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A Physicist Who Denies Dark Matter

nautil.us

111–120 of 182 posts

Re: A Physicist Who Denies Dark Matter

#111

Earlier quoted context omitted.

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.

As the official self appointed Em-Drive denier here, my recommendation is to provide more information in the comments. Sometimes it's difficult. Most commenters here are not experts in the particular field, but are curious. Sometimes it's better to center in the worst part of the comment if it has too many errors. Sadly, I don't know enough cosmology and general relativity, so I use this approach to this problem http…

Apparently General Relativity alone could be enough to avoid the need for both Dark Matter and Dark Energy:

https://books.google.no/books?id=MBjkuQAoyZIC&pg=PA58&lpg=PA...

Re: A Physicist Who Denies Dark Matter

#112
post #105

Earlier quoted context omitted.

>This subthread deals with the completely different issue, it's about bad logic. No matter how well Milgrom and/or his theory could be discredited, that doesn't change the fact we can dismiss something prior to fully understand it It's not bad logic, it only seems like it is because you're approaching it from an Aristotlean view of logic. These things can't be proven, so dismissing them is never an option in science.

We're actually dealing with one complex sentence here, the second of these two: > But, dark matter isn't something to be denied. Because it isn't understood yet, to the point where we can doubt its existence I'm lousy in English and my knowledge of dark matter is irrelevant. With those two lemmas in mind, please answer the only question in this subthread: could something be dismissed if we don't fully understand it?

No, as the entire concept of "fully understand" is ridiculous. We can't fully understand anything, so if you assume the answer is yes then we could dismiss everything.

The actual quote agrees with me here. If we understood it better the best you could do is doubt its existence.

Re: A Physicist Who Denies Dark Matter

#113
post #109
post #73

Earlier quoted context omitted.

Well yes, if you ignore all the evidence of something then you can confidently say there is no evidence. Christian genesis: There was a garden of Eden, and a god. Evidence: No garden of Eden, no evidence of angels or god, no reason those things would suddenly stop being apparent. Direct contradictory evidence that YHWH[1] was a minor god in the original jewish pantheon rather than an actual creator god. Big Bang: The…

> Christian genesis: There was a garden of Eden, and a god. That's a really bad example to go to. The tale of Eden follows a poem, and if you take both literally, then you end up with contradictions. For why? Genre. Neither were intended to be literal. They were designed to convey meaning. > YHWH[1] was a minor god in the original jewish pantheon rather than an actual creator god. Origins are highly disputed, but El…

>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 never be allowed back, and that place doesn't exist. I'm saying god says he talks to us and appears to us, and those things don't happen. The basic, central tenants of the bible aren't real. These are important things, not minutia.

>Origins are highly disputed, but El seems to be the most likely title, who is the head of the Caananite pantheon, and influential enough to be remembered in Babylon. Not a minor deity.

That's not true. The introduction of Yahweh to the Semetic religion was very visibly followed by a shift in personal names referencing El (eg Michael) to names referencing Yahweh. Yahweh was an individual, entirely separate god that aggressively replaced El, and El was relegated to an increasingly minor role. The thing called YHWH in 1200 BC is a 4th tier divine warrior, and the thing called YHWH now is a sole god.

Bare minimum, the Semetic religion was demonstrably polytheistic before it was monotheistic, and that alone massively undermines the bible.

Re: A Physicist Who Denies Dark Matter

#114
post #18

the non light emitting mass could be Dyson spheres of space based computers

Dark matter isn't just dark, it doesn't interact with normal matter. When galaxies collide when can verify via gravitational lensing that the normal matter smashes together while the dark matter continues unimpeded in straight lines through each other.

Stars also don't interact with other stars that way. AFAIK, the bullet cluster is not evidence for WIMPs.

Re: A Physicist Who Denies Dark Matter

#115
post #105

Earlier quoted context omitted.

We're actually dealing with one complex sentence here, the second of these two: > But, dark matter isn't something to be denied. Because it isn't understood yet, to the point where we can doubt its existence I'm lousy in English and my knowledge of dark matter is irrelevant. With those two lemmas in mind, please answer the only question in this subthread: could something be dismissed if we don't fully understand it?

No, as the entire concept of "fully understand" is ridiculous. We can't fully understand anything, so if you assume the answer is yes then we could dismiss everything. The actual quote agrees with me here. If we understood it better the best you could do is doubt its existence.

>> could something be dismissed if we don't fully understand it? > No, as the entire concept of "fully understand" is ridiculous. We can't fully understand anything, so if you assume the answer is yes then we could dismiss everything.

It's not a concept, it's just my lousy English and awkward abbreviation of "to the point where" with "fully".

I'm here just to play a game of logic.

Did we dismiss the ether at the point when we managed to understand it better/enough or we managed to dismiss it after we started to play with other cards?

Re: A Physicist Who Denies Dark Matter

#116

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.

I didn't get that from the comment. Please post resume.

Re: A Physicist Who Denies Dark Matter

#117
post #109

Earlier quoted context omitted.

> Christian genesis: There was a garden of Eden, and a god. That's a really bad example to go to. The tale of Eden follows a poem, and if you take both literally, then you end up with contradictions. For why? Genre. Neither were intended to be literal. They were designed to convey meaning. > YHWH[1] was a minor god in the original jewish pantheon rather than an actual creator god. Origins are highly disputed, but El…

>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't a metaphor, its an allegory, using as its basis a common Mesopotamian myth, as was common at the time. Its origin lies in the story of Lilitu.

The directions to the Euphrates are in Babylonian and Egyptian myths too. It was an area considered symbolic of the spiritual world. You get similar directions to forests that never existed in Japanese myths.

And as a people, the Caananites, and their descendants, were incredibly symbolic. See Kabbalah's number system, and references to it throughout the Bible.

> The introduction of Yahweh to the Semetic religion was very visibly followed by a shift in personal names referencing El (eg Michael) to names referencing Yahweh.

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).

El wasn't replaced, nor were his attributes. The Caananites set out to seize their promised land, backed by their warrior god.

> the thing called YHWH is a sole god.

Not to begin with, in Biblical record. Or commands such as:

> I am a jealous god, you will have no gods before me

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.

> that alone massively undermines the bible.

I wasn't arguing for or against it. I was simply explaining a couple of documents in a large collection have different intended meaning than that which you gave it.

We don't simply lift out parts of Herodotus and think that we should take his mentions of Achilles literally.

The Bible is a collection of documents. The meaning ascribed to them doesn't exempt them from treating them as ancient documents.

I'm sure they seem insane to you, but no moreso than our ancient Greek records, or the Roman ones either.

Re: A Physicist Who Denies Dark Matter

#118
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 matter. No modification to gravity can explain that without giving up the idea that gravity is a https://en.wikipedia.org/wiki/Central_force .

Re: A Physicist Who Denies Dark Matter

#119
post #18

Earlier quoted context omitted.

Dark matter isn't just dark, it doesn't interact with normal matter. When galaxies collide when can verify via gravitational lensing that the normal matter smashes together while the dark matter continues unimpeded in straight lines through each other.

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.

Re: A Physicist Who Denies Dark Matter

#120
post #99
post #51

Earlier quoted context omitted.

When we're confronted with something we can't explain using our existing equations and theories, the conclusion is that there must be some mysterious thing there that fixes our current equations and makes them work again? A thing we can't detect or see or have any other evidence of ... other than our equations and theories need that thing there for them to work? > In other words situations where we see twin images of…

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)?

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