Excess light stunts astronomy and sea turtles

James Tytko spoke with Imma Barrera and Xander Byrne about the disruption of light pollution on the study of the stars, and also Thomas Reischig about the harm done from light at critical points in the lives of sea turtles...

James - The temperament of an Astrophotographer is one of patience…

Imma - ’I tried 3 nights in a row, I needed no clouds in the sky, low tides, no winds so that the water was calm enough for the reflection.’

James - Imma Barrera is describing the lengths she went to capture the stunning picture of the Milky Way she’s sent me. Shot in the Acadia National Park in Maine, it depicts our galaxy in magnificent detail, the stars mirrored in the tranquil water below. Imma travels the United States, taking pictures of the awe inspiring vastness  and beauty of our universe.

Imma - ‘That’s what makes that picture unique - always the story behind that picture.’

James - Recently, though, her work, and that of all astrophotographers, has been made even more trying than it already was…

Imma - ‘Last time I was tracking in New Jersey I was mostly guessing where the North Star was.’

James - Fewer people than ever have the simple pleasure of staring up into the sky at night and witnessing the breathtaking beauty above. That’s because its mostly concealed by sky glow as it’s known, an effect of light pollution…

Imma - ‘I just started in 2015, it’s getting harder because of the intensity of the light pollution.

‘For instance, here in New Jersey, I can forget going in the summer, the same I can say for North Carolina; when the tourist season starts you can forget it.’

James - Imma’s pursuit is artistic, but sky glow is hampering other disciplines as well. To find out how light pollution is impacting the scientific study of the stars, I visited the University of Cambridge’s Institute of Astronomy to catch up with Xander Byrne…

Xander - So we're currently in the 16 inch telescope dome which we have here at the Institute of Astronomy. We mostly use it for outreach stuff, but yeah, we're in a big dome, which is why it's so echoey.

James - You mentioned that this telescope these days is mainly used for outreach purposes. I wonder if you could tell me why that is?

Xander - When the institute was being established, centuries ago, it was right out on the edge of Cambridge beyond the boundaries. And this is because there was a little bit of light pollution from the city, mostly like candle lit street lamps, for example. But as the city has expanded in that time, the institute is now within Cambridge proper and obviously there's a lot more in the way of street lighting and domestic lighting in the city. And so there's just too much pollution to do any kind of observational research from right here.

James - That's really interesting. So the institute was sort of strategically placed outside of the limits of where the light pollution would touch and research has had to stop going on here. So where is most astronomy based research done these days?

Xander - The biggest observatories that are in operation today are usually in very remote places, often where it's quite dry as well because humidity can also affect astronomical observations. So a very good place where a lot of observatories are is in the Atacama Desert in Chile. There's a lot of new ones being built there as well. The Vera C. Rubin Observatory in particular, which is coming online next year, hopefully. There are also other places on remote islands which are also quite good. So there are a couple in Hawaii, some in the Canary Islands as well. Coincidentally, also quite good places to go on holiday, but, I'm assured that that is just a coincidence.

James - I'm sure it is. You guys have got all sorts of cool kit to call upon when it comes to observing the sky. Is it really the case that the tools at your disposal are not able to overcome the light pollution problem?

Xander - To some extent, astronomy is always going in a direction of looking for fainter things because the brightest objects are sort of low hanging fruits and much easier to do science on. We kind of know what they're doing, so we are now really trying to probe the most distant, the faintest objects, and that's becoming a lot more difficult to do as a result of the light pollution.

James - And this is a problem that's only set to get worse, not just as countries industrialise further but the development into space and the satellites that orbit the earth.

Xander - So potentially quite a big problem facing observatories today is satellite tracks, which sometimes appear in astronomical images which are being taken, you have these bright streaks going all the way across. So for example, I mentioned the Vera C. Rubin Observatory: it's been estimated that they might have to throw away something like 40% of the images that they're going to be taking just because they're going to be contaminated with these satellite trails, which is pretty sad really. One argument that, unsurprisingly, Elon Musk has proposed is that we just put loads of telescopes into earth orbit and that would solve all the problems. But even the Hubble Space Telescope, which is obviously in orbit around the Earth, has sometimes seen trails of satellites orbiting at higher altitudes than it crosses its path. So even putting everything in space wouldn't necessarily solve all of our problems

James - And presumably makes it all a lot more expensive?

Xander - Yeah, by like a factor of 10 more expensive. So it's really not a solution