APOD: Earth at Night (2012 Dec 07)

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Expand view Topic review: APOD: Earth at Night (2012 Dec 07)

Re: APOD: Earth at Night (2012 Dec 07)

by CCheers » Wed Jan 16, 2013 10:41 pm

I have finally caught up with your full explanation of the lights in uninhabited regions of Australia. I know you want to close the discussion, but I happened to browse through the "nighttime images of our fair planet". I find there the same image under a display that you call "City Lights of Asia and Australia". You say that auras, fires and other stray lights have been removed to emphasise city lights. Yet the fires remain prominent. Is there something wrong with your imaging and filtering techniques, or just your knowledge of geography? :roll:

Re: APOD: Earth at Night (2012 Dec 07)

by owlice » Sat Dec 22, 2012 7:11 pm

Thanks for that, bystander!

Re: APOD: Earth at Night (2012 Dec 07)

by bystander » Sat Dec 22, 2012 6:29 pm

Re: APOD: Earth at Night (2012 Dec 07)

by owlice » Sat Dec 22, 2012 3:11 pm

Shadrack, you are welcome to research it, then. I'm okay with NASA's answer (which is bolstered by information from other sources); if you're not, I doubt anything I say is going to make a difference.

Re: APOD: Earth at Night (2012 Dec 07)

by Shadrack » Sat Dec 22, 2012 2:02 pm

Hi owlice,
I have read all of the discussion, feedback, explanations etc BUT still none of it is plausible. No explanation offered makes any sense. The Bush Fire scenario is unbelievable, as the Outback is empty....... much like Death Valley in California BUT it is hundreds of times bigger and there is no fuel to burn, just rocks, sand and more rocks and more sand and there is no one out there to produce a light of this magnitude. There are a few mining ventures but the size of the light distribution shown in "Earth at Night" is about a thousand kilometers wide, whereas a mining venture may extend for only a few kilometers. Confirmed, Plausible or Busted?
Yours in confusion,
Shadrack.

Re: APOD: Earth at Night (2012 Dec 07)

by owlice » Sat Dec 22, 2012 7:28 am

Shadrack, please read this whole discussion; the lights in Western Australia are covered in it. Thanks.

Re: APOD: Earth at Night (2012 Dec 07)

by Shadrack » Sat Dec 22, 2012 5:19 am

Hi All,
I am still at a loss as to a plausible explanation of the bright lights in Western Australia. There is literally no one out there where the lights are shown, not a living soul.
Major population centers with 1 to 4 million people resident can just be visualized, BUT to believe that the light sources shown "in the back of beyond" are actually out there is not believable.
Have a look on Google Earth in the same areas of Western Australia............. no one is out there!
How do you explain the lights?
Thanks,
Shadrack

Re: APOD: Earth at Night (2012 Dec 07)

by geckzilla » Wed Dec 12, 2012 1:49 pm

cwrosner@aol.com wrote:The earth at night, October 5, 2008 seems quite abit brighter than this one taken on December 7, 2012
Different satellites produce different results, I guess.

Re: APOD: Earth at Night (2012 Dec 07)

by cwrosner@aol.com » Tue Dec 11, 2012 9:39 pm

The earth at night, October 5, 2008 seems quite abit brighter than this one taken on December 7, 2012

Re: APOD: Earth at Night (2012 Dec 07)

by Perk Cartel » Tue Dec 11, 2012 1:54 pm

Thanks to all for the education regarding this image of the world at night tending to exaggerate the depiction of the intensity of constant global illumination. The almost comical interpretation by myself and others of the West Australian lights indicating invisible infrastruture and therefore querying the reliability of the data, when instead were depicting transient wild fires, fleeting in general time scales, suggests the same method applies to the rest of the image mapping, recording all transient nightime photopic events as apearing constant. A fascinating lesson in critical analysis well learned, many thanks again to all. The world just isn't any where near as bright on any one at night as the image suggests, and is as correctly described, an image compositally accumulated over time.

Re: APOD: Earth at Night (2012 Dec 07)

by ccheers » Mon Dec 10, 2012 11:50 pm

I find it hard to believe wildfire as an explanation for the lights over Central Australia. When were the images taken? I know there were grassfires around Alice Springs this summer (our summer) but most of the area is desert with insufficient fuel to light up the night sky.

