How we found the source of the mystery signals at Parkes Radio Telescope (2015)(theconversation.com)
theconversation.com
How we found the source of the mystery signals at Parkes Radio Telescope (2015)
https://theconversation.com/how-we-found-the-source-of-the-mystery-signals-at-the-dish-41523
12 comments
Does this mean microwaves don't stop quickly enough when opened early?
It all depends on the microwave oven. The majority of ovens open with a mechanical lever (in many cases, can be also be opened by hand by grabbing the edge of the door) which will trigger a sensor that shuts down the emitter while the door is opening. Depending on how fast the door was opened, microwaves may still be bouncing around and could leak out.
OTH some ovens, like the more modern builtin cabinet microwaves, have an electronic button that shuts down the emitter before triggering the door latch/spring to open.
In any case, the duration and the amount of energy released during the opening motion vs. emission lag will probably not be enough to significantly harm you as dielectric processes need to establish a field to polarize molecules that will heat up as consequence.
OTH some ovens, like the more modern builtin cabinet microwaves, have an electronic button that shuts down the emitter before triggering the door latch/spring to open.
In any case, the duration and the amount of energy released during the opening motion vs. emission lag will probably not be enough to significantly harm you as dielectric processes need to establish a field to polarize molecules that will heat up as consequence.
Not enough to harm you, but how about a nearby device with an antenna?
Would a microwave burst e.g. fry the speaker of a crystal radio (where the antenna bridges nearly directly to said speaker) which happened to be tuned to a radio-band frequency for which 2.4GHz is a harmonic?
Or, for regulated products like 2.4GHz wi-fi routers, does FCC “accepts interference” testing take microwave bursts into account, or are we slowly degrading some component in them every time we open microwave ovens near them?
Would a microwave burst e.g. fry the speaker of a crystal radio (where the antenna bridges nearly directly to said speaker) which happened to be tuned to a radio-band frequency for which 2.4GHz is a harmonic?
Or, for regulated products like 2.4GHz wi-fi routers, does FCC “accepts interference” testing take microwave bursts into account, or are we slowly degrading some component in them every time we open microwave ovens near them?
Anecdata, but for 2 years I have had a Chromecast Audio and a cheap Creative 2.1 system about 20cm away from my microwave, which is the type where you can just open the door to stop it. No problems so far.
Don't microwave ovens in large part depend on standing waves (resonant with the chamber size) to deliver the power levels they do?
Don't microwave ovens in large part depend on standing waves (resonant with the chamber size) to deliver the power levels they do?
Directed microwave energy can ruin electrical equipment nearby. You can find videos of this on YouTube, usually out of Russia.
Whether it'd do the same with a very short, unfocused momentary burst from reflection inside the oven cavity depends on your equipment I guess. I wouldn't leave my hackrf with RX amp turned on nearby, anyway.
Whether it'd do the same with a very short, unfocused momentary burst from reflection inside the oven cavity depends on your equipment I guess. I wouldn't leave my hackrf with RX amp turned on nearby, anyway.
Quickly enough for what?
If opening the door shuts down the emitter, then there'll necessarily be a brief period of microwave emission. Even if the emitter's power goes to zero instantly (it doesn't) then the microwaves that have been emitted and are still bouncing around can escape, that'll be quite a few nanoseconds.
If opening the door shuts down the emitter, then there'll necessarily be a brief period of microwave emission. Even if the emitter's power goes to zero instantly (it doesn't) then the microwaves that have been emitted and are still bouncing around can escape, that'll be quite a few nanoseconds.
I suspect the mechanical-style door switches on microwave ovens require some amount of door movement/opening before activating. The door is also I believe a part of the RF shield that contains the microwave radiation. As it opens and allows a gap before the off-switch activates — this seems likely your window of microwave leakage — not so much the residual waves that might linger after the device is powered off.
Pretty much. The cavity magnetron is highly resonant, I doubt it shuts off in less than 50ms or so. Same with transformer feeding it. Takes a bit for the magnetic fields to die out.
I wouldn't worry about it personally. The biggest danger is cooking your eyeballs and a few milliseconds isn't enough
I wouldn't worry about it personally. The biggest danger is cooking your eyeballs and a few milliseconds isn't enough
This is a story I'll never forget...
at a previous job I was sitting in the break room with a then-coworker.
A very funny older coworker of ours entered and went to heat something in the microwave. After waiting a couple of minutes he decided he'd crack the microwave open and check on his food.
The machine was old and malfunctioning and somehow the latching mechanism failed and the microwave didn't stop running! The older fellow, being fairly quirky, didn't think twice and stuck his head right in the running microwave to spy on his food.
We yelled in chorus "NO $NAME NO! Get out! Close the door!"
One of the strangest, and funniest things I'd seen at that place (and there had been ...many).
What do you figure a few seconds of a human head in a running microwave would do?
at a previous job I was sitting in the break room with a then-coworker.
A very funny older coworker of ours entered and went to heat something in the microwave. After waiting a couple of minutes he decided he'd crack the microwave open and check on his food.
The machine was old and malfunctioning and somehow the latching mechanism failed and the microwave didn't stop running! The older fellow, being fairly quirky, didn't think twice and stuck his head right in the running microwave to spy on his food.
We yelled in chorus "NO $NAME NO! Get out! Close the door!"
One of the strangest, and funniest things I'd seen at that place (and there had been ...many).
What do you figure a few seconds of a human head in a running microwave would do?
Nothing.
The microwave oven was actually invented by accident when a WWII-era magnetron technician noted that the candy bars in his pocket kept melting.
https://spectrum.ieee.org/tech-history/space-age/a-brief-his...
