JWST spots giant black holes all over the early universe
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JWST spots giant black holes all over the early universe
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Re: JWST spots giant black holes all over the early universe
#2> Galactic spectra, which JWST started to send back in earnest at the end of last year, are useful for two reasons.
> First, they let astronomers nail down the galaxy’s age. The infrared light JWST collects is reddened, or redshifted, meaning that as it traverses the cosmos, its wavelengths are stretched by the expansion of space. The extent of that redshift lets astronomers determine a galaxy’s distance, and therefore when it originally emitted its light.
Won't a photon climbing out of a huge gravity well have a huge redshift, thus confounding estimates of distance from us and estimated age?
Re: JWST spots giant black holes all over the early universe
#3This is super cool. I think it's funny how Quanta writes, "It is expected because JWST was built, in part, to find the ancient objects." "Ancient" is equivalent to "distant" because of special relativity. It's an odd thing, astronomy - it's a real world time-traveling observation, except we're limited in resolution and we can't look here only there. If it was a game mechanic I'd call it a cunning way to impose internally consistent limits on what the player can know.
Re: JWST spots giant black holes all over the early universe
#4> Galactic spectra, which JWST started to send back in earnest at the end of last year, are useful for two reasons. > First, they let astronomers nail down the galaxy’s age. The infrared light JWST collects is reddened, or redshifted, meaning that as it traverses the cosmos, its wavelengths are stretched by the expansion of space. The extent of that redshift lets astronomers determine a galaxy’s distance, and therefo…
> Won't a photon climbing out of a huge gravity well have a huge redshift,
Yes
> thus confounding estimates of distance from us and estimated age?
Not if you know, or can get a good estimate of, the potential well it's climbing out of.
That said, Brian Cox does sometimes joke that astronomers round π to 1; while I wouldn't know about the reality, it's probably safe to infer at least some frustration on his part about the precision of things in this field.
Re: JWST spots giant black holes all over the early universe
#5> Galactic spectra, which JWST started to send back in earnest at the end of last year, are useful for two reasons. > First, they let astronomers nail down the galaxy’s age. The infrared light JWST collects is reddened, or redshifted, meaning that as it traverses the cosmos, its wavelengths are stretched by the expansion of space. The extent of that redshift lets astronomers determine a galaxy’s distance, and therefo…
My understanding is that a particles, like photons, don't have wave shifts. That's an emergent property of many particles
Re: JWST spots giant black holes all over the early universe
#6> Galactic spectra, which JWST started to send back in earnest at the end of last year, are useful for two reasons. > First, they let astronomers nail down the galaxy’s age. The infrared light JWST collects is reddened, or redshifted, meaning that as it traverses the cosmos, its wavelengths are stretched by the expansion of space. The extent of that redshift lets astronomers determine a galaxy’s distance, and therefo…
My understanding is that a particles, like photons, don't have wave shifts. That's an emergent property of many particles
The conventional Doppler shift and the equivalence principle imply a gravitational redshift for a photon. See page 102:
https://preposterousuniverse.com/wp-content/uploads/grnotes-...
Re: JWST spots giant black holes all over the early universe
#7> Galactic spectra, which JWST started to send back in earnest at the end of last year, are useful for two reasons. > First, they let astronomers nail down the galaxy’s age. The infrared light JWST collects is reddened, or redshifted, meaning that as it traverses the cosmos, its wavelengths are stretched by the expansion of space. The extent of that redshift lets astronomers determine a galaxy’s distance, and therefo…
My understanding is that a particles, like photons, don't have wave shifts. That's an emergent property of many particles
No, individual particles can indeed be redshifted. The particle's wavelength is a fundamental property.
Re: JWST spots giant black holes all over the early universe
#8This is super cool. I think it's funny how Quanta writes, "It is expected because JWST was built, in part, to find the ancient objects." "Ancient" is equivalent to "distant" because of special relativity. It's an odd thing, astronomy - it's a real world time-traveling observation, except we're limited in resolution and we can't look here only there . If it was a game mechanic I'd call it a cunning way to impose inter…
> internally consistent limits on what the player can know
Interesting thought. Can you expand? What do you mean by this?
Re: JWST spots giant black holes all over the early universe
#9> Galactic spectra, which JWST started to send back in earnest at the end of last year, are useful for two reasons. > First, they let astronomers nail down the galaxy’s age. The infrared light JWST collects is reddened, or redshifted, meaning that as it traverses the cosmos, its wavelengths are stretched by the expansion of space. The extent of that redshift lets astronomers determine a galaxy’s distance, and therefo…
> Won't a photon climbing out of a huge gravity well have a huge redshift, Yes > thus confounding estimates of distance from us and estimated age? Not if you know, or can get a good estimate of, the potential well it's climbing out of. That said, Brian Cox does sometimes joke that astronomers round π to 1; while I wouldn't know about the reality, it's probably safe to infer at least some frustration on his part about…
I also don't know how accurate that description is, but this comic comes to mind:
But I mean, space is really, really big and we are observing from one single spot with (on cosmological scale probably) primitive technology. So of course most of it is guessing and when you "guess" a lot of things, it maybe does not matter a lot, if you have 3.41 Pi or 1, when the data you have are rough estimates anyway. But sure, when you do sloppy math, when you could have precision - that would be just wrong and unscientific.
Re: JWST spots giant black holes all over the early universe
#10Earlier quoted context omitted.
> Won't a photon climbing out of a huge gravity well have a huge redshift, Yes > thus confounding estimates of distance from us and estimated age? Not if you know, or can get a good estimate of, the potential well it's climbing out of. That said, Brian Cox does sometimes joke that astronomers round π to 1; while I wouldn't know about the reality, it's probably safe to infer at least some frustration on his part about…
I also don't know how accurate that description is, but this comic comes to mind: https://xkcd.com/2205/ But I mean, space is really, really big and we are observing from one single spot with (on cosmological scale probably) primitive technology. So of course most of it is guessing and when you "guess" a lot of things, it maybe does not matter a lot, if you have 3.41 Pi or 1, when the data you have are rough estimate…
What if you have 3.14Pi?