Light Pollution - Artificial Sky Brightness
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- Added to the Catalog
- Available for
- Land: Human Impact
- People: Demographics
- Light Pollution
- Milky Way
- Nighttime Lights
DescriptionPermalink to Description
Light pollution in urban centers creates a sky glow that can blot out the stars. The brighter the area in this map the harder it is to see stars and constellations in the night sky.
The Milky Way, the brilliant river of stars that has dominated the night sky and human imaginations since time immemorial, is just a faded memory for one third of humanity and 80 percent of Americans, according to a new global atlas of light pollution produced by Italian, Israeli, and American scientists.
“We’ve got whole generations of people in the United States who have never seen the Milky Way,” said Chris Elvidge, a scientist with NOAA’s National Centers for Environmental Information. “It’s a big part of our connection to the cosmos—and it’s been lost.”
The artificial sky brightness levels are those used in legend and indicate the following: up to 1% above the natural light (black); from 1 to 8% above the natural light (blue); from 8 to 50% above natural nighttime brightness (green); from 50% above natural to the level of light under which the Milky Way is no longer visible (yellow); from Milky Way loss to estimated cone stimulation (red); and very high nighttime light intensities, with no dark adaption for human eyes (white).
For the purpose of this atlas, we set the level of artificial brightness under which a sky can be considered “pristine” at 1% of the natural background. The dark gray level (1 to 2%) sets the point where attention should be given to protect a site from a future increase in light pollution. Blue (8 to 16%) indicates the approximate level where the sky can be considered polluted on an astronomical point of view. The winter Milky Way (fainter than its summer counterpart) cannot be observed from sites coded in yellow, whereas the orange level sets the point of artificial brightness that masks the summer Milky Way as well. In areas that appear red, people never experience conditions resembling a true night because it is masked by an artificial twilight.
To learn more about this map, read the Science Advances paper. Also available is a book entitled, The World Atlas of Light Pollution.
Next Generation Science StandardsPermalink to Next Generation Science Standards
Cross-cutting ConceptsPermalink to Cross-cutting Concepts
C1 Patterns. Students identify similarities and differences in order to sort and classify natural objects and designed products. They identify patterns related to time, including simple rates of change and cycles, and to use these patterns to make predictions.
C2 Cause and Effect. Students routinely identify and test causal relationships and use these relationships to explain change. They understand events that occur together with regularity might or might not signify a cause and effect relationship
C3 Scale Proportion and Quantity. Students recognize natural objects and observable phenomena exist from the very small to the immensely large. They use standard units to measure and describe physical quantities such as weight, time, temperature, and volume.
C3 Scale Proportion and Quantity. Students observe time, space, and energy phenomena at various scales using models to study systems that are too large or too small. They understand phenomena observed at one scale may not be observable at another scale, and the function of natural and designed systems may change with scale. They use proportional relationships (e.g., speed as the ratio of distance traveled to time taken) to gather information about the magnitude of properties and processes. They represent scientific relationships through the use of algebraic expressions and equations
C5 Energy and Matter. Students learn matter is conserved because atoms are conserved in physical and chemical processes. They also learn within a natural or designed system, the transfer of energy drives the motion and/or cycling of matter. Energy may take different forms (e.g. energy in fields, thermal energy, energy of motion). The transfer of energy can be tracked as energy flows through a designed or natural system.
C7 Stability and Change. Students explain stability and change in natural or designed systems by examining changes over time, and considering forces at different scales, including the atomic scale. Students learn changes in one part of a system might cause large changes in another part, systems in dynamic equilibrium are stable due to a balance of feedback mechanisms, and stability might be disturbed by either sudden events or gradual changes that accumulate over time
C2 Cause and Effect. Students understand that empirical evidence is required to differentiate between cause and correlation and to make claims about specific causes and effects. They suggest cause and effect relationships to explain and predict behaviors in complex natural and designed systems. They also propose causal relationships by examining what is known about smaller scale mechanisms within the system. They recognize changes in systems may have various causes that may not have equal effects.
