Streetlights

[Jocko]

A lot has been spoken on recent news broadcasts about the pollution caused by artificial lighting around the world. How it is affecting flora and fauna, including ourselves, and rendering the night sky lost to many.

https://astronomynow.com/2017/11/26/a-brightening-world-study-shows-rise-in-global-light-pollution/



Our local council are installing new, high efficiency, lighting units, which cast a pool of light onto the ground but nothing goes up. It is amazing. You turn into a street where they have been fitted and your initial thought is, "the street lights are out". You then realise they are all on, but you can see the sky above them.
I appreciate that this is a tiny step but, hopefully, more councils up and down the land and eventually people elsewhere in the world will do the same. Perhaps the night sky is not lost forever.

[JohnAlways]

Good morning Jocko

The council my way have done this and they are energy saving leds or similar. They are a very white light and I often think it is from an oncoming car about to come round the corner in the dark because they are so White. Now I know where this happens locally, I think this and I proceed a bit further rather than wait and can verify once round the corner it's clear. Don't know if that's good or bad but I usually pull in if an oncoming car is coming to save any dithering with persons who are not comfortable with reversing.

Have a nice day, John 

[culzean]

I welcome the lessening of light pollution,  the night sky is a marvelous thing and we only see a fraction of it in urban areas of UK.  It was forcibly bought home to me when we lived in South Africa and Australia how much we miss in most of UK, my first thought was 'where did all those stars come from' - the night sky is a thing of wonder that firmly puts is in our place, tiny creatures living on a lump of rock whose surface is rotating at 1000 mph and hurtling through space at 66,000 mph on our yearly orbit of the Sun.

Orbiting the Galaxy

In addition to the individual motions of the stars within it, the entire Galaxy is in spinning motion like an enormous pinwheel. Although the details of the Galaxy's spin are complicated (stars at different distances move at different speeds), we can focus on the speed of the Sun around the center of the Milky Way Galaxy5.

It takes our Sun approximately 225 million years to make the trip around our Galaxy. This is sometimes called our "galactic year". Since the Sun and the Earth first formed, about 20 galactic years have passed; we have been around the Galaxy 20 times. On the other hand, in all of recorded human history, we have barely moved in our long path around the Milky Way.

How fast do we have to move to make it around the Milky Way in one galactic year? It's a huge circle, and the speed with which the Sun has to move is an astounding 483,000 miles per hour (792,000 km/hr)! The Earth, anchored to the Sun by gravity, follows along at the same fantastic speed. (By the way, as fast as this speed is, it is still a long way from the speed limit of the universe—the speed of light. Light travels at the unimaginably fast pace of 670 million miles per hour or 1.09 billion km/hr.)

https://astrosociety.org/edu/publications/tnl/71/howfast.html

[peteo48]

Good post Culzean - we need that perspective some times.

On the energy saving street lamps - we've got them on our road and they are much better. Living in a bungalow with a bedroom at the front it has helped with unwanted light coming into the room as well.

[guest5079]

We could certainly do with them here. Two years ago I asked the chairman to the parish council if the street lights timing could be altered. In summer they go off at  2am in Winter 1am. No nothing to do with him despite Devon County Council saying the opposite. In our road there are at least  two who leave home circa 5.30 am of course its pitch black. The lights come on just before 6am in Winter and 7am in Summer!!!!!!!!!!!!!!.I know of nobody here that comes home after say 11pm so we have lights costing money for no purpose but of course we musn't question those that know. Yes I have a vested interest as the light outside shines into our bedroom and despite 'blackout liners etc' the light still gets through.
It's no good quoting light pollution either. Means nothing to him.

[John Ratsey]

I agree that the latest generation of LED streetlights are very good directing light only downwards but those LED lights of a few years ago are somewhat less good - I get some good background illumination in my bedroom from an LED streetlamp nearly 100m away.

However, the satellites may not see much difference in illumination as they detect both the illuminated ground as well as any upwards light fram the lamps but, hopefully, if the light is better directed to where it is needed then there will be less of it.

[richardfrost]

However, the satellites may not see much difference in illumination as they detect both the illuminated ground as well as any upwards light

Not sure why we would be bothered what satellites see.

Light pollution is light wastefully directed or reflected upwards, which is then refracted or reflected in the atmosphere, making the night sky less visible through this haze. If we lived on the moon, this would not be an issue as there is no atmosphere to reflect misdirected light.

[Jocko]

Not sure why we would be bothered what satellites see.

Only in so far as the image was taken by the satellite, which recorded the ground light as well as the direct light. LED lighting is actually making the issue worse, due to low cost of running them. This allows much more light units to be installed.

[culzean]

Not sure why we would be bothered what satellites see.

Only in so far as the image was taken by the satellite, which recorded the ground light as well as the direct light. LED lighting is actually making the issue worse, due to low cost of running them. This allows much more light units to be installed.

Agreed

When I drive at night I put the sun visor down to stop that hypnotic flashing of streetlights as you drive under them,  works for me.

Also due to human nature and the law of unintended consequences --- we have LED lights throughout our house (and LED outside lights  - they are under the eaves facing vertically down to minimise light pollution to neighbours) - but because our LED  lights use less power they tend to get left on for longer - we used to be careful about switching filament lamps off when not needed,  but now at any one time you can find at least half the lights in our house left on