4 ms·

Ask HN: Worst gravity and black hole art, and CG labeling guidelines for science

2 points by westurner 2y ago

I think that computer graphic simulations of gravity and black holes should be labeled as simulations. The same technology that we use to label or watermark genai image and video content could be used to label n-body gravity and black hole images. "Is this a direct physical observation? Is this retouched; did they add color, did they refocus, etc? Is this a presumptively contrived simulation rendering that shouldn't have same strength of evidence as a less biased direct physical observation?" Almost all images and videos of black holes are simulations just. This likely affects our intuition. People try to fit models to observations. If the observations are conjecture but aren't so labeled, then the people have unfortunately biased intuition. In the interest of progress in science, What are some of the worst black hole and gravity computer graphics you've seen? How could science programming improve its citations in presenting simulated computer graphics as science evidence? How could an "unproven science rendering labeling guideline" be politely and effectively shared with CG artists, physicists, and science content producers?

deleted 2y ago
[deleted]
westurner 2y ago
> The same technology that we use to label or watermark genai image and video content could be used to label n-body gravity and black hole images. "IPTC publishes metadata guidance for AI-generated “synthetic media”" (2023) https://iptc.org/news/iptc-publishes-metadata-guidance-for-ai-generated-synthetic-media/ https://iptc.org/news/iptc-publishes-metadata-guidance-for-a... C2PA: Coalition for Content Provenance and Authenticity (C2PA) > Specifications > Attestation: https://c2pa.org/specifications/specifications/1.4/attestations/attestation.html https://c2pa.org/specifications/specifications/1.4/attestati...
- westurner 2y ago
  And also or instead just "Computer Generated" visible in the image would avoid unhelpfully biasing science. Maybe also "See [...] for information on how" and a DOI, shorturl, or a hashtag.
westurner 2y ago
"[EHT Sagittarius A* (Sgr A*)] Milky Way black hole has 'strong, twisted' magnetic field in mesmerizing new [polarized (phase filtered)] image" (2024-03) https://www.npr.org/2024/03/28/1241403435/milky-way-black-hole-spiral-new-image-magnetic-field https://www.npr.org/2024/03/28/1241403435/milky-way-black-ho... "Astronomers unveil strong magnetic fields spiraling at the edge of Milky Way’s central black hole" (2024-03) https://www.eso.org/public/news/eso2406/ https://www.eso.org/public/news/eso2406/ ScholarlyArticle: "First Sagittarius A* Event Horizon Telescope Results. VII. Polarization of the Ring" (2024) https://doi.org/10.3847/2041-8213/ad2df0 https://doi.org/10.3847/2041-8213/ad2df0 https://iopscience.iop.org/article/10.3847/2041-8213/ad2df0 https://iopscience.iop.org/article/10.3847/2041-8213/ad2df0 ScholarlyArticle: "First Sagittarius A* Event Horizon Telescope Results. VIII.: Physical interpretation of the polarized ring" (2024) https://doi.org/10.3847/2041-8213/ad2df1 https://doi.org/10.3847/2041-8213/ad2df1 https://iopscience.iop.org/article/10.3847/2041-8213/ad2df1 https://iopscience.iop.org/article/10.3847/2041-8213/ad2df1
- westurner 2y ago
  "First image of our Milky Way's black hole [Sagittarius A*] may be inaccurate, scientists say" (2024-10) https://news.ycombinator.com/item?id=42087932 https://news.ycombinator.com/item?id=42087932 https://www.space.com/the-universe/black-holes/1st-image-of-our-milky-ways-black-hole-may-be-inaccurate-scientists-say https://www.space.com/the-universe/black-holes/1st-image-of-... : > "We hypothesize that the ring image resulted from errors during EHT's imaging analysis and that part of it was an artifact, rather than the actual astronomical structure." > The ring-like structure, which really represents intense radio waves blasted from the brilliant disk of gas, known as the "accretion disk," that's swirling around the black hole, may in fact be more elongated than appears, the researchers argue "An Independent Hybrid Imaging of Sgr A* from the Data in EHT 2017 Observations" (2024-10) https://doi.org/10.1093/mnras/stae1158 https://doi.org/10.1093/mnras/stae1158 https://academic.oup.com/mnras/article/534/4/3237/7660988 https://academic.oup.com/mnras/article/534/4/3237/7660988 : > To mitigate the time variability in the Sgr A* structure, data weighting strategies derived from general relativistic magnetohydrodynamical (GRMHD) simulations with the source-size assumption are used. In addition, the EHTC analysis uses a unique criterion for selecting the final image. It is not based on consistency with the observed data, but rather on the highest rate of appearance of the image morphology from a wide imaging parameter space. Our concern is that these methods may interfere with the PSF deconvolution and cause the resulting image to reflect more structural features of the PSF than of the actual intrinsic source. > On the other hand, our independent analysis used traditional very long baseline interferometry (VLBI) imaging techniques to derive our final image. We used the hybrid mapping method, which is widely accepted as the standard approach, namely iterations