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72-723: The Kilpisjärvi Atmospheric Imaging Receiver Array ( KAIRA ) is an astronomical observatory operated by the Sodankylä Geophysical Observatory on behalf of Oulu University . It is located at Kilpisjärvi , Enontekiö near the border with Norway . It comprises two LOFAR -derived radio telescope systems and is capable of observing at HF and VHF radio frequencies. It is used for atmospheric, near-Earth space and astronomical research. KAIRA uses LOFAR phased-array antennas and digital signal-processing hardware. The phased array configuration has no moving parts and with digital control, allows KAIRA to quickly scan

144-702: A large percentage of clear nights per year, dry air, and are at high elevations. At high elevations, the Earth's atmosphere is thinner, thereby minimizing the effects of atmospheric turbulence and resulting in better astronomical " seeing ". Sites that meet the above criteria for modern observatories include the southwestern United States , Hawaii , Canary Islands , the Andes , and high mountains in Mexico such as Sierra Negra . Major optical observatories include Mauna Kea Observatory and Kitt Peak National Observatory in

216-584: A mechanism for processing citizen inquiries and complaints. The U.S. Green Building Council (USGBC) has also incorporated a credit for reducing the amount of light trespass and sky glow into their environmentally friendly building standard known as LEED . Light trespass can be reduced by selecting light fixtures that limit the amount of light emitted more than 80° above the nadir. The IESNA definitions include full cutoff (0%), cutoff (10%), and semi-cutoff (20%). (These definitions also include limits on light emitted above 90° to reduce sky glow.) Over-illumination

288-567: A meeting in 2009 on Circadian Disruption and Cancer. In different wavelengths of light, red light has the least inhibitory effect on melatonin. In June 2009, the American Medical Association developed a policy in support of control of light pollution. News about the decision emphasized glare as a public health hazard leading to unsafe driving conditions. Especially in the elderly, glare produces loss of contrast, obscuring night vision. A new 2021 study published in

360-454: A particular geographic area ( European Audiovisual Observatory ). Astronomical observatories are mainly divided into four categories: space-based , airborne , ground-based, and underground-based. Historically, ground-based observatories were as simple as containing an astronomical sextant (for measuring the distance between stars ) or Stonehenge (which has some alignments on astronomical phenomena). Ground-based observatories, located on

432-537: A planned network of KAIRA-like phased array systems for three-dimensional imaging. The system consists of a phased array receivers grouped in two separate arrays – one composed of 48 LOFAR Low-Band Antennas (LBA) covering the 10–90 MHz band and another composed of 48 LOFAR High-Band Antenna (HBA) covering the 110–270 MHz range. The HBA array is oriented in the direction of the EISCAT Tromsø radar, which transmits at approximately 224 MHz. Together with

504-596: A remote 5,640 m (18,500 ft) mountaintop in the Atacama Desert of Chile. The oldest proto-observatories, in the sense of an observation post for astronomy, The oldest true observatories, in the sense of a specialized research institute , include: Space-based observatories are telescopes or other instruments that are located in outer space , many in orbit around the Earth. Space telescopes can be used to observe astronomical objects at wavelengths of

576-419: A week at the absolute reference point calibration measurements are performed. Example magnetic observatories include: Example seismic observation projects and observatories include: Example gravitational wave observatories include: A volcano observatory is an institution that conducts the monitoring of a volcano as well as research in order to understand the potential impacts of active volcanism. Among

648-833: Is a facility which precisely measures the total intensity of Earth's magnetic field for field strength and direction at standard intervals. Geomagnetic observatories are most useful when located away from human activities to avoid disturbances of anthropogenic origin, and the observation data is collected at a fixed location continuously for decades. Magnetic observations are aggregated, processed, quality checked and made public through data centers such as INTERMAGNET . The types of measuring equipment at an observatory may include magnetometers (torsion, declination-inclination fluxgate, proton precession, Overhauser-effect), variometer (3-component vector, total-field scalar), dip circle , inclinometer , earth inductor, theodolite , self-recording magnetograph, magnetic declinometer, azimuth compass. Once

