Meteor Showers: Light Pollution's Impact

Light pollution is a growing problem, with national levels increasing by 10% each year. This is due to high-powered LED bulbs lighting up highways, parking lots, and buildings. As a result, stargazing is becoming increasingly difficult, with the Perseid meteor shower being one of the potential casualties. While it is still possible to see meteor showers with light pollution, the experience is greatly diminished. The number of meteors visible per hour is reduced, and the clarity of the night sky is affected, with a sickly orange-brown glow cast over everything. To combat this, people are encouraged to choose dark sky locations for optimal viewing.

Light pollution reduces the number of meteors you can see

Light pollution can significantly reduce the number of meteors you can see during a meteor shower. Urban areas, with their high levels of light pollution, can obscure the clarity of the night sky, diminishing the beauty of the celestial spectacle. The issue of light pollution underscores the importance of choosing dark sky locations for optimal meteor shower viewing.

The Perseids, for example, is a prolific meteor shower that occurs every August and can offer a stunning display of shooting stars. However, light pollution can greatly impact how well this meteor shower can be observed. In areas with high light pollution, you may only be able to catch a glimpse of the brighter meteors or "fireballs". The number of meteors visible per hour can be significantly reduced, and the experience may not live up to the hype and expectations set by social media and popular culture.

To combat light pollution, it is recommended to find a dark site away from city lights with a clear, unobstructed view of the sky. Ideally, a location with a Bortle Scale rating of 5 or lower is preferable for a decent view of a meteor shower. The Bortle Scale is a numerical scale that assesses the darkness of a night sky, with Class 1 being the darkest skies and Class 9 being the brightest, typical of city centres.

Additionally, turning off exterior lights and encouraging neighbours to do the same can help improve viewing conditions. While it may not be possible to completely eliminate light pollution, taking these steps can increase the chances of witnessing a meteor shower and enjoying the shared experience of marvelling at the wonders of the universe.

The Perseids are one of the few meteor showers visible with light pollution

The Perseids are one of the few meteor showers visible from light-polluted areas, although the number of meteors you can see per hour will be significantly reduced. The Perseids are active from mid-July until late August, with the peak occurring in mid-August. During the peak, viewers in rural areas with minimal light pollution can expect to see around 100 meteors per hour. However, light pollution and moonlight can reduce the number of visible meteors to about one or two every few minutes.

The Perseids are considered one of the best meteor showers of the year due to their high rates and pleasant late-summer temperatures. They are caused by the Earth passing through the path of Comet Swift-Tuttle, which was discovered in 1862 and last passed close to Earth in 1992. The Perseids are known for their swift and bright meteors, which often leave long "wakes" of light and colour behind them. They are also known for their fireballs, which are larger explosions of light and colour that originate from larger particles of cometary material.

To optimise your viewing experience, it is recommended to find a dark location away from city lights and other sources of light pollution. If you cannot access a dark site, you can still try to reduce light pollution by turning off exterior lights and encouraging your neighbours to do the same. It is also important to give your eyes time to adjust to the darkness, which can take up to 30 minutes. Additionally, try to minimise your use of bright screens, as this can negatively affect your night vision and reduce the number of meteors you see.

The Perseids appear to radiate from the constellation Perseus, which is also where they get their name. However, Perseids can appear in all parts of the sky, so it is not necessary to look in any particular direction. The best time to view the Perseids is typically during the pre-dawn hours, although they can sometimes be seen as early as 9 or 10 pm local time.

Light pollution is caused by human-made outdoor lighting

Light pollution is the human-made alteration of outdoor light levels from those occurring naturally. It is caused by inefficient, annoying, and unnecessary artificial lighting. The world has become awash in electric light, with powerful lamps lighting up streets, yards, parking lots, and billboards. Common sources of light pollution include street lamps, parking lot/shopping mall lights, exterior lights on homes/businesses, neon signs, and illuminated signboards.

Light pollution comes in several forms: light trespass, over-illumination, light clutter, and sky glow. Light trespass occurs when unwanted light escapes from one property into adjacent properties. Over-illumination refers to the use of excessive light where it is not needed, such as keeping the lights on all night in an empty office building. Light clutter refers to the redundant clusters of lighting found in many urban centers. Sky glow is the collective light pollution found over big cities, creating a bright halo over urban areas at night.

