ISF Logo   IS Forum
Forum Index Register Members List Events Mark Forums Read Help

Go Back   International Skeptics Forum » General Topics » Science, Mathematics, Medicine, and Technology
 


Welcome to the International Skeptics Forum, where we discuss skepticism, critical thinking, the paranormal and science in a friendly but lively way. You are currently viewing the forum as a guest, which means you are missing out on discussing matters that are of interest to you. Please consider registering so you can gain full use of the forum features and interact with other Members. Registration is simple, fast and free! Click here to register today.
Reply
Old 3rd September 2017, 09:40 AM   #1
dasmiller
Just the right amount of cowbell
 
dasmiller's Avatar
 
Join Date: Oct 2008
Location: Well past Hither, looking for Yon
Posts: 5,818
Misbehaving Galaxy (Breakthrough Listen and FRB 121102)

I haven't seen a thread on this yet, but has anyone else been reading about the series of Fast Radio Bursts (FRBs) from a galaxy 3 billion light years away?

Astronomer Telegram article

Berkeley Blog

I'm intrigued by the plots I've seen. If I'm reading them right, the bursts sweep from 8 GHz down to about 4.5 GHz over ~50 ms, and appear to be relatively narrow-band. And, of course, they're immensely powerful to be detected 3 billion light years away.

If I were a betting man, my first bet would be that it's some very rare natural phenomenon. There are a lot of galaxies within 3GLY, and many billions of stars within each galaxy, so even extremely rare phenomenon should occur pretty regularly somewhere in that volume.

My second bet would be some terrestrial event that's being inadvertently detected. There are billions of RF sources on earth, including every cell phone, microwave oven, and bluetooth device.

But for the "aliens" theory is more fun, so I've been pondering that. One article mentioned a suggestion that we were seeing spillover of some giant emitter that was being used to push or power distant probes, but if so, why would the signal be pulsed, and why the frequency sweep? Similarly, for an ordinary comm signal, I don't know why you'd sweep it like that. It could be a form of spreading, but that would suggest a very low data rate (a few hundred bps, I think) and . . . well, to my untrained eye, it doesn't look like the structure of any of our comm signals that I'm familiar with.

Radar transmissions are often "chirped," which means that the frequency sweeps up or down during the pulse, much like these FRBs. And radars are pulsed, just like these FRBs. If I have time this week*, I may try playing around with some numbers to see if I can come up with a combination of parameters (aperture, transmit power) that would give the signal strength we're seeing and be useful for doing radar images of other solar systems in the host galaxy.

When I was still a gainfully-employed satellite engineer, I had a lot of smart technical people around to bounce ideas off of, but since my retirement, there are fewer around. I think there are still some here, though, and I'd welcome any insights, speculations, corrections**, etc.


*I'm getting married on Saturday, and this sort of thing isn't high on my fiancee's priority list right now.

**I consider this to be the most likely
__________________
"In times of war, we need warriors. But this isn't a war." - Phil Plaitt
dasmiller is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 3rd September 2017, 03:33 PM   #2
Steve
Illuminator
 
Steve's Avatar
 
Join Date: May 2005
Posts: 3,530
Originally Posted by dasmiller View Post
I haven't seen a thread on this yet, but has anyone else been reading about the series of Fast Radio Bursts (FRBs) from a galaxy 3 billion light years away?

Astronomer Telegram article

Berkeley Blog

I'm intrigued by the plots I've seen. If I'm reading them right, the bursts sweep from 8 GHz down to about 4.5 GHz over ~50 ms, and appear to be relatively narrow-band. And, of course, they're immensely powerful to be detected 3 billion light years away.

If I were a betting man, my first bet would be that it's some very rare natural phenomenon. There are a lot of galaxies within 3GLY, and many billions of stars within each galaxy, so even extremely rare phenomenon should occur pretty regularly somewhere in that volume.

My second bet would be some terrestrial event that's being inadvertently detected. There are billions of RF sources on earth, including every cell phone, microwave oven, and bluetooth device.

But for the "aliens" theory is more fun, so I've been pondering that. One article mentioned a suggestion that we were seeing spillover of some giant emitter that was being used to push or power distant probes, but if so, why would the signal be pulsed, and why the frequency sweep? Similarly, for an ordinary comm signal, I don't know why you'd sweep it like that. It could be a form of spreading, but that would suggest a very low data rate (a few hundred bps, I think) and . . . well, to my untrained eye, it doesn't look like the structure of any of our comm signals that I'm familiar with.