720-446: Is a hormone that regulates photoperiodic physiology and behaviour. Some species of frogs and salamanders utilize a light-dependent "compass" to orient their migratory behaviour to breeding sites. Introduced light can also cause developmental irregularities, such as retinal damage, reduced juvenile growth, premature metamorphosis, reduced sperm production, and genetic mutation. Close to global coastal megacities (e.g. Tokyo, Shanghai),

792-528: Is a nine-level measuring system used to track how much light pollution there is in the sky. A Bortle scale of four or less is required to see the Milky Way whilst one is "pristine", the darkest possible. Inspection of the area surrounding Madrid reveals that the effects of light pollution caused by a single large conglomeration can be felt up to 100 km (62 mi) away from the center. Global effects of light pollution are also made obvious. Research in

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864-418: Is a public-health hazard—especially the older you become. Glare light scattering in the eye causes loss of contrast and leads to unsafe driving conditions, much like the glare on a dirty windshield from low-angle sunlight or the high beams from an oncoming car." In essence bright and/or badly shielded lights around roads can partially blind drivers or pedestrians and contribute to accidents. The blinding effect

936-444: Is a scientific institution whose main task is to make observations in the fields of meteorology, geomagnetism and tides that are important for the navy and civil shipping. An astronomical observatory is usually also attached. Some of these observatories also deal with nautical weather forecasts and storm warnings, astronomical time services, nautical calendars and seismology. Example marine observatories include: A magnetic observatory

1008-592: Is also used to refer to artificial light indoors. Adverse consequences are multiple; some of them may not be known yet. Light pollution competes with starlight in the night sky for urban residents, interferes with astronomical observatories , and, like any other form of pollution , disrupts ecosystems and has adverse health effects. Light pollution is a side-effect of industrial civilization. Its sources include building exterior and interior lighting, advertising, outdoor area lighting (such as car parks), offices, factories, streetlights, and illuminated sporting venues. It

1080-449: Is caused by inefficient or unnecessary use of artificial light. Specific categories of light pollution include light trespass, over-illumination, glare, light clutter, and skyglow. A single offending light source often falls into more than one of these categories. Solutions to light pollution are often easy steps like adjusting light fixtures or using more appropriate light bulbs. Further remediation can be done with more efforts to educate

1152-417: Is caused in large part by reduced contrast due to light scattering in the eye by excessive brightness, or to the reflection of light from dark areas in the field of vision, with luminance similar to the background luminance. This kind of glare is a particular instance of disability glare, called veiling glare. (This is not the same as loss of accommodation of night vision which is caused by the direct effect of

1224-475: Is most severe in highly industrialized, densely populated areas of North America, Europe, and Asia and in major cities in the Middle East and North Africa like Tehran and Cairo , but even relatively small amounts of light can be noticed and create problems. Awareness of the harmful effects of light pollution began in the second half of the 19th century, but efforts to address its effects did not begin until

1296-400: Is natural. To precisely measure how bright the sky gets, night time satellite imagery of the earth is used as raw input for the number and intensity of light sources. These are put into a physical model of scattering due to air molecules and aerosoles to calculate cumulative sky brightness. Maps that show the enhanced sky brightness have been prepared for the entire world. The Bortle scale

1368-519: Is no replacement pollinator that would not be affected by the artificial light. This can lead to species decline of plants that are unable to reproduce, and change an area's longterm ecology . Among nocturnal insects, fireflies ( Coleoptera : Lampyridae, Phengodidae and Elateridae) are especially interesting study objects for light pollution, once they depend on their own light to reproduce and, consequently, are very sensitive to environmental levels of light. Fireflies are well known and interesting to

1440-574: Is not excessive in all developed countries. Amongst developed countries there are large variations in patterns of light use. American cities emit three to five times more light to space per capita compared to German cities. Over-illumination stems from several factors: Most of these issues can be readily corrected with available, inexpensive technology , and with the resolution of landlord/tenant practices that create barriers to rapid correction of these matters. Most importantly, public awareness would need to improve for industrialized countries to realize

