APOD: Earth at Night (2017 Jul 09)

Comments and questions about the APOD on the main view screen.
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APOD: Earth at Night (2017 Jul 09)

Postby APOD Robot » Sun Jul 09, 2017 4:11 am

Image Earth at Night

Explanation: Can you find your favorite country or city? Surprisingly, on this world-wide nightscape, city lights make this task quite possible. Human-made lights highlight particularly developed or populated areas of the Earth's surface, including the seaboards of Europe, the eastern United States, and Japan. Many large cities are located near rivers or oceans so that they can exchange goods cheaply by boat. Particularly dark areas include the central parts of South America, Africa, Asia, and Australia. The featured composite was created from images that were collected during cloud-free periods in April and October 2012 by the Suomi-NPP satellite, from a polar orbit about 824 kilometers above the surface, using its Visible Infrared Imaging Radiometer Suite (VIIRS).

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davidtrap
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Re: APOD: Earth at Night (2017 Jul 09)

Postby davidtrap » Sun Jul 09, 2017 4:19 am

I'm concerned about the accuracy of this map - there's very little settlement in the mid western regions of Australia to generate that much light??? And there's almost no light over Indonesia or PNG???

DT

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Re: APOD: Earth at Night (2017 Jul 09)

Postby alter-ego » Sun Jul 09, 2017 4:40 am

davidtrap wrote:I'm concerned about the accuracy of this map - there's very little settlement in the mid western regions of Australia to generate that much light??? And there's almost no light over Indonesia or PNG???

DT

City lights aren't the only light sources in the image:
Night Lights 2012 wrote:The nighttime view of Earth was made possible by the “day-night band” of the Visible Infrared Imaging Radiometer Suite. VIIRS detects light in a range of wavelengths from green to near-infrared and uses filtering techniques to observe dim signals such as gas flares, auroras, wildfires, city lights, and reflected moonlight.

Away from the cities, much of the nightlight observed by Suomi NPP is wildfire. In other places, fishing boats, gas flares, lightning, oil drilling, or mining operations can show up as points of light. The number of rural lights is also a function of composite imaging. Fires and other lighting could have been detected on any one day and integrated into the composite picture even though they were temporary. That seems to be the case in central and western Australia, where many lights appear in this map. Different areas burned with wildfire at different times that the satellite passed over, giving the impression (in the composite view) that the entire area was lit up at once.
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Re: APOD: Earth at Night (2017 Jul 09)

Postby Confused » Sun Jul 09, 2017 6:07 am

davidtrap wrote:I'm concerned about the accuracy of this map - there's very little settlement in the mid western regions of Australia to generate that much light??? And there's almost no light over Indonesia or PNG???

DT

In addition to that, look at northern Alaska. Is there much civilization there? Probably not as much as this image shows. I wonder if the area in the northern Alaska area that appears lit up is Prudhoe Bay and wherever it is, is it temporary or relatively permanent.

So this image shows where civilization might be or might not be. Can we at least trust that everywhere that there is a significant amount of civilization there will be something indicating there is?

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Re: APOD: Earth at Night (2017 Jul 09)

Postby ta152h0 » Sun Jul 09, 2017 8:27 am

Lot of light betwee about 35 North and 50 North. Can life be detected from let's say 50 light years away ? or even 4.8 LY away ?
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Re: APOD: Earth at Night (2017 Jul 09)

Postby Wombat » Sun Jul 09, 2017 9:56 am

This picture has been posted at least three times and each time been discreditied - I'm amazed that it is still in the archives! Surely there are more recent/better ones to post!
The answer that the light comes from more than just cities is of course correct; but bush fires in the Great Sandy Desert(?) have you ever been there? Its a desert! Nothing to burrn there... How about the massive light show east of Siberia!? ... or the other massive amount in northern Canada?
Come on APOD get rid of this one and get back to your normal high quality images.

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Re: APOD: Earth at Night (2017 Jul 09)

Postby Greg Parker » Sun Jul 09, 2017 1:16 pm

Wombat is entirely correct. There is nothing in that NW region of Australia to produce that amount of light, infrared or otherwise.

