00:00You know what, 8 out of 10 people worldwide can't see the Milky Way anymore, and in
00:06just 100 years, it might turn into a forgotten tale from the past.
00:10It's not that the galaxy is disappearing, but that the cosmos is fading from view.
00:16Back in our grandparents' day, they could look up and see this vibrant tapestry of stars.
00:21But nowadays, we're lucky if we can even count them on one hand.
00:25This has nothing to do with nature.
00:27It's all because of the creeping threat of something called light pollution.
00:31Next time you walk around a big city after dark, take a moment to notice the large number
00:36of streetlights, neon billboards, and office buildings shining all night long.
00:41Those endless city lights create an artificial brightness that competes with the natural
00:46glow of the stars.
00:48This is light pollution, and it's getting worse.
00:51Every year, Earth gets 10% brighter.
00:54That means if someone is born today in an area where you can typically see around 250
00:59stars, when they reach 18, they'll only be able to see about 100 of them.
01:06Unfortunately, that's already a problem in big cities, where looking up at the stars
01:12is becoming something that you can only do in planetariums.
01:16It's gotten to a point where, during an earthquake that knocked out the power in Los Angeles
01:20in the 90s, many residents called emergency centers to report a massive silvery cloud
01:26in the night sky.
01:27But what they were actually seeing, perhaps for the first time, was the Milky Way.
01:32When you look at Earth from space, you can see vast areas of North America, Europe, the
01:37Middle East, and Asia all lit up.
01:40Singapore, Qatar, and Kuwait are some of the most light-polluted countries.
01:45On the flip side, remote places like Siberia, the Sahara, and the Amazon rainforest are
01:50in total darkness.
01:54Light pollution shows up in many forms.
01:56First there is glare, like when you're driving and those bright lights literally make your
02:01eyes hurt, leaving you very uncomfortable.
02:04Then there is clutter, like Times Square with its crazy mishmash of different bright lights
02:09all over the place.
02:11Light trespass is when light sneaks into places it shouldn't, like a streetlight shining
02:16right into your bedroom.
02:18And finally, there is over-illumination, which is just using way too much artificial light
02:23for no good reason, like keeping all the office lights on throughout the night when no one
02:27is even there.
02:29All these forms of light pollution aren't just stealing the beauty of the night sky.
02:33They're also interfering with astronomical studies.
02:36When we rely too heavily on artificial lights, it messes up the work of Earth-based telescopes.
02:42And when that equipment can't do their job properly, we end up needing even more expensive
02:47space telescopes like Hubble and James Webb.
02:50And let's face it, that costs us billions.
02:55Turning night into day actually affects all of us, not just astronomers.
03:00Nighttime light messes with our sleep schedule and our body's internal clock.
03:04This clock keeps things like brain activity, hormone levels, and cell functions on track.
03:09So when it's disrupted, it can lead to serious issues like depression, insomnia, heart problems,
03:16or worse.
03:17One key process that gets messed up is the production of melatonin, the hormone that
03:22kicks in when it's dark.
03:24Too much light at night lowers melatonin levels, leading to stress, anxiety, headaches, and
03:29sleep deprivation.
03:31Blue light is the main villain here.
03:34You might think that turning on night mode and getting that orange glow on your phone
03:37screen is enough, but it's not.
03:40Blue light is also present in LED bulbs, the kind we use at home and in city lighting,
03:45because they're cheap and energy-efficient.
03:48My point is that blue light is basically everywhere, and it's a real challenge to avoid it completely.
03:54This is also a big part of why we're not entirely sure how bad light pollution is nowadays.
03:59I mean, some statistics suggest that this issue increased by 49% over 25 years, up to
04:062017.
04:08But the real figure may be even higher.
04:11The thing is, blue light has shorter wavelengths, and the satellites we depend on today struggle
04:16to detect it accurately.
04:18Meaning, they don't quite capture the full extent of the light pollution caused by LED
04:23lights.
04:26Animals are lost and confused too.
04:29Their sleep patterns are also affected.
04:31A study from Germany revealed that blackbirds in urban areas are getting active much earlier
04:36than those in natural habitats.
04:39They wake up and start singing up to 5 hours sooner than their country cousins.
04:44Migration behaviors are messed up, especially for birds like sparrows and thrushes who travel
04:49at night.
04:50You see, they rely on the moon and stars as their internal GPS.
04:55So you can imagine how disoriented they get when they spot something like Las Vegas'
05:00massive sphere, lit up by 1.2 million LED bulbs.
05:04The intense brightness hides stars and disrupts their navigation across thousands of miles
05:09and continents.
05:11And it's not just that.
05:12Artificial lighting is unfortunately causing more birds to crash into skyscrapers and high-rise
05:17buildings.
05:18Insects, like mosquitoes, are also affected by light pollution.
05:22Yep, they're kinda gross, so it might not bug you if they're attracted to artificial
05:26lights and, uh, meet their fate.
05:29But remember, they're a crucial food source for many animals, like bats or frogs.
05:34So disrupting their populations could throw off entire food chains.
05:40Nighttime lights are causing problems underwater as well.
05:44Marine creatures near brightly lit panels off the Welsh coast are changing their behaviors,
05:49and fewer sea squirts and sea bristles are hanging out near those lights.
05:54Another example involves sea turtles.
05:56They typically lay their eggs on beaches and often return to the same spots for years.
06:02But when those beaches are too bright at night, female turtles might become confused and decide
06:07not to lay their eggs there.
06:10Now, do we really need all this light?
06:14It's hard to say.
06:15Some people might feel safer at night, while others think the opposite.
06:20You see, it's usually the glare that messes up our sight.
06:22Here's an example.
06:24If there's a super bright lamp blocking our view, say at a gate, we can't see anything
06:29but the light.
06:30But check this out.
06:31If we partially cover the light with our hands, suddenly we can spot an intruder.
06:36Wow.
06:37What I mean is that more lamps don't always mean more safety.
06:41It's all about using them the right way.
06:43And doing things like dimming lights can actually enhance security.
06:48Plus, it could save you some cash.
06:50Speaking of which, light waste has a pretty big impact on the economy.
06:54Take a Cobra Head street light, for instance.
06:56The light projected directly by it is only 30% of the total light it emits.
07:01In the US alone, roughly one-third of the light at night goes to waste, and that adds
07:06up to a staggering annual cost of $2.2 billion.
07:14Electric lights aren't all bad, of course.
07:16They have done some good stuff for us, like making our days longer so we can get more
07:21done and have some fun afterward.
07:23But we can totally minimize this issue.
07:26Turning off all the lights would be awesome, but let's be real.
07:29That is very difficult, if not impossible, these days.
07:32So what can we do?
07:34Get those fancy controls like dimmers, timers, and motion sensors to make sure our lights
07:39are super efficient.
07:40Go for warmer-colored lamps instead of those harsh blue ones.
07:44Oh, and consider using fully shielded light fixtures, like those cool vintage table lamps.
07:49They direct the light down where you need it, so you don't get that annoying glare
07:53or light scattering everywhere.
07:55Plus, when you cut down on wasted light, you're not just helping out the planet, you're
08:00also saving some cash on your electric bill.
08:03Talk about a win-win!
08:04That's it for today, so hey, if you pacified your curiosity, then give the video a like
08:11and share it with your friends.
08:12Or if you want more, just click on these videos and stay on the Bright Side of life!
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