Radar transmissions are often "chirped," which means that the frequency sweeps up or down during the pulse, much like these FRBs. And radars are pulsed, just like these FRBs. If I have time this week*, I may try playing around with some numbers to see if I can come up with a combination of parameters (aperture, transmit power) that would give the signal strength we're seeing and be useful for doing radar images of other solar systems in the host galaxy.

When I was still a gainfully-employed satellite engineer, I had a lot of smart technical people around to bounce ideas off of, but since my retirement, there are fewer around. I think there are still some here, though, and I'd welcome any insights, speculations, corrections**, etc.


*I'm getting married on Saturday, and this sort of thing isn't high on my fiancee's priority list right now.

**I consider this to be the most likely
Are you sure she is the right woman for you?

Interesting stuff. I have no comment right now but you have got me interested in digging into is further.

And congratulations on your upcoming marriage.
__________________
Caption from and old New Yorker cartoon - Why am I shouting? Because I'm wrong!"
Steve is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 4th September 2017, 08:38 PM   #3
dasmiller
Just the right amount of cowbell
 
dasmiller's Avatar
 
Join Date: Oct 2008
Location: Well past Hither, looking for Yon
Posts: 5,818
Originally Posted by Steve View Post
Are you sure she is the right woman for you?
its more of a "marry her before she realizes she can do better" thing.

Quote:
Interesting stuff. I have no comment right now but you have got me interested in digging into is further.

And congratulations on your upcoming marriage.
Thanks!
__________________
"In times of war, we need warriors. But this isn't a war." - Phil Plaitt
dasmiller is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 4th September 2017, 09:25 PM   #4
quadraginta
Becoming Beth
 
quadraginta's Avatar
 
Join Date: May 2009
Location: Central Vale of Humility
Posts: 21,177
Originally Posted by dasmiller View Post
<snip>

But for the "aliens" theory is more fun, so I've been pondering that. One article mentioned a suggestion that we were seeing spillover of some giant emitter

<snip>

So much for the promise of advanced civilization.

Damned kids and their boom boxes.
__________________
"It never does just what I want, but only what I tell it."
***********************************************
"A great deal of intelligence can be invested in ignorance when the need for illusion is deep." - Saul Bellow
quadraginta is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 4th September 2017, 10:20 PM   #5
marplots
Penultimate Amazing
 
Join Date: Feb 2006
Posts: 29,167
Is there some pattern in the broadcast that helps eliminate a closer source - one between us and the galaxy so far away?

I ask because knowing how far away the source is feeds into other assumptions (primarily power).
marplots is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 5th September 2017, 05:52 AM   #6
dasmiller
Just the right amount of cowbell
 
dasmiller's Avatar
 
Join Date: Oct 2008
Location: Well past Hither, looking for Yon
Posts: 5,818
Originally Posted by marplots View Post
Is there some pattern in the broadcast that helps eliminate a closer source - one between us and the galaxy so far away
I haven't seen any discussed so far. If the source is really 3 GLY away, I'd think there would be some absorption lines due to interstellar gas, though it's far enough that those lines might be badly smeared by Hubble spreading (if that's a thing). But a little quick googling suggests that there's very little absorption at C-band, which has wavelengths of a few cm.
__________________
"In times of war, we need warriors. But this isn't a war." - Phil Plaitt
dasmiller is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 5th September 2017, 06:24 AM   #7
theprestige
Penultimate Amazing
 
Join Date: Aug 2007
Posts: 26,610
Let me see if I understand: Whatever it is, it happened 3 billion years ago. The other galaxy was a lot closer at the time. Now it's like we're getting a transmission from a parallel universe we can never reach.

This signature is intended to irradiate people.
theprestige is online now   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 5th September 2017, 09:44 AM   #8
Hercules Rockefeller
Woof!
 
Hercules Rockefeller's Avatar
 
Join Date: Jan 2011
Posts: 3,032
Originally Posted by theprestige View Post
Let me see if I understand: Whatever it is, it happened 3 billion years ago. The other galaxy was a lot closer at the time. Now it's like we're getting a transmission from a parallel universe we can never reach.

This signature is intended to irradiate people.
Not quite. The galaxy is still well within our Hubble sphere.
__________________
Quantum physics means that anything can happen at anytime and for no reason. Also, eat plenty of oatmeal, and animals never had a war! - Deepak Chopra
Hercules Rockefeller is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 5th September 2017, 12:18 PM   #9
quadraginta
Becoming Beth
 
quadraginta's Avatar
 
Join Date: May 2009
Location: Central Vale of Humility
Posts: 21,177
Originally Posted by Hercules Rockefeller View Post
Not quite. The galaxy is still well within our Hubble sphere.

