121–130 of 182 posts
"Sure, if there was dark matter, the speed of stars would be greater, but the rotation curves, meaning the rotational speed drawn as a function of the radius, could still go up and down depending on its distribution. But they didn’t. "
MOND might explain rotation curves of galaxies. But it doesn't explain all the other places in astrophysics, where one needs dark matter. Especially MOND (and any modification to gravity) cannot explain the Bullet Cluster: https://en.wikipedia.org/wiki/Bullet_Cluster#Significance_to... The Bullet Cluster is especially significant, because it shows gravitational lensing by dark matter spatially separated from visible…
The creator of MOND addressed that:
Earlier quoted context omitted.
>Neither were intended to be literal. They were designed to convey meaning. Even Genesis has direct geographical references to it. It has directions. Calling it a metaphor is moving the goalposts. Ad reductio Abrahamic religion is simply that god made whatever we can't understand. It's not like I'm saying the world wasn't made in seven days. I'm saying that god said we were kicked out of where we came from and would…
> Even Genesis has direct geographical references to it. It has directions. Treating Genesis as a single book is insane. Its a collection of oral traditions. Multiple authours, genres, and hundreds of years separate each tale. > geographical references to it. It has directions. Calling it a metaphor is moving the goalposts. Ad reductio Abrahamic religion is simply that god made whatever we can't understand. Eden isn'…
>Firstly, "Yahweh" was a best guess about an unspoken name that wasn't allowed to be written in complete form. We are fairly certain that guess was wrong, and the actual name was "Elohim". They're the same name, and yes, the same spelling. (We transliterate to English using sounds in this case).
I have no idea where you're getting this from. They are quite different. Aleph lamed he yud mem vs. yud he waw he. There was heavy redaction in the 5th century BC in favor of "Elohim" but YHWH definitely existed first. Elohim in ugaritic originally meant "children of god" ie the pantheon under El, which Yahweh was a part of. Later, with the revisionist history, Elohim became "God of gods". What's more, YHWH is forbidden to speak aloud whereas elohim is not.
There was an outright movement as YHWH became more important and El became less important. It wasn't just a name change. They literally switched, and even after Yahweh became the most important god he still didn't fully absorb El's traits until later.
>Wouldn't make sense. Nor would the Caananites hospitality to those of the Ba'al religions. The Biblical record shows this, and it doesn't undermine the record. The Psalms frequently reference belief in other gods. The first reference to monotheism comes in the Davidic era, after Israel has been established, but it isn't entirely fixed, and instead is something that slowly took hold over a great deal of time. Different scholars and theologians have different theories on the why of that.
I dropped a "now", that was meant to say "the thing now called YHWH is a sole god". But even in Kings, Baal and others are no more than false idols eg Ahab, Jezebel and Elijah.
>The Bible is a collection of documents. The meaning ascribed to them doesn't exempt them from treating them as ancient documents.
I did not mean to imply that. Certainly it is not nothing. However it is not realistic evidence for a god any more than the Greek pantheon. We know that there are no gods on top of Olympus. The hyperbolic and contradicted aspects of the bible are likewise not real.
MOND might explain rotation curves of galaxies. But it doesn't explain all the other places in astrophysics, where one needs dark matter. Especially MOND (and any modification to gravity) cannot explain the Bullet Cluster: https://en.wikipedia.org/wiki/Bullet_Cluster#Significance_to... The Bullet Cluster is especially significant, because it shows gravitational lensing by dark matter spatially separated from visible…
Dark energy, though, currently appears to be a "stuff we really don't understand" factor.
Earlier quoted context omitted.
Stars also don't interact with other stars that way. AFAIK, the bullet cluster is not evidence for WIMPs.
you're correct, but it is very strong evidence for dark matter in general.
Earlier quoted context omitted.
Dark matter is predicted at every level of astrophysics. It's not just "hey, galaxies look weird". The amount of visible matter only accounts for 4% of the cosmic microwave background. The CMB is extremely smooth, but visible matter is highly clumped up. This can only be explained by a huge amount of matter that doesn't clump up ie non-baryonic. The ratio of deuterium to hydrogen rises based on the density, since the…
> The amount of visible matter only accounts for 4% of the cosmic microwave background. Could you explain what do you mean by 'accounts for 4% of the cosmic microwave background'? How is one supposed to account for CMB by matter density, when its spectrum is almost equilibrium one (thus consistent with almost any value of matter density)?
What is puzzling about MOND and to lesser extent about Dark Matter is that both uses violation of Newton mechanics to justify themselves when we know that Newtonian mechanics is wrong. The problem is that we cannot yet model behavior of galaxies using just General Relativity. Typically models assumes Newtonian physics with minimal accounting for relativity. However there is no sound proof that it is a valid approxima…
There is something that always puzzles me and I would like if something could illuminate me. How are those kind of massive scale astrophysical calculations made? Do they take into account every visible mass aggregate in the galaxy and simulate them, or just apply cinematic at scale assuming the galaxy centre is a point of certain mass? I have played a little with N body simulations and I can't but be amazed about how…
[1] https://en.wikipedia.org/wiki/Uncertainty_quantification
Earlier quoted context omitted.
And the second word of the only sentence in your comment is wrong. Please provide a constructive, substantive critique or don't comment at all.
The fact that someone with more expertise is warning that a discussion is going off the rails is a useful, constructive fact. Demanding that that person explain in detail why in order to contribute is a good way to make sure they don't bother.
Additionally, no where was it "demanded that you explain in detail". I don't mean to be too blunt here, but there is quite a huge gap of comments between a detailed explanation and what you posted.
As an example: "There were a number of things incorrect in this post. The largest one of them was stating X when in fact Y. For more reading on it, look at Z."
And notably this response required fewer words than those spent defending your initial comment.
Almost ever sentence in this comment is wrong.
This almost an exact duplicate: http://cosmos.nautil.us/short/144/the-physicist-who-denies-t... and original HN comments here: https://news.ycombinator.com/item?id=13743439 Do people not search Agolia before posting? Is it acceptable to repost things? (I'm not HN expert).
As per the HN FAQ (link at bottom of page), you can repost something if it hasn't gotten significant attention in the last year. The previous discussion of this story is only three months old.