1512-539: Is orchestrated by the natural diurnal patterns of light and dark, so disruption to these patterns impacts the ecological dynamics. Many species of marine plankton, such as Calanus copepods, can detect light levels as low as 0.1 μWm ; using this as a threshold a global atlas of marine Artificial Light at Night has been generated, showing its global widespread nature. Studies suggest that light pollution around lakes prevents zooplankton, such as Daphnia , from eating surface algae , causing algal blooms that can kill off

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1584-658: Is that, because of their location above the Earth's atmosphere, their images are free from the effects of atmospheric turbulence that plague ground-based observations. As a result, the angular resolution of space telescopes such as the Hubble Space Telescope is often much smaller than a ground-based telescope with a similar aperture . However, all these advantages do come with a price. Space telescopes are much more expensive to build than ground-based telescopes. Due to their location, space telescopes are also extremely difficult to maintain. The Hubble Space Telescope

1656-613: Is the Mauna Kea Observatory , located near the summit of a 4,205 m (13,796 ft) volcano in Hawaiʻi. The Chacaltaya Astrophysical Observatory in Bolivia, at 5,230 m (17,160 ft), was the world's highest permanent astronomical observatory from the time of its construction during the 1940s until 2009. It has now been surpassed by the new University of Tokyo Atacama Observatory , an optical-infrared telescope on

1728-597: Is the excessive and unnecessary use of light. A large and overabundant amount of electricity is required to support light consumption in the United States. U.S homes consumed 81 billion kilowatthours (kWh) of electricity for lighting in 2020 according to the U.S. Energy Information Administration's (EIA). Additionally, the EIA reported that 208 billion kWh and 53 billion kWh of electricity were used for commercial and manufacturing buildings respectively in 2018. Light use

1800-488: Is the presence of any unwanted, inappropriate, or excessive artificial lighting . In a descriptive sense, the term light pollution refers to the effects of any poorly implemented lighting sources, during the day or night. Light pollution can be understood not only as a phenomenon resulting from a specific source or kind of pollution, but also as a contributor to the wider, collective impact of various sources of pollution. Although this type of pollution can exist throughout

1872-479: The IAU , fear that light pollution will increase significantly, one of many concerns reported in the media regarding satellite overcrowding. Public discourse surrounding the continuing deployment of satellite constellations includes multiple petitions by astronomers and citizen scientists, and has raised questions about which regulatory bodies hold jurisdiction over human actions that obscure starlight. Measuring

1944-503: The International Dark-Sky Association has developed a set of model lighting ordinances. The Dark-Sky Association was started to reduce the light going up into the sky which reduces the visibility of stars (see Skyglow below). This is any light that is emitted more than 90° above nadir . By limiting light at this 90° mark they have also reduced the light output in the 80–90° range which creates most of

2016-457: The Milky Way galaxy. Light trespass occurs when unwanted light enters one's property, for instance, by shining over a neighbour's fence. A common light trespass problem occurs when a strong light enters the window of one's home from the outside , causing problems such as sleep deprivation . A number of cities in the U.S. have developed standards for outdoor lighting to protect the rights of their citizens against light trespass. To assist them,

2088-493: The Solar cycle ) but given optimal conditions, the darkest possible sky has a brightness of about 22 magnitude/square arc second. If a full moon is present, the sky brightness increases to about 18 magnitude/sq. arcsecond depending on local atmospheric transparency, 40 times brighter than the darkest sky. In densely populated areas a sky brightness of 17 magnitude/sq. an arcsecond is not uncommon, or as much as 100 times brighter than

2160-478: The Stratospheric Observatory for Infrared Astronomy use airplanes to observe in the infrared , which is absorbed by water vapor in the atmosphere. High-altitude balloons for X-ray astronomy have been used in a variety of countries. Example underground, underwater or under ice neutrino observatories include: Example meteorological observatories include: A marine observatory

