Author Topic: Could Fast Radio Bursts Be Powering Alien Probes?  (Read 6303 times)

Offline KelvinZero

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Re: Could Fast Radio Bursts Be Powering Alien Probes?
« Reply #20 on: 03/25/2017 11:00 PM »
... oh wait the studies I have seen all project no visible civilizations at very reasonable probabilities. It is a universe where life would not be real detectable. Look at old  BIS journals from decades ago. Plus some G. Landis papers - with very reasonable assumptions, The models predict nobody over running anything. Space is big and time is long and travel energy costs are high. I haven't  actually seen an in depth study that came to another conclusion. Just some simple projections like Fermi's and a few others the other way.
As I said, off topic here.

Im really busy at the moment but if you start another thread Im sure people can flood you with references.

I find it discouraging if you claim to have simply never encountered them though. That does not bode well for a future debate. Disagree, yes. But not encountered?

This is not a paper, but I remember the book https://en.wikipedia.org/wiki/The_Eerie_Silence as being something that struck the nail repeatedly on the head for me.

In any case, if we were seeing the flashes of interstellar travel from multiple different directions, that totally changes the parameters. Most of those arguments that attempt to explain underachievement that might allow other races to exist without detection are ruled out by multiple races all over the place succeeding in dabbling in interstellar flight.
« Last Edit: 03/25/2017 11:09 PM by KelvinZero »

Offline Star One

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Could Fast Radio Bursts Be Powering Alien Probes?
« Reply #21 on: 04/03/2017 09:12 PM »
The first interferometric detections of Fast Radio Bursts

(Submitted on 29 Mar 2017)

Quote
We present the first interferometric detections of Fast Radio Bursts (FRBs), an enigmatic new class of astrophysical transient. In a 180-day survey of the Southern sky we discovered 3 FRBs at 843 MHz with the UTMOST array, as part of commissioning science during a major ongoing upgrade. The wide field of view of UTMOST (≈9 deg2) is well suited to FRB searches. The primary beam is covered by 352 partially overlapping fan-beams, each of which is searched for FRBs in real time with pulse widths in the range 0.655 to 42 ms, and dispersion measures ≤2000 pc cm−3. Detections of FRBs with the UTMOST array places a lower limit on their distances of ≈104 km (limit of the telescope near-field) supporting the case for an astronomical origin. Repeating FRBs at UTMOST or an FRB detected simultaneously with the Parkes radio telescope and UTMOST, would allow a few arcsec localisation, thereby providing an excellent means of identifying FRB host galaxies, if present. Up to 100 hours of follow-up for each FRB has been carried out with the UTMOST, with no repeating bursts seen. From the detected position, we present 3σ error ellipses of 15 arcsec x 8.4 deg on the sky for the point of origin for the FRBs. We estimate an all-sky FRB rate at 843 MHz above a fluence Flim of 11 Jy ms of ∼78 events sky−1 d−1 at the 95 percent confidence level. The measured rate of FRBs at 843 MHz is of order two times higher than we had expected, scaling from the FRB rate at the Parkes radio telescope, assuming that FRBs have a flat spectral index and a uniform distribution in Euclidean space. We examine how this can be explained by FRBs having a steeper spectral index and/or a flatter logN-logF distribution than expected for a Euclidean Universe.

https://arxiv.org/abs/1703.10173
« Last Edit: 04/03/2017 09:14 PM by Star One »

Offline Star One

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Re: Could Fast Radio Bursts Be Powering Alien Probes?
« Reply #22 on: 04/04/2017 03:47 PM »
More to the above.

New Options for Locating Fast Radio Bursts

http://www.centauri-dreams.org/?p=37448

Offline Vultur

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Re: Could Fast Radio Bursts Be Powering Alien Probes?
« Reply #23 on: 04/09/2017 05:25 AM »
Any collection of beings would inevitably have to follow the same pattern unless somehow constrained by a single central entity.  That's just because whichever individuals reproduce more will become more prevalent. 