Re: APOD: Earth at Night (2012 Dec 07)

by Anthony Barreiro » Mon Dec 10, 2012 8:28 pm

ta152h0 wrote:if you work the words well, you may coinvince them to have a telescope night tailgate party with no lights the enrire block and have the kids ( all of us have the kids in us ) to come out and see jupiter while having a hot dog , just like campind. SWho knows, the great poohbah may even throw a large pebble overhead and give a show
That's a great idea, Wolf. Fortunately there's another park on a nearby hill that's above all the street lights and considerably darker. I often take a small telescope up there and accost unsuspecting passersby with views of the cosmos.

Re: APOD: Earth at Night (2012 Dec 07)

by ta152h0 » Mon Dec 10, 2012 7:12 pm

if you work the words well, you may coinvince them to have a telescope night tailgate party with no lights the enrire block and have the kids ( all of us have the kids in us ) to come out and see jupiter while having a hot dog , just like campind. SWho knows, the great poohbah may even throw a large pebble overhead and give a show

Re: APOD: Earth at Night (2012 Dec 07)

by Anthony Barreiro » Mon Dec 10, 2012 7:04 pm

I live in San Francisco, in the middle of one of the bright patches on the west coast of North America. Fortunately there are relatively dark skies within an hour's drive of my home, and very dark skies within a day's travel. Even in the middle of the city, my back yard is dark enough to see a lot. This morning before dawn I was looking at M13 and M51 through binoculars. The Moon, planets, double stars, and star clusters show up well even through light pollution.

I've talked to my immediate neighbors about my skywatching hobby and they've been helpful in turning off outdoor lights when they're not using them. I convinced the local park supervisor to turn off the playground lights at 10 pm.

Everybody who's interested in skywatching and astronomy should join the International Dark Sky Association.

Re: APOD: Earth at Night (2012 Dec 07)

by scruffy1 » Mon Dec 10, 2012 12:10 am

i was amazed enough to finally subscribe to the site, having been a keen watcher of apod since last century :)

and as an australian i too am bemused at such illumination that is in the arse end of nowhere, but accept the explanations i have read

sadly it means that the value of such mapping to recognise how "city lights identify major population centers, tracking the effects of human activity and influence across the globe" when accuracy is significantly diminished by spurious light sources

and it demonstrates as others have said why we don't get to see the real marvel of space from where we mostly congregate (cities), as light pollution directly ruins the seeing

Re: APOD: Earth at Night (2012 Dec 07)

by one_iota » Sun Dec 09, 2012 11:49 pm

WRT the West Australian fire explanation: this is plausible.

From the Australian Government's Sentinal web site (http://sentinel.ga.gov.au/acres/sentinel/index.shtml) is this screen shot of the continent of Australia showing "hotspots" during the month of October 2012. Note the density over the subject area.

Image

Re: APOD: Earth at Night (2012 Dec 07)

by geoffreybrent » Sun Dec 09, 2012 6:51 am

owlice wrote:Reynardo, really? You think others are kidding?? Evidence for wildfires in Australia is so easily found online that I think you must be joking (or something) to suggest they are impossible. Googling "Australian wildfires" will demonstrate that yes, they do occur, sometimes resulting in great devastation.
You may not have intended it as such, but when you start lecturing Australians about how "Australian wildfires" work based on your five minutes of Googling, that comes across as quite unnecessarily patronising.

We are very aware that Australia has a lot of wildfires. (We call them "bushfires", BTW). The reason we're finding the "fires" explanation rather baffling is that we also know enough Australian geography to be aware that those lights on the map are mostly in areas with names like "Gibson Desert", "Great Sandy Desert", "Little Sandy Desert", and "Great Victoria Desert", which don't have a lot of vegetation to burn.

I'm not saying the explanation is impossible - some parts of those deserts have enough vegetation to allow grass fires - but something as spectacular and widespread as depicted in this photo seems a little hard to believe, unless there's some quirk of the image creation process that acts to exaggerate them.

Re: APOD: Earth at Night (2012 Dec 07)

by tekic545 » Sun Dec 09, 2012 2:59 am

Fires don't sit in the same place when they burn. They move. Kind of like a comet. Taking 22 images of a comet 24 hours apart then combining the image stack would give the improbable impression of 22 comets all in a row.

So perhaps the earth at night image recorded 22 times (or some smaller but significant multiple) as many fires as actually existed. That wouldn't be a problem with the other components of the image. Well-gas flares and cities don't move.

Bob Gillette

Re: APOD: Earth at Night (2012 Dec 07)

by ta152h0 » Sat Dec 08, 2012 11:45 pm

it is also the home of the deadliest snakes..

