311–320 of 329 posts
Earlier quoted context omitted.
https://www.wolframalpha.com/input?i=50+microarcseconds+*+%2... The answer is ~200 picometers. Wolfram lists some helpful comparisons: 1/2 the distance between base pairs in DNA 3x the atomic diameter of helium (the smallest atom) Suffice to say you'd have a hard time seeing it as it would be 3,000x smaller than the wavelength of visible light.
Hydrogen isn’t smaller than helium? Or hydrogen isn’t an atom?
Earlier quoted context omitted.
The resolution of these telescopes is limited by diffraction, not by the number of pixels on the sensors. The achievable angular resolution is roughly the wavelength divided by the aperture diameter [1]. JWST works in the few µm wavelength range and has a 6.5 m aperture, such that the angular resolution is ~0.1 arcsec. The EHT works with 1.3 mm wavelength and has an effective aperture of roughly the earth diameter (~…
Should have clarified. Does a black hole have fuzzy edges or sharp edges?
Earlier quoted context omitted.
General Relativity has pretty much nothing to do with planet formation. Newtonian gravity is good enough for that problem, and the problems have nothing to do with not understanding gravity well enough. The problems have to do with things like complex chemistry in stellar accretion disks, how grains in these disks stick to one another to eventually form rocks, and so on.
Whether the problems with the models are with general relativity, Newtonian gravity or other issues, the point is that the models have problems.
The fact that some models somewhere have problems has no bearing on whether the image reconstruction for Sgr A* is valid.
Earlier quoted context omitted.
The resolution of these telescopes is limited by diffraction, not by the number of pixels on the sensors. The achievable angular resolution is roughly the wavelength divided by the aperture diameter [1]. JWST works in the few µm wavelength range and has a 6.5 m aperture, such that the angular resolution is ~0.1 arcsec. The EHT works with 1.3 mm wavelength and has an effective aperture of roughly the earth diameter (~…
Should have clarified. Does a black hole have fuzzy edges or sharp edges?
Earlier quoted context omitted.
Absolutely, but those retractions are led by other astronomers/astrophysicists, not lay people presenting straw men. I think people's priors here are out of whack -- perhaps the truth does lie somewhere in the middle, but if so, it will be much closer to ETH's version than the OP's.
Astronomers/astrophysicists started first, by misrepresenting the process and bringing the talk of taking photos and having "visual evidence". "...We have seen, and taken a picture, of a Black Hole." https://youtu.be/lnJi0Jy692w?t=456
Earlier quoted context omitted.
Astronomers/astrophysicists started first, by misrepresenting the process and bringing the talk of taking photos and having "visual evidence". "...We have seen, and taken a picture, of a Black Hole." https://youtu.be/lnJi0Jy692w?t=456
Yes? He’s correct.
Now the you have published the data from 2017, If I publish my own "photo", and I chose blue with spots of white, using the same library you used and the same color maps:
https://github.com/liamedeiros/ehtplot/blob/docs/docs/COLORM...
Why yours will be more a picture than mine in blue? Maybe I will even splint a little bit of red in there...
Earlier quoted context omitted.
Yes? He’s correct.
There we go again...If you had a photo you not would need to make the merge of the four different images achieved by the four different teams. Now the you have published the data from 2017, If I publish my own "photo", and I chose blue with spots of white, using the same library you used and the same color maps: https://github.com/liamedeiros/ehtplot/blob/docs/docs/COLORM... Why yours will be more a picture than mine…
Earlier quoted context omitted.
[pushes up glasses] The Sun is nowhere near massive enough to become supernova. https://en.wikipedia.org/wiki/Sun#After_core_hydrogen_exhaus... It will become a red giant, and then eventually end up a white dwarf.
Thanks for the correction. You're right, current scientific thinking is that the sun is not capable of going "supernova".
It seems like the assignment of "nova" to a common stage of solitary low-mass stellar development is outmoded, so a change in nomenclature could help explain my confusion. For instance, this 1986 book https://archive.org/details/privatelivesofst00gall/page/68/m... states "Stars called novae explode and grow much brighter over a period of days or weeks, then return to normal again, usually over several years. Although we have ideas about nova stars, we have a lot more to learn about them. [...] When a red giant collapses and is well on its way to white dwarfhood, it may go through one or more periods of being unstable. At such times the star may erupt as a nova. This may be especially so of the more massive stars."
Earlier quoted context omitted.
There we go again...If you had a photo you not would need to make the merge of the four different images achieved by the four different teams. Now the you have published the data from 2017, If I publish my own "photo", and I chose blue with spots of white, using the same library you used and the same color maps: https://github.com/liamedeiros/ehtplot/blob/docs/docs/COLORM... Why yours will be more a picture than mine…
I’m looking forward to reading your scientific paper.
I also would like to notice you did not explain why my blue "picture" would be less a "picture" than yours.
One of the findings they announced at the press conference is that the spin of the black hole is not aligned with the galactic plane but is tilted "towards us" so that it is viewed face on. How unexpected is that?
For quasars, don't the beams shoot out of the poles? Let's hope our nearby buddy doesn't become that active.
The beams come from the accretion disk. There are two opposing beams because the disk has two opposing faces. The profile of the disk is narrow, so it stands to reason that very little radiation would leak out around the edge. On the other hand, there is a black hole in the middle of the disk and that should be smearing the beam out quite a lot. Somehow the magnetic fields and currents within the disk must conspire to keep the beam fairly narrow.