The Night Sky: Pre-Light Pollution

Light pollution is the excess or inappropriate artificial light outdoors. Sources of artificial light include street lamps, automotive factories, and storefront lighting. Light pollution has been documented at distances over 200 miles from national parks, and 80% of Americans can no longer see the Milky Way. Light pollution has various impacts on humans, wildlife, and the environment. It can affect our vision and nighttime recreation experiences, cause blind spots, and create potential safety issues. It can also disrupt our natural circadian rhythms and the natural food chain. Before light pollution, the night sky would have looked similar to what we see today in remote and high-altitude locations, such as mountaintops, where there is very little light pollution.

The Milky Way was visible to the naked eye

Before light pollution, the night sky was a stunning sight to behold, and the Milky Way was visible to the naked eye. Light pollution is a modern phenomenon, caused by the excess or inappropriate artificial light that illuminates the night sky and obscures our view of the stars. In the pre-industrial world, people would have been treated to a dazzling display of stars, with the Milky Way clearly visible.

The Milky Way, our own galaxy, is a magnificent sight, appearing as a white band stretching across the sky, with subtle variations. It is a huge, distant milky cloud, and witnessing it can make one feel incredibly small. While it is difficult to see in its entirety from Earth, as we are located inside it, we can observe its galactic core and outer arms. The Milky Way is best observed in locations far from cities and large towns, as light pollution can drown out the faint light of the Milky Way.

In ancient times, people would have been able to observe the Milky Way regularly, and it is no wonder that many premodern cultures believed the stars held magical significance. The Milky Way would have appeared as a breathtaking sight, with its light far surpassing that of the torches illuminating pre-industrial cities. The night sky would have been a familiar friend to our ancestors, a constant presence in their lives, and the Milky Way would have been a prominent feature in this celestial landscape.

Today, light pollution has drastically reduced our ability to observe the Milky Way with the naked eye. The glow from cities can be observed from over 200 miles away, and artificial light has substantially altered the natural pattern of darkness. However, there are still locations where one can escape light pollution and observe the Milky Way. These include remote areas such as Utah's Bryce Canyon, Death Valley, and the Canary Islands, where the Milky Way can be seen in all its glory.

The Milky Way is a testament to the beauty and wonder of the universe, and it is a tragedy that light pollution is robbing us of this natural treasure. Efforts to reduce light pollution and protect dark skies are essential to ensuring that future generations can continue to experience the awe and inspiration that come from gazing upon the Milky Way.

Light pollution is caused by glare, light trespass, and skyglow

Before light pollution, the night sky was a lot less obscured by artificial light, and people in pre-industrial times would have had a regular view of the Milky Way. The night sky would have looked similar to how it does today in remote, rural areas far from cities or at very high altitudes. There may have been some light pollution from torches in cities, but it would have been minor compared to modern light pollution.

Light pollution is the presence of any unwanted, inappropriate, or excessive artificial lighting, and it occurs in three main ways: glare, light trespass, and skyglow.

Glare is excessive brightness that causes visual discomfort and can be a safety concern. It can reduce visibility and affect nighttime experiences and recreation. Glare can also negatively impact astronomical research, which depends on dark skies. Poor lighting designs can create harsh glare and unsafe conditions, and may even aid criminal activity.

Light trespass is the unintended spill of artificial light into areas where it is not wanted or needed, such as a neighbour's property or bedroom window. This can cause issues like sleep deprivation and be a source of conflict. Light trespass can also impact astronomy observations by reducing the ability of visual observers to adapt to the dark and causing a glow across the field of view, reducing contrast.

Skyglow is the scattering of light in the atmosphere, causing the sky to never be truly dark. It is caused by human-made light sources, which brighten the night sky and obscure the view of the stars. The glow from cities can be observed from over 200 miles away, and 80% of Americans can no longer see the Milky Way due to skyglow. Aerosols, haze, dust, and air pollutants enhance skyglow, and clouds over cities can increase sky brightness by up to 1000 times compared to a clear night.

Light pollution has severe negative consequences, impacting ecosystems and human health by disrupting the natural rhythm of the day-night cycle. It diminishes the ability to see the stars and negatively affects the experience of the night sky.