between imaging by the clean algorithm and calibrating the data by self-calibration, following well-established precautions. In addition, we performed a comparison with the PSF structure, noting the absence of distinct PSF features in the resulting images. Finally, we selected the image with the highest degree of consistency with the observational data." > Our final image shows that the eastern half of this structure is brighter, which may be due to a Doppler boost from the rapid rotation of the accretion disc. We hypothesize that our image indicates that a portion of the accretion disc, located approximately 2 to several R_S (where R_S is the Schwarzschild radius) away from the black hole, is rotating at nearly 60% of the speed of light and is seen at an angle of 40°−45° (Section 4).
westurner 2y ago
Sagittarius A*: https://en.wikipedia.org/wiki/Sagittarius_A\\\\ https://en.wikipedia.org/wiki/Sagittarius_A\\\\* : > Astronomers have been unable to observe Sgr A* in the optical spectrum because of the effect of 25 magnitudes of extinction (absorption and scattering) by dust and gas between the source and Earth. [26] > [...] > In May 2022, astronomers released the first image of the accretion disk around the horizon of Sagittarius A*, confirming it to be a black hole, using the Event Horizon Telescope, a world-wide network of radio observatories. [13] This is the second confirmed image of a black hole, after Messier 87's supermassive black hole in 2019. [14][15] The black hole itself is not seen; as light is incapable of escaping the immense gravitational force of a black hole," only nearby objects whose behavior is influenced by the black hole can be observed. The observed radio and infrared energy emanates from gas and dust heated to millions of degrees while falling into the black hole. [16]* EHT: Event Horizon Telescope: https://en.wikipedia.org/wiki/Event_Horizon_Telescope https://en.wikipedia.org/wiki/Event_Horizon_Telescope First EHT image of Sagittarius A*: (2017, 2022) https://commons.wikimedia.org/wiki/File:EHT_Saggitarius_A_black_hole.tif#mw-jump-to-license https://commons.wikimedia.org/wiki/File:EHT_Saggitarius_A_bl...
- westurner 2y ago
  /? How does the rotation of our solar system relate to the rotation of Sagittarius A* https://www.google.com/search?q=How+does+the+rotation+of+our+solar+system+relate+to+the+rotation+of+Sagittarius+A\\\\\\\ https://www.google.com/search?q=How+does+the+rotation+of+our...* Milky Way > Astrography > Sun's location and neighborhood: https://en.wikipedia.org/wiki/Milky_Way#Sun's_location_and_neighborhood https://en.wikipedia.org/wiki/Milky_Way#Sun's_location_and_n... : > The apex of the Sun's way, or the solar apex, is the direction that the Sun travels through space in the Milky Way. The general direction of the Sun's Galactic motion is towards the star Vega near the constellation of Hercules, > at an angle of roughly 60 sky degrees to the direction of the Galactic Center. > The Sun's orbit about the Milky Way is expected to be roughly elliptical with the addition of perturbations due to the Galactic spiral arms and non-uniform mass distributions. In addition, the Sun passes through the Galactic plane approximately 2.7 times per orbit. [109] [unreliable source?] This is very similar to how a simple harmonic oscillator works with no drag force (damping) term.* [...] > It takes the Solar System about 240 million years to complete one orbit of the Milky Way (a galactic year), [112] so the Sun is thought to have completed 18–20 orbits during its lifetime and 1/1250 of a revolution since the origin of humans. > The orbital speed of the Solar System about the center of the Milky Way is approximately 220 km/s (490,000 mph) or 0.073% of the speed of light. > The Sun moves through the heliosphere at 84,000 km/h (52,000 mph). At this speed, it takes around 1,400 years for the Solar System to travel a distance of 1 light-year, or 8 days to travel 1 AU (astronomical unit). [113] The Solar System is headed in the direction of the zodiacal constellation Scorpius, which follows the ecliptic. [114] From an Answer to "Does our solar system orbit Sagittarius A (location of the SMBH)?" https://www.quora.com/Does-our-solar-system-orbit-Sagittarius-A-location-of-the-SMBH/answer/Lucas-Curtis?ch=15&oid=38519061&share=608a0791&srid=p4lp&target_type=answer https://www.quora.com/Does-our-solar-system-orbit-Sagittariu... : > [...] Think about this: the mass of the entire Milky Way galaxy is about 1 trillion solar masses; however, Sgr A is only about 4 million solar masses: about 0.0001% of the galaxy’s total mass. The force that is most responsible for keeping the solar system in orbit around the galaxy is not Sgr A, but the gravity of the galaxy itself. > Need evidence? Consider the fact that as the Sun moves around the galaxy, it also bobs “above” and “below” the galactic plane. It’s orbital path resembles the edge of a warped record instead of a flat ellipse. This wouldn’t happen if the Sun were simply orbiting a point mass in the center of the galaxy, but it makes perfect sense if the Sun is being tugged “up” and then “down” by the galaxy’s collective gravity. > So yes, the Sun is orbiting around a point corresponding to the location of Sgr A, but no, the Sun is not just orbiting Sgr A.

