Here is an index of different theories that astrophysics departments have developed to explain these FRBs (Fast Radio Bursts): https://frbtheorycat.org/index.php/Main_Page. There are links to all of the corresponding papers as well.
> Researchers monitored the known repeater FRB 121102 with the Lovell Telescope, a 250-foot-wide (76 meters) radio dish at Jodrell Bank Observatory in England, over the course of five years. They found strong indications of a 157-day activity cycle; 121102 seems to flare up for 90 days and then go silent for 67, the team reported in a new study.
> It's unclear what's behind such cyclic activity, though scientists do have a few ideas. For example, periodic flare-ups could be caused by a wobble in the rotational axis of a highly magnetized neutron star known as a magnetar. Or they could be linked to the orbital motions of a neutron star in a binary system.
Could this be the Dzhanibekov Effect ? Funny I just stumbled upon it today!
If Earth can maintain a stable axis, such wobbly oscillating axis could be that star's "normal". Just guessing! Or may be am too wrong. I am not a physicist!
The idea that aliens would use these to propel ships is rather ludicrous, and highly unlikely. The nearest galaxy is 25k light years away so even at the maximum speed it would take 25 thousand years to travel here.
That being said, it must be something exceptionally energetic.. wish I could see it.
Why do you assume they need to travel between galaxies? They could be going to the next solar system over and we're simply seeing the leakage of their propulsion. Just because the light travels across galaxies doesn't mean it's purpose is to travel across galaxies. Moreover, a species that can unleash this much energy has probably conquered such things as mortality and age related decay.
> The nearest galaxy is 25k light years away so even at the maximum speed it would take 25 thousand years to travel here.
Given your arithmetic, I assume by "maximum speed" you mean the speed of light, in which case travel wouldn't take 25k years. It would in fact be instantaneous. At relativistic speeds, distances contract and time dilates.
Now, this is all moot because this:
> The idea that aliens would use these to propel ships is rather ludicrous, and highly unlikely.
... is absolutely correct. No amount of energy will propel a massive object to the speed of light.
edit: I realized I may have misinterpreted. From the perspective of someone watching their own kind travel that expanse, it would indeed appear to the outside observer to take 25k years to travel.
>> The nearest galaxy is 25k light years away so even at the maximum speed it would take 25 thousand years to travel here.
We're talking about aliens, right? Who says they must have human life spans? Perhaps a 25k year trek is a walk in the park for them.
I find this assumption (that life on other planets will have the same duration as life on Earth) very often in discussions of possible discovery of or interaction with alien civilisations. It is a huge assumption, on par with assuming that aliens must have a head, two hands and two feet and communicate by making sounds, like we do.
Accordingly, the fact that we are limited in our ability to travel from star to star because of short duration of our life spans relative to the speed of light, is not to be taken for granted as a universal characteristic of all life in the universe.
I think it's extremely unlikely to be aliens, since each time in the past something like this has come up a non-aliens explanation has been found.
That said, I don't think distances/timescales is a great argument against aliens, since it makes a lot of assumptions. They could use robotic ships, or generation ships (no telling how long their generations might last.) If they're moving at a significant fraction of the speed of light, relativistic effects could be dramatically reducing their perceived mission duration. Maybe the biology of their species is such that cloning or suspended animation is straight forward.
What if it's something simple like a galactic lighthouse of sorts? Not sure why I'm being downvoted. Lighthouses use directional light and if you're stationary you'll see the light at certain increments of time. An advanced race might be saying "don't go here" or "be careful." Just like we do for ships here.
There are lots of naturally occurring ones such as pulsars, enough to the point they could be used for 3D navigation, if you can find your distance to them.
It's an old idea: Pioneer and later spacecraft have a plaque showing our location relative to distances to pulsars we can see from Earth.
edit: I guess if you're a Type 3 civilization with nothing better to do, you wouldn't have to set up lighthouses but you could better direct your attention to moving galaxies around or whatever.
AFAIK, not directly. The only way possible would be to observe one behind a gravitational lens. That would appear as multiple sources, allowing us to observe the object from slightly different directions, confirming that the flashes are indeed at least cone-shaped.
"They found strong indications of a 157-day activity cycle; 121102 seems to flare up for 90 days and then go silent for 67, the team reported in a new study."
Maybe there's nothing to it, but both 157 and 67 are primes.
They may be primes, but they are primes of an Earth day, which, as far as I am aware, is the only place where those numbers would be 157 & 67.
As an example, our day on Earth is roughly 1440 minutes, while on Mars it is 1477 minutes. So on Mars it would be 153 & 65 day intervals.
I deliberately chose the closest comparison to Earth. Had I chosen any other planet in our solar system, the numbers would have been much, much more different (on Jupiter it would be 406 & 173 days, respectively).
A "day" has no meaning anywhere but on Earth. So if you are going to make the leap that the usage of primes is a sign of intelligence, you would also have to believe that this message was meant for us and only us. However the burst seems to originate from 3 billion light-years away so they would have had to start sending the message very shortly after life began on the Earth. Seems incredibly unlikely.
EDIT: Also an Earth day is not a constant value. It would have been much shorter 3 billion years ago and this cycle wouldn't be repeating in prime numbers. This theoretical alien intelligence would therefore need to not only be able to recognize life on Earth in the first few hundred million years it existed. It would also need to be able to accurately model the Earths orbit over the next 3 billion years in order to customize the message for when it would be received. All that work to send the message and they still needed to luck out that the 3 billion year journey happened to reach us at nearly the perfect time for our technology to advance enough so we could hear it.
