It's still March 31 in my time zone. --Dan

On Mar 31, 2015, at 9:07 PM, Keith F. Lynch <kfl@KeithLynch.net> wrote:

This news has gotten remarkably little coverage. So for those who have not heard:

Project Ozma failed. Project Durin succeeded. It turned out SETI (the Search for ExtraTerrestrial Intelligence) was looking in the wrong direction all along. It was looking up when it should have been looking down.

Evolution works much the same everywhere in the universe. It selects for different attributes in different environments, but one commonality is that it never selects for extreme patience.

How long would anyone keep transmitting a few gigawatts at a silent planet? A decade? A century? A millennium? The one serious human attempt to send such a message (the Arecibo message) lasted less than three minutes, and was never repeated.

If the phone doesn't answer, you leave a message.

As Fermi pointed out decades ago, there's nothing special about the present age. A solar system which is just a little older, or in which evolution happened just a little more quickly, would result in a race millions of years ahead of us. If they sent signals to Earth, they'd get no reply. If they visited Earth, they'd find nothing more advanced than dinosaurs, or perhaps blue-green algae. And they certainly could have visited Earth. Even at the speed of our current spacecraft, it's possible to reach every part of the galaxy on a geological time scale.

That is why Ayeph Dee, professor of exobiology at Frank Drake University, had his students come up with a way to leave a message on an Earthlike planet that would be detectable and readable for hundreds of millions of years.

They came up with the idea of buried hollow titanium spheres, a few meters in diameter, containing tuning forks. Over the course of ages some would come to the surface and be weathered to dust, and others would be be subducted to depths at which temperature and pressure would destroy them. But if there were enough of them, and if they were carefully placed, some would survive for hundreds of millions of years at relatively shallow depths, embedded in bedrock.

Project Durin, named for the ruler of Tolkien's fictional underground land of Moria, consists of a grid of ten thousand broad-spectrum microphones embedded in the bedrock of the Canadian Shield. Recordings are made available to the SETIunderground@Home distributed computing project, whose software turns the array into an acoustic version of a passive phased array radar. It searches the bedrock for narrow-band point sources of acoustic energy from tuning forks excited by natural seismic activity.

Such a source was found, approximately 41 kilometers deep, with a strong high-Q (~100) resonance at about 14 Hz. This is consistent with a tuning fork inside a hollow sphere, possibly made of titanium or tungsten, and possibly filled with oil. There were also several seconds of broad-spectrum noise, which could be from multiple smaller tuning forks inside the same sphere. Dee conjectured that such a set of tuning forks could be used to encode a message, based on their relative frequencies and their relative locations within the sphere.

Unfortunately, we don't yet have the technology to excavate anything at that depth. (The deepest borehole ever drilled is just 12 kilometers.) This also means that the rock surrounding the sphere hasn't been analyzed, so we have no idea of its age, except that it's certainly Precambrian, probably at least a billion years old, and possibly two or three times that age.

It's believed that it was originally buried at a shallow depth. It's not known whether this was on land or under an ocean, or whether the builders were from our solar system or not. (Venus and Mars may have been much more hospitable to life eons ago.) It's even possible that it was constructed by an indigenous terrestrial sapient race, though it's hard to imagine it would have left no signs of its existence that we would have noticed by now.

The planned next step is to detonate several embedded explosives, one at a time, in various locations, as a form of active sonar, to more closely locate the sphere. Once that is done, a large number of larger explosives (about 100 of approximately one ton each) will be detonated almost simultaneously, such that their shock waves will reach the sphere simultaneously from multiple directions, to excite a strong and sharp resonance of all the tuning forks.

Searches for additional spheres elsewhere on Earth are encouraged.

Project Durin is always open to suggestions.

