Sub-atomic Particles Used To Map Pyramid

firegate writes "Yahoo News is reporting on a pyramid-mapping project focusing on an ancient Aztec site in Teotihuacan, Mexico. Scientists are attempting to map an ancient pyramid by detecting muons - sub-atomic particles which are left as remnants of ancient cosmic rays. A similar method was used to scan Egypt's Khephren Pyramid in the 1960's."

Cool..

[adeyadey]

Let us know when they find the Stargate thats buried there..

FP by the way..

Bad News

[trentfoley]

This can only mean that they broke the Stargate and are looking for a replacement.

<cantresist>In the meantime, I welcome our new Goa'uld overlords.</cantresist>

Re:Bad News

[HTH NE1]

This can only mean that they broke the Stargate and are looking for a replacement.

What, again?

"Alvarez proved there were no hidden chambers in that pyramid and it is now in scientific literature," said Menchaca

So no, no Stargate found. No teleport rings either. Unless they covered it up.

And are you sure it wouldn't be Tlak'khan technology hidden in that kind of a pyramid instead?

Re:Bad News

[adeyadey]

{whingemode++} That gets +5, and mine gets -1 for exactly the same joke (only mine being first)? Go figure.. {whingemode--}

So how does it work, exactly?

[notyou2]

Anybody able to discern useful details? Does it work by detecting latent muons in the Pyramid, that spontaneously "activate" and get knocked out? Or does it measure the muons that make it THROUGH the pyramid at that moment (from space), and determine from that the density of the material (since solid rock will absorb more muons than alternating rock and air-filled chambers).

Re:So how does it work, exactly?

[Anonymous Coward]

It detects the amount of shielding that the walls provide. I = I_0 * 10 ^ (- x/ x_1/10), where I is the intensity measured, I_0 is the unshielded intensity, x is the thickness of material, and x_1/10 is the tenth thickness of attenuation for that material (i.e. the amount of material required for the intensity to drop to 1/10 of its original value). All they have to do is solve for x. Obviously, if x drops somewhere there is 'missing' shielding.

Re:So how does it work, exactly?

[elcausado]

It is some time since i did phy102 or whatever, so be warned!

This *looks* like a normal decay equation which assumes that the number of particles decaying/getting anhiliated at any time is a fraction of those present.

The article says "Since there are fewer muons in an empty space than in solid rock or earth.."

So, if we assume muons are formed when the cosmic rays pass through the walls(which is what the article sasy) and assume that empty space offers lesser resistance to the rays than, say a brick wa

Re:So how does it work, exactly?

[Anonymous Coward]

The author of the story was misleading. Muons are created in the atmosphere in high energy cosmic ray to atmosphere interactions. While the equation looks like a decay rate equation, that is not the case. If (- x / x_(1/10) ) were replaced by ( - t / t _(1/10) ) (normally shown as t_(1/2), but there is no reason you can't measure tenth-lives vice half-lives) it would be *a* decay rate equation. The shielding eqaution has a similar concept (exponential decay), so it takes a similar form. Everything has a tenth-thickness of attenuation to a different degree for different types of radiation (for example an opaque substance will have an almost zero tenth thickness for some frequencies, but a window will have a very large tenth thickness for some frequencies).

The article is written by a scientific illiterate

[Tau Zero]

Anybody able to discern useful details?

You'll get few from that article, unfortunately. For instance, the muons come from the collision of cosmic rays with nuclei high in the atmosphere; some of the resulting particles are pions, which decay to muons on the way down. But the author (or editor, in some idiotic attempt to make the article more "accessible") completely misled his readers by writing nonsense such as

Remnants of space dust that constantly showers the world....

when "space dust" has nothing to do with it, and

Since there are fewer muons in an empty space than in solid rock or earth...

which has no relation to reality that I can see.

The system works a lot like a CAT scanner, where the absorption of penetrating radiation is measured over a variety of different paths through the object to be scanned. The only real difference is that the radiation is muons rather than X-rays (less easily absorbed, thus able to provide detectable signals through a hundred meters of rock - you should see what Fermilab uses to absorb muons so they can do neutrino experiments) and the source is natural. If you had enough money you could make your own muon source and scan the thing yourself, but when nature has been so obliging there's really no great need.

Next week, on a very special Stargate SG-1...

[Kris_J]

Isn't this how Hathor was awakened? We think you should let sleeping Goa'uld lie.

Re:Next week, on a very special Stargate SG-1...

[CTachyon]

Actually, we should be much more worried about crystal skulls that teleport people to offworld caverns populated by giant white aliens [gateworld.net]. Oh, and some old geezer named Nick who sees dead people.

