File:Human presence, light pollution.jpg

From Wikimedia Commons, the free media repository
Jump to navigation Jump to search
Original file(2,500 × 1,934 pixels, file size: 1.81 MB, MIME type: image/jpeg)

Levels of light pollution tend to correspond to where people are located.

This illustration shows two maps of the continents (excluding Antarctica) indicating different types of human activity.

The upper map combines night time views for each part of the earth. The illumination indicates the presence of human populations affluent enough to generate light at night. "Earth at night" views can be misleading, because pollution caused by industrialisation and urbanisation can cause relative dimming, whereas - for example - high altitude mountain fires shine disproportionately brightly in the clear, thin air.

This Earth Night Lights image is from <a href="" rel="nofollow">Tor Øra's website</a> which includes resources for CGI-ists. He also credits <a href="" rel="nofollow">NGDS</a> / <a href="" rel="nofollow">NOAA</a> / <a href="" rel="nofollow">DMSP</a> who presumably measured, collected and processed the original data.

The lower map shows the self declared locations of users of <a href="" rel="nofollow">Heavens Above</a>, a website that provides astronomical information customised to geographical locations. (For example, localised information relating to viewing satellite passes.) The information is effectively an aggregate of population density, internet access availability and usage, and the relative levels of interest in astronomy among internet users.

This Earth Night Lights image dates from 2003 (or before); the Heavens Above image uses 30 days of data dating from July / August 2010. North America, Brazil, Europe, South Africa, Japan, Australia and New Zealand romp ahead in both night light production and astronomy website use. The most notable disparity between the two images is in India and Eastern China - both regions generate substantial amounts of light, but with lower usage of Heavens Above - although, to be fair, the website is English Language. Central Africa appears depressingly impoverished on both maps.

Interestingly, many of the Heavens Above locations appear to be in the oceans. These are either user entry errors, islands, or bored cargo ship navigators enjoying the clean, clear, maritime night sky. There is also a "suspicious" seam down the Greenwich Meridian (Longitude 0°).

<a href="" rel="nofollow">Light pollution</a> annoys astronomers. They will no doubt be disheartened to learn that human beings are addicted to light, spending 0.7% of their income on light, regardless of income or technology. The development of cheaper, more efficient, LED lighting <a href="" rel="nofollow">is predicted to result in more light... </a> [or read the free academic paper <a href="" rel="nofollow">"Solid-state lighting: an energy-economics perspective"</a> directly]

Part of a <a href="">set</a> / <a href="">Slideshow</a> featuring images of stars, the night sky and the occasional meteor taken during the peak of the Perseid Meteor Shower in August 2010.

Source Flickr: Human Presence / Light Pollution
Author Dominic Alves
(Reusing this file)
Checked copyright icon.svg This image, which was originally posted to Flickr, was uploaded to Commons using Flickr upload bot on by Basilicofresco. On that date, it was confirmed to be licensed under the terms of the license indicated.
w:en:Creative Commons
This file is licensed under the Creative Commons Attribution 2.0 Generic license.
You are free:
  • to share – to copy, distribute and transmit the work
  • to remix – to adapt the work
Under the following conditions:
  • attribution – You must attribute the work in the manner specified by the author or licensor (but not in any way that suggests that they endorse you or your use of the work).

File history

Click on a date/time to view the file as it appeared at that time.

current09:57, 23 October 2011Thumbnail for version as of 09:57, 23 October 20112,500 × 1,934 (1.81 MB)Flickr upload bot (talk | contribs)Uploaded from using Flickr upload bot
  • You cannot overwrite this file.

There are no pages that link to this file.