2 points by westurner 2y ago

deleted 2y ago

[deleted]

westurner 2y ago

> The same technology that we use to label or watermark genai image and video content could be used to label n-body gravity and black hole images. "IPTC publishes metadata guidance for AI-generated “synthetic media”" (2023) https://iptc.org/news/iptc-publishes-metadata-guidance-for-ai-generated-synthetic-media/ https://iptc.org/news/iptc-publishes-metadata-guidance-for-a... C2PA: Coalition for Content Provenance and Authenticity (C2PA) > Specifications > Attestation: https://c2pa.org/specifications/specifications/1.4/attestations/attestation.html https://c2pa.org/specifications/specifications/1.4/attestati...

westurner 2y ago
And also or instead just "Computer Generated" visible in the image would avoid unhelpfully biasing science. Maybe also "See [...] for information on how" and a DOI, shorturl, or a hashtag.

westurner 2y ago

"[EHT Sagittarius A* (Sgr A*)] Milky Way black hole has 'strong, twisted' magnetic field in mesmerizing new [polarized (phase filtered)] image" (2024-03) https://www.npr.org/2024/03/28/1241403435/milky-way-black-hole-spiral-new-image-magnetic-field https://www.npr.org/2024/03/28/1241403435/milky-way-black-ho... "Astronomers unveil strong magnetic fields spiraling at the edge of Milky Way’s central black hole" (2024-03) https://www.eso.org/public/news/eso2406/ https://www.eso.org/public/news/eso2406/ ScholarlyArticle: "First Sagittarius A* Event Horizon Telescope Results. VII. Polarization of the Ring" (2024) https://doi.org/10.3847/2041-8213/ad2df0 https://doi.org/10.3847/2041-8213/ad2df0 https://iopscience.iop.org/article/10.3847/2041-8213/ad2df0 https://iopscience.iop.org/article/10.3847/2041-8213/ad2df0 ScholarlyArticle: "First Sagittarius A* Event Horizon Telescope Results. VIII.: Physical interpretation of the polarized ring" (2024) https://doi.org/10.3847/2041-8213/ad2df1 https://doi.org/10.3847/2041-8213/ad2df1 https://iopscience.iop.org/article/10.3847/2041-8213/ad2df1 https://iopscience.iop.org/article/10.3847/2041-8213/ad2df1

westurner 2y ago
"First image of our Milky Way's black hole [Sagittarius A*] may be inaccurate, scientists say" (2024-10) https://news.ycombinator.com/item?id=42087932 https://news.ycombinator.com/item?id=42087932 https://www.space.com/the-universe/black-holes/1st-image-of-our-milky-ways-black-hole-may-be-inaccurate-scientists-say https://www.space.com/the-universe/black-holes/1st-image-of-... : > "We hypothesize that the ring image resulted from errors during EHT's imaging analysis and that part of it was an artifact, rather than the actual astronomical structure." > The ring-like structure, which really represents intense radio waves blasted from the brilliant disk of gas, known as the "accretion disk," that's swirling around the black hole, may in fact be more elongated than appears, the researchers argue "An Independent Hybrid Imaging of Sgr A* from the Data in EHT 2017 Observations" (2024-10) https://doi.org/10.1093/mnras/stae1158 https://doi.org/10.1093/mnras/stae1158 https://academic.oup.com/mnras/article/534/4/3237/7660988 https://academic.oup.com/mnras/article/534/4/3237/7660988 : > To mitigate the time variability in the Sgr A* structure, data weighting strategies derived from general relativistic magnetohydrodynamical (GRMHD) simulations with the source-size assumption are used. In addition, the EHTC analysis uses a unique criterion for selecting the final image. It is not based on consistency with the observed data, but rather on the highest rate of appearance of the image morphology from a wide imaging parameter space. Our concern is that these methods may interfere with the PSF deconvolution and cause the resulting image to reflect more structural features of the PSF than of the actual intrinsic source. > On the other hand, our independent analysis used traditional very long baseline interferometry (VLBI) imaging techniques to derive our final image. We used the hybrid mapping method, which is widely accepted as the standard approach, namely iterations between imaging by the clean algorithm and calibrating the data by self-calibration, following well-established precautions. In addition, we performed a comparison with the PSF structure, noting the absence of distinct PSF features in the resulting images. Finally, we selected the image with the highest degree of consistency with the observational data." > Our final image shows that the eastern half of this structure is brighter, which may be due to a Doppler boost from the rapid rotation of the accretion disc. We hypothesize that our image indicates that a portion of the accretion disc, located approximately 2 to several R_S (where R_S is the Schwarzschild radius) away from the black hole, is rotating at nearly 60% of the speed of light and is seen at an angle of 40°−45° (Section 4).