"I claim this Hubble Sphere in the name of the Empire of Spain forever!"
__________________
"It never does just what I want, but only what I tell it."
***********************************************
"A great deal of intelligence can be invested in ignorance when the need for illusion is deep." - Saul Bellow
quadraginta is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 25th October 2017, 08:04 AM   #10
dasmiller
Just the right amount of cowbell
 
dasmiller's Avatar
 
Join Date: Oct 2008
Location: Well past Hither, looking for Yon
Posts: 5,818
Finally got around to setting up a spreadsheet to see what an interstellar radar might look like. As it turns out, the things I don't know about radar fundamentals could fill a book, and the book would probably be named something like "An Introduction To Radar" or "Radar Modelling for Dummies."

Part The First: Analysis

I started with a sample calculation for a 1 MW radar detecting an airplane at 60 KM (with many other parameters). My spreadsheet works for that case. Then I tried to scale it up to detect planets at many LY, to see if it matches what we see from Earth. Exactly as you'd expect, it depends heavily on the assumptions. My 'baseline' case (1 TW pulse, 50,000 km aperture, 1 MHz bandwidth, etc), which is designed to detect an Earth-sized planet at 100 LY, could indeed give a signal that looks about like we saw in the links. However,
A) I could come up with many other configurations that would look very different from here.
B) There's no particular reason to pick "Earth-sized planet at 100 LY." Radar power varies as R^4, so the results are very, very sensitive to distance. Detecting an Earth-sized planet at, say, 1,000 LY would require 10,000X the power, if all other terms were equal.
C) There are a few terms in the spreadsheet that I don't really grok yet; I suspect that there are 3 places that could affect the power levels by at least a factor of 1000. I will work on this.

Quick summary for the analysis: The "Alien Radar" theory is not yet ruled out, with about the confidence level that you'd have in a tinfoil-hatted homeless guy insisting that tomorrow's winning lottery number will be twelfty.

Part The Second: Additional Speculations, because doing the link budget forced me to think about the conops.

A) One big difference from terrestrial radar is that the propagation times are HUGE. If you're imaging a solar system that may be many light-hours across, then you'll have to turn off your transmitter for many hours during the time that the signal could be returning. And that time will be years after you sent the signal. I'd be very tempted to have separate Tx and Rx antennas, because it'll probably take a long time to reorient a 50,000 km array (even a phased array will likely want coarse mechanical steering) and I wouldn't want to be constrained to have the Tx and Rx pointed at the same thing. I might want multiple receive arrays, too - I suspect there are all kinds of neat things you could do with them.

B) Related to that, the transmit duty cycle will be very low. A pulse that lasts a fraction of a second should produce hours of returns (years later). Though once you'd built such a system, I suspect you'd be transmitting pulses almost continuously for the first few years, because it'll likely take that long before you start getting returns. That's assuming they're in an area like ours; if they're in the middle of a cluster, or in a galactic core, the returns could start within a month or so, and this radar would be detecting 10-meter asteroids rather than mid-sized planets.

C) To examine a solar system, you'd probably do one-or-more pulses, wait a few days, do one-or-more pulses, wait several days, and do a third set of pulses. That way, you'd get a good look at how the planets are moving through their orbits.

D) The Tx and Rx would be big phased arrays. It's very difficult for me to imagine a solid 50,000 km reflector (this is at C-band, so it could be a mesh, but the holes in the mesh shouldn't be more than a few centimeters across, and the surface should be accurate to within a cm or so over 50,000 km). It could be a pretty sparse array, and wouldn't necessarily be a single rigid structure; if you had many well-coordinated elements at well-known locations, 50,000 km probably isn't too difficult. I'm picturing the arrays being a few light-hours away from the central star. If there's a central star, which leads me to

E) There are a lot of assumptions here. It's unavoidable, and I'm okay with that, but I worry that I'm making assumptions that I don't realize I'm making, like "the alien civilization is based in a solar system, so they'd want to put the arrays several light-hours away to minimize gravitational perturbations."

