Mysterious fast radio bursts come in two distinct flavours | Hacker News Reader

Mysterious fast radio bursts come in two distinct flavours

nature.com

182 pointsbryan055 comments

I hadn't read about the CHIME (Canadian Hydrogen Intensity Mapping Experiment) telescope before.

From the wikipedia article:

> The telescope's low-noise amplifiers are built with components adapted from the cellphone industry and its data are processed using a custom-built FPGA electronic system and 1000-processor high-performance GPGPU cluster.

that's super interesting. My limited exposure to radio astronomy relies on a lot more custom collection hardware (super cooled LNAs, with hydrogen maser clocks, ...) and mostly pure software processing. Seeing this very COTS hardware with careful processing systems is neat.

> The telescope consumes 250 kilowatts of power.

woah.

> The telescope consumes 250 kilowatts of power

A better investment than bitcoin, IMHO.

I completely agree. I think it makes sense when they have 256 processing nodes with GPUs plus everything else, just the number caught me off guard at first.

I work on a plasma confinement device that has a linear regulator in its 100 kV gyrotron power supply that uses 6 kW just to keep the filament warm. The coils use 10 MW during a shot. And this is considered a small machine.

Science takes power.

> Science takes power

And brains. Thank you for contributing yours.

And, just like that, donating your body to science has new meaning.

Either that or a zombie apocalypse.

Well the pay is about half the market rate and I'm leaving soon because my SO's research group is moving across the country. I suppose I'll just go work for industry and be able to pay off student loans/own a house in my life.

Science could hold on to talent if only there was a budget for it.

Neat! How long does it take to charge capacitors before a shot? Or do you have a transmission feeder directly into your lab?

We use 18 DC train motors with 1-ton flywheels on them. Currently they spin up to 1650 RPM then get turned into generators. It takes about a second to spin up the very inductive copper coils to the desired current then the shot lasts 100 ms. After the shot the motors are spinning at 1200 RPM and it takes 5 minutes to get back up to 1650 RPM.

You can’t even make the Bitcoin transaction that investment would require for that pathetic energy usage.

As if "bitcoin investors" actually make transactions! If they did, it would matter that the network isn't functional

Bitcoin's efficiency is not relevant to the discussion. Every other comment about energy consumption pulls replies with complaints about Bitcoin mining. It brings nothing new, it distracts from the topic, generally lowers the quality of the discussion. Don't do it. If you must vent, do it where it's on topic.

Why start this discussion. It's slightly expediting the heat death of the universe for no reason. Are you trying to eliminate all order in the universe???

A silly argument. Electricity isn’t finite and we can essentially generate as much as is demanded.

> The telescope consumes 250 kilowatts of power.

250 toasters.

Which is not a small amount- around 140 of your standard 15A home circuits in the US with 120V service. And this is listening, not a transmitter.

It's a small amount compared to the 100MW of a larger data centre.

Yes but this is something useful, instead of something we consider important as a society right now like making people click ads.

> this is something useful, instead of something we consider important as a society right now

Could you explain how radio astronomy is more useful than click ads?

Early warning of various potential extinction events

It encourages people into the sciences, instead of making people hate their lives...

And a duck is small compared to a schooner! Is this the thread where we just list relative characteristics of unrelated things?

My vote is that these aren't bursts, so much as constant directional radiation that we infrequently intersect.

Multi-messenger observations will eventually solve this, e.g. a correlation with LIGO, if the sensitivity is good enough and they're 'low mass' collisions.

The energy needed for these signals already narrows down the category of objects it could be. As the article says, neutron star collisions and mergers, magnetars, and of course black holes.

If there were space crafts jumping into warp speed or shit like that, then how that would look like?

Imagine if FRB’s were signs of cosmic traffic it would certainly change “life out there” conversation :)

Something like that was in HN two days ago:

Fast Radio Bursts from Extragalactic Light Sails (2017): https://news.ycombinator.com/item?id=27431999

Jumping to warp speed is the optimistic case. Here's a pessimistic case: weapons. Maybe we're seeing signs of space faring civilisations at war.

> Now CHIME has reversed that trend, he says, “I don’t think theorists will catch up with us.”

Funny stuff. I like to imagine they're virtual galaxies resulting from perturbation theory of gravity field theory. With ordinary galaxies described in terms of exchanges of virtual galaxies. Of course, they wouldn't necessarily carry the same mass as the corresponding real galaxies.

Will we ever find out what this actually means in our lifetime?

Aren’t these just quasars? Not necessarily anything that special. Are people thinking this is extra terrestrial communication of some sort?

Correct, and it is pretty special to learn that (while still rare), they're far more common than we initially thought

I agree. As a child I thought these would be extremely rare. In my naive little kid brain I guess I figured there must be only a handful of them known to exist, and I had endless ideas about how such a rare and unique celestial entity must have alien origins. Haha.

The article says otherwise.

Nope, fast-radio-bursts (FRB's) aren't commonly attributed to quasars.

From ["Not all fast radio bursts are created equal"](https://www.nature.com/articles/d41586-019-03894-6), 2020-01-06:

> Curiously, because the luminosity of a typical quasar is not dissimilar to the peak luminosity of an FRB, we cannot yet completely discount the involvement of supermassive black holes. But Marcote and colleagues’ results argue against that possibility, and the timescales for quasar variability are more likely to be days to months than milliseconds.

Wikipedia has a [section on hypotheses](https://en.wikipedia.org/wiki/Fast_radio_burst#Origin_hypoth...).

I favor "asteroid falling on the neuron stars" theory. Both are common and it would also explain periodical ones.

I just imagined how a neuron star would look like. Creepy.

That must be a heck of a big asteroid.

So, not Aliens. Author really had a minimum page count limit, huh?

H E L P

in an unknown alien tongue

I think extraterrestrial porn is more likely.

SCNR

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