I dunno. That would assume that the cultural traits that lead to reproducing more are "reliably" transmitted between generations, so that a culture that reproduces more becomes dominant. There are many reasons that might not hold true.

Higher reproduction might also be tied to higher instability in other ways, thus greater tendency towards collapse or destructive war... or just unwillingness to undertake interstellar colonization.

If FTL is impossible and Bussard ramjets etc. don't prove practical for anyone, then interstellar stuff will require very long timescales. Interstellar colonization then can't be driven by population pressures... it's just too slow.

Perhaps the only civilizations which do anything interstellar are those composed of extremely long-term thinkers, possibly extremely-long-lifespan entities.

--

And the universe as a whole shouldn't be "terraformed" or whatever by now.

If (as I rather expect) high-relativistic speeds are impractical for anyone, intergalactic travel should be insanely difficult even for the most advanced civilizations (making a vehicle, even a worldship, last the 29 million years it would take to get from here to Andromeda at 10% lightspeed, without any significant time-dilation benefit?)

Offline MP99

Re: Could Fast Radio Bursts Be Powering Alien Probes?
« Reply #24 on: 04/09/2017 07:55 PM »
The huge problem with any alien hypothesis is that it has to explain why they are such underachievers.

If these radiobursts were all aliens travelling from A to B, why haven't they converted the universe yet? Any sort of exponential growth would have radically changed the universe's appearance by now.

We don't have an explanation for dark energy. Possibly this is some side effect or intentional effect of advanced civilisations?

I wonder whether Mach Effect thrusters might have this as a side effect?

Cheers, Martin

Offline MP99

Re: Could Fast Radio Bursts Be Powering Alien Probes?
« Reply #25 on: 04/09/2017 08:32 PM »
Assuming they could get up to 50% of c and they were 1 billion light years from Earth their first ships wouldn't start showing up any sooner than a billion years after they were first detected.

Note that the paper discusses that the beams sweep across us, not that they are necessarily aimed at us. Of course, there could be further launches aimed at us which we wouldn't necessarily see.

Although I take the point that watching over a long enough period may eventually reveal beams from closer sources.

Cheers, Martin
« Last Edit: 04/09/2017 08:33 PM by MP99 »

Offline ChrisWilson68

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Re: Could Fast Radio Bursts Be Powering Alien Probes?
« Reply #26 on: 04/13/2017 10:30 PM »
The universe doesn't get converted instantly.  There is some lapse of time where it is being converted,
I won't continue this here because I would be pulling the thread too far off topic.

This is a more general problem that has been explored in detail. Lots of people have done the math and come to the same conclusion.

You've got to be kidding.  There's no consensus on this at all.  There's vigorous debate about this among scientists.  The math is only as good as the assumptions you put into your calculations.

Offline ChrisWilson68

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Re: Could Fast Radio Bursts Be Powering Alien Probes?
« Reply #27 on: 04/13/2017 10:34 PM »
Any collection of beings would inevitably have to follow the same pattern unless somehow constrained by a single central entity.  That's just because whichever individuals reproduce more will become more prevalent. 

I dunno. That would assume that the cultural traits that lead to reproducing more are "reliably" transmitted between generations, so that a culture that reproduces more becomes dominant.

It's not really reproduction if the offspring don't share traits like that.  For your theory to hold, there would have to never be true reproduction.  For my point to hold, there would only rarely have to be civilizations that actually reproduce and they would quickly dominate.

Offline KelvinZero

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Re: Could Fast Radio Bursts Be Powering Alien Probes?
« Reply #28 on: 04/14/2017 03:15 AM »
The universe doesn't get converted instantly.  There is some lapse of time where it is being converted,
I won't continue this here because I would be pulling the thread too far off topic.

This is a more general problem that has been explored in detail. Lots of people have done the math and come to the same conclusion.

You've got to be kidding.  There's no consensus on this at all.  There's vigorous debate about this among scientists.  The math is only as good as the assumptions you put into your calculations.
I can't respond to this because I don't really know what you are referring to. Im not even sure if I would agree with your interpretation of what I said. For all I know you are just reversing Cinder's statement.

