Saviez-vous que la magnifique Voie lactée pourrait bientôt disparaître de notre ciel nocturne ? La pollution lumineuse, causée par toutes les lumières vives des villes, rend les étoiles plus difficiles à voir. Les scientifiques disent que d'ici seulement 20 ans, la plupart des gens sur Terre ne pourront plus repérer la Voie lactée sans faire de voyages spéciaux dans des zones reculées. C'est comme perdre un morceau d'histoire cosmique juste au-dessus de nos têtes ! Heureusement, certains endroits s'efforcent de réduire la pollution lumineuse en utilisant des lumières plus faibles et protégées afin de préserver la vue. Si nous agissons maintenant, les générations futures pourraient encore profiter de l'observation des étoiles et de la magie de notre galaxie. 🌌✨ Animation créée par Sympa. ---------------------------------------------------------------------------------------- Musique par Epidemic Sound https://www.epidemicsound.com Pour ne rien perdre de Sympa, abonnez-vous!: https://goo.gl/6E4Xna ---------------------------------------------------------------------------------------- Nos réseaux sociaux : Facebook: https://www.facebook.com/sympasympacom/ Instagram: https://www.instagram.com/sympa.officiel/ Stock de fichiers (photos, vidéos et autres): https://www.depositphotos.com https://www.shutterstock.com https://www.eastnews.ru ---------------------------------------------------------------------------------------- Si tu en veux encore plus, fais un tour ici: http://sympa-sympa.com
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00:008 out of 10 people in the world can no longer see the Milky Way, and in a hundred years only, it could be nothing more than a forgotten story.
00:07It is not the galaxy that disappears, but the cosmos that disappears.
00:11At the time of our grandparents, we could raise our eyes and see this brilliant starry road,
00:16but today, we are lucky when we can count the stars on the fingers of the hand.
00:21It has nothing to do with nature, it is simply due to the growing threat of what is called light pollution.
00:27The next time you walk around a big city at nightfall,
00:31take the time to note how many streetlights, neon billboards, and office buildings remain on all night.
00:39These urban lights create an artificial brightness that rivals the natural light of the stars.
00:45This is what is called light pollution, and it keeps getting worse.
00:50Every year, the Earth increases its brightness by 10%.
00:54This means that a person who is now born in a region where you can see about 250 stars,
01:00will only be able to see about a hundred at the age of 18.
01:07Unfortunately, this problem already occurs in large cities, where observing the stars is only done in planetariums.
01:13So much so that, during an earthquake that deprived Los Angeles of electricity in the 90s,
01:19many residents called the emergency centers to report the presence of a huge silver cloud in the night sky.
01:25What they actually saw, perhaps for the first time, was the Milky Way.
01:31When you look at the Earth from space, you can see the vast regions of North America,
01:36Europe, the Middle East, and Asia all illuminated.
01:40Singapore, Qatar, and Kuwait are among the countries most polluted by light.
01:46Conversely, remote places like Siberia, the Sahara, and the Amazon rainforest are plunged into total darkness.
01:54Light pollution manifests itself in several forms.
01:57First of all, there is dazzling.
01:59For example, when you drive and all these bright lights literally hurt your eyes.
02:04It's very unpleasant.
02:05Then, there is accumulation, like in Times Square, with all these bright lights scattered all over the place.
02:11Light intrusion is when the light penetrates subtly into places where it should not be,
02:17like a reverberator in your bedroom.
02:20Finally, there is overexposure, which consists of using far too much artificial light for no valid reason,
02:26like when offices remain lit all night when there is no one.
02:30And all these forms of light pollution are not content to steal the beauty of the night sky from us.
02:35It also disturbs astronomical studies.
02:38When we rely too much on artificial lights, the work of terrestrial telescopes is disturbed.
02:43And when these equipment cannot do their job properly,
02:47we need even more expensive space telescopes, like Hubble and James Webb.
02:52And let's be honest, we're talking about billions of euros.
02:55The transformation of night into day concerns all of us, and not just astronomers.
02:59Night light disturbs our sleep schedules and the internal clock of our body.
03:04This clock controls brain activity, hormone levels, and cellular functions.
03:09When it is disturbed, it can lead to serious problems such as depression, insomnia, heart problems, or even worse.
03:17One of the key processes that is disturbed is the production of melatonin, a hormone that appears at nightfall.
