Instant Genius - Light pollution, with Dr Greg Brown

Episode Date: February 3, 2023

A recent study carried out by the Globe at Night project – a citizen science program involving more than 50,000 observations from volunteers around the world – has found that the brightness of the night sky has increased by an average of 7 to 10 per cent a year for the last decade. This trend is making it increasingly difficult to observe the stars, especially from built-up urban areas. We speak to Dr Greg Brown, an astronomer and science communicator based at the Royal Observatory Greenwich. He tells us how bad the current situation really is, what it means for laypeople, astronomers and animals, and what measures we can take to get our view of the stars back. Learn more about your ad choices. Visit podcastchoices.com/adchoices

Ambition comes in all shapes and sizes. At First Citizens Bank, we roll with your goals because we're built for what you're building. Fit for your ambition for Citizens Bank. Now more people than ever can bring in their bill for a better deal at Verizon. Got AT&T or T-Mobile? We got you. Xfinity or Spectrum? You too. So tell your friends, your family, your quirky neighbor Jeff.

Grab your megaphone and yell it from the rooftop. Get a better deal at Verizon. Because chances are anyone in shouting distance is included. in your AT&T, T-Mobile, Xfinity, or Spectrum bill, and we'll give you a better deal on the best network network. Come by Verizon today. Best Network based on root metrics, best overall mobile network performance U.S. second half, 25, all rights reserved.

Must provide recent consumer mobile bill on the name of the person redeeming the deal. Additional terms, conditions, and restrictions apply. You said this place was steps from the water. We just haven't found the steps yet. How much did we save? Enough. Enough to get lost! Or you could book a stay with Hilton.

Welcome to your ocean front room. Just steps from the water. The Hilton sale is on now. Book on Hilton.com or the Hilton app and save up to 20% to get the stay you expected. When you want savings, not surprises. It matters where you stay. Hilton, for the stay.

This podcast is sponsored by name, audio and focal. Streaming has made music more accessible than ever, but true listening is about more than ease. It's about quality. British audio experts name audio, alongside French acoustic specialist Focal, combine handcrafted tradition with cutting-edge innovation and high-end materials, delivering digital precision with analogue warmth.

So you can experience exceptional sound at home. Music just as the artist intended. Visit name audio.com to learn more. And welcome to Instant Genius, a bite-sized masterclass in podcast form. I'm Jason Goodyear, a commissioning editor at BBC Science Focus magazine. A recent study carried out by the Globe at Night Project, a citizen science program involving more than 50,000 observations from volunteers around the world, has found that the brightness of the night sky has increased by an average of 7% to 10% a year for the last decade.

This trend is making it increasingly difficult to observe the stars, especially from built-up urban areas. We speak to Dr Greg Brown, an astronomer and science communicator based at the Royal Observatory Greenwich. He tells us how bad the current situation really is. what it means for lay people, astronomers and animals, and what measures we can take to get our view of the stars back? Okay, so recently a global citizen science project called the Globe at Night project that was carried out in Germany found that the night sky is becoming between 7% and 10% brighter each year,

and this is due to something called light pollution. So what exactly are we talking about when we talk about light pollution? Well, light pollution is any artificial source of light. Unfortunately, the light's coming from our cities, from our cars, from everything that modern society has, bounces up into the atmosphere and then comes straight back down again. A certain amount of it is scattered back down. And that's what produces a lot of the often orangey glow that you get around cities, although in the modern day the orange is being replaced with a lot more blue light. So how do we go about measuring or studying the amount of light pollution? With some difficulty, a lot of the past tests of doing this

have been using satellites, which are great for analysing red light, but they struggle somewhat with blue, which is a problem as modern light pollution tends to be bluer, a result of replacing sodium lamps, for example, in street lighting with LEDs. And so a lot of studies nowadays, have to be done from the ground, at least in part, in order to be able to make up for that. And that is where the citizen science angle comes from. There simply aren't enough people studying this sort of thing around the world. So there has to be a certain amount of involvement from the general public to make up that deficit. So one kind of shocking thing that I saw in the study was the research has said that if this trend were to continue at the same pace,

then a child born now in a place where you can see 250 stars in the night sky. By the time they're 18, they'd only be able to see 100. I mean, that's quite shocking. Are we looking at a potential scenario where future generations won't be allowed, you know, to enjoy looking at the stars? To an extent, yes. I mean, the brightest objects in the sky are going to be visible beyond any reasonable level of light pollution that we could ever reach.