2232-470: The beam pattern of the array. The LBA array is used for solar astronomy, general radio astronomy , ionospheric scintillation , multi-frequency riometry and other passive receiver experiments. Observatory The term observatoire has been used in French since at least 1976 to denote any institution that compiles and presents data on a particular subject (such as public health observatory ) or for

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2304-404: The 1950s. In the 1980s a global dark-sky movement emerged with the founding of the International Dark-Sky Association (IDA). There are now such educational and advocacy organizations in many countries worldwide. About 83% of people, including 99% of Europeans and Americans, live under light-polluted skies that are more than 10% brighter than natural darkness. 80% of North Americans cannot see

2376-542: The CfDS handbook "Blinded by the Light?". Chapter 4, "Human health implications of light pollution" states that "...   light intrusion, even if dim, is likely to have measurable effects on sleep disruption and melatonin suppression. Even if these effects are relatively small from night to night, continuous chronic circadian, sleep and hormonal disruption may have longer-term health risks". The New York Academy of Sciences hosted

2448-455: The EISCAT transmitter, KAIRA forms a bistatic radar system, capable on performing observation with at least 20 simultaneously beams pointing at different altitudes along the EISCAT transmitter beams. The LBA array has been configured approximately the same as the inner configuration of a LOFAR remote station (RS-INNER). The circular, quasi-random antenna distribution has been chosen to optimise

2520-518: The Southern Economic Journal indicates that light pollution may increase by 13% in preterm births before 23 weeks of gestation. While light at night can be beneficial, neutral, or damaging for individual species , its presence invariably disturbs ecosystems. For example, some species of spiders avoid lit areas, while other species are happy to build their webs directly on lamp posts. Since lamp posts attract many flying insects,

2592-453: The U.S. Fish and Wildlife Service of the number of birds killed after being attracted to tall towers range from four to five million per year to an order of magnitude higher. The Fatal Light Awareness Program (FLAP) works with building owners in Toronto , Ontario , Canada and other cities to reduce mortality of birds by turning out lights during migration periods. Another study has found that

2664-526: The U.S. Sky quality in the U.S. ranges from pristine ( Capitol Reef National Park and Big Bend National Park ) to severely degraded ( Santa Monica Mountains National Recreation Area and Biscayne National Park ). The National Park Service Night Sky Program monitoring database is available online (2015). Light pollution in Hong Kong was declared the 'worst on the planet' in March 2013. In June 2016, it

2736-631: The US, Roque de los Muchachos Observatory in Spain, and Paranal Observatory and Cerro Tololo Inter-American Observatory in Chile . Specific research study performed in 2009 shows that the best possible location for ground-based observatory on Earth is Ridge A  — a place in the central part of Eastern Antarctica. This location provides the least atmospheric disturbances and best visibility. Beginning in 1933, radio telescopes have been built for use in

2808-428: The atmosphere The effect of sky glow can be harmful in astronomy and on the health of many organisms. It worsens the visibility of the stars, the Milky Way , and significantly increases the natural light levels at night. Also contributing to light pollution are artificial satellites . With increasing numbers of satellite constellations such as OneWeb and Starlink , members of the astronomical community, notably

2880-733: The best known are the Hawaiian Volcano Observatory and the Vesuvius Observatory . Mobile volcano observatories exist with the USGS VDAP (Volcano Disaster Assistance Program), to be deployed on demand. Each volcano observatory has a geographic area of responsibility it is assigned to whereby the observatory is tasked with spreading activity forecasts, analyzing potential volcanic activity threats and cooperating with communities in preparation for volcanic eruption . Light pollution Light pollution

2952-705: The blue band. In North America the situation is comparable. There is a significant problem with light pollution ranging from the Canadian Maritime Provinces to the American Southwest. The International Dark-Sky Association works to designate areas that have high-quality night skies. These areas are supported by communities and organizations that are dedicated to reducing light pollution (e.g. Dark-sky preserve ). The National Park Service Natural Sounds and Night Skies Division has measured night sky quality in national park units across

