> But that sense of relief is tinged with anticipation: So much data takes time to process, and the team must wait months to find out if their massive effort was truly a success.
It could be a few months before something comes out.
I have the same sentiment that you expressed.
Eagerly awaiting pics. What wonderful times we live in.
That's not what's in the article. The object falling into the black hole might emit a lot of light, but black holes can't emit from within, and Hawking radiation is very weak.
It's not the Hawking radiation, it's the friction caused by the gravitational forces (also thought to include magnetic fields) compressing and superheating the matter, which in turn causes it to emit light.
It's apparently thought that the hole doesn't just immediately swallow up matter whole, and that it's not easy for matter to enter the hole at all. Rather the matter is sort of captured and slowly ground down by friction, leaving an accretion disc surrounding the event horizon. Black holes also emit "x-ray jets" that are thought to be observable.
That said, I'm not a physicist. This is just what I've gleaned from articles and Horizon documentaries.
But I am a physicist, who works in this field. I know people in the article personally. You can't become an expert by watching documentaries, even though they thrive on making people feel like that.
It's my personal opinion that popular science articles on new research (like this one), are ultimately unhelpful and are just an excuse for us to get funding.
All that said it's great to see people interested in high-energy astro. If you wanted to know more I'd recommend Longair[0], even though it would be tough going for a non-scientist.
I went back to the article, which does say more or less what I wrote:
What astronomers hope to finally see when they add
up all the signals is a halo of light surrounding
a dark circle -- the shadow of the black hole. The
crescent of light comes from luminous gases, heated
to hundreds of billions of degrees, that orbit just
outside the black hole, tracing the region just
beyond the event horizon.
So when the grandparent said, "a completely black rectangle", that's probably not true. Which is was what I was responding to.
Please feel to correct us non-experts (but it's not terribly useful to shut down discussion without explanation other than "I am a physicist").
Stars are bright, we can see black holes that stars fall into because they interact with the star. Black holes all by themselves (almost) do not emit light and we observe them by seeing how they interact with light from further away objects.
Jets are more complicated and have some open questions, but the conclusion is unchanged, if you really care then read the book.
But if you want to think you know better then you can do that too.
I don't think anyone (at least I hope not) would claim to be an expert after watching some documentary.
When reading your reply it does feel like you're suggesting that people shouldn't be allowed to watch light information on the subject that you work on. To me, that sounds similar to me suggesting that anyone interested in computing shouldn't be allowed to make a basic web page unless they read SICP first.
If you are complaining about the state of science reporting, then I agree with you. It's really terrible. But, the solution isn't to get rid of it. The solution is to improve it.
I think that people should be allowed to learn about the research they are paying for through their taxes. And it's the job of the scientists to share that information.
> What astronomers hope to finally see when they add up all the signals is a halo of light surrounding a dark circle—the shadow of the black hole. The crescent of light comes from luminous gases, heated to hundreds of billions of degrees, that orbit just outside the black hole, tracing the region just beyond the event horizon.
Probably some sort of ring image captured from the side or something like the artist's rendering in the article maybe.
From the point of view that the data was successfully collected, yes, it sounds like it went well. Actual data analysis will take some time. I imagine it will be published in Nature which means that the results may be embargoed for a few more months after data analysis is complete. I'd say that we might hear something in 1.5-2 years.
Pretty wild we potentially have technology to photograph a black hole and accumulate 1024 HDDs of data pertaining to something light years away but not have the tech to transmit them electronically on our planet.
We have the tech, it's just not economically feasible to do it. They do have satellite communication access but it's lower bandwidth and only available during part of the day due to the way polar orbits work.
Kinda click-baity title. There's nothing new here. They still need to process the collected data to get an actual image.
Also, it has started to bother me the way that popular science articles overly dramatize things. For example, the description of waiting for good weather as "nerve-racking." I almost laughed out loud when I read this trying to imagine the action-movie-like intensity they were attributing to what was probably a predicted and fairly routine part of the project.
> trying to imagine the action-movie-like intensity they were attributing to what was probably a predicted and fairly routine part of the project.
As someone who is one step removed from the EHT project (several friends/colleagues of mine were up at the Atacama Large Millimeter/submillimeter Array [ALMA] assisting with the data-collection), these types of observations are not routine at all. This was part of a special campaign, coordinated between major observatories across the world. In order to ensure the data are useful, the precision of the calibration and timing is typically in excess of what the observatories do normally as part of their day-to-day operations. So while the observing campaign was set up well in advance, it is certainly not a routine part of operations.
Regarding the title, it's a little bit click-bait-y, but it's also true that we don't know if there will be an image of the black hole (shadow). The data are not yet in their final form; even the cross-correlation between observatories (necessary to resolve the approximate size of the black hole's shadow) haven't yet been done. So it's entirely possible (though perhaps unlikely) the data that were acquired end up being unsuitable for making an image of the black hole (shadow).
> these types of observations are not routine at all.
Perhaps you think I was saying that the EHT project as a whole is uninteresting. I wasn't suggesting this at all. I understand that this project calls for a novel type of data collection that requires more coordination, etc. My opinion was that the author's use of certain wordings made things sound more dramatic than they actually were. I imagine that the possibility of bad weather would have been foreseen and planned for (i.e. routine).
> it's a little bit click-bait-y, but it's also true that we don't know if there will be an image of the black hole (shadow).
This was my point. We still don't know. But, in my opinion, the wording of the title (which is now different than the link text) sort of suggested that we do know.
"The telescope zeroed in on two supermassive black holes: a beast as massive as four million suns". It's incredible thinking about how tiny and insignificant our planet is compared to the rest of the cosmos.
