RSSAll Entries Tagged With: "light pollution"

Earth from Space – Night turns to day

The Mediterranean region at night

The Mediterranean region, illuminated by manmade lights and natural sources (moonlight, starlight etc).

ONE OF THE EXPEDITION 29 crewmembers aboard the International Space Station took this oblique angle photo showing the Mediterranean Sea area, including the Nile River and the river’s delta, and the Sinai Peninsula, on October 15, 2011. Cyprus is visible at left.

At first look, the image appears to have been photographed in daylight, but actually it was taken in the early hours of the morning, local time.

Some areas of the photo like the river and river delta appear as the brightest areas because of either man-made lighting (mostly incandescent) or man-made lighting reflected off nearby surfaces.

The rest of the region is illuminated naturally by moonlight, starlight, or back-scattered light from the atmosphere.

Also visible is a green band following the curve of the horizon. This is airglow.

Below is another, slightly wider view.

Download full-size, high-resolution versions of the images:

Image 1

Image 2

The Mediterranean region at night

A wider view photographed at roughly the same time.

Adapted from information issued by NASA.

Get SpaceInfo.com.au daily updates by RSS or email! Click the RSS Feed link at the top right-hand corner of this page, and then save the RSS Feed page to your bookmarks. Or, enter your email address (privacy assured) and we’ll send you daily updates. Or follow us on Twitter, @spaceinfo_oz

Like this story? Please share or recommend it…

Seeing Earth’s night-lights

Orbital night-time view of southern California, Mexico's Baja California and the Gulf of Cortez

City lights illuminate this night time view of southern California, Mexico's Baja California and the Gulf of Cortez, as photographed by one the Expedition 28 crew members onboard the International Space Station flying at altitude of approximately 220 miles. The Salton Sea can be seen in the lower right quadrant of the frame. A solar panel and part of one of the space station's modules are silhouetted at right. A 15-mm focal length was used to capture the time-lapse image. The thin line of Earth's atmosphere is visible above the horizon.

IN ONE SENSE IT LOOKS PRETTY, but in another it reveals enormous and callous waste. Poorly designed and implemented lighting results in a lot of light being sent straight up into space, instead of down onto the ground where most of it is supposed to go.

This waste light consumes enormous amounts of energy, which ordinary citizens are paying for.

Not only that, but this upward-directed light also bounces around in the air, making the sky glow in a phenomenon astronomers call “light pollution“.

Comparison of light-polluted and non-light polluted skies.

The combined image shows how light pollution affects the appearance of clouds at night. The photo at left, taken by Ray Stinson in Glacier National Park, shows that in pristine areas clouds appear black, because they block out starlight. The photo at right, taken by Christopher Kyba in Berlin, was published as a part of a light pollution research paper, and shows how clouds are lit from below by light pollution, dramatically brightening the night sky. Photo courtesy Ray Stinson and Christopher Kyba, used under the Creative Commons Attribution-Share Alike 3.0 Unported licence.

Light pollution is a major problem, not just for astronomers—who find that many of the faint astronomical objects they want to see are “drowned out” by sky glow—but also for the environment. Wasted energy means more power-generated pollution than there needs to be, and waste light also can affect animal and plant life.

A lot of good work has been done in recent decades to begin correcting this problem, but there is still a long way to go.

As ideal illustrations of the scale of the problem, shown below are some recent nighttime photos taken by astronauts aboard the International Space Station.

More information:

Light pollution

International Dark Sky Association

Orbital nighttime view of the Nile River and the Sinai Peninsula

The Nile River and the Sinai Peninsula can be easily delineated in this nighttime photo captured by one of the Expedition 28 crewmembers aboard the International Space Station, flying at an altitude of approximately 220 miles. A 42-mm focal length was used to record the image.

Orbital nighttime view of the Nile River Delta and part of the Mediterranean Sea

The Nile River Delta and part of the Mediterranean Sea can be seen in this night time photo captured by one of the Expedition 28 crew members aboard the International Space Station, flying at an altitude of approximately 220 miles. A 38-mm focal length was used to record the image.

Orbital nighttime view of Sicily

Sicily is featured in this nighttime image captured by one of the Expedition 28 crewmembers aboard the International Space Station, approximately 220 miles above Earth. The landmass at left edge is part of the "toe" of Italy's "boot." A 38-mm lens was used to record the image.

Orbital nighttime view of the "boot" of Italy

The "boot" of Italy is featured in this nighttime image photographed by one of the Expedition 28 crewmembers aboard the International Space Station. A tip of Sicily is at top centre of the frame, photographed from approximately 220 miles above Earth. A 35-mm lens was used to record the image.