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Re: APOD: Earth at Night (2017 Jul 09)

Postby Chris Peterson » Sun Jul 09, 2017 1:21 pm

Wombat wrote:This picture has been posted at least three times and each time been discreditied - I'm amazed that it is still in the archives! Surely there are more recent/better ones to post!
The answer that the light comes from more than just cities is of course correct; but bush fires in the Great Sandy Desert(?) have you ever been there? Its a desert! Nothing to burrn there... How about the massive light show east of Siberia!? ... or the other massive amount in northern Canada?
Come on APOD get rid of this one and get back to your normal high quality images.

It has not been "discredited", it merely shows transient phenomena in some places.

That said, people continue to work on this, and have produced much higher quality results since this map was originally published. Rather than a Sunday repeat, what's needed here is an entirely new APOD.

earth_vir_2016.jpg

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Re: APOD: Earth at Night (2017 Jul 09)

Postby neufer » Sun Jul 09, 2017 2:52 pm

Wombat wrote:
The answer that the light comes from more than just cities is of course correct;
but bush fires in the Great Sandy Desert(?) have you ever been there?
Its a desert! Nothing to burrn there...
https://en.wikipedia.org/wiki/Triodia_(grass) wrote:
<<Triodia is a large genus of hummock-forming grass endemic to Australia; they are commonly known as spinifex, although they are not a part of the coastal genus Spinifex. The vegetation of the Great Sandy Desert is dominated by spinifex. Triodia is a perennial Australian grass which grows in arid regions and has awl-shaped, pointed leaves. The leaf tips (high in silica) can break off in the skin, leading to infections. Leaves are 30–40 centimetres long. Spinifex has traditionally had many uses for Australian Aborigines. The seeds were collected and ground to make seedcakes. Spinifex resin was an important adhesive used in spear-making. Smoke signals were made to communicate with families and groups a long distance away, as burning spinifex produces a strong black smoke. The species Triodia wiseana is used for building shelters; bunched together it is used for trapping fish against creek beds. It is called baru in the languages of the Yindjibarndi and Ngarluma people, the English term is hard spinifex.>>
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Re: APOD: Earth at Night (2017 Jul 09)

Postby De58te » Sun Jul 09, 2017 4:25 pm

I'm from Canada and I'm puzzled by the massive light comment in northern Canada. Perhaps you mean Goose Bay, Labrador in the east, or Edmonton, Calgary in the west. As to the massive light in northern Alaska. I watched a show a few years ago called Ice Road Truckers, where they drove up the Dalton highway to the Arctic Coast, and they have huge oil drilling sites that are decked out in lights to rival Las Vegas, and they drill 24 hours a day. That's probably them on the map.

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Re: APOD: Earth at Night (2017 Jul 09)

Postby Keep the Mana Strong » Sun Jul 09, 2017 5:55 pm

That's the poorest representation of what the Earth Lights look like today. Put on a recent photo and show the people of Earth what overpopulation really looks like. We are killing the Earth and people think it's pretty. Wake up!!!

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Re: APOD: Earth at Night (2017 Jul 09)

Postby Boomer12k » Sun Jul 09, 2017 11:07 pm

I thought there would be more lights in Greenland... looks more like "Whiteland"...

Awesome.

"Come to me, Children of the Night".....

8" LS scope going back to Meade for fixin'... computer seems to have totally failed. No display at all, and won't boot off the chip. Me do emotional technique on that.

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Re: APOD: Earth at Night (2017 Jul 09)

Postby Greg Parker » Mon Jul 10, 2017 8:10 am

O.K. so it looks like the light coming down from the NW of Australia could possibly be lightning. Take a look at the lake Maracaibo region in Venezuela.If this is time-integrated lightning strikes - then the map is certainly not a good representation of the Earth at Night due to human influence.

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Re: APOD: Earth at Night (2017 Jul 09)

Postby neufer » Mon Jul 10, 2017 10:27 am

Boomer12k wrote:
I thought there would be more lights in Greenland... looks more like "Whiteland"...

