Found this image on a NASA site.
http://science.nasa.gov/science-news/science-at-nasa/2012/05dec_earthatnight/
It’s a recently updated view of the US at night. Two questions arise for me - 1) are all the little light dots in the Gulf of Mexico south of New Orleans oil rigs? If so - they’re mighty bright. 2) across the midwest, there appear to be lines of lights - almost a grid. They mostly lie E-W, but many appear to be N-S. A very rough estimate would have the points of light from 20-50 miles apart. Are these Interstate highway oases? That seems very unlikely. I’d think they were not that bright and not that evenly spaced. Dopers? xo, C.
Yeah, the lights in the Gulf are probably gas flares off oil rigs. But for a more dramatic illustration of that, do you remember there being a major metropolitan area in western North Dakota?
I think your lights in the Midwest are just very evenly-spaced towns.
As I look at a road atlas, I’m tempted to say they’re exchanges on the interstates.
I’ve always wondered if these photos are doctored or enhanced in any way.
There aren’t nearly enough interstates to account for all the lights; most of the towns are along US highways or state highways. But yes, they’re towns that are roughly evenly spaced along these major highways.
As to why they’re roughly evenly spaced, I expect it would have something to do with the settlement patterns of states like Iowa, and specifically how it was divided up into counties and where the county seats were chosen to be. But that’s just speculation on my part.
Yes, in many ways. First of all, these are composite photos (smaller ones stitched together).
Then, the satellites usually “see” in infrared which is invisible to humans. So the colors are adjusted to look like what a human might expect to see(dark ground and white lights)
I noticed that too. What the heck could it be?
It’s the Williston Basin, where there’s currently a major oil drilling boom going on. Because there’s no gas pipeline infrastructure (and natural gas prices are low anyways) most of the gas found in association with the oil is simply being flared off.
Although if Dog80 is right that this is really an IR image, that might be over-representing the actual amount of light being put off by the flares.
Nasa’s site explains the different frequencies and types of data that go into the construction of such an image.
In many areas, the evenly spaced towns are a relica of the steam locomotive age. Steam locomotives required regular servicing to take on fuel and water, so these stops were evenly spaced along the railroad. These were accompanied by small whistle-stop stations and amenities for the train crews, and local communities gradually grew around these railroad stops. Later roads and then highways were built to connect towns that had formed along the railway - some larger, some smaller.
Oh, that’s just the Lake Sakakawea metro area!
Comparing the image with google maps & google earth, it looks to me like the almost regularly spaced ones are small towns on rural highways, many at rural highway intersections.
There’s an arc of lights in the countryside south of San Antonio that is another gas/oil boom area (Eagle Ford Shale). If that same satellite had taken the same pictures 5 years ago the region would have been mostly dark.
Railroads originally marked the spots where those evenly spaced towns grew up in the Great Plains, highways came later.
ETA: Oops, didn’t see your answer Skammer.
That’s amazing. I never realized that the towns were so evenly spaced. The pattern doesn’t become evident when you look at a map. And it must be that the country is cris-crossed by railroads, although that’s also hard to figure. Has anyone ever come across a map of the US showing JUST the railroad lines? Do those grids show up? I’ve never seen such a thing.
The evenly spaced lights throughout the midwest, (and in other places), are cities, not interchanges. The Interstate Highway system connected the same cities that existed before it was built, and the towns did not leave. There is a very clear line from just south of Pittsburgh, through Columbus and Indianapolis, then angling south to St. Louis, however it is not following I-70, but US-40 that I-70 “replaced.” If you look closely, you can even see that the “line” passes north of Dayton, as marked by Springfield, OH and Richmond, IN. In a ring around the Detroit Metro glare are the fairly bright Port Huron, Flint, Lansing, (with Ann Arbor closer in to Detroit), Adrian (fainter than the others), and Toledo, OH. Following I-94, (or US-12) west from Detroit are Ann Arbor, Jackson, Kalamazoo, and Battle Creek.
another factor in spacing of Midwest towns was the crops they grew in the area. Some crops required more train stations , others less.
There’s a “Nasa - Earth City Lights” overlay for Google Earth. Most of the lights are the same as in the image linked in the OP, but that particular patch of brightness is absent. Either it’s a timing issue, or it is a matter of different images/filters being used.
So who here can calculate the wattage that represents?
One of the basics of urban geography is the idea that on a Lösch plain (a flat area of fertile soil), towns will spring up at relatively predicatable intervals. Iowa comes pretty close to proving that theory.
The Williston and South Texas smears are striking, but I think it’s mostly because the drilling rigs are so dispersed. The huge amount of infrared produced by flaring is an interesting possibility, though.
Railroad maps are not particularly hard to find in old atlases or at the Library of Congress, but they tend to be dendritic (treelike) patterns rather than grids. The “granger roads” through the western prairies built many branch lines to collect the grain from the prairies.
KarlGauss asked about the view for Australia in this thread http://boards.straightdope.com/sdmb/showthread.php?t=674588 … some very odd lighting on the west side of Australia that isn’t explained.
Are there errors in the images?
Let’s play “Guess where the major roads are”!