Reclaiming the Darkness

Earlier this year, an international group of astronomers called for legal action at the International Court of Justice that would halt the placing of thousands of artificial communication satellites in Earth’s orbit - at least until their impact on the night sky could be properly assessed. On the one hand, these new ‘constellations’ - US company SpaceX, for example, plans to send up some 1,500 Starlink satellites during 2020 - will offer high-speed internet around the globe; on the other, professional astronomers are already concerned by the potential - depending on their altitude and surface reflectivity - for the satellites to seriously impact on ground-based observations.

Some might feel that increased restrictions on astronomical observations is a price worth paying for easily accessing the internet anywhere on the planet. But this isn’t simply about astronomers and their livelihoods. The group calling for legal action argues that the night sky is a shared human right under the World Heritage Convention; that the unrestricted commercial exploitation represented by these thousands of small satellites would damage our cultural heritage. As our global population becomes increasingly urban, however, the night sky that has hung over us as a species for hundreds of thousands of years has become increasingly out of sight, out of mind.

One example: during a power cut in Los Angeles several years ago, local observatories received numerous calls from concerned citizens, wondering what the strange sky was - they had simply never seen the Milky Way so clearly before. For most of us, especially in our biggest cities, the night sky consists of just a few pin-pricks - and that’s even with the introduction of more directional, more effective street lighting, reducing light pollution above our heads. It’s little wonder, then, that in recent years the idea of ‘dark skies’ has become something of a selling point for both music and astronomy festivals and our national parks: a star-filled night sky is something many of us miss.

Arguably, there’s something quite primal about it; after all, we lived as a species for thousands of years without electricity and would go to sleep when it got dark, thanks in part to internal body rhythms triggered by the changing frequencies of sunlight, during the day, on our eyes and brains. Now, most of us live very different lives, and the consequences are being increasingly recognised: in 2012, the American Medical Association found that light pollution affects our circadian biological rhythms, which has a negative impact on both our physical and mental health. About two years ago, a friend of mine made the deliberate decision to move from the city to one of the darkest places in Britain, on the west coast of Scotland. He really likes the winters there, not least because the darkness at night is what he calls ‘enveloping’. We can’t all make such a move, of course, but his experiences suggest it’s easy for us to rebalance ourselves once we’re away from constant human-created light pollution - more, that darkness is something we should value and enjoy.