1960s!?

[bhima]

So, Now I am wondering why they didn't just go around to all the various temples and man-made wonders and give them the old "muon once over". Once they built the device they could have subsequently rented it to all of those busy archeologists and museum curators and had a look at everything.

Come to think of it, it might have been useful in my old house...

Re:1960s!?

[cft_128]

I would think it would require some way of placing the muon detector under whatever it is evaluating as the free muon source is above.

Useful resources on this technique

[thesp]

This was on my Physics undergraduate course; a rather nice technique. Releated resources from my lecture notes give:

An abstract [if.usp.br], a presentation [unimelb.edu.au] on applying similar techniques to volcanoes, a citation [L. Alvarez et al, Science 167, 832 (1970)] (accessible only to subscribers of Science, I'm afraid), a Physics Today [physicstoday.com] article, a useful paper [bnl.gov].

is the conference where the experiment was originally proposed. [www.smf.mx]

Comment removed

[account_deleted]

Comment removed based on user account deletion

Re:Replacement for the X-Ray machine?

[dtl]

Well to scan in a reasonable time, say 10 sec or less you would need much more than the background level of muons from cosmic rays.

Generating muons would require a particle accelerator. This is already pushing the cost beyond that of standard x-ray gear.

Then you have to consider the interaction of muons with the human body. They are penetrating ionizing radiation, and they decay into more fast ionizing particles once they are inside the body. Not something you really want.

Best to stick with metal detectors at airports I think.

Nah....

[purduephotog]

... I've already survived cancer. I don't want any more xrays (in fact my doctor said "No more for you" for some time because he was more afraid he'd give me lung cancer from the extra xrays)... and any high energy particle decays would be a bad thing (as parent said).

Some PET systems and NM applications require a particle accelerator right at the lab- they make the compounds and then they are carried (or shot) right up into the patient.

A large NM detector scans the body over looking for tumours that pic

Re:Replacement for the X-Ray machine?

[CXI]

They already have terahertz frequency [slashdot.org] scanners in the works as an airport security imaging solution, pretty much exactly like Total Recall.

Re:Replacement for the X-Ray machine?

[QEDog]

Cosmic Ray muons are particles with very high energy. That means that to stop them you need a lot of material. This technique is good for geology, big buildings, volcanos, etc. And still you need weeks of collecting data to get any results.

Teotihuacan is not Aztec

[T-Punkt]

It's even mentioned in the article the editor cites. *sigh*

The culture of Teotihuacan predates the Aztecs by a few hundred years. It climaxed around 500, went under around 600 (my sources say 700). The so-called Aztecs arived around 1200 and gave the site its name, but that's the only Aztec connection to Teotihuacan.

Re:Teotihuacan is not Aztec

[ParticleGirl]

So they a) lived there and b) gave the place its name. Seems like a good enough pair of reasons to call it an "Aztec site" to me. Would you prefer "mysterious Teotihuacan culture" on all references?

Actually, they didn't live there. They lived nearby, and considered the enormous ruins a holy site. They thought that that city was where humans came into being ("Teotihuacan [mexicocity.com.mx]" means "City of the Gods" in the Aztec language, Nahuatl [iastate.edu].) In the literature, it really is referred to as a Mysterious Teotihuacan Culture (also called "Toltec" because this is what the Aztec called the Mysterious Teotihuacano Culture.) They had an enormous empire, conquering and trading with groups as far as 1500 km [wikipedia.org] to the south, and Teotihuacan was the FIRST major urban center in the New World. It was enormous, with big, government-issue apartment complexes, sewage systems, and public market places.

Aztecs thought it a high compliment to be considered Toltec-ish, since when they established themselves in the area a thousand years after the place had peaked they claimed legitimacy by claiming to be at least the spiritual descendents of the Toltec (hey, look, they were fierce warriors and so are we!) even though they and everyone else acknowledged that they were entirely different peoples.

And this really is just about the extent of what we do know about the truly Mysterious Teotihuacano Culture (with some other random speculations about how they came to be the only big culture in the New World without someone like a king, how and why the city of hundreds of thousands came to be burned to the ground and abandoned within about 50 years, et cetera.) We know a hell of a lot about the Aztec. They were separated by time, space and culture. Saying 'what's the difference' between Aztec and Teotihuacano is like saying 'what's the difference' between you and an Ancient Greek.

Re:Teotihuacan is not Aztec

[valdis]

Actually, they didn't live there

Must have been one hell of a commute when you don't got wheels.

