In news- Increasing urbanisation and the installation of new streetlights, security floodlights and outdoor ornamental lighting have all contributed to sky glow, a type of light pollution.
What is Skyglow?
- Skyglow is an omnipresent sheet of light across the night sky in and around cities that can block all but the very brightest stars from view.
- It is a commonly noticed aspect of light pollution.
The natural component of sky glow has five sources:
- Sunlight reflected off the moon and earth.
- Faint air glows in the upper atmosphere (a permanent, low-grade aurora).
- Sunlight reflected off interplanetary dust (zodiacal light).
- Starlight scattered in the atmosphere and background light from faint.
- Unresolved stars and nebulae (celestial objects or diffuse masses of interstellar dust and gas that appear as hazy smudges of light).
Human-made sources:
- Electric lighting
- Light that is either emitted directly upward by luminaires or reflected from the ground is scattered by dust and gas molecules in the atmosphere, producing a luminous background
Impact of Skyglow and Night pollution on ecosystem-
- Recent study findings confirm that beetles exposed to light pollution both directly through the glare of bright artificial lights and indirectly via skyglow, abandoned their sky compass and rely instead on earthbound artificial lights as beacons.
- Like beetles, other species that can rely on other compass references also suffer from the loss of the stars due to skyglow.
- Nocturnal ants use landmarks for outbound journeys, but need their sky compass when returning home.
- Migratory birds have a magnetic compass, with which they check latitude and magnetic North, but use their sky compass to calibrate their magnetic compass to geographic North.
- In the worst case, animals that need the stars to find their home or breeding site may never make it.
- Starless skies may cause them to gradually deviate off course, wasting energy and risking predator encounters.
Source: DownToEarth