Orbital nighttime view of northwestern Europe

This nighttime view of northwestern Europe is featured in this image photographed by an Expedition 28 crewmember on the International Space Station. Several of the oldest cities of northwestern Europe are highlighted in this photograph taken at 00:25:26 Greenwich Mean Time (GMT). While the landscape is dotted with numerous clusters of lights from individual urban areas, the metropolitan areas of London (United Kingdom), Paris (France), Brussels (Belgium) and Amsterdam (Netherlands) stand out due to their large light "footprints". The metropolitan area of Milan, Italy is also visible at lower left. This photograph was taken with a short camera lens, providing the large field of view recorded in the image. To give a sense of scale, the centres of the London and Paris metropolitan areas are approximately 340 kilometres distant from each other. The image is also oblique, or taken while looking outward at an angle from the station; this tends to foreshorten the image, making the distance between Paris and Milan (approximately 640 kilometres) appear less than that of Paris to London. In contrast to the land surface defined by the city lights, the English Channel at right presents a uniform dark appearance. Similarly, the Alps (bottom centre) to the north of Milan are also largely devoid of lights. While much of the atmosphere was clear at the time the image was taken, the lights of the Brussels metropolitan area are dimmed by thin cloud cover.

Story by Jonathan Nally, SpaceInfo.com.au. Orbital images and captions courtesy NASA.

Get SpaceInfo.com.au daily updates by RSS or email! Click the RSS Feed link at the top right-hand corner of this page, and then save the RSS Feed page to your bookmarks. Or, enter your email address (privacy assured) and we’ll send you daily updates. Or follow us on Twitter, @spaceinfo_oz

Like this story? Please share or recommend it…

Night light is bad for you

Artificial lighting on Earth at Night

Poor lighting standards mean that much of Earth's nighttime artificial lighting shines straight up and is lost into space. This not only affects astronomers' views of the universe, but research has shown that it interferes with natural processes that purge the air of pollution.

  • Light pollution is the unintended spread of artificial light
  • It ruins astronomers’ views of the universe
  • And now it has been shown to increase air pollution too

Excess light at night can contribute to air pollution, according to a study by scientists at the US National Oceanic and Atmospheric Administration (NOAA) and the Co-operative Institute for Research in Environmental Sciences (CIRES) at the University of Colorado.

Findings presented at the American Geophysical Union meeting in San Francisco indicate that upwardly directed light from outdoor lighting that contributes to sky glow over cities, also interferes with chemical reactions that naturally clean the air during nighttime hours.

Every night, chemicals from vehicle exhaust and other human created sources are broken down and prevented from becoming smog, ozone, or other irritants by a form of nitrogen oxide called the nitrate radical.

Sunlight destroys the naturally occurring nitrate radical, so this process occurs only in hours of darkness.

Measurements taken over Los Angeles by aircraft show that light pollution from cities is suppressing the radical.

Though the lights are 10,000 times dimmer than the Sun, the study’s first results indicate that city lights can slow down the nighttime cleansing by up to 7% and they can increase the starting chemicals for ozone pollution the next day by up to 5%.

As many cities are close to their limits of allowable ozone levels, this news is expected to generate immediate interest in light pollution reduction as a way to improve air quality among city, state and federal bodies.

Las Vegas at night

Light pollution from Las Vegas at night. All that light shining straight up is wasted energy.

“[This effect] is more important up in the air than it is directly on the ground so if you manage to keep the light pointing downward and not reflected back up into sky, into the higher parts of the air, then you would certainly have a much smaller effect of this,” NOAA investigator Harald Stark told BBC News.

International Dark-Sky Association (IDA) Executive Director Bob Parks is hopeful that results of this study will encourage cities to adopt environmentally responsible dark sky lighting practices that include using fully shielded fixtures, minimum lighting levels, and lighting only when necessary.

“The impending transition to LED outdoor lighting will also allow cities to utilise adaptive lighting controls to dim or turn off lights when not needed,” says Parks.

“Not only will this vastly reduce energy consumption, based on this new research, it could also improve air quality,” he adds. “This reinforces IDA’s long term goal to reduce total lumens in the environment.”

Starting in 2008, IDA has held yearly educational briefings for both houses of US Congress to raise federal awareness of light pollution. After the 2008 event, eleven members of Congress signed a letter to Environmental Protection Agency (EPA) Administrator Johnson requesting support for research and education on the environmental, health, and safety effects artificial light at night.

On 9 October 2008 EPA was petitioned to review light pollution to monitor and reduce atmospheric discoloration of the night sky under the Clean Air Act. The EPA has made no formal response to the petition.

Adapted from information issued by IDA. Image credits – Earth at night: C. Mayhew & R. Simmon (NASA/GSFC), NOAA/ NGDC, DMSP Digital Archive; Las Vegas: ISS Crew Earth Observations experiment and Image Science & Analysis Laboratory, NASA Johnson Space Centre.

Get SpaceInfo.com.au daily updates by RSS or email! Click the RSS Feed link at the top right-hand corner of this page, and then save the RSS Feed page to your bookmarks. Or, enter your email address (privacy assured) and we’ll send you daily updates. Or follow us on Twitter, @spaceinfo_oz