Comments by "H. de Jong" (@h.dejong2531) on "" video.

  1. It's possible, but expensive.
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  2. Yes. Earth's rotation drags the pixel across the target, so they end up with lines of imaging data.
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  3. Eh, we've known about this black hole for decades. This is just the first time we've been able to see it.
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  4. In theory, yes. We'd have to solve some problems first though: transferring PB of data over such long distances, and measuring the distance exactly enough for VLBI to work.
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  5. In theory, yes. We'd have to solve some problems first though: transferring PB of data over such long distances, and measuring the distance exactly enough for VLBI to work.
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  6. Keep in mind this image was done at radio wavelengths. For high-res images of the Moon, we have the Lunar Reconnaissance Orbiter. LRO images of Apollo landing sites: https://www.youtube.com/watch?v=Pnhnx95LkCc
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  7. We have photos of stars orbiting an object that's mostly invisible. From those orbits we can calculate how much mass there must be: 4 million solar masses in a tiny amount of space. The only theory that can explain those observations is a black hole. Now we've imaged that invisible object, and our observations match the theory. That means black holes are real, not theoretical, not imaginary.
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  8. We'd have to solve some problems first though: transferring PB of data over such long distances, and measuring the distance exactly enough for VLBI to work.
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  9. In theory, yes. We'd have to solve some problems first though: transferring PB of data over such long distances, and measuring the distance exactly enough for VLBI to work.
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  10. Not all rainbows are political.
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  11. In theory, yes. We'd have to solve some problems first though: transferring PB of data over such long distances, and measuring the distance exactly enough for VLBI to work.
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  12. Yes. It's possible now, just very expensive.
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  13. The resolution of this EHT image is 1000 times better than what the JWST will achieve. That's the advantage of having a telescope the size of Earth. What JWST will see is comparable to that timelapse of stars orbiting the black hole.
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  14.  @robertbutsch1802  Not quite. We already have near-IR observations made by the VLT that show the stars closest to the black hole. This telescope made the timelapse of these stars orbiting the black hole.
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  15. We have photos of stars orbiting an object that's mostly invisible. From those orbits we can calculate how much mass there must be: 4 million solar masses in a tiny amount of space. The only theory that can explain those observations is a black hole. Now we've imaged that invisible object, and our observations match the theory. That means black holes are real, not theoretical, not imaginary. Welcome to science.
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  16. If you find it, let us know. The telescope used for that timelapse was probably the VLT.
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  17. Normal black holes are generated when a large star goes supernova. Supermassive black holes occur ing the center of a galaxy.
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  18. The more telescopes, the less interpolation they'd have to do.
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  19. In theory, yes. We'd have to solve some problems first though: transferring PB of data over such long distances, and measuring the distance exactly enough for VLBI to work.
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  20. No. JWST is infrared, the EHT works in mm wave radio. All the parts of the EHT have to observe at the same wavelength, otherwise you can't do interferometry.
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  21. Observation at THz wavelengths? As I understand it, their main observations are done at 1.3 mm, which is 230 GHz.
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  22. Different parts of the EM spectrum reveal different things. JWST is an IR telescope because we want to look at the spectra of stars and galaxies, and those spectra have a lot of information in the IR range. And we want to use it to detect visible light that has been redshifted into IR. The EHT can't do that.
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  23. The EHT team went to great lengths to make sure their algorithms would work on any image, not just black holes. They deliberately didn't put in preconceived notions of what a black hole would look like. They tested this with non-astronomical images. https://www.youtube.com/watch?v=UGL_OL3OrCE
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  24. NASA's experimenting with laser communication, to replace radio. This would offer a huge increase in bandwidth.
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  25. Unlike you and your images, the EHT team has lots of corroborating evidence for this being a black hole.
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  26. The Russians operated a radio telescope in space (Spektr-R) and they did interferometry experiments with it, at much lower frequencies though.
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  27.  @mrpicky1868  Nope, it's both a particle and a wave.
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  28.  @mrpicky1868  In physics, both the particle and wave representations are useful. Both can be used to calculate and predict behavior in a wide range of circumstances. The 'particle and wave' claim isn't something I'm making on my own: this is the common way physicists describe all forms of electromagnetic radiation.
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  29. about 20 (distance to the moon / diameter of Earth), I expect.
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  30. No. JWST is infrared, the EHT works in mm wave radio. All the parts of the EHT have to observe at the same wavelength, otherwise you can't do interferometry.
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  31. No, general relativity requires energy and mass that we haven't found yet. Not mass/energy that's fundamentally impossible to detect. The distinction is important.
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  32. The resolution of this image is about 1000 times better than what JWST can achieve.
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  33.  @b1blancer1  Andromeda is huge: its apparent size is 3º x 1º. This black hole is 60 microarcseconds, or 1/(3600*1000000) of 1 degree. And HST can see those stars as single pixels. 'Resolving' a star means seeing it as a disk, which HST can't do. Galaxies billions of ly away cover maybe 10x10 pixels in an HST image.
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  34.  @b1blancer1  In astronomy, the term "resolve" is used when we can see details. E.g. to the naked eye, Mars appears as a single point of light, but telescopes like HST can resolve it as a disk and see details within that disk. When HST observes Andromeda, each star is smaller than one pixel. It's still bright enough that that pixel will register the star. This works for really bright objects like stars. HST's resolution is 30 milliarcseconds: when 2 stars are 30 mas apart, it will see them as 2 stars. Any closer, and the two appear as a single point of light. This black hole is 60 microarcseconds wide. HST might be able to see it as a single single pixel, if it's bright enough. We don't know how bright the black hole appears in visible light because it's obscured by dust at these wavelengths. The VLT has observed this region in IR. It made the timelapse that shows stars orbiting the black hole. In that timelapse, you can see an occasional flicker that I suspect is the black hole. It appears as a single pixel.
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  35. Yes. I think we'd need to constantly measure the distance between telescopes very accurately.
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  36. ​ @HarzemTube  We can measure the distance to our deep space missions down to the meter or so.
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  37. In theory, yes. We'd have to solve some problems first though: transferring PB of data over such long distances, and measuring the distance exactly enough for VLBI to work.
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  38. Yes. We'd have to solve some problems first though: transferring PB of data over such long distances, and measuring the distance exactly enough for VLBI to work.
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  39.  @olasek7972  Movement can be accommodated: we just need to measure the distance between the telescopes accurately.
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  40. Yes. Well, we'd need radio telescopes, not JWST-type infrared ones.
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  41.  @guleria88  We have many telescopes in orbit, but only one has been used for interferometry: Spektr-R. And this used very low frequencies, which makes interferometry easier.
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  42. It's probably going to take a look, but yeah, it won't see this level of detail.
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  43. That would improve the resolution, but we'd still have gaps between the observations.
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  44. Yes, that's all correct.
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  45. We can't do interferometry at IR wavelengths yet. Interferometry gets harder for shorter wavelengths: your timing requirement gets tighter. We haven't gotten to the point where we can store IR observations as data in small enough timeslices to do interferometry.
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  46. It has been done for low-frequency radio (the Spektr-R radio telescope). For mm wave radio, we'd have to solve some problems first: transferring PB of data over such long distances, and measuring the distance exactly enough for VLBI to work.
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  47. Yes.
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