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Egyptian pyramids found by infra-red satellite images

bbc.co.uk

11–20 of 52 posts

Re: Egyptian pyramids found by infra-red satellite images

#13

I wonder how they get permission to scour Egypt with a satellite camera. And even if permission was given, will Egyptian authorities allow control of the satellite and the images captured to remain with a university outside the country? Anyone have a better idea how this process works?

Today you can order high-resolution satellite images online. Some countries will limit the resolution available by non-technical means.

Well, if you order images from a US company, you get limited resolution over US military bases and Israel. But say a Russian company will give you full resolution everywhere.

Re: Egyptian pyramids found by infra-red satellite images

#14
My searching on this topic turned up this interesting book - http://www.amazon.com/Remote-Sensing-Archaeology-Interdiscip...

Seems like these techniques are going to radically change how we find new archaeological sites. Tech. project idea: Build some tools to help archaeologists learn and share from each other with this data. Build a world wide database of IR imagery just a few meters below the surface?

Re: Egyptian pyramids found by infra-red satellite images

#15
post #9

How does this work exactly? The wikipedia page on Infrared did not turn up any such use... or I missed it. How can you see a mud brick under sand because it is " much denser than the soil that surrounds it "?

Denser == absorbs more of the light/different regions of the spectrum. This is detectable in the light that is reflected back. It's not dissimilar to how an ultrasound scanner is used to look at a baby in the womb. In fact, ultrasound is used in archaeology as well to do this sort of stuff, obviously on a smaller scale. This is the wikipedia page you want: http://en.wikipedia.org/wiki/Infrared_spectroscopy Although t…

I am a physicist, and I'm afraid that the page on infra-red spectroscopy isn't really relevant due to (as you say) the very different length scales.

What I think is really going on is thermodynamics. Suppose I bury a big stone pyramid under the sand. Stone is (I assume) a much better conductor of heat than sand. When the sun comes up after a cold night, it heats the sand, but the sand on top of the pyramid has its heat conducted away more efficiently than the sand far from the pyramid, so it'll show up as slightly cooler when imaged with the infra-red satellite.

Re: Egyptian pyramids found by infra-red satellite images

#16
post #9

How does this work exactly? The wikipedia page on Infrared did not turn up any such use... or I missed it. How can you see a mud brick under sand because it is " much denser than the soil that surrounds it "?

Denser == absorbs more of the light/different regions of the spectrum. This is detectable in the light that is reflected back. It's not dissimilar to how an ultrasound scanner is used to look at a baby in the womb. In fact, ultrasound is used in archaeology as well to do this sort of stuff, obviously on a smaller scale. This is the wikipedia page you want: http://en.wikipedia.org/wiki/Infrared_spectroscopy Although t…

While I'm not archaeologist that sounds about right in very theoretical level. To explain this more practically it comes down to heating properties of matter.

As specific heat capacity is inverse proportional to density, sand and pyramids react to temperature changes differently. In desert temperature changes between day and night are huge causing sand and pyramids to have different temperatures. As thermal radiation is infrared in temperatures near human body temperatures (didn't check the exact temperatures but pyramids should fit in infrared spectrum), sand and pyramids will show up in different 'colors' in infrared mapping of area.

This is probably the basic idea behind these findings, of course what they are doing certainly goes beyond this level of explanation with use of infrared spectroscopy.

Re: Egyptian pyramids found by infra-red satellite images

#17
post #15

Earlier quoted context omitted.

Denser == absorbs more of the light/different regions of the spectrum. This is detectable in the light that is reflected back. It's not dissimilar to how an ultrasound scanner is used to look at a baby in the womb. In fact, ultrasound is used in archaeology as well to do this sort of stuff, obviously on a smaller scale. This is the wikipedia page you want: http://en.wikipedia.org/wiki/Infrared_spectroscopy Although t…

I am a physicist, and I'm afraid that the page on infra-red spectroscopy isn't really relevant due to (as you say) the very different length scales. What I think is really going on is thermodynamics. Suppose I bury a big stone pyramid under the sand. Stone is (I assume) a much better conductor of heat than sand. When the sun comes up after a cold night, it heats the sand, but the sand on top of the pyramid has its he…

Do they look at day-night differential images? That would a priori seem to confirm your hypothesis and also provide a better imaging result.

No I didn't read the article.

Re: Egyptian pyramids found by infra-red satellite images

#18
A colleague of mine worked with Sarah Parcak (the researcher featured) and says: "They use standard satellite images taken by NASA and then apply various photoshop filters to those images to find subtle differences in the terrain. Egypt works great because the starting palette is so clean. They've tried the same technology in South America and haven't had as much success."

Not sure if this is the exact technique they are using in this article, but it's what we featured in an exhibit on Egypt he worked on.

Re: Egyptian pyramids found by infra-red satellite images

#19
Is it me or does news like this throw anyone else into a frenzy of daydreaming for a short while: using my computer expertise to enhance infrared images to reveal hitherto unknown pyramids (combining images from multiple spectral bands, SIFT object detection), battling with corrupt local authorities and looters, digging for the pyramid (and unfortunately losing a few of the team when the tunnel gives in), deciphering the Old Egyptian hieroglyphs on the door (with some help from my hardy MBP and my custom linguistic text analysis tools, written in a mixture of C++, Perl, and Scheme), going in and getting stumped by an empty chamber, but wait, there's a small tunnel leading away, investigating it with a remote controlled Arduiono-based robot I control with my Android tablet (e.g. http://www.gizapyramid.com/hidden.htm) and awakening a long-sleeping evil force within. Then, the final battle to save Earth.

OK, back to a rainy day in Chicago and trying to understand Puppet.

Re: Egyptian pyramids found by infra-red satellite images

#20
post #15

Earlier quoted context omitted.

I am a physicist, and I'm afraid that the page on infra-red spectroscopy isn't really relevant due to (as you say) the very different length scales. What I think is really going on is thermodynamics. Suppose I bury a big stone pyramid under the sand. Stone is (I assume) a much better conductor of heat than sand. When the sun comes up after a cold night, it heats the sand, but the sand on top of the pyramid has its he…

Do they look at day-night differential images? That would a priori seem to confirm your hypothesis and also provide a better imaging result. No I didn't read the article.

That would a priori seem to confirm your hypothesis

I'm not sure that a priori means what you think it means.

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