![]() Drivers then needed roads and lighting to keep them safe on those roads. Railroads became the dominant transportation method for people and cargo in the middle of the nineteenth century.Įventually, cars and trucks became the dominant form of transportation in the United States. In the early days of the republic, post roads and toll roads for horse-drawn carts and carriages were built to connect eastern cities like Boston, New York, Baltimore, and Philadelphia, though relatively few travelers made the long, unlit journeys. Comparing the two images, you quickly see how the cities and settlements align with the transportation corridors. The roadway map traces the path of the major interstate highways, railroads, and rivers of the United States. The VIIRS DNB on the Suomi NPP satellite acquired this nighttime view of the continental United States on October 1, 2013. The imprint of that transportation web becomes easy to see at night. The country also has 127,000 miles (204,000 kilometers) of railroad tracks and about 25,000 miles (40,000 kilometers) of navigable rivers and canals (not including the Great Lakes). About 47,000 miles (75,639 kilometers) of those roads are part of the Interstate Highway System, established by President Dwight Eisenhower in the 1950s. The United States has more miles of roads than any other nation in the world-4.1 million miles (6.6 million kilometers) to be precise, which is roughly 40 percent more than second-ranked India. ![]() While airglow can also be green or blue, red airglow like this comes from excited oxygen atoms at heights of about 90 to 190 miles (150 to 300 kilometers). The glowing line along Earth’s limb-or edge of the atmosphere-is airglow, a type of light that is produced by chemical reactions in the upper atmosphere. The blue-white patch on the far left is a flash of lightning, a common sight for astronauts. In addition to the human activity, the photograph also showcases a few natural splashes of light and color. The same study pointed out that two of the brighter points of light in the area are gas flares emanating from offshore oil infrastructure. According to one estimate based on satellite observations, there were over 500 fishing boats in the area on a single night in September 2014. Many of these vessels are likely fishing boats using bright lights to attract squid and other sea life. North of the city of Surabaya, the capital of East Java province, large numbers of boat lights dot the darkened Java Sea. The photo, taken on October 20, 2014, captured light from roads and cities, fishing boats, lightning, airglow, and even a few gas flares. To the discerning eye, these lights reveal intricate details of both natural phenomena and the unmistakable footprints of human civilization. However, as this photograph-taken over the Java Sea by a member of the Expedition 42 crew onboard the International Space Station-reveals, at night these “nighttime lights” become visible. You are contributing to debate and discussion, and helping to make this website a more open place.The visible lights produced by modern civilization are often obscured by the more intense light of the Sun during the day. Thank you for following these guidelines and contributing your thoughts. We will not publish comments that link to outside websites.If you're using an alias, make sure it's unique.We will not publish: Comments written that are poorly spelled or are written in caps or which use strange formatting to get noticed.We screen for comments that seek to spread information that is false or misleading.We will not publish comments that are profane, libelous, racist, or engage in personal attacks.Preference is given to commenters who use real names.Please be advised:Ĭomments are moderated and will not appear on site until they have been reviewed.Ĭomments are not open on some news articles Bell Media reserves the right to choose commenting availability. Bell Media reviews every comment submitted, and reserves the right to approve comments and edit for brevity and clarity.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |