since then, time zones proved so useful that other countries adopted the concept and now the world itself is divided up into them, with the standard set at Greenwich Observatory in England, i.e., Greenwich Mean Time.  So, even though railroads played a large part in the development of time zones, their origin is due in small part to trying to understand phenomena in the sky better.  (The Transits of Venus in 1974 and 1882 were also influential in standardizing time.)  Those interested in knowing more about how science has influenced the measurement of time in society can read up on the subject in a new book published by McGill-Queens University Press called “The Clocks are Telling Lies: Science, Society, and the Construction of Time,” by Scott Alan Johnson.  By the way, aurorae have been since measured to occur at 100-300 km above the ground, as charged particles emitted by the Sun are guided by Earth’s magnetic field and slam into the upper atmosphere, exciting its component atoms and causing them to emit light at specific wavelengths.

Next, Doug Johnstone reported to me over the weekend about the sudden brightening of the young star EX Lupi by about two magnitudes in the g-band.  He and the JCMT Transients Team have been monitoring the fluctuations of light from these young stars because the changes in their brightness can be related to how much gas and dust are accreting onto the young star.  EX Lupi appears to be on quite a tear recently, but just how bright it will become remains to be seen. Hopefully, changes in brightness will also be observed at longer, submillimetre wavelengths at a later time so the structure of EX Lupi’s surrounding envelope of dust can be explored.  Stay tuned!