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3024-406: The day, because direction of natural polarization of sun light and its reflection is a source of information for a lot of animals). This form of pollution is named polarized light pollution (PLP). Unnatural polarized light sources can trigger maladaptive behaviors in polarization-sensitive taxa and alter ecological interactions. Lights on tall structures can disorient migrating birds. Estimates by

3096-606: The day, its effects are magnified during the night with the contrast of the sky's darkness. It has been estimated that 83 percent of the world's people live under light-polluted skies and that 23 percent of the world's land area is affected by skyglow . The area affected by artificial illumination continues to increase. A major side effect of urbanization , light pollution is blamed for compromising health, disrupting ecosystems, and spoiling aesthetic environments. Studies show that urban areas are more at risk. Globally, it has increased by at least 49% from 1992 to 2017. Light pollution

3168-560: The development and trial of new lighting technologies in the North Sea. In early 2007, the lights were installed on the Shell production platform L15. The experiment proved a great success since the number of birds circling the platform declined by 50 to 90%. Birds migrate at night for several reasons. Save water from dehydration in hot day flying and part of the bird's navigation system works with stars in some way. With city light outshining

3240-598: The direct lighting effect by adding softening filters or other solutions, though intensity will be reduced. Glare can be categorized into different types. One such classification is described in a book by Bob Mizon, coordinator for the British Astronomical Association's Campaign for Dark Skies, as follows: According to Mario Motta, president of the Massachusetts Medical Society , "...   glare from bad lighting

3312-467: The effect of sky glow on a global scale is a complex procedure. The natural atmosphere is not completely dark, even in the absence of terrestrial sources of light and illumination from the Moon. This is caused by two main sources: airglow and scattered light . At high altitudes, primarily above the mesosphere , there is enough UV radiation from the sun at very short wavelengths to cause ionization . When

3384-463: The electromagnetic spectrum that cannot penetrate the Earth's atmosphere and are thus impossible to observe using ground-based telescopes. The Earth's atmosphere is opaque to ultraviolet radiation, X-rays , and gamma rays and is partially opaque to infrared radiation so observations in these portions of the electromagnetic spectrum are best carried out from a location above the atmosphere of our planet. Another advantage of space-based telescopes

3456-406: The entire upper portion of the telescope dome can be rotated to allow the instrument to observe different sections of the night sky. Radio telescopes usually do not have domes. For optical telescopes, most ground-based observatories are located far from major centers of population, to avoid the effects of light pollution . The ideal locations for modern observatories are sites that have dark skies,

3528-670: The field of radio astronomy to observe the Universe in the radio portion of the electromagnetic spectrum. Such an instrument, or collection of instruments, with supporting facilities such as control centres, visitor housing, data reduction centers, and/or maintenance facilities are called radio observatories . Radio observatories are similarly located far from major population centers to avoid electromagnetic interference (EMI) from radio , TV , radar , and other EMI emitting devices, but unlike optical observatories, radio observatories can be placed in valleys for further EMI shielding. Some of

3600-521: The general public (unlike many other insects) and are easily spotted by non-experts, and, due to their sensibility and rapid response to environmental changes, good bioindicators for artificial night lighting. Significant declines in some insect populations have been suggested as being at least partially mediated by artificial lights at night. A 2009 study also suggests deleterious impacts on animals and ecosystems because of perturbation of polarized light or artificial polarization of light (even during

3672-407: The higher layers and thus no appreciable ionization occurs. Apart from emitting light, the sky also scatters incoming light, primarily from distant stars and the Milky Way , but also the zodiacal light , sunlight that is reflected and backscattered from interplanetary dust particles. The amount of airglow and zodiacal light is quite varied (depending, amongst other things on sunspot activity and

