Archaeologists have mapped a Roman city using ground-penetrating radar | Hacker News Reader

Archaeologists have mapped a Roman city using ground-penetrating radar

archaeology.wiki

99 pointsmutnedjemet198019 comments

Here's the published article with more images: https://www.cambridge.org/core/services/aop-cambridge-core/c...

Thank you.

I always thought something like the Ground Penetrating Radar GPR would be very useful to determine where to the ruins are and avoid them while building a subway. One of the (many) reasons why Rome has only 3 subway lines is that it's very common to find ancient rome building while digging.

Looks like we're entering a Golden Age of non invasive archeology!

The invasiveness is still necessary. We want to get to the goodies. However we might be able to know what’s there without having to manually dig first.

I imagine a huge number of new sites being explored cheaply with radar, with only the most promising few percent actually being dug out.

a monumental discovery in Mexico was also recently made possible with non-invasive technology (excavation is now underway, though).

https://www.smithsonianmag.com/smart-news/largest-and-oldest...

I wonder what the tradeoffs are between ground penetrating radar and Muon tomography?

https://en.wikipedia.org/wiki/Muon_tomography

http://www.bldgblog.com/2008/08/mayan-muons-and-unmapped-roo...

Muons scanning works for seeing through things, not into them. There are no muons coming from underground because the Earth blocks them. Scanning the pyramids (fun fact: you can DIY a muon detector for <$100) relies on the fact that muons coming from the sun are all highly collimated- they're all travelling in the same direction. Because of that you know that a muon coming from direction x passed through point y.

If you wanted to image underground with muons, you're basically using them as backlight- muons come from behind the detector, penetrate the ground, and occasionally reflect backwards into the detector. Since the return point and angle are random you wouldn't be able to do it without a very expensive muon source or detector.

Nothing prevents you from digging deep holes at a known position, and wait for the tomography magic to happen :) I don't think it has ever been used this way, though.

If the area to image at once is large, or to use the sun while it is higher up in the sky, one would need to dig deeper... I also guess that this works better at higer latitudes, where the sun has a wider range of angles over the year.

You'll find the water table is a bit of an issue and the deeper you dig, the more expensive it gets. In general, archaeologists don't have a lot of funding, so you'll see extreme cost sensitivity in methodologies.

Touché :)

But a dumb detector with a nice protective layer might be achievable, I guess? And maybe archeologists can get support from a local drilling company? Not sure how deep you'd need to dig, TBH, but that would be an interesting experiment.

Is there hobbyist ground penetrating radar?

Yes. I've got a friend who digs privies for fun (that's a loaded intro, search for The Privy Diggers or The Boghouse if you're curious) and he bought a GPR cart last year for a pretty reasonable price - I think the price was in the hundreds, rather than the thousands. Some guy assembles the electronic components into a Pelican case, essentially, and it hooks up to free iPad software.

This got my curiosity peaked. I was able to dig up an open source GPR rig that even utilizes building a rover to do scanning.

https://hackaday.io/project/4440-open-ground-penetrating-rad...

Fun fact: magnetic resonance (a la hospital MRI machines) is also a common method of underground imaging. MRI is quite neat in that the time-space resolution tradeoff is extremely flexible, and you can get quite good pictures if you leave a cheap imager long enough. Instead of using massive superconducting magnets they just use the Earth's field. It's especially good for imaging underground water, as well as other hydrogen-containing materials like hydrates or hydroxides.

I think there may be a DIY version on hackaday, but I know for a fact theres a project where someone took a DIY MRI of an apple. The hardware for a low-field MRI actually has a fair amount in common with GPR- the hydrogen atoms emit lowish frequency radio waves when they realign with the magnetic field.

https://hackaday.io/project/5030-low-field-mri

Just took a tour on http://hackaday.io, it's refreshing to browse through what feels like genuine innovation.

Definitely check out the hackaday prize finalists; everything in the top ten every year is usually spectacular. Example: https://hackaday.io/project/5030-low-field-mri

Is this possible with SDR?

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