------------------

Bottom Line: Twelfty.
__________________
"In times of war, we need warriors. But this isn't a war." - Phil Plaitt
dasmiller is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 25th October 2017, 08:25 AM   #11
theprestige
Penultimate Amazing
 
Join Date: Aug 2007
Posts: 26,610
I don't understand half of it, but it sounds awesome. Thanks for sharing this with us!
theprestige is online now   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 25th October 2017, 09:00 AM   #12
CORed
Philosopher
 
Join Date: Dec 2008
Location: Central City, Colorado, USA
Posts: 7,942
Originally Posted by quadraginta View Post
"I claim this Hubble Sphere in the name of the Empire of Spain forever!"
Just slightly more presumptuous than Balboa claiming the Pacific Ocean and all land it touches.
CORed is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 26th October 2017, 06:30 AM   #13
Peregrinus
Graduate Poster
 
Join Date: Feb 2015
Posts: 1,213
Originally Posted by quadraginta View Post
"I claim this Hubble Sphere in the name of the Empire of Spain forever!"
Everything you know is wrong.
Peregrinus is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 26th October 2017, 07:14 AM   #14
Craig B
Penultimate Amazing
 
Join Date: May 2011
Posts: 22,231
Originally Posted by quadraginta View Post
"I claim this Hubble Sphere in the name of the Empire of Spain forever!"
That sounds like Madrid and the Catalans. Is Barcelona a Hubble Sphere, I wonder?
Craig B is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 26th October 2017, 08:29 AM   #15
quadraginta
Becoming Beth
 
quadraginta's Avatar
 
Join Date: May 2009
Location: Central Vale of Humility
Posts: 21,177
Originally Posted by Peregrinus View Post
Everything you know is wrong.

__________________
"It never does just what I want, but only what I tell it."
***********************************************
"A great deal of intelligence can be invested in ignorance when the need for illusion is deep." - Saul Bellow
quadraginta is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 26th October 2017, 09:01 AM   #16
Steve
Illuminator
 
Steve's Avatar
 
Join Date: May 2005
Posts: 3,530
Originally Posted by Peregrinus View Post
Everything you know is wrong.
I know that.
__________________
Caption from and old New Yorker cartoon - Why am I shouting? Because I'm wrong!"
Steve is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 26th January 2018, 12:17 PM   #17
dasmiller
Just the right amount of cowbell
 
dasmiller's Avatar
 
Join Date: Oct 2008
Location: Well past Hither, looking for Yon
Posts: 5,818
Just a quick update: Two weeks ago, there was an release that says the bursts are almost completely linearly polarized.

If the signal was unpolarized, I'd consider that a (mild) strike against radar, since AFAIK most antenna types generate strongly polarized signals, but evidently there are also natural reasons why a bunch of photons might be strongly polarized.


So, IMO, while the polarization is consistent with the "twelfty" theory, it doesn't do much to rule out the 'natural' explanations, either.
__________________
"In times of war, we need warriors. But this isn't a war." - Phil Plaitt
dasmiller is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 27th January 2018, 11:46 AM   #18
CORed
Philosopher
 
Join Date: Dec 2008
Location: Central City, Colorado, USA
Posts: 7,942
Originally Posted by quadraginta View Post
"I claim this Hubble Sphere in the name of the Empire of Spain forever!"
You're too late. I already claimed it in the name of Portugal. Of course, you can appeal to the Pope, and he might give Spain half of it.
CORed is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 21st April 2018, 08:19 AM   #19
dasmiller
Just the right amount of cowbell
 
dasmiller's Avatar
 
Join Date: Oct 2008
Location: Well past Hither, looking for Yon
Posts: 5,818
I've done a cursory reading the SciAm article "Flashes In The Night" (April 2018), which talks about FRBs in general and this one in particular. It has an explanation of the frequency sweep for this signal. If they're correct (and I'm virtually certain they are), then the original signal was simply a broadband burst rather than a narrowband signal that changed frequency over time. That severely weakens the "alien radar" theory; I can still come up with ways that it makes sense*, but the natural explanations seem easier to me now.



Bottom line: Things are looking bad for the "alien radar" theory; the feature of the signal that made me think "radar" turns out to be a natural feature of broadband pulses at very long distances.


*Explanation #1: While a true broadband burst isn't what I'd want in a radar pulse, it might be unavoidable if one was using a nuke to generate the pulse. I don't know what the characteristics of such a nuke-pumped directional pulse might be, but surely they have some distinguishing characteristics.