The microwave oven was actually invented by accident when a WWII-era magnetron technician noted that the candy bars in his pocket kept melting.
https://spectrum.ieee.org/tech-history/space-age/a-brief-his...
Hahahaha that's awesome. he's prolly okay, skull is sorta thick and humans have lots of water.
I have heard that pain will warn you before heat damage is done, at least for realistic power levels and frequencies. And not including the eyes because they have poor blood flow and little feeling beneath the surface. Not sure where I heard that though, so it could be BS.
I have heard that pain will warn you before heat damage is done, at least for realistic power levels and frequencies. And not including the eyes because they have poor blood flow and little feeling beneath the surface. Not sure where I heard that though, so it could be BS.
The brain has some of the best blood flow in the body, so maybe nothing.
Nothing happens instantly. I'd assume after opening the door cuts the power you still have 1/120 of a second or more where the magnetic field in the transformer is collapsing and it's still generating microwaves.
Yes, you're letting non-ionizing radiation out.
This is a good illustration of the core problem we have in "anomaly detection" in data science. Often we are presented with a challenge that if solved, would negate the presence of the challenge itself: We have to look for events that aren't explained or predicted to exist by our current understanding of the given system. To find them, we collect all events and evaluate their likelihood under our best model, taking the least-likely as our "anomalous" events. Then, once found, we have to explain them. But to explain them requires that we understand the system well enough to predict the existence of those events. If we did, we could have produced a better model, and that model would have rated those events as more likely. So they wouldn't have shown up. This contradiction seems to be inherent to the whole concept of anomaly detection.
It's not a contradiction. The anomalous events tell you to improve your model, so while your model yesterday was insufficient your model tomorrow will not be. If you're wondering why the model yesterday is not the best possible already, it's because you make guesses about what's important and what's not; guesses which are refined by correcting your model in the presence of anomalous events.
If you start with a weak model that doesn't contain all the knowledge you have available, your anomalies will contain many irrelevant or already known things. If you start with a strong model representing the best current understanding, then correcting the model is not so straightforward.
Suggesting any model that’s not 100% consistent with all known information is weak clearly misses the point. Models which can be automated in a reasonable timeframe on limited hardware beat those who can’t.
The goal is to find interesting things in the data, not simply take years of data and return “everything looks normal.”
The goal is to find interesting things in the data, not simply take years of data and return “everything looks normal.”
We still don’t know exactly what is causing the FRBs that started this whole peryton investigation, although we find that they cannot be explained by the same microwave ovens and many properties of FRBs point towards a genuine astrophysical origin.
I wouldn't be surprised if those also eventually were found to be caused by something on this planet.
I wouldn't be surprised if those also eventually were found to be caused by something on this planet.
The strange behavior of FRBs is that they appear to be point sources -- only some of the "pixels" in the Parkes detectors are saturated when they are detected. It seems (at least to me) very unlikely that something which looks like a point source would be emitted from the local area. The way signals are reflected off the dish[+] would mean that any local source would almost certainly saturate all the "pixels" (as was the case with "perytons").
It could possibly be an atmospheric effect, but even then I think that might still be too close (and thus too large of an angular diameter) to the detector to only saturate one or two "pixels" rather.
[+]: The detector is in the stalk that is above the dish, and signals are reflected off the dish and converge at the focus which is where the detector is placed. So any local source is likely to envelop the entire detector unless it is directly underneath the dish and is a very angle-sensitive effect.
It could possibly be an atmospheric effect, but even then I think that might still be too close (and thus too large of an angular diameter) to the detector to only saturate one or two "pixels" rather.
[+]: The detector is in the stalk that is above the dish, and signals are reflected off the dish and converge at the focus which is where the detector is placed. So any local source is likely to envelop the entire detector unless it is directly underneath the dish and is a very angle-sensitive effect.
A bit of trivia: "the support that holds the receiver above an antenna's reflector" doesn't seem to have a word in the English language. At least one couldn't be found when it was discussed on the Sydney Wireless mailing list 15 years ago. Is anyone aware of such a word?
At the time I proposed "yongcat", but it doesn't see to have caught on as it draws a blank on all search engines!
At the time I proposed "yongcat", but it doesn't see to have caught on as it draws a blank on all search engines!
Are you suggesting that there are extraterrestrials on this planet?
The source being microwave ovens being stopped by opening the door letting a short burst of radio signal escape
So the signal would appear only around dinner/lunch time, I suppose.
What about second breakfast?
I don't think he knows about second breakfast
What about elevenses? Luncheon? Afternoon tea? Dinner? Supper? He knows about them, doesn’t he?
TFA says that a peryton, a class of astronomical signal, is named for a mythological beast, a winged elk. After first shuddering over the idea of an elk flying over one's head, I went to Google to find more about this as I've never heard of this beast before. Its source appears to be from author Jorge Borges who claims to have found a reference in an medieval manuscript. There appears to be no substantiating evidence elsewhere which is why it isn't as well known as other creatures of mythology.
Borges used to deliberately make up medieval sources and reference non-existent works of literature. It's in his genre, see [1].
[1] https://en.wikipedia.org/wiki/Tl%C3%B6n,_Uqbar,_Orbis_Tertiu...
[1] https://en.wikipedia.org/wiki/Tl%C3%B6n,_Uqbar,_Orbis_Tertiu...
Not a single reference in the OED.
* Navy pilots report unexplained flying objects | Hacker News || https://news.ycombinator.com/item?id=20018535
I saw this as the follow up article on the front page, and it got my hopes up.
I saw this as the follow up article on the front page, and it got my hopes up.
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This is why you should not open a microwave without stopping it, unless you want a dose of radiation
This is old news i remember this.