The end of night
Graihagh - I’m Graihagh Jackson. As we enter the darkest depths of winter, the days are getting shorter and the nights get longer. Or at least that’s how it’s supposed to be. But since the invention of the light bulb, we’ve long been working towards the end of night. But does this matter? I’ll be investigating this month on Naked Astronomy. Happy Christmas by the way - I couldn’t not say it since our publishing day falls on this very merry day. If you’re anything like my family, you’ve probably pickled yourself in port and are unable to move from the amount of turkey you’ve eaten. But maybe you’re by a window enjoying your food coma and if so, what do you see? If it’s 5 o’clock, you shouldn’t see a dicky bird but I bet you can, all thanks to light pollution. 80% of Northern Americans and Europeans now can’t see the Milky Way and that means the nine thousand and ninety-six stars you should be able see with the naked eye are no longer visible. Does that matter though? Light is a miracle invention and has allowed us to do wonderful things but it is also becoming a problem for us:
Mari - Many of these screens have quite bright light and some of the blue light might impact your hormone production or the sleep hormone, so it actually sets your clock off a little bit. So in the same sense that being outside in the morning helps your sleep, having very bright light in the evening will probably delay your sleep pattern making it harder for you to fall asleep at night.
Graihagh - Norway’s Mari Hysing, from Uni Health Research in Bergen. Essentially, all this light is resetting our body clocks, driving hormones such as cortisol - a wakey wakey hormone - up, and delaying sleepy counterparts like melatonin and this is not good for our health. John O’Neil from the MRC.
John - We know that circadian disruption as occurs during shift work for example, is really bad for you in the long term so there’s a very strong association with chronic diseases such as diabetes, neurodegenerative disorders, a load of different cancers.
Graihagh - But it’s not just us humans that are suffering. Here’s Bob Mizon from Britain’s Commission for Dark Skies.
Bob - Verlin Klinkenberg in the National Geographic a few years ago said “that we have invaded the night as if it were an occupied country” when, in fact, nothing can be further from the truth. Every creature almost in the world has evolved for millions of years to have a day and a night and if we give them a day and a day they're certainly not going to thrive.