But the fainter objects in the sky are. the sky, the array of stars. The Milky Way, for example, is basically impossible to see from even suburban areas, let alone in the centre of cities. So yes, absolutely, light pollution is very much hampering our ability for the average person to be able to explore the cosmos. Yeah, so you mentioned the brighter objects in the night sky. Would that be things like planets? Yeah, so planets like Venus, Mars, Jupiter, they're bright enough that it's, it's, extremely unlikely that light pollution would ever reach the point that they would be completely swamped, although it's not impossible. It just seems rather unlikely. So the study that we're

talking about was carried out over the last, I think, 12 years. But this isn't necessarily a new problem, is it? How long has it been going on? Well, light pollution has become an increasing problem since about the 70s. That was when the issue of light pollution started to become a serious issue. and it has been accelerated in the modern day with the expansion of cities and an urbanisation and also because of people relocating from rural areas to the city, there's a lower fraction of the population in relatively dark places anyway. Now, there are potential ways to get around this that have been trialled. So one of the things like switching over to LED lighting was thought potentially,

to be a way to help with this problem because more efficient lighting means that you can, you need less of them. Potentially, there's a way to reduce the amount of lighting. But actually, there's also the reverse argument, which is that with more efficient lighting, you can get away with having more of it for the same amount of power. And so actually, you make the problem worse. And it's, it's difficult to tell which way it's gone, but certainly this study seems to be suggesting it's gone the wrong way. Are there any alternatives to these blue LED lights that are currently on the table that people are considering?

It's difficult to suggest that there would be a, obviously with the need to go for more energy efficient solutions with the issues of climate change and just generally being more power efficient, LEDs are likely to be with us to stay. They are extremely efficient compared to previous examples. But the main way to potentially improve things is by reducing unnecessary usage of lighting, so not having too much in the way of exterior lights around your own house, for example, having them on motion sensors or even placing things like baffles or cones to direct the light downwards rather than up.

After all, any light that's going up is useless. It's not helping anyone on the ground do anything. So it is actually reducing the efficiency of the system. in itself. So obviously it's going to vary from countries to country, but are there any laws to protect about this thing like there are, you know, say other forms of pollution? There are places which are designated dark sky sites and these are excellent places to be able to go to to experience the night sky in much, much closer to what our ancestors would have seen. And these are places like downs and national parks and that sort of thing, where lights are specifically kept down.

But as to laws that affect the rest of the country, I'm afraid I don't know. So before we got into the more sort of technical aspects of this, the effect on professional astronomers and so on, do you think there's a psychological effect to the everyday person? You know, like humans have always looked up at the stars in awe and reverence, and it seems such a pity that we're not able to enjoy that like we used to be able to. Certainly, absolutely. It is a great shame that a lot of people are denied the view of the night sky in the planetarium that we run here at the Royal Observatory.

We often start some of our shows with a sort of an estimate of the current light pollution around London. Even in our relatively dark site in the middle of a park, we still have to deal with Canary Wharf and the main part of the city around us. And then we turn off that light pollution and you can see what the night sky would look like from a dark sky site. And the difference is massive. And absolutely no doubt that that's going to have an impact on our appreciation of the night sky. When you need to build up your team to handle the growing chaos at work, use Indeed sponsor jobs. It gives your job post the boost it needs to be seen and helps reach people with the right skills, certifications and more.