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3744-563: The highest levels of ALAN reported the highest number of cases of breast cancer. Seoul, which had the highest levels of light pollution, had 34.4% more cases of breast cancer than Ganwon-do, which had the lowest levels of light pollution. This suggested a high correlation between ALAN and the prevalence of breast cancer. It was also found that there was no correlation between other types of cancer such as cervical or lung cancer and ALAN levels. A more recent discussion (2009), written by Professor Steven Lockley, Harvard Medical School, can be found in

3816-992: The human body suggests that a variety of adverse health effects may be caused by light pollution or excessive light exposure, and some lighting design textbooks use human health as an explicit criterion for proper interior lighting. Health effects of over-illumination or improper spectral composition of light may include: increased headache incidence, worker fatigue , medically defined stress , decrease in sexual function and increase in anxiety. Likewise, animal models have been studied demonstrating unavoidable light to produce adverse effect on mood and anxiety. For those who need to be awake at night, light at night also has an acute effect on alertness and mood. Outdoor artificial light at night – exposure to contemporary types such as current types of street lighting – has been linked to risks for obesity, mental disorders, diabetes , and potentially other health issues by preliminary studies. In 2007, "shift work that involves circadian disruption"

3888-424: The ions collide with electrically neutral particles they recombine and emit photons in the process, causing airglow . The degree of ionization is sufficiently large to allow a constant emission of radiation even during the night when the upper atmosphere is in the Earth's shadow. Lower in the atmosphere all the solar photons with energies above the ionization potential of N 2 and O 2 have already been absorbed by

3960-424: The lakes' plants and lower water quality. Light pollution may also affect ecosystems in other ways. For example, entomologists have documented that nighttime light may interfere with the ability of moths and other nocturnal insects to navigate. It can also negative impact on insect development and reproduction. Night-blooming flowers that depend on moths for pollination may be affected by night lighting, as there

4032-424: The large payoff in reducing over-illumination. In certain cases, an over-illumination lighting technique may be needed. For example, indirect lighting is often used to obtain a "softer" look, since hard direct lighting is generally found less desirable for certain surfaces, such as skin. The indirect lighting method is perceived as cozier and suits bars, restaurants, and living quarters. It is also possible to block

4104-444: The late 1990s showed that the entire area consisting of southern England, Netherlands, Belgium, West Germany, and northern France have a sky brightness of at least two to four times normal. The only places in continental Europe where the sky can attain its natural darkness are in northern Scandinavia and in islands far from the continent. The growth of light pollution on the green band has been 11% from 2012–2013 to 2014–2020, and 24% on

4176-407: The light itself on the eye.) Light clutter refers to excessive groupings of lights. Groupings of lights may generate confusion, distract from obstacles (including those that they may be intended to illuminate), and potentially cause accidents. Clutter is particularly noticeable on roads where the street lights are badly designed, or where brightly lit advertisements surround the roadways. Depending on

4248-546: The light trespass issues. U.S. federal agencies may also enforce standards and process complaints within their areas of jurisdiction. For instance, in the case of light trespass by white strobe lighting from communication towers in excess of FAA minimum lighting requirements the Federal Communications Commission maintains an Antenna Structure Registration database information which citizens may use to identify offending structures and provides

4320-462: The lights produced by the Post Tower has affected 25 bird species. As a result, they discovered that decreasing the use of excessive lights increased the survival rate of bird species. Similar disorientation has also been noted for bird species migrating close to offshore production and drilling facilities. Studies carried out by Nederlandse Aardolie Maatschappij b.v. (NAM) and Shell have led to

4392-431: The motives of the person or organization that installed the lights, their placement and design can even be intended to distract drivers, and can contribute to accidents. Sky glow is the bright haze above cities that is produced from excessive artificial lighting at night. This type of light pollution is created from artificial light reflecting in the sky and bouncing around the different types of particles that reside in

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4464-521: The natural illumination cycles provided by the moon in the marine environment are considerably disrupted by light pollution, with only nights around the full moon providing greater radiances, and over a given month lunar dosages may be a factor of 6 less than light pollution dosages. In September 2009, the 9th European Dark-Sky Symposium in Armagh, Northern Ireland had a session on the environmental effects of light at night (LAN). It dealt with bats, turtles,