03:23Too much light at night lowers the rate of melatonin,
03:26which leads to stress, anxiety, headaches, and lack of sleep.
03:31Blue light is particularly harmful in this regard.
03:34You may think that just turning on night mode on your phone screen is enough, but you are wrong.
03:40Blue light is also present in LED bulbs,
03:43the ones we use at home and in urban lighting because they are cheap and save energy.
03:49What I mean is that blue light is omnipresent and that it is very difficult to avoid it completely.
03:56This is also largely the reason why we are not quite sure of the extent of light pollution today.
04:02Some statistics suggest that this problem increased by 49% in 25 years, until 2017.
04:09But the real figure could be even higher.
04:12The fact is that blue light has shorter wavelengths,
04:15and the satellites we rely on today struggle to detect it with precision.
04:19This means that they do not realize the extent of the light pollution caused by LED bulbs.
04:26Animals are also lost and disoriented.
04:29Are their sleeping habits also affected?
04:32A German study has revealed that the marmots in urban areas become active much earlier than those in natural habitats.
04:38They wake up and start singing about five hours earlier than their country cousins.
04:43Migratory behaviors are disturbed,
04:46especially among birds such as swallows and cranes that move at night.
04:51You can imagine how disoriented they are when they see something like the Las Vegas sphere,
04:58lit by one or two million LED bulbs.
05:01The intense brightness hides the stars and disturbs their migration over thousands of kilometers and continents.
05:08And that's not all.
05:09Artificial lighting is also the cause of the increase in the number of birds
05:14that crash into skyscrapers and high-rise buildings.
05:18Insects, especially mosquitoes, are also affected by light pollution.
05:22Yes, they are a little disgusting.
05:24And it may not bother you that they are attracted to artificial lights,
05:28and that they suffer their fate.
05:31But don't forget that they are an essential source of food for many animals,
05:35such as bats or frogs.
05:37And that a disturbance of their population could disrupt entire food chains.
05:43Night lights also cause problems underwater.
05:46Marine creatures that live near luminous panels off the coast of the Galician coast
05:51modify their behavior.
05:53And there is less and less acidity and sea anemones in these illuminated areas.
05:58Another example concerns sea turtles.
06:01They usually lay their eggs on beaches and often return to the same place for years.
06:06But when these beaches are too illuminated at night,
06:09female turtles can be disoriented and decide not to lay their eggs there anymore.
06:16Do we really need all this light?
06:18Difficult to say.
06:20Some people think it's safer that way.
06:22But not everyone agrees.
06:24You see, it is usually the dazzling light that disturbs our vision.
06:28Here is an example.
06:29A powerful lighthouse blocks your view near a portal.
06:33And you see nothing but the light.
06:35But if you partially cover the light with your hands,
06:38you can suddenly spot an intruder.
06:40Wow!
06:41What I mean is that more light is not always synonymous with more security.
06:47It's about using it correctly.
06:49And the fact of reducing the intensity of the lighting can actually strengthen security.
06:54In addition, it can save you money.
06:57In this regard, the waste of light has a considerable impact on the economy.
07:01Take, for example, a classic lamp.
07:04The light it projects directly represents only 30% of the total light it emits.
07:09In the United States alone, about a third of the night light is wasted.
07:13This represents a staggering annual cost of 2.2 billion dollars.
07:19Electric lights are not only disadvantages, of course.
07:23They have brought us good things,
07:25such as the lengthening of our days,
07:27which allows us to do more things and have fun after work.
07:30But we can completely minimize this problem.
07:33Turning off all lights would be great,
07:35but let's be realistic.
07:37It's very difficult, if not impossible, nowadays.
07:40So, what can we do?
07:42Use sophisticated devices such as light variators,
07:46stopwatches and motion detectors
07:49to ensure that our lighting is ultra-efficient.
07:52Choose rather warm-colored lamps
07:54than too raw blue lights.
07:56And use closed-envelope lighting devices,
07:59like these beautiful old-fashioned table lamps.
08:02They direct the light downwards,
08:04where you need it and avoid being dazzled
08:07and lighting up what is not meant to be.
08:09In addition, by reducing the waste of light,
08:11you are not only helping the planet,
08:13you are also saving money on your electricity bill.
08:16Everyone wins.