The thing with these is that they have to be very directional to even reach us, and (in the article), it mentions the bursts have the energy of a century of our sun's output; if it is alien networking gear, they'd have to be able to generate that power somehow. Dyson spheres wouldn't cut it.
[+] [-] mandarg|5 years ago|reply
[+] [-] airstrike|5 years ago|reply
https://ui.adsabs.harvard.edu/abs/2017ApJ...837L..23L/abstra...
[+] [-] raghava|5 years ago|reply
> It's unclear what's behind such cyclic activity, though scientists do have a few ideas. For example, periodic flare-ups could be caused by a wobble in the rotational axis of a highly magnetized neutron star known as a magnetar. Or they could be linked to the orbital motions of a neutron star in a binary system.
Could this be the Dzhanibekov Effect ? Funny I just stumbled upon it today!
https://www.youtube.com/watch?v=1VPfZ_XzisU
If Earth can maintain a stable axis, such wobbly oscillating axis could be that star's "normal". Just guessing! Or may be am too wrong. I am not a physicist!
[+] [-] simonebrunozzi|5 years ago|reply
Man, don't be too modest. With these few lines I'd be tempted to award you a Nobel prize if I were the judge :)
(exaggerating a bit, but more seriously: you seem to have your chops in this department).
[+] [-] Vysero|5 years ago|reply
That being said, it must be something exceptionally energetic.. wish I could see it.
[+] [-] marcinzm|5 years ago|reply
[+] [-] TomBombadildoze|5 years ago|reply
Given your arithmetic, I assume by "maximum speed" you mean the speed of light, in which case travel wouldn't take 25k years. It would in fact be instantaneous. At relativistic speeds, distances contract and time dilates.
Now, this is all moot because this:
> The idea that aliens would use these to propel ships is rather ludicrous, and highly unlikely.
... is absolutely correct. No amount of energy will propel a massive object to the speed of light.
edit: I realized I may have misinterpreted. From the perspective of someone watching their own kind travel that expanse, it would indeed appear to the outside observer to take 25k years to travel.
[+] [-] simonebrunozzi|5 years ago|reply
[+] [-] YeGoblynQueenne|5 years ago|reply
We're talking about aliens, right? Who says they must have human life spans? Perhaps a 25k year trek is a walk in the park for them.
I find this assumption (that life on other planets will have the same duration as life on Earth) very often in discussions of possible discovery of or interaction with alien civilisations. It is a huge assumption, on par with assuming that aliens must have a head, two hands and two feet and communicate by making sounds, like we do.
Accordingly, the fact that we are limited in our ability to travel from star to star because of short duration of our life spans relative to the speed of light, is not to be taken for granted as a universal characteristic of all life in the universe.
[+] [-] catalogia|5 years ago|reply
That said, I don't think distances/timescales is a great argument against aliens, since it makes a lot of assumptions. They could use robotic ships, or generation ships (no telling how long their generations might last.) If they're moving at a significant fraction of the speed of light, relativistic effects could be dramatically reducing their perceived mission duration. Maybe the biology of their species is such that cloning or suspended animation is straight forward.
[+] [-] unknown|5 years ago|reply
[deleted]
[+] [-] kristopolous|5 years ago|reply
[+] [-] DrBazza|5 years ago|reply
"At its equator it is spinning at approximately 24% of the speed of light, or over 70,000 km per second."
https://en.wikipedia.org/wiki/PSR_J1748%E2%88%922446ad
Magnetars, even more so - and can have a measurable effect on the Earth's atmosphere:
https://slate.com/technology/2012/12/cosmic-blast-magnetar-e...
https://en.wikipedia.org/wiki/SGR_1806%E2%88%9220
[+] [-] kitd|5 years ago|reply
[+] [-] zachrip|5 years ago|reply
[+] [-] imglorp|5 years ago|reply
It's an old idea: Pioneer and later spacecraft have a plaque showing our location relative to distances to pulsars we can see from Earth.
https://en.wikipedia.org/wiki/Pulsar
https://en.wikipedia.org/wiki/Pulsar#/media/File:Pioneer_pla...
edit: I guess if you're a Type 3 civilization with nothing better to do, you wouldn't have to set up lighthouses but you could better direct your attention to moving galaxies around or whatever.
[+] [-] zatel|5 years ago|reply
[+] [-] throw1234651234|5 years ago|reply
[+] [-] aruggirello|5 years ago|reply
Edit: clarified
[+] [-] bkrishnan|5 years ago|reply
Maybe there's nothing to it, but both 157 and 67 are primes.
[+] [-] MR4D|5 years ago|reply
As an example, our day on Earth is roughly 1440 minutes, while on Mars it is 1477 minutes. So on Mars it would be 153 & 65 day intervals.
I deliberately chose the closest comparison to Earth. Had I chosen any other planet in our solar system, the numbers would have been much, much more different (on Jupiter it would be 406 & 173 days, respectively).
[+] [-] slg|5 years ago|reply
EDIT: Also an Earth day is not a constant value. It would have been much shorter 3 billion years ago and this cycle wouldn't be repeating in prime numbers. This theoretical alien intelligence would therefore need to not only be able to recognize life on Earth in the first few hundred million years it existed. It would also need to be able to accurately model the Earths orbit over the next 3 billion years in order to customize the message for when it would be received. All that work to send the message and they still needed to luck out that the 3 billion year journey happened to reach us at nearly the perfect time for our technology to advance enough so we could hear it.
[+] [-] teraflop|5 years ago|reply
https://arxiv.org/pdf/2003.03596.pdf
[+] [-] biolurker1|5 years ago|reply
[+] [-] unknown|5 years ago|reply
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