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The first seismic tests have succeeded in returning a signal. It turns out that there are two sets of tuning forks deep in the bedrock, whose resonant frequencies appear to be incommensurable. When their ratio is expanded in binary, its first few thousand digits reveal an image of an eldritch race, barrel-shaped creatures with pentagonal symmetry and diaphanous wings... who knows what secrets are buried deeper inside its binary expansion. Cris On Mar 31, 2015, at 10:07 PM, "Keith F. Lynch" <kfl@KeithLynch.net> wrote:

This news has gotten remarkably little coverage. So for those who have not heard:

Project Ozma failed. Project Durin succeeded. It turned out SETI (the Search for ExtraTerrestrial Intelligence) was looking in the wrong direction all along. It was looking up when it should have been looking down.

Evolution works much the same everywhere in the universe. It selects for different attributes in different environments, but one commonality is that it never selects for extreme patience.

How long would anyone keep transmitting a few gigawatts at a silent planet? A decade? A century? A millennium? The one serious human attempt to send such a message (the Arecibo message) lasted less than three minutes, and was never repeated.

If the phone doesn't answer, you leave a message.

As Fermi pointed out decades ago, there's nothing special about the present age. A solar system which is just a little older, or in which evolution happened just a little more quickly, would result in a race millions of years ahead of us. If they sent signals to Earth, they'd get no reply. If they visited Earth, they'd find nothing more advanced than dinosaurs, or perhaps blue-green algae. And they certainly could have visited Earth. Even at the speed of our current spacecraft, it's possible to reach every part of the galaxy on a geological time scale.

That is why Ayeph Dee, professor of exobiology at Frank Drake University, had his students come up with a way to leave a message on an Earthlike planet that would be detectable and readable for hundreds of millions of years.

They came up with the idea of buried hollow titanium spheres, a few meters in diameter, containing tuning forks. Over the course of ages some would come to the surface and be weathered to dust, and others would be be subducted to depths at which temperature and pressure would destroy them. But if there were enough of them, and if they were carefully placed, some would survive for hundreds of millions of years at relatively shallow depths, embedded in bedrock.

Project Durin, named for the ruler of Tolkien's fictional underground land of Moria, consists of a grid of ten thousand broad-spectrum microphones embedded in the bedrock of the Canadian Shield. Recordings are made available to the SETIunderground@Home distributed computing project, whose software turns the array into an acoustic version of a passive phased array radar. It searches the bedrock for narrow-band point sources of acoustic energy from tuning forks excited by natural seismic activity.

Such a source was found, approximately 41 kilometers deep, with a strong high-Q (~100) resonance at about 14 Hz. This is consistent with a tuning fork inside a hollow sphere, possibly made of titanium or tungsten, and possibly filled with oil. There were also several seconds of broad-spectrum noise, which could be from multiple smaller tuning forks inside the same sphere. Dee conjectured that such a set of tuning forks could be used to encode a message, based on their relative frequencies and their relative locations within the sphere.

Unfortunately, we don't yet have the technology to excavate anything at that depth. (The deepest borehole ever drilled is just 12 kilometers.) This also means that the rock surrounding the sphere hasn't been analyzed, so we have no idea of its age, except that it's certainly Precambrian, probably at least a billion years old, and possibly two or three times that age.

It's believed that it was originally buried at a shallow depth. It's not known whether this was on land or under an ocean, or whether the builders were from our solar system or not. (Venus and Mars may have been much more hospitable to life eons ago.) It's even possible that it was constructed by an indigenous terrestrial sapient race, though it's hard to imagine it would have left no signs of its existence that we would have noticed by now.

The planned next step is to detonate several embedded explosives, one at a time, in various locations, as a form of active sonar, to more closely locate the sphere. Once that is done, a large number of larger explosives (about 100 of approximately one ton each) will be detonated almost simultaneously, such that their shock waves will reach the sphere simultaneously from multiple directions, to excite a strong and sharp resonance of all the tuning forks.

Searches for additional spheres elsewhere on Earth are encouraged.

Project Durin is always open to suggestions.

_______________________________________________ math-fun mailing list math-fun@mailman.xmission.com https://mailman.xmission.com/cgi-bin/mailman/listinfo/math-fun