
Astronomers may soon have the first picture of a black hole - hownottowrite
http://news.nationalgeographic.com/2017/04/black-hole-event-horizon-telescope-pictures-genius-science/
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killjoywashere
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.

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duetosymmetry
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.

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killjoywashere
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.

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codezero
They won't have the data processed until later this year, there is no picture
right now.

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covercash
> 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.

Yeah, it'll be a while.

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wand3r
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.

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melling
It says it's equal of 10,000 laptops. We probably don't have a general need
for that in the South Pole, so no one paid for it to be installed.

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edge17
What's 1 laptop unit? From what I can gather 7PB/10000 = 700GB, so 1 laptop is
700GB?

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groestl
Funny, just a few days ago I watched a TEDx talk about this by a computer
scientist on the team. Maybe you enjoy it as well:
[https://www.ted.com/talks/katie_bouman_what_does_a_black_hol...](https://www.ted.com/talks/katie_bouman_what_does_a_black_hole_look_like)

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kseistrup
Pics, or it didn't happen!

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gjkood
> 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.

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ourmandave
_...the team must wait months to find out..._

This is like previews to a Pixar movie.

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gjkood
Even more delay...

> 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.

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roywiggins
Now that's some latency

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graycat
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?

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wl
(1) Atomic clocks.

(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.

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graycat
Super! Thanks! I wondered how they would get an analog to digital converter to
work a sub-millimeter frequencies. So, right, they don't!

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maverick_iceman
A slightly better explanation: [https://www.universetoday.com/134996/black-
hole-imaged-first...](https://www.universetoday.com/134996/black-hole-imaged-
first-time-event-horizon-telescope/#)

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cspags
"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.

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duetosymmetry
That's the one in our galaxy, and the other target—in the galaxy M87—is around
5 _billion_ times the mass of the sun!

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viola11
I think it went well? For an article essentially about the data taking it was
surprisingly vague on how the actual observation went...

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goodcanadian
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.

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whorleater
The project's page is:
[http://eventhorizontelescope.org/](http://eventhorizontelescope.org/)

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davesque
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.

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privong
> 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).

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davesque
> 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.

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Entangled
Is there a slight chance that they are not "holes" but massive vantablack
spheres?

