Could fast radio bursts be alien radar signals?

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Discussion Overview

The discussion revolves around the hypothesis that fast radio bursts (FRBs) could be signals generated by extraterrestrial technology, specifically radar signals. Participants explore the characteristics of FRBs, their detection across various frequencies, and the potential implications of their duration and power. The conversation touches on both astrophysical explanations and speculative ideas regarding artificial origins.

Discussion Character

  • Debate/contested
  • Exploratory
  • Technical explanation

Main Points Raised

  • Some participants note that FRBs have been detected across a wide range of frequencies, suggesting a diversity of sources and conditions contributing to their occurrence.
  • One hypothesis posits that FRBs could be artificially generated within our galaxy, potentially resembling radar pulses in duration.
  • Others express skepticism about the feasibility of FRBs as radar signals, questioning the practicality of using such signals for detection over interstellar distances.
  • Concerns are raised regarding the effectiveness of FRBs as radar pulses, with suggestions that more sophisticated techniques, such as pseudo-random binary sequences, are typically employed in radar technology.
  • Some participants reference a leading theory that magnetars may be a source of FRBs, while acknowledging that the evidence supporting this theory is still limited.
  • Discussion includes the potential distortion of signals as they travel through the interstellar medium, which may affect their characteristics and detectability.
  • Participants highlight the lack of a clear statistical link between FRBs and the plane of the Milky Way, complicating the alien hypothesis.

Areas of Agreement / Disagreement

Participants do not reach a consensus on whether FRBs could be artificial signals or the implications of their characteristics. Multiple competing views remain regarding their origins, detection methods, and the validity of the alien radar hypothesis.

Contextual Notes

Limitations include the unresolved nature of the evidence linking FRBs to magnetars, the assumptions regarding the distances involved in potential radar applications, and the complexities of interpreting galactic coordinates in relation to FRB distributions.

Line_112
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TL;DR
Fast radio bursts are rarely identified with galaxies and according to some hypotheses they may be a form of alien signals. I have found many similarities with pulse radar signals, but my knowledge in this area is not enough to draw any definite conclusions.
Both have short pulses of emission and a wide spectral bandwidth, covering a wide variety of frequencies:
"Fast Radio Bursts (FRBs) are detected over a wide range of radio frequencies, including frequencies around 1400 MHz, but have also been detected at lower frequencies, particularly in the 400–800 MHz range. Russian astronomers recently detected a powerful burst at 111 MHz, expanding our understanding of the FRB range.
Frequency Ranges:
1400 MHz:
Many of the known FRBs have been detected at these frequencies, making them one of the prime observing ranges.
400–800 MHz:
Some FRBs have been detected at lower frequencies, demonstrating that these phenomena are not limited to high frequencies.
111 MHz:
This is an example of an FRB being detected at an even lower frequency, indicating the diversity of sources and conditions that contribute to their occurrence."

According to one hypothesis, the bursts occur within our galaxy and may be artificially generated. In this case, their power will be much lower, and the pulses will probably be similar to radar pulses. Overall, this hypothesis is consistent with the data on fast radio bursts:
"Since the first FRB was detected in 2007, astronomers have catalogued more than 100 such events from distant sources scattered throughout the Universe, beyond our own Galaxy. Most of these events have been isolated. They last a short time and then disappear completely. In a few cases, astronomers have observed FRBs multiple times from the same source, but without any rhythm." https://indicator.ru/astronomy/obnaruzheny-povtoryayushiesya-bystrye-radiovspleski-18-06-2020.htm

The duration of radio bursts is approximately the same as that of radar pulses - thousandths of a second or less:
"Analyzing a 400-terabyte array of astronomical data that the Green Bank radio telescope (USA) has been collecting since 2017 for Yuri Milner's Breakthrough Listen project to search for extraterrestrial intelligent life, the researchers found several dozen fast radio pulses in it. Of this number, eight had a very short duration - only microseconds. The shortest of them lasted 6.5 microseconds, the longest - 86. Let us recall that a fast radio burst usually lasts at least a millisecond (there are 1000 microseconds in it)."
https://naked-science.ru/article/astronomy/astronomy-obnaruzhili-2

Radar pulses generally to be shorter radio burst pulses, but I found a natural explanation for this difference. It is known that when moving through the interstellar medium, radio pulses are stretched due to differences in the speed of high and low frequencies. Therefore, distant radar signals will seem longer than they actually are. Very short pulses will lose more peak power when stretched than longer ones, so they may be undetectable from large distances.

It seems that, at a superficial examination by a non-specialist, the hypothesis looks quite respectable. Perhaps there are some nuances of differences that are unknown to me.
 
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There are a lot of reasons to doubt that FRBs are deliberately engineered and fabricated. But their application for radar is especially doubtful.
What range are you supposing for this radar? Perhaps 1 light year? Which would mean that the operator will need to be very patient - his radar return will take 2 years. He also needs to light up his target with enough power to detect it - at a range of 1 light year!

With regard to the frequency ranges - radar frequency bands are selected for the specific purpose at hand. Are you suggesting that this radar is intended to "track" rocket-size objects? How much energy would need to be reflected off Elon's star ship before it could be detected from the nearest star? (perhaps that is why, until last night, they were blowing up).