Re: APOD: Earth at Night (2012 Dec 07)

by rstevenson » Sat Dec 08, 2012 11:37 pm

owlice wrote:Rob, I agree with you: the image seems to be exaggerating a natural occurrence, and why it seems to be was explained -- to my satisfaction anyway -- on the page that says "the cumulative result in the composite view gives the appearance of a massive blaze." Did you follow the link to that page? Did everyone else who questioned that image on this thread?

I'm thinking that the answer to at least one of those questions is "no," hence the sigh. I'm weary.
You're weary because you do such a good job. :)

Yes, I followed all the links, and I learned a lot doing so. But I found others, one which told me the 22 passes by the satellite didn't occur during the usual fire season, another that told me this isn't even a particularly bad year for fires -- yet. Which is the only reason why I kept wondering about the extent and brightness of the fires as shown in this image. I'll give it a rest now, but only because I can't find anything else worth saying at this point.

Australia is on my short list of places to visit if I ever stop working long enough. Maybe I'll just go and see those fires in the desert for myself. I might come back converted!

Rob

Re: APOD: Earth at Night (2012 Dec 07)

by ta152h0 » Sat Dec 08, 2012 10:54 pm

Si !

Re: APOD: Earth at Night (2012 Dec 07)

by owlice » Sat Dec 08, 2012 10:42 pm

rstevenson wrote:
owlice wrote:~~~~~ sigh ~~~~~
...and other such disrespectful comments will not endear you to those scientists you want to sit next to. I said...
No, I'm not suggesting a conspiracy. But the image seems to be exaggerating a relatively minor natural occurance.
I don't think that rather mild stance warrants such a response.

Rob
Rob, I agree with you: the image seems to be exaggerating a natural occurrence, and why it seems to be was explained -- to my satisfaction anyway -- on the page that says "the cumulative result in the composite view gives the appearance of a massive blaze." Did you follow the link to that page? Did everyone else who questioned that image on this thread?

I'm thinking that the answer to at least one of those questions is "no," hence the sigh. I'm weary.

I don't know that the point of the imaging is to "show the ... human presence" on our planet; I think rather it is one of the results of, rather than the reason for, the imaging, but fully acknowledge I could be completely wrong about that.
neufer wrote:Especially considering what owlice is being paid to do this :!:
:lol2:

I often have questions about APODs, and when I do, 99% of the time, following the links provided answers those questions, and if they don't, following subsequent links takes care of most of the remaining 1%. But maybe I'm incurious, gullible, or easily satisfied if I think the source (NASA, NOAA [even retirees from NOAA], etc.) reliable.

Re: APOD: Earth at Night (2012 Dec 07)

by neufer » Sat Dec 08, 2012 9:34 pm

Click to play embedded YouTube video.
rstevenson wrote:
owlice wrote:~~~~~ sigh ~~~~~
...and other such disrespectful comments will not endear you to those scientists you want to sit next to. I said...
No, I'm not suggesting a conspiracy. But the image seems to be exaggerating a relatively minor natural occurance.
I don't think that rather mild stance warrants such a response.
Especially considering what owlice is being paid to do this :!:

Re: APOD: Earth at Night (2012 Dec 07)

by rstevenson » Sat Dec 08, 2012 8:09 pm

owlice wrote:~~~~~ sigh ~~~~~
...and other such disrespectful comments will not endear you to those scientists you want to sit next to. I said...
No, I'm not suggesting a conspiracy. But the image seems to be exaggerating a relatively minor natural occurance.
I don't think that rather mild stance warrants such a response.

Rob

Re: APOD: Earth at Night (2012 Dec 07)

by owlice » Sat Dec 08, 2012 5:31 pm

~~~~~ sigh ~~~~~
The extent of the night lights in this area ["this area" being western Australia] is also a function of composite imaging. These new images were assembled from data acquired over nine days in April 2012 and 13 days in October 2012. This means fires and other lighting (such as ships) could have been detected on any one day and integrated into the composite picture, despite being temporary phenomena.

Because different areas burned at different times when the satellite passed over, the cumulative result in the composite view gives the appearance of a massive blaze. These fires are temporary features, in contrast to cities which are always there.
Emphasis mine, and that from the link I've supplied twice earlier in this thread.

I'll sit quite happily next to the NOAA and NASA scientists ("scientists have confirmed, there were fires in the area when Suomi NPP made passes over the region. This has been confirmed by other data collected by the satellite."), thank you very much.

If others want to seek out alternative explanations, have at it, but at this point IMHO it's on you to prove what is shown is something different than the explanation already given. Have fun with that!

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