Physics Using LIDAR to reveal the past

[Werewolf]

I've posted this before (Mysteries & Paranormal board), but it's worth having here too. The use of airborne LIDAR (Light Detection and Ranging) to scan where ancient cities once stood. This often uses infrared light (but can also use visible or UV) - the shorter wavelength provides higher resolution and can see through a jungle canopy. This produces a detailed topographic map that allows artificial features to be identified.

Example: Scientists find 60,000 Mayan structures preserved under dense Guatemalan jungle

Researchers using a high-tech aerial mapping technique have found tens of thousands of previously undetected Mayan houses, buildings, defence works and pyramids in the dense jungle of Guatemala's Peten region, suggesting that millions more people lived there than previously thought.

Researchers used a mapping technique called LiDAR, which stands for Light Detection And Ranging. It bounces pulsed laser light off the ground, revealing contours hidden by dense foliage... The 2,100 square kilometres of mapping detected about 60,000 individual structures, including four major Mayan ceremonial centres with plazas and pyramids.

 

[Pie eyed]

Really LIDAR is just revealing the present....
Thought I'd split that hair.

 

[The Dice Man]

2 years ago I visited the Caracol ruins in Belize, right near the Guatemalan border and it was interesting to hear the guide tell us that there is thousands and thousands more in Belize but they dont have the money or people to uncover them. They have maps using this sort of technology that they believe are many more. Interestingly when you travel the country you see thousands of pyramid like shapes under dense foliage. Could only wonder at what is underneath.

 

[Werewolf]

Really LIDAR is just revealing the present....
Thought I'd split that hair.

Well yes... the present minus the foliage, which has long since covered these ancient structures

 

[Pie eyed]

Well yes... the present minus the foliage, which has long since covered these ancient structures

I'm right you know, practically but wrong only on a technicality.
Anything (Yachting-lol) which is recorded via a ray or wave is actually "of the past" even if that past was only a few nano-seconds ago.
If we were looking at images of a planet a few light years away, certainly we would be looking at their past, even in though in our present.
Even the planet may well not exist anymore.
It's all relative.

 

[telsor]

Really LIDAR is just revealing the present....
Thought I'd split that hair.

Well if you're going to be technical about it....

It does actually reveal the past...because it records the moment when the light reflected off the earth.

It is not until after that the that light is received by the sensors, is processed and is assessed by the computers/humans.

Now, depending on the setup, that could only be a matter of seconds, but when is getting assessed (let alone reviewed afterwards) it *IS* the past that is being revealed.

 

[Haduken]

I've posted this before (Mysteries & Paranormal board), but it's worth having here too. The use of airborne LIDAR (Light Detection and Ranging) to scan where ancient cities once stood. This often uses infrared light (but can also use visible or UV) - the shorter wavelength provides higher resolution and can see through a jungle canopy. This produces a detailed topographic map that allows artificial features to be identified.

Example: Scientists find 60,000 Mayan structures preserved under dense Guatemalan jungle

what's mysterious or paranormal about LIDAR hmm?

 

[Werewolf]

what's mysterious or paranormal about LIDAR hmm?

It was a post in the thread about ancient civilizations (although this case isn't really ancient)

 

[Haduken]

It was a post in the thread about ancient civilizations (although this case isn't really ancient)

ahh ok fair enough, just making sure you weren't a nutter really..

 

[Pie eyed]

Well if you're going to be technical about it....

It does actually reveal the past...because it records the moment when the light reflected off the earth.

It is not until after that the that light is received by the sensors, is processed and is assessed by the computers/humans.

Now, depending on the setup, that could only be a matter of seconds, but when is getting assessed (let alone reviewed afterwards) it *IS* the past that is being revealed.

See my post above...

 

[Werewolf]

This has been done in quite a few places now. Here's an example of a LIDAR scan of the Mayan complex:

 

[Melsy]

I've posted this before (Mysteries & Paranormal board), but it's worth having here too. The use of airborne LIDAR (Light Detection and Ranging) to scan where ancient cities once stood. This often uses infrared light (but can also use visible or UV) - the shorter wavelength provides higher resolution and can see through a jungle canopy. This produces a detailed topographic map that allows artificial features to be identified.

Example: Scientists find 60,000 Mayan structures preserved under dense Guatemalan jungle

Think they use LIDAR to find buried bodies via helicopters too.