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Time Warp Detector

Continuously compare atomic clock signals
  (+4, -1)
(+4, -1)
  [vote for,

Sure, the chances are low, perhaps even lower than SETI@HOME finding aliens. But if you detect a time warp, say due to a micro black-hole whizzing through our solar system, you will likely get the fastest Nobel prize ever. And all you need to do is install a simple and fairly cheap detector at home. And then wait for it to find something.

Here's how it would work: At any moment we are being bombarded by multiple signals that code time from atomic clocks. These include signals from shortwave radio and GPS satellites, as well as from the Internet Network Time Protocol servers [see link]. When you first install the detector, it will need to calibrate itself, to take into account the relative delays and jitter of each signal for its specific location (there is a large literature on how to do this).

Then one day, if it finds that the clock of one of the GPS satellites is off by a few nanoseconds, meaning that a time warp formed somewhere between the satellites and the detector, it will set off an alarm - and Stockholm here I come. Needless to say, any such claims would have to be corroborated by hard-nosed scientists, to make sure it wasn't simply an electronic glitch in detector (or the satellite). But even if it proves to be unreproducible - it'll still make a neat Wow! signal [see link].


As one of the resident Astronomers in this forum. It's my job to make sure that the science is correct. So with a little more research I found a caveat to this idea. If you don't want to go through all the physics, here's the take-away: GPS signals aren't accurate enough to allow the detection of "conventional" micro black holes. But who knows what else could be out there...

OK, now for the nitty gritty.

First, we need to see how accurate our detector can be. Laser cooled atomic clocks can reach a stability of 0.1ns/day [see link]. However in practice, the variation in atmospheric conditions, which change its optical density (i.e. the speed of light through air), will bring about noise in a signal's arrival time, in the order of a nanosecond. This is one of the main bottlenecks for the accuracy of current GPS technology. However, with better atmospheric models it might be possible to improve these limitations in the future. In summary, let's adopt a GPS accuracy of dT = 1 ns = 10^-9 sec.

Next, we need to estimate the expected time delay due to a micro black hole. This value can vary depending on the black hole's spin and charge [see link], which will cause additional phenomena such as frame dragging. To keep this example simple, let's assume a vanilla black hole, and assume that the only important effect that takes place is the Shapiro time delay [see link]. If this assumption is wrong, please let me know. In its simplest form, the Shapiro time delay can be written as:

dT = (-2GM/c^3) * Ln(1 - cos x)

Where G = the universal gravitation constant [6.7*10^-11 m^3kg^-1s^-2], c = the speed of light [3*10^8 m/s], M = the mass of the black hole, and x = the observed angle between the signal source and the center of the black hole. We can rearrange this equation and fine the minimal detectable mass of a black hole:

M = -dT * c^3 / (2G * Ln(1 - cos x))

Note that with smaller angles x, we can detect less massive black holes. Though in theory we could have x=0, in practice we are limited to the physical size of the detector and transmitter. Given that GPS satellites have an altitude of about 20000km, a realistic lower bound for the angle might be, x > 10^-9 radians. Plugging all this in, we get M = 5*10^24 kg , which is almost as much as the mass of the earth.

Such a black hole would have an enormous tidal effect on Earth, and would be noticed through far less subtle effects, such as substantially warping the shape of Earth, and likely bringing about a mass extinction event. So even though this might not be a useful detector for black holes, it might be useful to detect even more bizarre astronomical objects, which distorts time without reeking gravitation havoc.

imho, Jun 28 2009

Wow! signal http://en.wikipedia.org/wiki/Wow!_signal
[imho, Jun 28 2009]

Time signals http://en.wikipedia.org/wiki/Time_signal
[imho, Jun 28 2009]

Micro Black Hole http://en.wikipedia...ki/Micro_black_hole
[imho, Jun 28 2009]

http://www.elyrics....me-warp-lyrics.html [hippo, Jun 28 2009]

Appendix - Shapiro time delay http://en.wikipedia...Time_delay_of_light
[imho, Jun 29 2009]

Appendix - Atomic clocks http://en.wikipedia.org/wiki/Atomic_clock
[imho, Jun 29 2009]

Appendix - Rotating black hole http://en.wikipedia...Rotating_black_hole
[imho, Jun 29 2009]


       Nice idea. If you find one, you could celebrate with a little dance (see link).
hippo, Jun 28 2009

       Like [hippo] said, If the person in front of you jumps to their left, and then steps to their right, there's a pretty good chance...
Dub, Jun 28 2009

       If you detected it, everyone using GPS at that moment would also detect it. Bye bye Nobel.
ldischler, Jun 28 2009

       ldischler makes a good point. However, most GPS receivers aren't designed to detect small anomalies. In fact, they usually just average them out. But even if they didn't - all you would see is that your position was off by a few feet. I don't think anyone would even notice that, unless they're specifically looking out for it.
imho, Jun 28 2009

       //if it finds that the clock of one of the GPS satellites is off by a few microseconds,//   

       If it was off by just one microsecond, your GPS position would be off by around a thousand feet. In a car, you'd be on the wrong block. So perhaps the time warp detector could be a feature of a standard navigation system, as the passage of the black hole would produce a sudden and quite impossible shift in the apparent position.
ldischler, Jun 28 2009

       Correction - I meant to say nanosecond, not microsecond. Description has been edited. Thanks ldischler.
imho, Jun 28 2009

       sp: timing
wjt, Jun 28 2009

       I have a sneaky feeling that this won't work at all. It is not that I doubt the general abundance of very small black holes. Indeed I think they are almost as prevalent as matter is, certainly prevalent in places where matter isn't (or was and is no longer).   

       However your little black hole is going to slingshot signals that encode time, just as fast as it swallows them. It has to, if you believe in entropy. Hell, it even creates an infinite infinity of its own signals, most of which cancel out, some of which mimic what's already happening, and a small percentage that create (usually unrepeatable) anomalies. That's why they are undetectable, even on large scales. Unless someone has actually observed "hawking radiation" working in a different manner.   

       Also this gravitational field is going to move into, and then out of, your frame of reference, or all parties' frame of reference if you like. The net result of this will be zero change.   

       I am also a big fan of [Ian...]'s interpretation. And that interpretation "turtles" all the way down...
4whom, Jun 29 2009


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