My first cut guess is that at each telescope at each relevant point in time, they need to capture both the intensity and the phase of the sub-millimeter wave electro-magnetic signal and, then, for each point in time add those signals.
So,
(1) How do they get the time points coordinated just right among all the telescopes?
(2) How do they capture both the amplitude and the phase of the signals?
Gee, maybe readers are not supposed to ask such questions?
(2) They mix the bands of interest down to intermediate frequencies that can be readily digitized. It's the same old superheterodyne principle we've used for the last century or so.
I saw one of these guys, Shep Doeleman, talk last year. What they do for this is nuts. They have to transport an atomic clock with them to each site, and something like a 20 of the biggest helium-filled disks available in a custom machine to each site (which is somewhere crazy, like the South Pole, the top of a mountain in Chile, a volcano, etc). And run them all at the exact same time.
They end up with something like 7 PB of data and process it all down to like a 10 MB image. They then throw the rest of the data away because they can't afford the disk space for storage.
I think they have serious plans for putting a constellation of satellites around a Lagrange point.
I believe every radio telescope has their own reference clock that lives at the site. The EHT team is not responsible for schlepping these clocks around. There are other reasons besides VLBI to have really good timing at the site—for example, pulsar timing.
I think there was a question about that: they had some issues with two different standards and decided it was better to pick one type and use that at all locations even if they had to bring it up themselves.
47 comments
[ 4.0 ms ] story [ 98.9 ms ] threadIt could be a few months before something comes out.
I have the same sentiment that you expressed.
Eagerly awaiting pics. What wonderful times we live in.
This is like previews to a Pixar movie.
> The hard drives from the South Pole telescope can’t be flown out until the end of the winter season there at the end of October.
The picture will be incomplete till end of October plus associated processing delays.
https://www.sciencealert.com/visible-light-emitted-from-a-bl...
It's apparently thought that the hole doesn't just immediately swallow up matter whole, and that it's not easy for matter to enter the hole at all. Rather the matter is sort of captured and slowly ground down by friction, leaving an accretion disc surrounding the event horizon. Black holes also emit "x-ray jets" that are thought to be observable.
That said, I'm not a physicist. This is just what I've gleaned from articles and Horizon documentaries.
It's my personal opinion that popular science articles on new research (like this one), are ultimately unhelpful and are just an excuse for us to get funding.
All that said it's great to see people interested in high-energy astro. If you wanted to know more I'd recommend Longair[0], even though it would be tough going for a non-scientist.
[0] https://www.amazon.com/High-Energy-Astrophysics-Malcolm-Long...
Please feel to correct us non-experts (but it's not terribly useful to shut down discussion without explanation other than "I am a physicist").
Jets are more complicated and have some open questions, but the conclusion is unchanged, if you really care then read the book.
But if you want to think you know better then you can do that too.
When reading your reply it does feel like you're suggesting that people shouldn't be allowed to watch light information on the subject that you work on. To me, that sounds similar to me suggesting that anyone interested in computing shouldn't be allowed to make a basic web page unless they read SICP first.
If you are complaining about the state of science reporting, then I agree with you. It's really terrible. But, the solution isn't to get rid of it. The solution is to improve it.
I think that people should be allowed to learn about the research they are paying for through their taxes. And it's the job of the scientists to share that information.
Probably some sort of ring image captured from the side or something like the artist's rendering in the article maybe.
Yeah, it'll be a while.
Or more kind of like how when I push the button on my camera, I have an exposed negative, but I need to develop it first to get a picture.
Except, the act of pushing the camera button is called "taking a picture". So maybe the title is not as misleading as we're making it out to be.
Also, it has started to bother me the way that popular science articles overly dramatize things. For example, the description of waiting for good weather as "nerve-racking." I almost laughed out loud when I read this trying to imagine the action-movie-like intensity they were attributing to what was probably a predicted and fairly routine part of the project.
As someone who is one step removed from the EHT project (several friends/colleagues of mine were up at the Atacama Large Millimeter/submillimeter Array [ALMA] assisting with the data-collection), these types of observations are not routine at all. This was part of a special campaign, coordinated between major observatories across the world. In order to ensure the data are useful, the precision of the calibration and timing is typically in excess of what the observatories do normally as part of their day-to-day operations. So while the observing campaign was set up well in advance, it is certainly not a routine part of operations.
Regarding the title, it's a little bit click-bait-y, but it's also true that we don't know if there will be an image of the black hole (shadow). The data are not yet in their final form; even the cross-correlation between observatories (necessary to resolve the approximate size of the black hole's shadow) haven't yet been done. So it's entirely possible (though perhaps unlikely) the data that were acquired end up being unsuitable for making an image of the black hole (shadow).
Perhaps you think I was saying that the EHT project as a whole is uninteresting. I wasn't suggesting this at all. I understand that this project calls for a novel type of data collection that requires more coordination, etc. My opinion was that the author's use of certain wordings made things sound more dramatic than they actually were. I imagine that the possibility of bad weather would have been foreseen and planned for (i.e. routine).
> it's a little bit click-bait-y, but it's also true that we don't know if there will be an image of the black hole (shadow).
This was my point. We still don't know. But, in my opinion, the wording of the title (which is now different than the link text) sort of suggested that we do know.
So,
(1) How do they get the time points coordinated just right among all the telescopes?
(2) How do they capture both the amplitude and the phase of the signals?
Gee, maybe readers are not supposed to ask such questions?
(2) They mix the bands of interest down to intermediate frequencies that can be readily digitized. It's the same old superheterodyne principle we've used for the last century or so.
They end up with something like 7 PB of data and process it all down to like a 10 MB image. They then throw the rest of the data away because they can't afford the disk space for storage.
I think they have serious plans for putting a constellation of satellites around a Lagrange point.