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Light Pollution

Light pollution is the overuse of artificial lighting commonly found in towns and cities worldwide. Light pollution drowns out the light from very distant stars and nebulae, and is very bad for astronomers.

249 Questions

What are the dangers of light pollution?

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Asked by Wiki User

Light pollution is mainly an issue for astronomers, but it can also be an issue to local residents living in light polluted cities. In many urban areas, unwanted light can easily enter someone's property during a night and may disrupt them from sleeping and having excess light while driving can dazzle someome's eyes and cause accidents.

Light pollution affects astronomers as the light from many street lamps goes up into the sky, therefore the light gets scattered by the atmosphere and drowns out the view of distant stars and galaxies.

Is light pollution a serious problem?

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Asked by Wiki User

Light pollution is an issue for two reasons, first of all, light from many streetlights and buildings is sent up into the night sky and that drowns out a great deal of stars and galaxies.

The second reason why it is an issue is because lights that are too bright can dazzle your eyes as a driver and unwanted light can enter someone's house, stopping them from sleeping.

How many birds die from light pollution?

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Asked by Wiki User

More then 5 thousand a year die from light pollution.

Impact of modern agriculture on environment?

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Asked by Wiki User

Excess use of man-made fertilizers, tillage equipment exposing the soil on a greater scale than in the past, herbicide usage on crops, manure management issues with intensive livestock production (dairy, poultry, feedlot beef, hogs), carbon emissions from use of machinery in the fields, methane emissions from inefficient manure management of intensive animal agricultural systems and from excess production of cattle, soil erosion by tilling over crops instead of using more sustainable and efficient crop management strategies like no-till seeding and by over-grazing from those who have poor pasture management strategies, the list goes on.

What light bulbs can you use to to decrease light pollution?

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Asked by Wiki User

No light bulbs can reduce light pollution. But you can reduce a number of bulbs in your house or building. If you own a building, you could reduce and\or space apart the number of light pannals from each other.

How can light pollution be prevented?

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Asked by Wiki User

There are valid arguments on each side of the "light pollution" debate. Astronomers dislike stray light that makes it difficult to see the stars, while police and city planners - and residents - know that street lighting and security lighting deter criminals, who would rather practice their vile trade in the dark, and makes it safer for drivers. So the question is, is there a way to light the cities, but not the skies?

There is no escape. Light bounces, reflects, scatters. You can't point lights at the ground and not have reflections back into the sky. Which is not to say that engineers can't try to minimize the effects.

Many street lights and city lights point UP. This may be pretty, but does nothing to enhance security while magnifying the problems of light pollution. Street lights and security lights should be shaded to not point to the sky.

Really, though, it boils down to a decision about who gets inconvenienced; a few astronomers, or millions of citizens?

Go out of the city so you can see the stars the only way to not have light pollution is to turn them all off

What countries are most affected by light pollution?

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Asked by Wiki User

the U.S, Eastern China, Western Europe, and Japan are the ones I know of.

What are 3 examples of light pollution?

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Asked by Wiki User

According to the China National Science and Technology Approval Committee announced the definition of light pollution, light pollution is a phenomenon of excess light radiation adverse impact on human life and production environments. Including the pollution caused by visible light, infrared and ultraviolet.

Experts suggest Lighting should vector photopic

Said Zhang Jian, the selected light is no fixed pattern, but must comply with the principle of light vector matching, that is to say we should use different brightness on different occasions. Must understand what kind of light environment of their own, different rooms have different functions, should use different light sources, different lighting determine different lighting design.

Illumination means, viewed from the same direction, to any surface in a given direction per unit projected area of ​​the light intensity (brightness), Lux. At present, China regulations, the general LUX of household lamps is 50Lux-100Lux.

Parlor

Mainly related to what the owner of the house used to do. In the living room welcome brightness is stronger so that the light evenly illuminates every corner of the interior, which ensure that visual space becomes large and people are more spiritual.

If the master prefer to watching TV in the living room, it is best to open the master rear lights, so you can moderately reduce visual fatigue. Should not open the dome light, because it will form a color screen, damage the human eye.

Restaurant

Choose a shade, and the upper and lower flexible stretch Warm lamps, at the same

time, contrast to color rendering index requirements so that the table delicacies

look more delicious,lift everyone's appetite, stressed to have shade to light dim around the desk , in order to cover up the people eating behavior.

Bedroom, studying room

Recommended a change in traditional practices, why not try to install light on curtains, if conditions permitting, can be made of the effect of light intensity gradient function, pay attention to the orientation of the room, installing a LED ceiling light ensure that most used natural light can emit to the center of the roof, combining natural lighting and lighting together so as to achieve the maximum effect of the light source complementary.

As for the cabinet and other local area local lighting can be installed to facilitate to find things.

In addition, the study room may be arranged in a number of green plants, these plants can not only absorb some computer electronic dust, but also can relieve eye fatigue.