C5 Energy and Matter. Students learn that the total amount of energy and matter in closed systems is conserved. They can describe changes of energy and matter in a system in terms of energy and matter flows into, out of, and within that system. They also learn that energy cannot be created or destroyed. It only moves between one place and another place, between objects and/or fields, or between systems. Energy drives the cycling of matter within and between systems. In nuclear processes, atoms are not conserved, but the total number of protons plus neutrons is conserved.
C7 Stability and Change. Students understand much of science deals with constructing explanations of how things change and how they remain stable. They quantify and model changes in systems over very short or very long periods of time. They see some changes are irreversible, and negative feedback can stabilize a system, while positive feedback can destabilize it. They recognize systems can be designed for greater or lesser stability
Disciplinary Core IdeasPermalink to Disciplinary Core Ideas
ESS1.A The Universe and its Stars. Stars range greatly in size and distance from Earth and this can explain their relative brightness.
ESS3.C Human Impact on Earth systems. Societal activities have had major effects on the land, ocean, atmosphere, and even outer space. Societal activities can also help protect Earth’s resources and environments.
PS3.A Definitions of Energy. Moving objects contain energy. The faster the object moves, the more energy it has. Energy can be moved from place to place by moving objects, or through sound, light, or electrical currents. Energy can be converted from one form to another form.
PS4.B Electromagnetic Radiation. Object can be seen when light reflected from their surface enters our eyes
ESS1.A The Universe and its Stars. The universe began with a period of extreme and rapid expansion known as the Big Bang. Earth and its solar system are part of the Milky Way galaxy, which is one of many galaxies in the universe.
ESS3.C Human Impact on Earth systems. Human activities have altered the biosphere, sometimes damaging it, although changes to environments can have different impacts for different living things. Activities and technologies can be engineered to reduce people’s impacts on Earth.
PS3.A Definitions of Energy. Kinetic energy can be distinguished from the various forms of potential energy. Energy changes to and from each type can be tracked through physical or chemical interactions. The relationship between the temperature and the total energy of a system depends on the types, states, and amounts of matter.
PS4.A Wave Properties. A simple wave model has a repeating pattern with a specific wavelength, frequency, and amplitude, and mechanical waves need a medium through which they are transmitted. This model can explain many phenomena including sound and light. Waves can transmit energy
ESS1.A The Universe and its Stars. The sun is just one of more than 200 billion stars in the Milky Way galaxy, and the Milky Way is just one of hundreds of billions of galaxies in the universe. The study of stars’ light spectra and brightness is used to identify compositional elements of stars, their movements, and their distances from Earth.
ESS3.C Human Impact on Earth systems. Sustainability of human societies and the biodiversity that supports them requires responsible management of natural resources, including the development of technologies that produce less pollution and waste and that preclude ecosystem degradation.
PS3.A Definitions of Energy. The total energy within a system is conserved. Energy transfer within and between systems can be described and predicted in terms of energy associated with the motion or configuration of particles (objects).
PS4.A Wave Properties. The wavelength and frequency of a wave are related to one another by the speed of the wave, which depends on the type of wave and the medium through which it is passing. Waves can be used to transmit information and energy.
PS4.B Electromagnetic Radiation. Both an electromagnetic wave model and a photon model explain features of electromagnetic radiation broadly and describe common applications of electromagnetic radiation.
Notable FeaturesPermalink to Notable Features
- Black indicates artificial brightness under which a sky can be considered “pristine” at 1% of the natural background.
- Dark gray (1 to 2%) sets the point where attention should be given to protect a site from a future increase in light pollution.
- Blue (8 to 16%) indicates the approximate level where the sky can be considered polluted on an astronomical point of view.
- Yellow indicates places where the winter Milky Way (fainter than its summer counterpart) cannot be observed.
- Orange indicates artificial brightness that masks the summer Milky Way as well.
- Red areas are where people never experience conditions resembling a true night because it is masked by an artificial twilight.
Data SourcePermalink to Data Source