Spend less time searching and more time actually interviewing candidates who check all your boxes. Listeners of this show will get a $75-sponsored job credit at Indeed.com slash podcast. That's Indeed.com slash podcast. Terms and conditions apply. Need a hiring hero? This is a job for Indeed's sponsored jobs. Bonjour, compadre. It's the Priceline negotiator. How do I negotiate so many great travel deals? My greatest gadget. The Priceline app. It's got hotel deals, flight deals, rental car deals, all of the those deals in a bundle. Deals, game day deals, concert trip deals. No one deals more deals than

price line. Hold your horses. There's more. The app let you filter hotels by neighborhood, vibe, star level, and amenities like pools and spas and beach fronts. Wait, I'm not done. Stop cutting me off. This podcast is sponsored by Name, Audio and Focal. With over 100 years of combined expertise, Name and Focal have been bringing music to listeners just as the artist intended. Since day one, this mantra has shaped every innovation in hi-fi design, technology and acoustic engineering, balancing craftsmanship and tradition with pioneering thinking. Name audio pushes cutting-edge technology to ensure digital precision whilst sustaining Pratt, pace, rhythm and timing, the elusive quality that makes music feel alive and gives it

emotional texture. Today, in partnership with French acoustic specialists, vocal, name audio creates systems that deliver exceptional sound and unforgettable listening experiences at home. Try it for yourself at a focal powered by name boutique. Visit focal powered by name.com for more information. Yeah, so moving on to professional astronomers then. So obviously, in order to be an astronomer, you need to look at the night sky, and you want to get the clearest picture possible. and obviously light pollution is going to have a big effect on this.

But how big is that effect? How much does it get in the way with observational astronomy? When we're talking about professional astronomy, a lot of the observations are done from specifically chosen dark sky sites. So we're talking about relatively unpopulated regions of the world, like the Atacama Deserts in Chile or the tops of mountain sides in the Canary Islands. So the effect of light pollution is not vast in those places because they are so far away from cities in the first place. That's one of the reasons why they've been chosen.

That said, not all observatories are placed well away from that. And there are issues of light pollution that go beyond just what we're putting up into the sky from the ground. Likewise, there are, of course, issues with increasing numbers of satellites, which are contaminating images from professional. observatories around the world that, while only sort of tangentially related, nonetheless are a light pollution issue. Yes, you mentioned the satellites there. That was something I was going to ask about. Do we anticipate more and more of these small satellites going up and making the situation worse? Unfortunately so, there are multiple plans in place for these so-called mega constellations where there are thousands and thousands of satellites just for one specific purpose. And while the

purposes of these satellites are in general very good. Some of them are even humanitarian. They nonetheless have a massive impact on professional astronomy and, of course, on amateur astronomy, depending on the situation. Yeah, the expectation is that the number of satellites going up into orbit is going to skyrocket over the course of the next few decades. And there really is very little legislation to hold them back. What we put into orbit above the Earth is remarkably unregulated in some ways. So is there anything that the astronomers themselves can do to get around that problem? With the satellites, yes and no. There are ways of being able to choose your observations and process your data that can remove some of the issues. But when you've got tens of thousands of

satellites orbiting in mockably sort of almost chaotic ways, at least from the point of view of an observer on the ground, it is impossible to remove all of that entirely. So back down on Earth, are there any big measures that

governments or institutions could take to stop this, well, at least, slow this effect, this runaway effect down? Certainly the need for careful planning when it comes to the use of lights, specifically street lights and lights in city centres, is an important aspect

to that. A lot of it is going to be come down to directional. This lighting is important. No one's denying that the streets need to be lit. That is a very important aspect of their existence. Same for pedestrian walkways need to be lit. The question is whether they need to be lit all the time and in the method that they're currently being done, is there a way to be able to have the lights come on at the specific times when

they're actually being used by an individual that would potentially reduce the light pollution overall? Is there a way of directing that light downwards? Because again, as I said, the efficiency of any light that goes upwards is useless. It's not helping anyone down on the ground. So anything that increases the efficiency by directing all of that light down onto the ground not only helps with light pollution, but it helps the specific purpose of those lights in the first place. So we've mentioned the kind of loss of poetry of us being able to observe the night sky and the effect that it might have on professional astronomers. Light pollution can also have an effect on our health by interrupting our sleep or our body clocks, etc. So that's a problem