Outdoor lighting also depends on the design of the house, using the most efficient lighting such as LED flood light is to get the most effective lighting brightness and width and reduce light pollution as far as possible, whether it is outdoor lighting or indoor lighting, It is vital that we should choose high-quality LED lighting, which put forward higher requirement of professional LED manufacturer.

Name two things that can be reduce light pollution?

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Asked by Wiki User

Lampshade. Lower wattage bulbs. Shorter 'on' times. And the off switch.

How do prisms affect light?

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Asked by Wiki User

First it is important to understand what a prism is in this context. A prism is a block of material that conforms to these requirements:

* Is transparent or at least translucent to light .

* Is not of the same composition as its surroundings (for example, there is little point in having a prism composed of water entirely immersed in water -- where would its boundaries be?)

* It may or may not have two (usually flat) faces not parallel to each other. The prism used by Isaac Newton when he first demonstrated the resolution of white light into its constituent colors more than 300 years ago is nearly always shown as being triangular in section.

It is also important to agree about what light is. As Einstein demonstrated in 1905, light may be considered either as a stream of particles (corpuscles), or as a bunch of waves. Here let us think of light as a bunch (pencil) of waves.

White light for instance contains light of many different wavelengths, just as by analogy white sound has sounds of many wavelengths. Thinking about the rainbow with all its colors, red light at one end of the visible spectrum has a longer wavelength than the violet light at the other end. All the colors in between have intermediate wavelengths.

Let us further consider a ray of light containing light of only one wavelength. This may be thought of as pure light. It can be of any color of the rainbow.

As the ray of pure light strikes a prism, two quite distinct things can happen. Either the ray is entirely reflected from the surface of the prism, or it is not. This depends on the nature of the surface of the prism.

The part of the ray that is reflected bounces off the prism as a ray in the plane defined by the striking ray (incident ray) and the perpendicular to the surface of the prism at the point of incidence. The angle between the incident ray and the perpendicular to the surface of the prism at the pint of incidence is called the angle of incidence. The angle at which the reflected ray leaves the surface, known as the angle of reflection, is equal to the angle of incidence, exactly the same as a ray might be reflected from a mirror. Indeed, for this reflected light, the surface of the prism is acting as a mirror.

If the ray is not reflected at all, or not completely reflected, then at least part of the incident ray of light actually enters the prism. This is said to be refracted. It enters the prism at an angle usually different from the angle of incidence. The angle of refraction (the angle between the ray and the perpendicular) depends on the angle of incidence, the wavelength of the incident light and on the material of the prism. It may be greater or less than the angle of incidence. If the incident ray travels through a vacuum, then the angle of refraction is always greater than the angle of incidence. This is because the prism is always denser (weighs more than the equivalent volume of) than the vacuum..

If the incident ray travels through a vacuum, then the angle of refraction is always greater than the angle of incidence. In this case, the ratio of the sine of the angle of refraction to the sine of the angle of incidence is called the refractive index of the prism material with respect to the wavelength of the incident ray. The ray of light in a vacuum travels at the "speed of light", c, as defined by Einstein's Theories of Relativity. In the medium of the prism, it travels somewhat slower. This is what causes the change of direction. The material of the prism, being denser than the vacuum, is more difficult for the ray of light to plow through. Think of a car with a blown front tire. It will pull to the side of the blown tire, changing the direction of the car. This is not a perfect analogy, but it might give you the idea. There are pretty diagrams available elsewhere (in some textbooks) showing how a wavefront changes direction when it slows down on an angle, but you will have to imagine that, or find one of those diagrams. See Snell's Law for the general case of the relationships of the angles of incidence and refraction, light velocities in each medium, and refractive indices.

Now we come to the nub of the matter. We have a ray of light traveling through the prism that must soon strike another of its surfaces. The ray emerges into the external medium (perhaps a vacuum) and the processes are reversed. The wavefront speeds up again to its former velocity (c in a vacuum) and keeps on going. If we assume that the surface it strikes is exactly parallel to the one whereby it entered, in this case the reversal will be exact and will produce the same angles as in entry, so that the ray will continue parallel to but offset from the course as followed before it entered the prism. This is not very exciting, though it is a way to offset the path of a ray of light. But if the exit surface is not parallel to the entry surface, the ray will shoot off in a quite different direction, having been bent twice (once at each surface), but not by the same amount each time.

The amount of bending depends on the refractive index. If we now think about what would happen to a ray of white (that is, not pure as regards wavelength) then its pure components will all shoot out in different directions. This is how a prism can resolve white light into a rainbow of colors.

See the related link for an interactive website dealing with rainbows, perhaps the best-known example of refraction. In this case the prism is a droplet of water embedded in air, and the ray is a ray of sunshine. The surface of the droplet is assumed to be spherical.

What are the causes of light pollution?

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Asked by Wiki User

Use of too much artificial light and having the lighting aimed up into the sky where it does no good for anyone. It is also called pollution when it shines any place anyone does not want it, such as flooding over wide areas onto other people's property and shining into the windows of their houses. It is a result of too many people, too much wasted energy, and improper installation.

