(astro.theoj.org)
I’m so fascinated by the fact that we can look back through time by looking at these distant objects. I wish I went into astrophysics instead of engineering…
Truly, only those who think about nothing but (astro)physics can bear it.
I still love thinking about fundamental problems and upcoming research however. That will never be gone.
I used to love engineering but with AI I feel like all the passion (learning things, making brain squeeze) is gone and I’m just managing another resource.
Don’t get me wrong, I like building things. I also like solving challenges and hard problems and I haven’t done that in a few years now.
There's a scene in Good Will Hunting where the two professors talk about Will [0] and Sean (Robin Williams) says it's "There's more to life than a fucking Fields medal". Both are correct but there's only a few names in history that will be remembered as "The Greats".
Note: I like arXiv links anyway, but in this case something about the page was killing my browser, had to reload a few times.
Or have I missed something?
As per your own link:
Solving for z_rec gives value around 1100, which converts to a cosmic time value around 400,000 years[Angular Diameter Turnaround](https://xkcd.com/2622/)
(Note: the reason to measure in red shift rather than light years is that when this comes up it suddenly gets very important to be very careful about what exactly you even mean by "how far away is that thing?")
So if I understand this correctly, the galaxy above in the paper is at Z=14.4 and that means it appears in the sky about as big as if it were a very small Z or roughly 350 megaparsecs away?
Unless stunning has a technical meaning I'm unaware of, I like this approach of starting a technical paper with something less dry.
It sounds like JWST found a galaxy where one wasn't expected to be for the time in which it takes light to reach where JWST is?
I assume it's important because we expected nothing and there was something?
But I am just guessing, honestly
And it found that everything was the same no matter where you looked, to about 10 parts per million. So that is the level of variation in the density of the universe about a half-million years after the Big Bang, the differences are measured at the level of parts per million.
And then back in the 1990s the Hubble Space Telesecope took pictures of the previously most luminous galaxy ever recorded, and it was really far back in time, within half a billion years of the Big Bang. And these luminous galaxies were something that we expected to mean that they were built around gigantic supermassive Black Holes. Which means that in a very short amount of time we must have gone from "everything is the same to parts per million" to "here is a gigantic accumulation of mass concentrated in this one spot so densely that all of our models of physics don't work any more."
And so the Webb Space Telescope was built specifically to look for things in between what the Hubble had seen (in Visual Light) and what the COBE had seen (in Microwave), that is Infrared. It is designed to look for these supermassive galaxies that had Red Shifted (1) so far they had left the visual spectrum and gone into Infrared. Figuring out how all of these super luminous galaxies formed is the main question that the whole thing was designed around.
1: As things move away from us, the photons shift to the red end of the spectrum. According to Hubble's Law, things the faster something is moving away from us the earlier it is in time, and the further its photons are shifted to the right: this is why the Cosmic Microwave Background is in microwave, because it has been red shifted so far it has gone into the Microwave part of the spectrum.
For far IR/submillimeter observations we had Herschel in space, SOFIA in the stratosphere (flying on a 747), and several large terrestrial telescopes at very high altitudes can also observe at FIR/submm wavelengths. But sure, there are likely many astronomers who would love nothing more than a new spaceborne FIR telescope, given that it’s been more than a decade since Herschel’s end of mission, and SOFIA was also retired in 2022.
For microwave we’ve had several space telescopes (COBE, then WMAP, then Planck), mainly designed to map the cosmic microwave background. That’s the farthest and reddest that you can see in any EM band, 300,000 years after the big bang.
Past microwave, that’s the domain of radio astronomy, with entirely different technology needed. We have huge radio telescope arrays on the ground – the atmosphere is fairly transparent to radio so there’s no pressing reason to launch radio telescopes to space, and their size would make it completely infeasible anyway, at least until some novel low-mass, self-unfolding antenna technology.
Though not the same thing, you may be interested in https://en.wikipedia.org/wiki/Laser_Interferometer_Space_Ant...
One would need to go to space for that of course.
But you can also use multiple, much smaller antennas to synthesize a narrow beam, and those little antennas are often dishes but can also be very simple and rather small antennas.
The longest wavelengths of light are generally classified as "radio".
So radio telescopes have been tasked to explore the very early universe.
https://en.wikipedia.org/wiki/Reionization
If I understand it correctly, the "Period of Reionization" is first light we can see from processes like stars and galaxies.
There was ionized plasma at the beginning but the universe was like a really thick fog everywhere, and that first light was scattered around and you can't really see stars. As the universe expanded, that fog cooled down, and you could see, but cold matter doesn't emit much light, so there wasn't much to see. It took a while for gas clouds to collapse into the first stars, heating up the gas to ionized plasma once again, so it's re-ionized matter.
The Low Frequency Array, LOFAR, has been used to study this "Cosmic Dawn".
The Square Kilometer Array was designed to explore this era.
But! Not a radio telescope JWST has revealed unexpected, huge globs that seem to be galaxy-sized gas clouds collapsing into (maybe) black hole cores; the thermal emission from the collapse isn't nuclear fusion, so I don't know if those are "stars". But it's very early light.
Honestly, every time a new class of telescope is built, it discovers fundamentally new phenomena.
https://duckduckgo.com/?q=LOFAR+square+kilometer+array+reion...
https://news.ycombinator.com/item?id=44739618
https://news.ycombinator.com/item?id=46938217
I searched "Reionization" and "Cosmic Dawn" plus some favorite telescopes via web and here using the Hacker News search (Agolia).
(Certainly you know the difference between radio and infrared, but I had to look into how those choices of telescope have observed different aspects of Reionization Era, got nerd-sniped, and just had to write it down in a couple of sentences.)
how about you go make yourself conversant with "just" the technical requirements of the main cryogenic pump onboard, leaving out the rest of the thermal management systems for whatever remains of your life, which will have to be long in order to fail honorably.
So to 'catch' a certain frequency with a receiver the size of the receiver gets proportionally larger as the frequency drops. Focusing light can be done with relatively small gear. Focusing radio waves, especially when the source is distant requires a massive structure and to keep that structure sufficiently cool and structurally rigid is a major challenge. It is already a challenge for the JWST at the current wavelengths, increasing the wavelength while maintaining the sensitivity would create some fairly massive complications.
In the end this is a matter of funding, and JWST already nearly got axed multiple times due to its expense.