Light pollution is increasing globally

The loss of the night sky is significant because it severs our connection to the universe, a connection that has existed since ancient times. People in pre-industrial times could regularly see the Milky Way, and it is no wonder that many cultures believed the stars held magical properties. Today, light pollution is so pervasive that even in remote areas, it is challenging to find truly dark skies.

The impact of light pollution goes beyond aesthetics. Artificial light can interfere with our vision, causing glare and blind spots, and creating potential safety issues. It can also affect our circadian rhythms, impacting our health and well-being. Additionally, light pollution can confuse flora and fauna, leading to early blooming of flowers, which can have knock-on effects on the natural food chain.

Some efforts are being made to address this issue. Countries like France have passed laws to restrict excessive lighting, and cities like Los Angeles are replacing old streetlamps with more efficient LEDs that reduce light scatter. However, light pollution remains a growing problem, and most people worldwide are affected by it.

As we continue to increase artificial lighting, we lose our connection to the night sky and the sense of wonder it inspires. The stars have guided and fascinated humans for millennia, and their disappearance is a loss that should not be taken lightly.

Light pollution affects human health and wellbeing

Before light pollution, the night sky would have been a lot darker, allowing for a clear view of the Milky Way. There may have been some light pollution from torches in cities, but it would have been nowhere near the level of artificial light pollution that we experience today.

Light pollution is the human-made alteration of outdoor light levels from those occurring naturally. It has been deemed one of the fastest-growing and most pervasive forms of environmental pollution. The brightening of the night sky is not limited to urban areas, as light pollution from cities has been documented at distances over 200 miles from national parks.

Light pollution affects human health and well-being in several ways. Firstly, it can negatively impact sleep patterns and quality. Research suggests that artificial light at night can disrupt circadian sleep rhythms, leading to reduced sleep times, dissatisfaction with sleep quality, excessive sleepiness, and impaired daytime functioning.

Secondly, light pollution has been linked to an increased risk of certain health conditions. Studies have found a correlation between exposure to artificial light at night and a higher risk of breast cancer, with one study showing a 73% higher risk for women in brightly lit areas. Additionally, light pollution has been associated with an increased risk of obesity, depression, sleep disorders, and diabetes.

Furthermore, light pollution can cause visual discomfort and safety concerns. Glare from bright LED lights can decrease visual acuity and create road hazards. It can also cause light trespass, where artificial light spills into unwanted areas, disturbing individuals and wildlife and impacting their natural behaviours.

To mitigate the effects of light pollution on human health and well-being, it is essential to reduce glare and minimise light trespass. This can be achieved by using shielded fixtures, dimming lights to appropriate levels, and implementing local lighting ordinances. By addressing light pollution, we can improve sleep quality, reduce health risks, and enhance visual comfort and safety for individuals and communities affected by this growing environmental concern.

Light pollution impacts flora and fauna

Before light pollution, the night sky would have looked like what we see today from remote and high-altitude locations far from cities. There may have been some light pollution from torches in preindustrial cities, but it would have been nowhere near the level caused by modern electric lights. People at the time would have had regular views of the Milky Way.

Light pollution has a significant impact on flora and fauna, affecting both plants and animals. It disrupts the natural rhythm of day and night, which is encoded in the DNA of all living things. This disruption has consequences for nocturnal animals, whose ecology is drastically altered by the introduction of artificial light. Predators can now hunt using light, while prey species that depend on darkness as cover are left vulnerable.

Insects are particularly affected by light pollution, as they are drawn to artificial lights, creating a fatal attraction. This has knock-on effects on all species that rely on insects for food or pollination. For example, artificial lights disrupt the nocturnal breeding rituals of amphibians such as frogs and toads, reducing their populations.

Light pollution can also disorientate adult and hatchling sea turtles, causing them to be unable to find the ocean. Birds are likewise affected, becoming disoriented and colliding with artificial structures, leading to higher bird mortality. Migratory shorebirds may also face increased predation when lighting makes them more visible.

Plants are not immune to the effects of light pollution either. It can disrupt photosynthesis, affecting the activities of plants and their ability to grow and survive. Overall, light pollution has far-reaching consequences for ecosystems, and addressing it can have a clear and immediate positive impact on the environment.

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