Light pollution has harmful effects on human health, wildlife, and ecosystems. Research suggests that artificial light at night can negatively affect human health, increasing the risk of obesity, depression, sleep disorders, diabetes, breast cancer, and more. The proliferation of artificial light at night means that most people no longer experience truly dark nights, disrupting the natural light/dark cycle that humans have evolved with.

Artificial light at night can disrupt the production of melatonin, a potent antioxidant and anticarcinogen responsible for regulating metabolism and immune responses. Lowered levels of melatonin have been linked to rising rates of breast cancer in the developed world. Exposure to artificial light at night has also been associated with sleep disorders, such as shift-work sleep disorder and delayed sleep-phase syndrome.

In addition to its impacts on human health, light pollution also affects wildlife. Sea turtles, for example, can be disoriented by bright lights on beaches, leading them away from the ocean and onto nearby roadways, where they are at risk of being struck by vehicles. Light pollution has also been shown to alter the behaviors, foraging areas, and breeding cycles of insects, turtles, birds, fish, reptiles, and other wildlife species.

To reduce light pollution, it is essential to turn off unnecessary lights and use fully shielded, light-efficient fixtures that prevent light from escaping and contributing to sky glow. By addressing light pollution, we can not only improve human health but also protect the natural habitats and behaviors of wildlife.

Light pollution can be reduced with simple changes to lighting

Light pollution is a human-made alteration of outdoor light levels from those occurring naturally. It has harmful effects on wildlife and ecosystems, energy and climate change, human health, and our quality of life.

The good news is that light pollution can be reduced with simple changes to lighting. Here are some ways to reduce light pollution and improve our quality of life:

Use Warm-Coloured Light Bulbs

LEDs and compact fluorescents (CFLs) can help reduce energy use and protect the environment, but only warm-coloured bulbs should be used. "Warm" toned or filtered LEDs (CCT 3000 K or lower; S/P ratio 1.2 or lower) should be used to minimize blue emission. Blue-rich white light sources are known to increase glare and compromise human vision, especially in the aging eye.

Use Dimmers, Motion Sensors, and Timers

Dimmers, motion sensors, and timers can help reduce average illumination levels and save energy. Motion sensors ensure that lights are only switched on when something moves nearby.

Use Shielded Outdoor Lighting Fixtures

Outdoor lighting fixtures that shield the light source to minimize glare and light trespass help prevent light pollution. Fixtures that focus the beams, pointing light downward, so the bulb is only visible from directly underneath, contribute less to light pollution and are more efficient.

Turn Off Unnecessary Indoor Lighting

Unnecessary indoor lighting, particularly in empty office buildings at night, should be turned off to prevent leakage of interior light into the night sky.

Avoid Blue Lights

The use of blue lights at night should be avoided as they worsen sky glow and have been shown to adversely affect wildlife behaviour and reproduction.

By implementing these simple changes to lighting, we can reduce light pollution and improve our connection to the night sky and the natural world around us.

Light pollution can have negative effects on human health

Light pollution, or photo pollution, is the presence of excess artificial light and is the result of urbanisation and industrialisation. It has harmful effects on wildlife and ecosystems, energy and climate change, and human health.

Research suggests that artificial light at night can negatively impact human health, increasing the risks of obesity, depression, sleep disorders, diabetes, breast cancer, and more.

Circadian Rhythm and Melatonin

Like most life on Earth, humans adhere to a circadian rhythm, or a sleep-wake pattern, governed by the natural day/night cycle. This cycle is largely influenced by photoreceptors in the eye that are more sensitive to blue wavelengths of light. It is important for humans to experience outdoor lighting during the day and minimise the amount of light entering their eyes at night to maintain a good circadian cycle. Artificial light at night can, unfortunately, disrupt that cycle.

Nighttime exposure to artificial light also suppresses melatonin production, which is needed to keep us healthy. Melatonin has antioxidant properties, induces sleep, boosts the immune system, lowers cholesterol, and helps the functioning of the thyroid, pancreas, ovaries, testes, and adrenal glands.

Not All Artificial Light is Created Equally

Exposure to any light at night can suppress melatonin, but the photoreceptors in the eyes that drive this suppression are more sensitive to blue light. This is why it is recommended to reduce blue light content at night to improve sleep. Unfortunately, most LEDs used for outdoor lighting, as well as computer screens, TVs, and other electronic displays, create abundant blue light.

Glare from Outdoor Lighting

Glare from poorly shielded outdoor lighting can also harm human health because it decreases vision by reducing contrast. This limits our ability to see potential dangers at night. Aging eyes are especially affected.

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