Re:Teotihuacan is not Aztec

[forkazoo]

I'm gonna agree. While Teotihuacan is also a Toltec site, and a Mexican site, and a Spansih Conquistadores site, IMHO, it counts as an Aztech site. Virginia counts as a George Washington place, but he didn't build the place, or even name it. He just lived there, and shot at some people and stuff. But, in the story of George Washinton, Virginia is important enough to be associated with him.

Muons

[yet another coward]

Muons are created high above the earth when cosmic rays interact with matter up there. They shoot out from those reactions at velocities near light speed. Because they are traveling at such high velocities, their lifetimes are extended as predicted by special relativity. Instead of nearly all decaying within a tiny fraction of a second, many of the muons exist long enough to travel down and reach us. They are a few seconds old--I think it is a few seconds; it might be less--when they reach us. They pass through objects on the surface of the earth at about the rate 1 / second / cm^2.

Muons can react with matter, but such interaction is very unlikely. If the matter is denser, such as stone, they are more likely to interact. By placing detectors inside the pyramid and counting muons coming from overhead for a long time, the scientists can estimate how much matter. They have another estimate of the matter is there by comparing to the number they would expect if they had passed through air. If that experimental estimate of the matter present is somewhat less than the expected amount based on the thickness and density of the pyramid above the detector and the density of the stone, there much be less stone than expected, possibly due to a secret chamber.

Disturbing mention...

[happyDave]

I hate to be political, but I was disturbed by the mention in this article about the use of technology in archaeology of the "War on Terror." Does everything have to be justified by that now? What happened to scientific inquisitiveness? I know that there are practicalities to deal with, but that's ridiculous. Scientists don't need to spend time justifying their research as aid to the war on terror.

Re:Disturbing mention...

[retinaburn]

What happened to scientific inquisitiveness?

Nothing, but you have to convince some knucklehead to give you the money and nothing hits home like a terrorist threat.

Similar project at UT

[apirkle]

There's a similar project at the University of Texas at Austin. It aims to image Mayan pyramids in Belize.

They have a fairly sparse website [utexas.edu], but there's a quite good PDF of a slides from a talk [utexas.edu] that Roy Schwitters (former director of the Superconducting Supercollider) gave.

MuT at UT

[QEDog]

I'm part of that project. We like to call it Applied Astro-Particle Physics to Archeology. Yes, it sounds like an oxymoron, but that is exactly what it is.

The basic concept is similar, except our detectors use modern HEP technology. Our detector is smaller and more versatile than the one in the article. The smaller detector will permit us to use it in a harsh enviroment. We plan to use it in a unexplored pyramid (still buried) in La Milpa, Belize. Read: in the middle of the jungle, as opposed to a well stu

Re:MuT at UT

[QEDog]

In fact, it is a completely different technique. While they use a spark chamber and iron to cut-off low energy particles, we use Scintillator Strips and a Cherenkov can. So, ours is smaller because it uses modern techniques.

Old news

[p3d0]

Napoleon examined the pyramids with subatomic "photon" particles back in 1799.

IIRC it didn't work (the 60s version), did it?

[Korpo]

Measuring cosmic rays to detect hollow spaces in the pyramids at Gizeh in the 60s didn't work actually. Or at least it did give unexpected results.

After the method was verified, they tried to apply it to at least one Gizeh pyramid. The measurement was really weird, and with contradictory results, that at least seem to suggest that either we know shit about the internals of those pyramids or the method didn't really work completely then.

Established Egyptology still derives the Cheops/Chufu connection to th

Re:IIRC it didn't work (the 60s version), did it?

[QEDog]

Or at least it did give unexpected results.

Quite contrary, it did work, but the results weren't interesting. Nothing new was found in the pyramid. Go read the paper.

Selling up

[CaptainCarrot]

Granted, Teotihuacan is the most impressive site in the Americas, but this is going a tad too far:

"Teotihuacan is up there with Rome, one of the biggest pre-industrial cities in the world. Constantinople is also maybe there but no Chinese city was of this magnitude. Egypt didn't even have cities," Manzanilla said.

Rome had over a million inhabitants at its peak in antiquity, and Constantinople just about the same by the time of Justinian according to most sources, and even those who lowball the populations of both places put them no lower than 400,000. Even classical Athens had 300,000 residents, and second-century Xi'an in China had at least 400,000 during the time Teotihuacan was inhabited with 150,000 according to the article.

Yes, it's a very large city for antiquity, but it's far from the largest.

Incidentally, one might quibble with the definition of a "city", but Memphis in Old Kingdom Egypt had a population of 30,000, which was the largest settlement in the world at the time. I think we can safely call that an Egyptian city.

Hmm

[DrkAngl]

How were the "ancient cosmic rays" originally found? Is it possible that these rays are not ancient, but rather they are only found in certain areas?