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The first section could use a rewrite, since it is hard to read for those outside the astronomy field. "Very Long Baseline Interferometry (VLBI) is a type of interferometry in which the data received at each antenna in the array is paired with timing information, usually from a local atomic clock, and then stored for later analysis on magnetic tape or hard disk.". A casual reader may wonder: which antenna, which array? Why is timing so crucial that it is mentioned in the very first sentence?
I'm not an expert in this field, so I hope someone else can do this. I suggest to first tell this has (1) something to do with radioastronomy and (2) involves multiple, geographically seperated, telescopes.
Macfreek 12:25, 6 January 2006 (UTC)
The pictures are inappropriate. Neither ALMA nor the SMA is a very long baseline array. The SMA has been used as one station of the event horizon telescope, in combination with CARMA in California and the Hertz telescope in Arizona, but the vast majority of the time it functions as a traditional interferometer. Someone should find a press photo montage of the VLBA instead. — Preceding unsigned comment added by 129.133.89.178 ( talk) 21:52, 2 April 2013 (UTC)
I suspect that the most important difference of interferometry and VLBI is not explained here. AFAIU, interference patterns happen when “collapse of quantum probability” (same as “measuring”) happens after mixing two signals. And storing signals on tape/disk requires that the measuring happens before the storage. Essentially, if correct, this would mean that classical sources would not lead to any interference patterns in VLBI. One would need a measurable fraction of pairs of photons in the same quantum state (“lasing”/“masing” effect) so that one photon may be captured (“measured”) at one antenna, and its identical twin is then captured at the other antenna. IIRC, this explains most illustrations of VLBI involving the “maser” word. 76.218.120.86 ( talk) 01:08, 7 June 2013 (UTC)iz
changed wikilink resolution to Angular resolution. please change if you know a better place to point artical too. STHayden [ Talk ] 01:58, 22 August 2006 (UTC)
HALCA is no longer active as of 2005. Refer to http://www.vsop.isas.ac.jp/ for updated information. ChrisTracy ( talk) 06:35, 10 December 2007 (UTC)
I'm not involved in the VLA but I have to wonder, in this day of computer networks, if the initial explanation of saving data and atomic clock timing to a tape is perhaps outdated. They must have power supplies and command signals running out to these things, why wouldn't they send timestamped signals back over the network. Also, why would they need an atomic clock at each antenna? Doesn't seem right.
Kruglick ( talk) 19:05, 14 February 2008 (UTC)
The result of the move request was: moved to Very-long-baseline interferometry per the discussion below. Malcolmxl5 ( talk) 23:26, 17 September 2012 (UTC)
Very Long Baseline Interferometry → Very long baseline interferometry –
Per WP:MOSCAPS ("Wikipedia avoids unnecessary capitalization") and WP:TITLE, this is a generic process, so the article title should be downcased. In addition, WP:MOSCAPS says that a compound item should not be upper-cased just because it is abbreviated with caps. Lowercase will match the formatting of related article titles. Tony (talk) 02:42, 9 September 2012 (UTC)
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An image of the M87 black hole has been added, with this caption: "VLBI was used to create the first direct image of a black hole, imaged by the Event Horizon Telescope and published in April 2019."
There has been a huge amount of hype from the team behind this effort.
I've watched two documentaries about this experiment (both Horizon, so both basically pop science). All of the scientists appearing on these programs insisted that they had made a direct image of a black hole.; they're all on-message. I don't doubt that the experiment was momentous; but the puff that appears in newspaper reports and TV documentaries fails to explain why.
As far as I can see, it might be the first time VLBI has been used to observe a black hole at millimetre wavelengths. That would be interesting, but it wouldn't justify all the puff that has been generated. I believe that millimetre wavelengths means hydrogen plasma (i.e. protons); but none of the material I've seen or read goes into that kind of silly scientific detail. I think I read somewhere that the experiment showed that there was a stream of very hot protons orbiting the black hole; I suspect that observation may relate to the claims that EHT has successfully confirmed a prediction made by A. Einstein (but AFAIK Einstein had never heard of a black hole, and didn't believe in singularities).
Can someone who knows more than me about this please strip out some of the puff and pop science, and replace them with some facts? MrDemeanour ( talk) 13:03, 26 April 2019 (UTC)
This article is rated C-class on Wikipedia's
content assessment scale. It is of interest to the following WikiProjects: | |||||||||||||||||||||
|
The first section could use a rewrite, since it is hard to read for those outside the astronomy field. "Very Long Baseline Interferometry (VLBI) is a type of interferometry in which the data received at each antenna in the array is paired with timing information, usually from a local atomic clock, and then stored for later analysis on magnetic tape or hard disk.". A casual reader may wonder: which antenna, which array? Why is timing so crucial that it is mentioned in the very first sentence?