westurner 2y ago

Sagittarius A*: https://en.wikipedia.org/wiki/Sagittarius_A\\\\ https://en.wikipedia.org/wiki/Sagittarius_A\\\\* : > Astronomers have been unable to observe Sgr A* in the optical spectrum because of the effect of 25 magnitudes of extinction (absorption and scattering) by dust and gas between the source and Earth. [26] > [...] > In May 2022, astronomers released the first image of the accretion disk around the horizon of Sagittarius A*, confirming it to be a black hole, using the Event Horizon Telescope, a world-wide network of radio observatories. [13] This is the second confirmed image of a black hole, after Messier 87's supermassive black hole in 2019. [14][15] The black hole itself is not seen; as light is incapable of escaping the immense gravitational force of a black hole," only nearby objects whose behavior is influenced by the black hole can be observed. The observed radio and infrared energy emanates from gas and dust heated to millions of degrees while falling into the black hole. [16]* EHT: Event Horizon Telescope: https://en.wikipedia.org/wiki/Event_Horizon_Telescope https://en.wikipedia.org/wiki/Event_Horizon_Telescope First EHT image of Sagittarius A*: (2017, 2022) https://commons.wikimedia.org/wiki/File:EHT_Saggitarius_A_black_hole.tif#mw-jump-to-license https://commons.wikimedia.org/wiki/File:EHT_Saggitarius_A_bl...

westurner 2y ago
/? How does the rotation of our solar system relate to the rotation of Sagittarius A* https://www.google.com/search?q=How+does+the+rotation+of+our+solar+system+relate+to+the+rotation+of+Sagittarius+A\\\\\\\ https://www.google.com/search?q=How+does+the+rotation+of+our...* Milky Way > Astrography > Sun's location and neighborhood: https://en.wikipedia.org/wiki/Milky_Way#Sun's_location_and_neighborhood https://en.wikipedia.org/wiki/Milky_Way#Sun's_location_and_n... : > The apex of the Sun's way, or the solar apex, is the direction that the Sun travels through space in the Milky Way. The general direction of the Sun's Galactic motion is towards the star Vega near the constellation of Hercules, > at an angle of roughly 60 sky degrees to the direction of the Galactic Center. > The Sun's orbit about the Milky Way is expected to be roughly elliptical with the addition of perturbations due to the Galactic spiral arms and non-uniform mass distributions. In addition, the Sun passes through the Galactic plane approximately 2.7 times per orbit. [109] [unreliable source?] This is very similar to how a simple harmonic oscillator works with no drag force (damping) term.* [...] > It takes the Solar System about 240 million years to complete one orbit of the Milky Way (a galactic year), [112] so the Sun is thought to have completed 18–20 orbits during its lifetime and 1/1250 of a revolution since the origin of humans. > The orbital speed of the Solar System about the center of the Milky Way is approximately 220 km/s (490,000 mph) or 0.073% of the speed of light. > The Sun moves through the heliosphere at 84,000 km/h (52,000 mph). At this speed, it takes around 1,400 years for the Solar System to travel a distance of 1 light-year, or 8 days to travel 1 AU (astronomical unit). [113] The Solar System is headed in the direction of the zodiacal constellation Scorpius, which follows the ecliptic. [114] From an Answer to "Does our solar system orbit Sagittarius A (location of the SMBH)?" https://www.quora.com/Does-our-solar-system-orbit-Sagittarius-A-location-of-the-SMBH/answer/Lucas-Curtis?ch=15&oid=38519061&share=608a0791&srid=p4lp&target_type=answer https://www.quora.com/Does-our-solar-system-orbit-Sagittariu... : > [...] Think about this: the mass of the entire Milky Way galaxy is about 1 trillion solar masses; however, Sgr A is only about 4 million solar masses: about 0.0001% of the galaxy’s total mass. The force that is most responsible for keeping the solar system in orbit around the galaxy is not Sgr A, but the gravity of the galaxy itself. > Need evidence? Consider the fact that as the Sun moves around the galaxy, it also bobs “above” and “below” the galactic plane. It’s orbital path resembles the edge of a warped record instead of a flat ellipse. This wouldn’t happen if the Sun were simply orbiting a point mass in the center of the galaxy, but it makes perfect sense if the Sun is being tugged “up” and then “down” by the galaxy’s collective gravity. > So yes, the Sun is orbiting around a point corresponding to the location of Sgr A, but no, the Sun is not just orbiting Sgr A.