It can be improved by shielding the outdoor lighting to prevent upward light rays (as easy as painting the tops of light globes black or installing shields made for the purpose). Good neighbors will be sure their lighting is not leaving their property either up or out and will ask the electric company installing the lighting to use appropriate shields.

Many people believe that having a lot of light at night improves their security and prevents vandalism. This has been proven to be a misconception.

Don't listen to the utility companies when they try to sell you giant night lights to protect you, or even put them up for free...why do you think they do that? To sell you more wasted energy is why.

What it does is provide lighting for trespassers and thieves to see what they are doing better. It also allows shadows to be created for them to hide in. I'd much rather they not be able to see where they are going well, so they trip over things and make noise for me to know they are lurking.

There have been studies that tested whether added lighting at vandalized locations at night prevented the continued vandalizing. It, instead, has proven to increase that...vandals like to see their dirty deeds and want others to see them do it, too. When lights at night in some Texas school systems were turned off, they had significant reductions in vandalism of the school property.

Answer:

An indirect cause of light pollution is the need for visibility at night, for reasons of safety. The direct cause is the solution to this problem: man-made lights.

Answer:

Much of the light pollution problem (at least for astronomers where the "waste" light obscures their viewing of the sky) is the poor design of city light. Many existing city street lights direct a portion of their light skyward where it serves no purpose. Some cities (like Calgary) are installing more purposeful light sources with reflectors to keep the skies dark. To keep the astronomers happy and the streets better lit (to aid the citizens and detract from criminal activities).

A second form of light pollution, interestingly enough, impacts mink breeders. The sex of minks determines the value of their pelts (males are better). However the sex ratio in litters is impacted by the quality of light in the breeding areas. Some cities have installed bluish lights on roads near mink farms. This color of light predisposes mink females to have female kits. Mink farmers often advocate for yellow or pinkish lights near their farms. In this case the cause of the light pollution is economic and a desire for better use of the lights for humans to make driving safer.

How does light pollution in cities affect astronomical observations?

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Asked by Wiki User

The additional lights from street lamps and buildings gets sent into the sky which in turn gets scattered by our atmosphere, and this hinders very faint galaxies, nebula, planets and stars to be seen.

How does Light Pollution affect the world?

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Asked by Wiki User

Light pollution makes astronomy extremly hard and makes sleeping difficult. Light pollution also affects animals and could make them sick. Also, light pollution is a problem, because it consumes a lot of power. To stop light pollution, just turn off your lights at night. If you own a building, do not illuminate your building and turn off your lights. If you work in a buildng and have to work late at night, close the blinds so light doen't escape the building.

Is there light pollution?

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Asked by Flame123456789

Light pollution causes more opacity in the night sky. The best observations are done in the darkest skies. As cities grow, areas with optimal viewing are reducing. Most lighting points in all directions. There are movements to get new lights that are directed downward, where they are most useful for the purpose they were invented for.

What impact does light pollution have on astronomy?

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Asked by Wiki User

No, it would not. Telescopes located on mountaintops ... above most of

the atmosphere ... work much better than telescopes located in valleys do.

And, viewed from the moon, where there's no atmosphere at all, the stars

are plainly visible in the sky even when the sun is too.

How long does it take to die after the jugular vein is cut?

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Asked by Wiki User

Since the blood flow of the IJV (internal jugular vein) is 700mL per minute when the head is lying flat, and at 70mL per minute when the head is at a right angle, and you need to lose approximately 40% of your blood to die, when the vein is cut it would take around 3 minutes to bleed out and die if the head is flat, and about 30 minutes to bleed out if the head is bent at a 90 degree angle. these numbers are further lengthened if a tourniquet or other blood loss device is applied.

Why is the night sky sometimes orange?

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Asked by Wiki User

Because of the moisture in the air, it reflects light differently. especially if a storm is coming. The more orange, the worse the storm.

This could also be caused from the reflection of the setting sun which tends to cause brilliant hues of orange, pink and coral.

Also maybe the city lights and/or pollution in your city is a factor.

Your 1995 Aspire's airbag light blinks code 34 is this a serious problem?

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Asked by Wiki User

Any SRS warning light with a corresponding code is serious. Take it to a professional as this is not a DIY repair.

Any light pollution slogan?

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Asked by Wiki User

a sweet slogan about noise pollution

How is light pollution is caused?

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Asked by CaptainAmerica

Light pollution is caused by the overuse of artificial lighting - particularly the lights from brightly lit buildings and street lights and as well as it washing out views of many distant stars, it also can affect our circadian rhythms (sleep cycles).

Where can you get outdoor lights that will not cause too much light pollution?

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Asked by Wiki User

Home Depot, Lowe's, or any other grocery store or hardware store has lights like this available. I would suggest Home Depot as they usually offer the best products and prices.

When did light pollution become a problem?

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Asked by Wiki User

Astronomical light pollution started as street and road lighting became widespread from the early 20th century. It was bad enough by the 1980's for the dark sky movement to gather momentum. Local light pollution, for instance from obtrusive security lights, is a more recent problem, perhaps from about the 1970's.