Surely you understand by now that science is done on grayscale images (or, more specifically, the numbers represented by those images), and that the color ones (like those showing Greenland as green) are almost exclusively used for outreach.
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Re: APOD: Earth at Night (2017 Jul 09)

Postby geckzilla » Mon Jul 10, 2017 1:47 pm

neufer wrote:
Boomer12k wrote:
I thought there would be more lights in Greenland... looks more like "Whiteland"...

Surely you understand by now that science is done on grayscale images (or, more specifically, the numbers represented by those images), and that the color ones (like those showing Greenland as green) are almost exclusively used for outreach.

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Re: APOD: Earth at Night (2017 Jul 09)

Postby neufer » Mon Jul 10, 2017 2:01 pm

geckzilla wrote:
neufer wrote:
Boomer12k wrote:
I thought there would be more lights in Greenland... looks more like "Whiteland"...

Surely you understand by now that science is done on grayscale images (or, more specifically, the numbers represented by those images), and that the color ones (like those showing Greenland as green) are almost exclusively used for outreach.

Stop, thief!

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And no one has ever accused me of being mature :!:
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Re: APOD: Earth at Night (2017 Jul 09)

Postby Chris Peterson » Mon Jul 10, 2017 2:16 pm

neufer wrote:And no one has ever accused me of being mature :!:

I guess that depends on what definition of "mature" you're working with.
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Re: APOD: Earth at Night (2017 Jul 09)

Postby neufer » Mon Jul 10, 2017 3:19 pm

Chris Peterson wrote:
neufer wrote:
And no one has ever accused me of being mature :!:

I guess that depends on what definition of "mature" you're working with.
http://www.etymonline.com/index.php?all ... rch=mature wrote:
mature (adj.) mid-15c., "ripe," also "careful, well-considered," from Latin maturus "ripe, timely, early."

maturation (n.) early 15c., "the coming to a head of a boil, etc.; a state of producing pus,"
from Middle French maturation and directly from Latin maturationem.
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Re: APOD: Earth at Night (2017 Jul 09)

Postby mikechillit » Mon Jul 10, 2017 5:34 pm

Glad to see so much discussion on this very misleading graphic. I noticed it for the Australian Outback first, but then noticed it all over the place. The image is simply wrong in so many ways it isn't reliable and shouldn't be used. There is a 2000 version variously listed as a National Geographic image, but it's also NASA. It is far more accurate in the areas I'm able to check. "Transient Light" is a euphemism for "we screwed up" and shouldn't be tolerated by NASA. Staying with Australia to illustrate, if one uses the combined light from Brisbane, Sydney, Melbourne, Adelaide, Perth as a comparison to that vastly greater light from NT and eastern WA, the logical population estimate would be in the 100 million range just in the Outback. That's absurd, and Kangaroos don't pack flashlights. Please retire this ridiculous example of NASA fail.

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Re: APOD: Earth at Night (2017 Jul 09)

Postby neufer » Mon Jul 10, 2017 5:58 pm

mikechillit wrote:
I noticed it for the Australian Outback first, but then noticed it all over the place. The image is simply wrong in so many ways it isn't reliable and shouldn't be used. There is a 2000 version variously listed as a National Geographic image, but it's also NASA. It is far more accurate in the areas I'm able to check. "Transient Light" is a euphemism for "we screwed up" and shouldn't be tolerated by NASA. Staying with Australia to illustrate, if one uses the combined light from Brisbane, Sydney, Melbourne, Adelaide, Perth as a comparison to that vastly greater light from NT and eastern WA, the logical population estimate would be in the 100 million range just in the Outback. That's absurd, and Kangaroos don't pack flashlights.
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Re: APOD: Earth at Night (2017 Jul 09)

Postby geezergazer » Fri Jul 14, 2017 12:20 am

Has anyone calculated the amount of light, or the dollar cost of the light energy being sent into outer space? It is a magnificent show, but just whom are we trying to impress? It is a waste, and the skyglow occludes the heavens from city sight.
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