I think the Paul Davies book "The eerie silence" pretty much covered positions that seem obvious to me. (been a while since I read it though) I think he is Chair of SETI so I don't think I am taking an extreme position against the possibility of aliens.

Im not saying there _cannot_ be reasons that prevent our spreading, just that if the "Great filter" is applied after this point in history then there is something strange, unexplained and dismal ahead of us. This is made even harder to explain if countless races all around us are achieving interstellar flight, and we are seeing their flashes all around us, but then we see nothing else... this is the only part that actually makes this conversation relevant to this thread.

Offline Vultur

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Re: Could Fast Radio Bursts Be Powering Alien Probes?
« Reply #29 on: 04/14/2017 05:27 AM »
Any collection of beings would inevitably have to follow the same pattern unless somehow constrained by a single central entity.  That's just because whichever individuals reproduce more will become more prevalent. 

I dunno. That would assume that the cultural traits that lead to reproducing more are "reliably" transmitted between generations, so that a culture that reproduces more becomes dominant.

It's not really reproduction if the offspring don't share traits like that.  For your theory to hold, there would have to never be true reproduction.  For my point to hold, there would only rarely have to be civilizations that actually reproduce and they would quickly dominate.

Not necessarily, if reproduction rate is not driven by genetic/biological traits. It already isn't on Earth - it's primarily driven by economic & social factors.


Im not saying there _cannot_ be reasons that prevent our spreading, just that if the "Great filter" is applied after this point in history then there is something strange, unexplained and dismal ahead of us.

Assuming there is anything like a 'Great Filter'. There needn't be, if extremely old/advanced civilizations tend not to be recognizable by us (either because they tend to be very stable, non-spreading & relatively low energy*, or because we have already observed their work but mistake it for natural phenomena).

*Advanced knowledge doesn't in itself imply high energy/resource use.

If there is a 'Great Filter', though, it seems likelier to be behind us than ahead. The technology you need to blow up civilization is the same technology that you need to get into space - it's inconceivable to me that there would be tons of civilizations but they all destroy themselves without exception in the 100 year window or so when they have the capacity for globally destructive war but before they have significant space colonies. (And if you built 'Project Orion' ships, that window could be something like 20 years.)

Especially since a civilization-destroying war wouldn't necessarily destroy the species, and even a thousand years or so to struggle back from a Dark Age is an eye-blink on an astronomical scale.

Offline KelvinZero

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Re: Could Fast Radio Bursts Be Powering Alien Probes?
« Reply #30 on: 04/14/2017 11:18 AM »
Is it worth starting a thread just on the Fermi paradox?

I find this guy quite entertaining, and he has a section on the Fermi paradox and various proposed solutions.
https://www.youtube.com/playlist?list=PLIIOUpOge0LulClL2dHXh8TTOnCgRkLdU

Online RonM

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Re: Could Fast Radio Bursts Be Powering Alien Probes?
« Reply #31 on: 04/14/2017 02:37 PM »
Is it worth starting a thread just on the Fermi paradox?

It's been discussed many times in many threads. The actual "Fermi's Paradox" thread was moved to moderation, never to be seen again. Might work if people remember to respect other points of view, but for some reason people get really worked up over this purely theoretical discussion.

Offline high road

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Re: Could Fast Radio Bursts Be Powering Alien Probes?
« Reply #32 on: 04/14/2017 03:16 PM »
Any collection of beings would inevitably have to follow the same pattern unless somehow constrained by a single central entity.  That's just because whichever individuals reproduce more will become more prevalent. 

I dunno. That would assume that the cultural traits that lead to reproducing more are "reliably" transmitted between generations, so that a culture that reproduces more becomes dominant.

It's not really reproduction if the offspring don't share traits like that.  For your theory to hold, there would have to never be true reproduction.  For my point to hold, there would only rarely have to be civilizations that actually reproduce and they would quickly dominate.

