There was a time where Hawking's A brief history of time gave a decent overview of the universe to beginners. Does anyone know how well it holds up today and if anything better exists?
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Astrophysicists Puzzle over Webb’s New Universe
81–90 of 141 posts
Re: Astrophysicists Puzzle over Webb’s New Universe
#82Earlier quoted context omitted.
The supermassive black hole in the giant elliptical galaxy M87 is merely ~53 million light years away, close enough that we have now imaged it: https://en.wikipedia.org/wiki/Messier_87#Supermassive_black_...
Sagittarius A* is "merely" 26 thousand light years away (but we probably won't be imaging it, since there's a lot more in the way)
The M87 supermassive blackhole is thousands of times as massive as Sagittarius A*, but since Sagittarius A* is a lot closer their emission rings appear roughly the same size in the sky (42 μas vs 51 μas). Both have already been imaged by the Event Horizon Telescope. https://en.wikipedia.org/wiki/Event_Horizon_Telescope
Re: Astrophysicists Puzzle over Webb’s New Universe
#83Instead of questioning whether the Big Bang assumption is true, astrophysicists prefer to perform endless "gymnastics" to try to make the mounting contrary data fit their theory about how the universe began.
Are you kidding? An astrophysicist that could come up with a new model that explains the current data would win a Nobel prize and earth shattering levels of notoriety.
The data found doesn't contradict the big bang in any shape or form. It does challenge beliefs around black hole formation.
The reason for the big bang model is because based on all our measurements of all the visible universe, it appears that everything is spreading out. Any new model needs to explain why it is the universe appears to be spreading out.
There's not a scientist alive that wouldn't like to discover that "actually a fundamental principle about my field of study is completely wrong". But that takes hard work, evidence, and models which better fit than the previous ones did. You need to find something that can't be explained with the old model and can only be explained with the new model.
Re: Astrophysicists Puzzle over Webb’s New Universe
#84> Recent ideas suggest that little red dots could be black holes cocooned in thick gas, possibly representing a completely new type of object called a black hole star, in which the tight shroud of gas emits light like a stellar atmosphere. Just be sure to name the members of Soundgarden on the paper.
Would you say this research is out of... Cornell?
Re: Astrophysicists Puzzle over Webb’s New Universe
#85Quanta magazine is a glorified university press release and marketing shop for Simons associated institutions. Take it with a grain of salt, and know for sure its leaving out a huge range of scientists views.
The institutions, projects and individuals named in the article are, in order of appearance: --1-- Charlotte Mason (not, so far as I can tell, affiliated with or funded by the Simons Foundation) of the Cosmic Dawn Center (not, so far as I can tell, affiliated with or funded by the Simons Foundation) which is associated with the Niels Bohr Institute at the University of Copenhagen (not, so far as I can tell, affiliate…
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Re: Astrophysicists Puzzle over Webb’s New Universe
#86Instead of questioning whether the Big Bang assumption is true, astrophysicists prefer to perform endless "gymnastics" to try to make the mounting contrary data fit their theory about how the universe began.
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Re: Astrophysicists Puzzle over Webb’s New Universe
#87Quanta magazine is a glorified university press release and marketing shop for Simons associated institutions. Take it with a grain of salt, and know for sure its leaving out a huge range of scientists views.
The institutions, projects and individuals named in the article are, in order of appearance: --1-- Charlotte Mason (not, so far as I can tell, affiliated with or funded by the Simons Foundation) of the Cosmic Dawn Center (not, so far as I can tell, affiliated with or funded by the Simons Foundation) which is associated with the Niels Bohr Institute at the University of Copenhagen (not, so far as I can tell, affiliate…
Did my PhD at Princeton, knew Jenny Greene personally (not my adviser though). There is zero conflict of interest in Astronomy generally. No one has anything to gain. Various institutions, Simons included, are just one source of much needed funding. Jim Simons is also a legend in the field, known for Chern-Simons (major result), then founding the medallion fund which netted him billions which he then durned around and used to fund fundemental science. Astrophysics is too low paying for anyone who doesn’t genuinely care about it to do it.
Funding institutions can influence which research gets done, that’s what they do by definition. This can steer people towards and away from various topics or questions, but people will loudly speak their mind if they don’t think something is right. It’s a core tenant of the culture. Go to a colloquia and watch people debate and critique each other.
Re: Astrophysicists Puzzle over Webb’s New Universe
#88Earlier quoted context omitted.
There was never a time when a book gave the public an overview of the universe. ABHOT was so popular for being a book no one actually read, theres even an index named after Hawking due to it: https://en.wikipedia.org/wiki/Hawking_Index Did _you_ read that book? There however definitely was a piece of media that captured public minds and educated them about the cosmos. And that was the show Cosmos. The original of cou…
I am pretty certain this "hawking index" meme must be a new-ish thing. I read the book as teenager and know also others who did. It is a fairly easily readable book imo, so I don't think this characterisation is warranted by the qualities of the book itself. I suspect that a popsci book becoming a bestseller creates a larger-than-the-usual-nerds audience, a big part of which lacks the motivation to actually finish it…
> this "hawking index" meme must be a new-ish thing
TBF the methodology and hypotheses that it's based on aren't that bad. I'm sure Amazon has better data, but for a "publicly accessible" data (at that time) I can see it. The problem is that while lots of people might abandon the book, that doesn't mean that still loads of people don't read it fully. They are, after all, extremely popular books. Obviously some people will have received / impulse bought / FOMO / new year resolution / etc the books, but from the sales numbers that's still a lot of people that did enjoy them. Marketing aside, the book is pretty approachable, like were Sagan's books and so on.
Re: Astrophysicists Puzzle over Webb’s New Universe
#89Earlier quoted context omitted.
JWST has 4 different instruments on it. While they all share the same focusing mirrors, but otherwise are 4 different measurement devices. For the red dot observations, I believe this things have been measured by at least 3 of the 4 devices on board - NIRCam (near infrared camera, has very limited spectral capabilities through its filter wheel), NIRSpec (near infrared spectrograph) and MIRI (mid infrared instrument).…
Unless there was a flaw in the mirrors they all use. I’m not saying this is so, but the software developer in me would immediately try to figure out what was wrong with the component they shared.
A flaw in the mirrors wouldn't leave the anomaly in a consistent place, it would keep causing problems no matter where you look.
But I'm pretty sure they thought of all of this and many more objections already. It's not like this is a super advanced thread of skepticism that physicists would have overlooked
Re: Astrophysicists Puzzle over Webb’s New Universe
#90Earlier quoted context omitted.
The supermassive black hole in the giant elliptical galaxy M87 is merely ~53 million light years away, close enough that we have now imaged it: https://en.wikipedia.org/wiki/Messier_87#Supermassive_black_...
Sagittarius A* is "merely" 26 thousand light years away (but we probably won't be imaging it, since there's a lot more in the way)
We’ve already imaged it with the event horizon telescope. https://en.wikipedia.org/wiki/Sagittarius_A*?wprov=sfti1#