If all you are trying to do is detect planets, you don't need radar at all and you certainly would use radar in the VHF range. We humans are doing a fair job of finding planet using other methods.
 
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Line_112 said:
The duration of radio bursts is approximately the same as that of radar pulses - thousandths of a second or less:
FRBs make the worst RADAR pulses. Chirps, sweeps, and bursts of spaced pulses are much better suited for RADAR, since they allow lower power to be used, with an improved signal-to-noise ratio.

Pseudo Random Binary Sequences are used for long distance ranging between spaceships in the solar system. PRBS codes are also used for GPS satellites. The reason PRBS are used is that they are spread spectrum signals, and detection involves de-spreading the signal, lifting it out of the noise, while pulses, noise and jamming are spread across the spectrum into the noise.

FRBs seem to be brute force, using none of the clever tricks we use for RADAR today.
 
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Baluncore said:
FRBs seem to be brute force, using none of the clever tricks we use for RADAR today.
It can be assumed that on the way to Earth under the influence of the interstellar medium the signal is heavily distorted and becomes little like an artificial structured signal. I read that this is what is associated with the distortion of signals coming from radio pulsars.
 
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willyengland said:
The observations add evidence to a leading theory that magnetars, or the highly magnetized remnants of dead stars, could be a source of fast radio bursts.
But the evidence base is very thin so far.
"Most of them are not repeatable, most of them are highly unpredictable, and only five out of more than 100 have been traced back to their source galaxy."
https://www.sciencealert.com/a-gala...-something-shockingly-like-a-fast-radio-burst

One was associated with a magnetar in the Milky Way, as stated in the same article. The probability of a random coincidence (spatial or temporal) of a radio burst and an X-ray burst is not indicated there. According to the link you provided, there is - 0.36, that is, 36%, and this is quite a lot. Even if some of them are associated with magnetars or other astrophysical sources, perhaps another part is associated with something else.
But the lack of a statistical link between the radio bursts and the plane of the Milky Way is confusing. If we adhere to the alien hypothesis, then almost all bursts should come from relatively close distances to us (no more than half the thickness of the galactic disk), otherwise the concentration in the plane of the galaxy would be noticeable. This, of course, is a big challenge for the artificial origin hypothesis. Unfortunately, I do not understand galactic coordinates, but this diagram from Wikipedia (https://en.wikipedia.org/wiki/Fast_radio_burst#/media/File:CHIME-FRBcatalog1.jpg) seems to show the concentration of bursts in a certain area, although this article says there is no reference to the plane of the Milky Way. If these are extragalactic objects, then it is obvious that they should not be in the plane of the galaxy, since the galaxy itself will screen the radiation. If they come from all directions equally, then the hypothesis of localization within a radius of half the galactic disk seems the most plausible.
 
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Line_112 said:
Unfortunately, I do not understand galactic coordinates, but this diagram from Wikipedia (https://en.wikipedia.org/wiki/Fast_radio_burst#/media/File:CHIME-FRBcatalog1.jpg) seems to show the concentration of bursts in a certain area, although this article says there is no reference to the plane of the Milky Way.
It's an equal-area projection of the sky. You're looking towards the centre of the galaxy, edge-on, with the 0th latitude being the plane of the Galaxy.
The only concentration I see is the one associated with exposure times - you catch more events where you look at longer.

Line_112 said:
If these are extragalactic objects, then it is obvious that they should not be in the plane of the galaxy, since the galaxy itself will screen the radiation.
I don't think it's obvious at all. The interstellar medium may screen all of it, some of it, none of it, or not enough to matter. You'd have to quantify this before basing an argument on it.
 
Baluncore said:
FRBs make the worst RADAR pulses. Chirps, sweeps, and bursts of spaced pulses are much better suited for RADAR, since they allow lower power to be used, with an improved signal-to-noise ratio.
[bolding added]

This important distinction bears repeating. Pulsed RADAR systems operate optimally at low power, to improve signal-to-noise-ration (SNR) but also to minimize clutter returns and generated RF interference. RAdio Detection And Ranging implies not just artificial source but a use scenario such as detecting objects at certain size ranges at predetermined distances.

Pulsed RADAR system wavelengths are selected to detect objects in expected size ranges such as spacecraft or asteroids. Examining wavelengths of suspected alien pulses could provide rough estimates of expected target dimensions.

Artificial pulse duration and repetition rates provide rough estimates of expected target velocity and persistence; that is, how long operators expect an object to be illuminated. A suspect RF signal that exhibits pulse characteristics that vary significantly from expected natural sources might elicit further examination.

Articial RADAR pulses often contain additional encoded information riding a primary signal, not expected in natural RF sources. Similar observations apply across the EM spectrum as the OP mentions, including visible light and infrared. A different but related question becomes how we use natural RF sources to illuminate, detect and track other objects in space.
 
If every transmission from a radio source was transmitted temporally, the resolt would be picked up a "noise" because of wave compression.
 
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Mork728 said:
If every transmission from a radio source was transmitted temporally, the resolt would be picked up a "noise" because of wave compression.
I'm not understanding what you are trying to say. Can you please try again with more details? Thanks.
 

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