They would dominate, reproduce ever faster until the growth in production of rare desirable goods can no longer keep up with their population growth and they are diminished by the resulting wars every time. If interstellar travel is hard, a quickly reproducing species cannot cross to another star. The only ones that can, are the ones that limit their population growth. As a result they don't achieve the population densities our telescopes would pick up, even if they do colonize many stars.

 
Call it a filter if you want. I rather see it as an example that the exponential growth model is a simplification that doesn't live up to reality.

Offline wes_wilson

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Re: Could Fast Radio Bursts Be Powering Alien Probes?
« Reply #33 on: 04/17/2017 11:34 PM »
The huge problem with any alien hypothesis is that it has to explain why they are such underachievers.

If these radiobursts were all aliens travelling from A to B, why haven't they converted the universe yet? Any sort of exponential growth would have radically changed the universe's appearance by now.

I don't think you can even argue that every single species is obsessed with conservation, because the universe as it is, is very wasteful, with suns pouring all but a billionth of their energy into the void.

About 70% of the universe is "dark matter"...  Maybe the universe's appearance has been changed radically and we're just still looking for a non-intellect driven process to explain it.
@SpaceX "When can I buy my ticket to Mars?"

Offline KelvinZero

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Re: Could Fast Radio Bursts Be Powering Alien Probes?
« Reply #34 on: 04/18/2017 04:27 AM »
About 70% of the universe is "dark matter"...  Maybe the universe's appearance has been changed radically and we're just still looking for a non-intellect driven process to explain it.
I have speculated about dark matter myself, wondered if most of the universe is hidden away in dark "matrioshka brain" like objects. Could be Dyson spheres. Could be as dense as neutron stars, could be some material beyond our comprehension at the moment. Maybe we are living in the scraps. What if suns could hold civilisations of thinking plasma vortices or something, and all the planets were just like dandruff to them? Just of no interest?

These sorts of ideas have also been considered by other people and you can probably find mention of them and some discussion of the common objections in that Isaac Arthur link I posted just a bit earlier.

Offline stefan r

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Re: Could Fast Radio Bursts Be Powering Alien Probes?
« Reply #35 on: 04/18/2017 05:13 PM »
The lack of any relatively local aliens scooting around in their light sail starships isn't fatal to the hypothesis. The FRBs have been only observed in galaxies billions of light years away. The method of travel isn't faster than light. So the aliens would show up some time after their beams could be detected equivalent to how much slower their ships are. Likewise if we assume an alien civilization spreading out in all directions then they would do so only as fast as their ships could take them and their efforts to do so would be detectable long before their ships spread out. That also assume that they don't spend any time stopping to colonize or get some fresh air which would add even more time between the first detections and their arrival.

Assuming they could get up to 50% of c and they were 1 billion light years from Earth their first ships wouldn't start showing up any sooner than a billion years after they were first detected. If we are waiting for some company to drop by it gets even worse if we use some more conservative figures. FRB 121102 is thought to have happened 3 billion LY away and if their travel speed is only 20% (Breakthrough Starshot's speed) of c then it would take 15 billion years for them to get here and they would have been detectable for 12 billion years.
Not quite.  The standard model has the universe expanding.  v = H0D  So at 1 Gpc distance:
 v = 68,000 km/s. 
Launching at 20% c gives 59,600 km/s
So they would still drifting away from us if H0 is correct.

Online punder

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Re: Could Fast Radio Bursts Be Powering Alien Probes?
« Reply #36 on: 04/18/2017 05:31 PM »
About 70% of the universe is "dark matter"...  Maybe the universe's appearance has been changed radically and we're just still looking for a non-intellect driven process to explain it.
I have speculated about dark matter myself, wondered if most of the universe is hidden away in dark "matrioshka brain" like objects. Could be Dyson spheres. Could be as dense as neutron stars, could be some material beyond our comprehension at the moment. Maybe we are living in the scraps. What if suns could hold civilisations of thinking plasma vortices or something, and all the planets were just like dandruff to them? Just of no interest?

These sorts of ideas have also been considered by other people and you can probably find mention of them and some discussion of the common objections in that Isaac Arthur link I posted just a bit earlier.