Explanation #2: If the pulse is actually a bunch of simultaneous discrete narrowband pulses rather than a continuous broadband pulse, then if we had better resolution of the spectrum, we'd see evenly-spaced peaks and notches. This would let the radar operator see the radial velocity of whatever the radar detected, which would be nice, but frankly I'd have some BIG notches, and we're not seeing them.
__________________
"In times of war, we need warriors. But this isn't a war." - Phil Plaitt
dasmiller is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 21st April 2018, 12:37 PM   #20
W.D.Clinger
Illuminator
 
W.D.Clinger's Avatar
 
Join Date: Oct 2009
Posts: 3,349
Originally Posted by dasmiller View Post
Just a quick update: Two weeks ago, there was an release that says the bursts are almost completely linearly polarized.
Originally Posted by dasmiller View Post
I've done a cursory reading the SciAm article "Flashes In The Night" (April 2018), which talks about FRBs in general and this one in particular. It has an explanation of the frequency sweep for this signal. If they're correct (and I'm virtually certain they are), then the original signal was simply a broadband burst rather than a narrowband signal that changed frequency over time. That severely weakens the "alien radar" theory; I can still come up with ways that it makes sense*, but the natural explanations seem easier to me now.

Thank you for the updates, and for the thread itself.
W.D.Clinger is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 22nd April 2018, 05:17 AM   #21
JeanTate
Graduate Poster
 
Join Date: Nov 2014
Posts: 1,648
My thanks too ... somehow I completely missed this the first (and second!) time round.

Quote:
It has an explanation of the frequency sweep for this signal. If they're correct (and I'm virtually certain they are), then the original signal was simply a broadband burst rather than a narrowband signal that changed frequency over time.
I think this is referred to, by radio astronomers, as "dispersion". If so, it is commonly seen in observations of pulsars, and the "dispersion measure" is a quite useful variable, as it can give a handle on electron density or distance.

Here's a one-pager on it: Pulsar Dispersion Measure.
JeanTate is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 23rd April 2018, 06:08 AM   #22
dasmiller
Just the right amount of cowbell
 
dasmiller's Avatar
 
Join Date: Oct 2008
Location: Well past Hither, looking for Yon
Posts: 5,818
Originally Posted by JeanTate View Post
I think this is referred to, by radio astronomers, as "dispersion". If so, it is commonly seen in observations of pulsars, and the "dispersion measure" is a quite useful variable, as it can give a handle on electron density or distance.

Here's a one-pager on it: Pulsar Dispersion Measure.
Thanks for the link.

I was generally aware of dispersion, but I had incorrectly associated it with simply spreading out a pulse. I'd thought that the frequency-dependent delay would be small compared to the spreading, so the effect on a "pure" broadband pulse would be to smear the high frequencies more* than the low frequencies, rather than differentially shifting the arrival times.

Of course, it's easier to spot the error in one's thinking after reading an article that explains the error in one's thinking.

*This is probably true for interstellar dust, but evidently the reverse is true for electrons.
__________________
"In times of war, we need warriors. But this isn't a war." - Phil Plaitt
dasmiller is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 25th April 2018, 12:58 PM   #23
JeanTate
Graduate Poster
 
Join Date: Nov 2014
Posts: 1,648
Originally Posted by dasmiller View Post
Thanks for the link.

I was generally aware of dispersion, but I had incorrectly associated it with simply spreading out a pulse. I'd thought that the frequency-dependent delay would be small compared to the spreading, so the effect on a "pure" broadband pulse would be to smear the high frequencies more* than the low frequencies, rather than differentially shifting the arrival times.

Of course, it's easier to spot the error in one's thinking after reading an article that explains the error in one's thinking.

*This is probably true for interstellar dust, but evidently the reverse is true for electrons.
While the basic physics is relatively straight-forward (YMMV of course), its use in a rather niche area of (radio) astronomy means that few otherwise extremely well-informed people are even aware of it.

And FRBs make it a niche of a niche ... AFAIK, they are the first observations of (time varying) dispersion outside the Milky Way (or perhaps the Local Group).
JeanTate is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 30th April 2018, 05:18 AM   #24
JeanTate
Graduate Poster
 
Join Date: Nov 2014
Posts: 1,648
This recent, short, review paper may be of interest (Katz, 2018): Fast Radio Bursts:

Quote:
More than a decade after their discovery, astronomical Fast Radio Bursts remain enigmatic. They are known to occur at "cosmological" distances, implying large energy and radiated power, extraordinarily high brightness and coherent emission. Yet their source objects, the means by which energy is released and their radiation processes remain unknown. This review is organized around these unanswered questions.
JeanTate is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Reply

International Skeptics Forum » General Topics » Science, Mathematics, Medicine, and Technology

Bookmarks

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -7. The time now is 05:51 AM.
Powered by vBulletin. Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
2014, TribeTech AB. All Rights Reserved.
This forum began as part of the James Randi Education Foundation (JREF). However, the forum now exists as
an independent entity with no affiliation with or endorsement by the JREF, including the section in reference to "JREF" topics.

Disclaimer: Messages posted in the Forum are solely the opinion of their authors.