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Unveiling the first-ever image of a black hole [video]

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Re: Unveiling the first-ever image of a black hole [video]

#121

Post by legatus »

patagonia wrote: post #80
legatus wrote: post #52

Earlier quoted context omitted.

Isn't that related to the fact that it has been announced across the world at the same time? In europe it was announced at 3 pm for example. I'm sorry, I don't understand your point

That showmanship counts. I don’t believe HN would argue with me if I said “a strong sales group can make or break a company”. Why is it unfashionable to suggest that, in the marketplace of ideas, with an announcement of this magnitude, this exciting, this “sexy”, the presentation of the announcement would benefit from being delivered in a likewise suitable atmosphere. At night, as an event, in a cool warehouse with c…

I would argue that "hype", or as you say "showmanship", is actually damaging when it comes to science. Maybe it's just me, but I try to stay away from pop-science news sites because of all the hype they're filled with. As others have said, I like scientific conferences to provide the evidence, that is enough for me. As for the "early in the morning", as I already said, is a consequence of trying to make it possible for as many people as possible to follow the conference, I don't think anyone would be against another conference in the evening for american viewers. There were 5 "locales": Brussels, Santiago, Taipei, Tokyo, Washington. Unless I missed something, I still disagree with you.

Re: Unveiling the first-ever image of a black hole [video]

#122

Post by peatmoss »

petschge wrote: post #101
alkonaut wrote: post #37

So much higher res than I thought (I was expecting a 3x3px black and white). Does anyone know if this is aggregated over a long time so it's unlikely to improve with more observation? And what is limiting the resolution at this point?

The limit in some sense is the size of the Earth. This picture is from an interferometer observing at very high radio frequencies (wavelength of 1.3 mm) using telescope around the Earth. To improve resolution you would either have to go to even higher frequencies (we have a very hard time doing interferometry there) or find baselines larger than what fits on Earth. And you don't just need a long baseline, but need to…

I wonder how important time is in collecting these data? Because if 6 months isn’t an issue, then the array size could be expanded in one axis to the diameter of Earth’s orbit around the sun, no?

Re: Unveiling the first-ever image of a black hole [video]

#124

Post by stargazer-3 »

alkonaut wrote: post #37

So much higher res than I thought (I was expecting a 3x3px black and white). Does anyone know if this is aggregated over a long time so it's unlikely to improve with more observation? And what is limiting the resolution at this point?

One thing missing from @petschge's reply: adding more telescopes! This will not improve the imaging the smallest possible features, but will make features larger (disk and / or jet components) more prominent. The more telescope pairs with different distance between them are added, the more complete the picture will get - up to a limit of having a single antenna roughly the size of Earth.

Furthermore, adding more telescopes will help better image the fainter features in the image (due to larger total collecting surface).

Re: Unveiling the first-ever image of a black hole [video]

#126

Post by andygates »

veryworried wrote: post #62

Is this what we would see with the naked eye if we were close enough to the black hole? Or would we see nothing, because at this distance we would be dead (or the universe ended all around us)?

These obs are in radio. We could replace your eyes with radio eyes... ..but it's friction heating so it ought to be broadly blackbody, so I would say yes.

Re: Unveiling the first-ever image of a black hole [video]

#129

Post by stargazer-3 »

peatmoss wrote: post #122
petschge wrote: post #101

Earlier quoted context omitted.

The limit in some sense is the size of the Earth. This picture is from an interferometer observing at very high radio frequencies (wavelength of 1.3 mm) using telescope around the Earth. To improve resolution you would either have to go to even higher frequencies (we have a very hard time doing interferometry there) or find baselines larger than what fits on Earth. And you don't just need a long baseline, but need to…

I wonder how important time is in collecting these data? Because if 6 months isn’t an issue, then the array size could be expanded in one axis to the diameter of Earth’s orbit around the sun, no?

The collecting time is important, but mainly to 1) sample the rotation of the Earth in the Fourier space for better angular resolution and 2) for raising your overall signal-to-noise ratio is the image (but the one released is already pretty good, so not much improvement can be done there unless you're trying to go for the faint features in the image).

Unfortunately, you can only do interferometry with simultaneous measurements (we need information about the difference in the phase of light hitting the receiving antennas), so the motion of Earth around the Sun is largely irrelevant, unless you can park another antenna at a trailing orbit (see space VLBI for that).

What you're thinking of is probably parallax measurements of distance - that's how missions like Gaia can pinpoint distances to stars in Milky Way (and some in its satellites as well).

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