I'm not an expert in this field, so I hope someone else can do this. I suggest to first tell this has (1) something to do with radioastronomy and (2) involves multiple, geographically seperated, telescopes.
Macfreek 12:25, 6 January 2006 (UTC)
The pictures are inappropriate. Neither ALMA nor the SMA is a very long baseline array. The SMA has been used as one station of the event horizon telescope, in combination with CARMA in California and the Hertz telescope in Arizona, but the vast majority of the time it functions as a traditional interferometer. Someone should find a press photo montage of the VLBA instead. — Preceding unsigned comment added by 129.133.89.178 ( talk) 21:52, 2 April 2013 (UTC)
I suspect that the most important difference of interferometry and VLBI is not explained here. AFAIU, interference patterns happen when “collapse of quantum probability” (same as “measuring”) happens after mixing two signals. And storing signals on tape/disk requires that the measuring happens before the storage. Essentially, if correct, this would mean that classical sources would not lead to any interference patterns in VLBI. One would need a measurable fraction of pairs of photons in the same quantum state (“lasing”/“masing” effect) so that one photon may be captured (“measured”) at one antenna, and its identical twin is then captured at the other antenna. IIRC, this explains most illustrations of VLBI involving the “maser” word. 76.218.120.86 ( talk) 01:08, 7 June 2013 (UTC)iz
changed wikilink resolution to Angular resolution. please change if you know a better place to point artical too. STHayden [ Talk ] 01:58, 22 August 2006 (UTC)
HALCA is no longer active as of 2005. Refer to http://www.vsop.isas.ac.jp/ for updated information. ChrisTracy ( talk) 06:35, 10 December 2007 (UTC)
I'm not involved in the VLA but I have to wonder, in this day of computer networks, if the initial explanation of saving data and atomic clock timing to a tape is perhaps outdated. They must have power supplies and command signals running out to these things, why wouldn't they send timestamped signals back over the network. Also, why would they need an atomic clock at each antenna? Doesn't seem right.
Kruglick ( talk) 19:05, 14 February 2008 (UTC)
The result of the move request was: moved to Very-long-baseline interferometry per the discussion below. Malcolmxl5 ( talk) 23:26, 17 September 2012 (UTC)
Very Long Baseline Interferometry → Very long baseline interferometry –
Per WP:MOSCAPS ("Wikipedia avoids unnecessary capitalization") and WP:TITLE, this is a generic process, so the article title should be downcased. In addition, WP:MOSCAPS says that a compound item should not be upper-cased just because it is abbreviated with caps. Lowercase will match the formatting of related article titles. Tony (talk) 02:42, 9 September 2012 (UTC)
Hello fellow Wikipedians,
I have just modified one external link on Very-long-baseline interferometry. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
When you have finished reviewing my changes, please set the checked parameter below to true or failed to let others know (documentation at {{
Sourcecheck}}
).
This message was posted before February 2018.
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regular verification using the archive tool instructions below. Editors
have permission to delete these "External links modified" talk page sections if they want to de-clutter talk pages, but see the
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source check}}
(last update: 18 January 2022).
Cheers.— InternetArchiveBot ( Report bug) 21:41, 20 July 2016 (UTC)
An image of the M87 black hole has been added, with this caption: "VLBI was used to create the first direct image of a black hole, imaged by the Event Horizon Telescope and published in April 2019."
There has been a huge amount of hype from the team behind this effort.
I've watched two documentaries about this experiment (both Horizon, so both basically pop science). All of the scientists appearing on these programs insisted that they had made a direct image of a black hole.; they're all on-message. I don't doubt that the experiment was momentous; but the puff that appears in newspaper reports and TV documentaries fails to explain why.
As far as I can see, it might be the first time VLBI has been used to observe a black hole at millimetre wavelengths. That would be interesting, but it wouldn't justify all the puff that has been generated. I believe that millimetre wavelengths means hydrogen plasma (i.e. protons); but none of the material I've seen or read goes into that kind of silly scientific detail. I think I read somewhere that the experiment showed that there was a stream of very hot protons orbiting the black hole; I suspect that observation may relate to the claims that EHT has successfully confirmed a prediction made by A. Einstein (but AFAIK Einstein had never heard of a black hole, and didn't believe in singularities).
Can someone who knows more than me about this please strip out some of the puff and pop science, and replace them with some facts? MrDemeanour ( talk) 13:03, 26 April 2019 (UTC)