4536-802: The night sky, birds (and also about mammals) no longer navigate by stars. Sea turtle hatchlings emerging from nests on beaches are another casualty of light pollution. It is a common misconception that hatchling sea turtles are attracted to the moon. Rather, they find the ocean by moving away from the dark silhouette of dunes and their vegetation, a behavior with which artificial lights interfere. The breeding activity and reproductive phenology of toads, however, are cued by moonlight. Juvenile seabirds are also disoriented by lights as they leave their nests and fly out to sea, causing events of high mortality. Amphibians and reptiles are also affected by light pollution. Introduced light sources during normally dark periods can disrupt levels of melatonin production. Melatonin

4608-401: The public in order to push legislative change. However, because it is a man-made phenomenon, addressing its impacts on humans and the environment has political, social, and economic considerations. Light pollution is the presence of anthropogenic artificial light in otherwise dark conditions. The term is most commonly used in relation to in the outdoor environment and surrounding, but

4680-440: The sky, giving KAIRA a large field of view. KAIRA can produce a continuous all-sky image of the radio transparency of ionosphere , using cosmic radio noise for "illumination" ( riometry ). KAIRA can also obtain electron density profiles in the atmosphere. This allows the study of the interaction of the solar wind with the atmosphere, such as in aurora borealis and other space weather phenomena. In addition to near-space imaging,

4752-508: The spiders that tolerate the light gain an advantage over the spiders that avoid it. This is a simple example of the way in which species frequencies and food webs can be disturbed by the introduction of light at night. Light pollution poses a serious threat in particular to nocturnal wildlife, having negative impacts on plant and animal physiology. It can confuse animal navigation , alter competitive interactions, change predator-prey relations, and cause physiological harm. The rhythm of life

4824-414: The surface of Earth, are used to make observations in the radio and visible light portions of the electromagnetic spectrum . Most optical telescopes are housed within a dome or similar structure, to protect the delicate instruments from the elements. Telescope domes have a slit or other opening in the roof that can be opened during observing, and closed when the telescope is not in use. In most cases,

4896-533: The use of KAIRA has been demonstrated for long-baseline interferometry observations of pulsars . It operates as either a stand-alone passive receiver, as a receiver for the EISCAT VHF incoherent scatter radar (a conventional dish-type emitter) located at Ramfjordmoen, near Tromsø , Norway, or for use in conjunction with other regional VHF experiments. The site is also a pathfinder for the EISCAT_3D system,

4968-795: The world's major radio observatories include the Very Large Array in New Mexico , United States, Jodrell Bank in the UK , Arecibo in Puerto Rico , Parkes in New South Wales , Australia, and Chajnantor in Chile . A related discipline is Very-long-baseline interferometry (VLBI). Since the mid-20th century, a number of astronomical observatories have been constructed at very high altitudes , above 4,000–5,000 m (13,000–16,000 ft). The largest and most notable of these

5040-483: Was able to be serviced by the Space Shuttles while many other space telescopes cannot be serviced at all. Airborne observatories have the advantage of height over ground installations, putting them above most of the Earth's atmosphere. They also have an advantage over space telescopes: The instruments can be deployed, repaired and updated much more quickly and inexpensively. The Kuiper Airborne Observatory and

5112-485: Was estimated that one third of the world's population could no longer see the Milky Way, including 80% of Americans and 60% of Europeans. Singapore was found to be the most light-polluted country in the world. Over the past 21 years, China's provincial capital cities have seen a major increase in light pollution, with hotspots along the eastern coastline region. Medical research on the effects of excessive light on

5184-584: Was listed as a probable carcinogen by the World Health Organization's International Agency for Research on Cancer. (IARC Press release No. 180). Multiple studies have documented a correlation between night shift work and the increased incidence of breast and prostate cancer. One study which examined the link between exposure to artificial light at night (ALAN) and levels of breast cancer in South Korea found that regions which had

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