too, isn't it? Absolutely. Yes, it's as humans we are used to being awake during the day and sleep at night and the more light we introduce into our nighttime skies, the harder it is for our bodies and our body clocks to be able to determine what time it actually is, issues of insomnia and the issues that come from that tiredness and fatigue, and not to mention also poor mental health can potentially be linked to the increase in light pollution in our skies. And it's not just a human issue either. Wildlife suffers. big time from the increase in light pollution, the cycle of predation and prey, so predators and prey, has in the past been sort of based on the light of the moon because predators need

light to be able to hunt by. But of course, if all of the time it is as light as though there were a full moon around, then predators have a constant way of being able to prey on various other animals out there. And that can be a serious problem for the diversity and the balance of the biosphere basically. Yeah, so we've mentioned the possible measures that institutions or governments could take. But is there anything that our individual readers and listeners could do to help with this situation?

So ensuring that you're not overusing lights externally, if you have lights in your garden or your driveway or something on those sort of lines, having them being motion-censored or only being on at times when you actually want to use them. And again, going for more directional light, light which is being directed downwards rather than upwards or in all directions, can very much improve the amount of light pollution that you are generating. So what advice would you give, say, to our listeners who'd like to go out and start observing the night sky? You would be surprised how much a small reduction in light pollution can help.

So even going, you don't necessarily have to travel halfway across the country to find a proper dark site to greatly benefit your ability to see the night sky. Even cutting yourself off from direct light pollution, so finding the middle of a park or a wide open area can help considerably. But in the end, there really is no, there's no full replacement for going out to one of these dark sky sites and seeing the night sky for yourself from there. So, and these are dotted around all over the UK? Yes, yeah, absolutely. So can anyone just go to visit one? Do you have to make an appointment, or how do we go about using these sites? These are fairly wide open areas.

Places like the Downs and heaths and moors of our countryside are often in with these dark sky sites. So depending on the situation with each individual area, whether there are areas which are open to the public or not, there will certainly be places around there where you can head to without any particular appointment or anything on those sort of lines and be able to make use of the dark skies found there. That was the Royal Observatory Greenwich's Dr Greg Brown. Thank you for listening to this episode of Instant Genius. Brought to you from the team behind BBC Science Focus magazine. If you'd like to read more about astronomy and all other things science-based,

The current issue of BBC's Science Focus magazine is out now. Pick up a copy wherever you buy your favourite magazines or download a digital copy from your preferred app store. You can of course also find us online at sciencefocus.com. This podcast is sponsored by Name, Audio and Focal. The texture and emotional depth of music can be lost through digital sources or poor signal. Name audio believes you can have digital precision

with analog warmth. Alongside French acoustic specialist vocal, Name creates high-end audio systems, combining innovation with craftsmanship, so you can listen to music, just as the artist intended. Discover more at name audio.com. Enjoy more ways to save at Ralph's,

like low prices in every aisle. And when you download the Ralph's app, you can clip and save more with digital coupons every week. Plus, you can earn fuel points to save up to $1.1. per gallon at the pump. At Ralph's, you can enjoy more ways to save and more rewards every time you shop. So it's always easy to save big every day with savings and rewards.

Ralph's SoCal for over 150 years. Savings may vary by state. Fuel restrictions apply. See site for details. Did you know if your windows are bare, indoor temperatures can go up 20 degrees? Get ahead of summer with custom window treatments like solar roller shades from blinds.com and save up to 45% during the Memorial Day Early Access sale. Whether you want to DIY it or have a pro handle everything, we've got you. Free samples, real design experts, and zero pressure. Just help when you need it.

Shop up to 45% off site wide right now during the early access Memorial Day sale at blinds.com. Rules and restrictions apply.