It could be a testable hypothesis... if the percentage of dark matter vs. "normal" is found to be increasing over time, a possible reason (of course the last resort, after all natural explanations are exhausted) is that We and Everything Else Are Being Assimilated.   :o

Offline stefan r

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Re: Could Fast Radio Bursts Be Powering Alien Probes?
« Reply #37 on: 04/19/2017 02:08 AM »
... wondered if most of the universe is hidden away in dark "matrioshka brain" like objects. Could be Dyson spheres....

Both the Dyson sphere and matrioshka brain radiate with the same luminosity as the star they draw energy from.  The luminosity is low temperature emission. 

Maybe something like this:  ll pegasi

Offline high road

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Re: Could Fast Radio Bursts Be Powering Alien Probes?
« Reply #38 on: 04/19/2017 06:12 PM »
... wondered if most of the universe is hidden away in dark "matrioshka brain" like objects. Could be Dyson spheres....

Both the Dyson sphere and matrioshka brain radiate with the same luminosity as the star they draw energy from.  The luminosity is low temperature emission. 

Maybe something like this:  ll pegasi

Sure, the luminosity is the same, but considering the re-emitted flux is much lower due to the bigger surface area, wouldn't a star with a partial Dyson Swarm/Matrioshka Brain/... appear to us as a smaller and/or colder star that is somehow much heavier than it seems to be based on its apparent luminosity? Isn't the star's brightness our main indicator of its size? So how would we know our formula to calculate their size is influenced by such phenomena unless we see large differences between the sizes we think they are and the gravity they appear to have? (which happens to be the case)

Offline stefan r

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Re: Could Fast Radio Bursts Be Powering Alien Probes?
« Reply #39 on: 04/20/2017 03:09 AM »
... wondered if most of the universe is hidden away in dark "matrioshka brain" like objects. Could be Dyson spheres....

Both the Dyson sphere and matrioshka brain radiate with the same luminosity as the star they draw energy from.  The luminosity is low temperature emission. 

Maybe something like this:  ll pegasi

Sure, the luminosity is the same, but considering the re-emitted flux is much lower due to the bigger surface area, wouldn't a star with a partial Dyson Swarm/Matrioshka Brain/... appear to us as a smaller and/or colder star that is somehow much heavier than it seems to be based on its apparent luminosity? Isn't the star's brightness our main indicator of its size? So how would we know our formula to calculate their size is influenced by such phenomena unless we see large differences between the sizes we think they are and the gravity they appear to have? (which happens to be the case)

A good example is four 15 watt florescent bulbs, a 60 watt incandescent bulb, and an electric heater using 60 watts.  Normal human reaction is to say that the florescent bulbs are much "brighter" and that the electric heater is not a light.  The bolometric luminosity is the same for each item (assuming we ignore convection or add watts to compensate).  The visual luminosity of the florescent is much higher.  In parts of the infrared the incandescent has highest luminosity.  In microwave frequency the heater is much "brighter". 

I was assuming total sphere.  If you had a 20% continuous coverage the spectrum would look odd.  At high frequencies you would have black body radiation 20% smaller than expected for a similar size star then a step up to a spectrum for a cooler black body with a much larger surface area.

My instinct is that variable coverage is more likely in a partial sphere.  As coverage varies from 1% to 20% the visual part of the star's spectrum would vary between 80 and 99% visual luminosity.  The far infra-red spectrum would also vary but not necessarily synchronized with the visual variability.  The radiators could be on multiple surfaces.  Is possible that most would radiate heat away from the star so far infra-red would vary inverse to visual. 

A partial dyson sphere acting as a Shkadov thruster would have less infra red (compared to stationary) if it was moving towards us or perpendicular.  If they are moving away from us the infra red luminosity would be much higher.  Mirrors could create strange stars with higher visual luminosity too but doubling is unlikely. 

Orbiting mirrors and radiators also red and blue shift as they move. 

All stars are a point of light in our telescopes. 

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