Community Messageboard: Re: I don't object to changing my mind, but can take more convincing than I really should. by Dreaded Anomaly

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Re: I don't object to changing my mind, but can take more convincing than I really should. Dreaded Anomaly Send a noteboard - 09/05/2011 11:32:17 PM

With so much matter unaccounted for, how is it certain a more distant gravity source isn't pulling the superclusters (and everything else)? I'm not saying that's the case, I'm just curious how we can KNOW that's not the case.

The presence of huge amounts of mass at the edges of the universe, causing inner clusters to accelerate away from each other, is not consistent with cosmic inflation, which made the universe flat and homogeneous at large scales. Inflation is well supported by cosmic microwave background measurements.

Yeah, but I'm a lot more comfortable with that. We know no theory perfectly explains all the evidence, so there's a known but undefined amount of inaccuracy in every theory. Reducing that inaccuracy through observation, hypothesis and experimentation is what I hope is occurring, up to and including completely abandoning any theory with as much or more evidence against it as for it. Maybe I am just giving into the sensationalism again, but it seems like dark energy is more than just a wrinkle of the cosmological constant. That's not necessarily a bad thing; if it becomes a complete revision justified by the evidence then I have no complaint with it--provided it IS justified by the evidence, not just a desire to replace an existing theory.

If you refer to the Wikipedia page on dark energy, the next-to-last sentence is "First results from the SNLS reveal that the average behavior (i.e., equation of state) of dark energy behaves like Einstein's cosmological constant to a precision of 10%." The paper which demonstrates that result is cited.

The distinction was that we'd expect a unique fundamental particle to have unique properties, but positing multiple particles with most or all of the same properties would make the properties no longer unique. That's what I meant by comparing them to neutrons and protons: They were recognized as different particles due to different properties; had they possessed all or most of the same properties with slightly different masses they would not have been considered different particles (and, in the sense of both being baryons, no longer are) but variations of a single particle. The notion of multiple fundamental particles with only a few slight but critical variations reminds me of how we were tipped to the existence of quarks in the first place.

This entire paragraph is gibberish. Particles with all of the same properties but slightly different masses are recognized as different particles, as you could see by looking at the hadronic "particle zoo." The same combinations of quarks can exist at different levels of total angular momentum and isospin, and therefore different rest masses. Compare, for example, with the Delta particles, some of which have the same valence quark content as the proton and neutron but are ~30% more massive.

Basically, you've come up with some mental model of particles that isn't well grounded in the Standard Model or quantum field theory, and therefore makes meaningless distinctions. None of this is in any way a reasonable objection to dark matter being a new exotic particle.

I find your surplus of faith disturbing.

Professional communities, the scientific among them, can and have made mistakes, sometimes big ones. I'm confident any such error will be caught eventually, but can't help remembering that "eventually" is the word Wikipedia uses to describe how other scientists ultimately vindicated Vera Rubins findings on gravitational rotation, which it also says were met with skepticism until then. Institutional errors happen, and thus no discipline is infallible collectively or individually. EVENTUALLY quarks were hypothesized (and also met a fair amount of skepticism) and eventually they were found, but prior to the former particle physics went through a period where list of new "fundamental" particles never stopped growing. Not centuries ago, but about fifty years ago. Certainty that "science marches on" and never needs to retrace its steps except briefly is, once again, less than reassuring since it's reminiscent of the same certainty that has led down many blind alleys.

Sometimes, we have to expend some effort ruling out incorrect theories. Sometimes, this takes a while, and yes, that can be due in part to personality conflicts and other psychological foibles. If you have any worthwhile suggestions for improving that process, feel free to share. What you were doing at the start of this thread, though? That ain't it.

OK, I'll wait and see. I still can't help thinking about the proton decay GUTs predict. Perfect Symmetry contained the statement that "we know in our bones" protons have a half-life>10^30 years because our bodies own radioactivity would kill us if they didn't. Neutrino detectors had recently established their half-life had to be>10^31 years because we hadn't seen any decay, so the GUT creators revised their theories to more complicated particles that only required a half-life of 10^32 years. Then bigger detectors ruled that out; more revision, more complexity, more observation. Recently crusing through Wikipedia I saw that the minimum estimate is up around 10^34 years and there's a real prospect we'll NEVER be able to build a detector large enough to reproducably observe proton decay, and still the revision and increased complexity continues. The possibility the theory might just be WRONG doesn't seem to have ever been on the table; there's too much fame to be had from achieving what Einstein attempted and failed.

But, OK, I know I'm out of my depth. I'll see what happens and hope that if any observer bias exists it's corrected sooner rather than later.

...what? The vast majority of physicists have discarded the viability of traditional GUTs and don't consider proton decay worth a second thought. Yeah, there are still a few people trying to find it, but so what? The field is not one solid monolith, taking only one step in one direction at a time. I'm not sure why you have that impression, but you should revise it.

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Exciting video about the universe Camilla - 28/04/2011 10:14:55 AM 1091 Views

Cool, and true *NM* Stephen - 28/04/2011 11:46:29 AM 332 Views

I still think dark matter's just non-luminous matter without a convenient light source to reflect. Joel - 28/04/2011 10:34:21 PM 817 Views

We've just about ruled out the idea that dark matter is just non-luminous "ordinary" matter. Dreaded Anomaly - 28/04/2011 11:44:34 PM 750 Views

I'm aware of the Bullet Cluster, though admittedly not much more than that. Joel - 29/04/2011 01:52:49 AM 680 Views

Re: I'm aware of the Bullet Cluster, though admittedly not much more than that. Dreaded Anomaly - 29/04/2011 02:56:32 AM 793 Views

Re: I'm aware of the Bullet Cluster, though admittedly not much more than that. Joel - 30/04/2011 05:02:49 PM 749 Views

Re: I'm aware of the Bullet Cluster, though admittedly not much more than that. Dreaded Anomaly - 30/04/2011 08:56:35 PM 619 Views

Re: I'm aware of the Bullet Cluster, though admittedly not much more than that. Joel - 02/05/2011 01:28:30 AM 653 Views

Re: I'm aware of the Bullet Cluster, though admittedly not much more than that. Dreaded Anomaly - 04/05/2011 04:18:18 AM 758 Views

There's such a thing as knowing when you're licked, and I believe I am.

Joel - 07/05/2011 02:04:53 AM 829 Views

Re: There's such a thing as knowing when you're licked, and I believe I am.

Dreaded Anomaly - 09/05/2011 11:28:48 PM 673 Views

Re: There's such a thing as knowing when you're licked, and I believe I am.

Joel - 14/05/2011 05:36:45 AM 618 Views

Re: There's such a thing as knowing when you're licked, and I believe I am.

Dreaded Anomaly - 17/05/2011 02:09:40 AM 707 Views

Re: There's such a thing as knowing when you're licked, and I believe I am.

Joel - 19/05/2011 04:55:21 AM 629 Views

Re: There's such a thing as knowing when you're licked, and I believe I am.

Dreaded Anomaly - 24/05/2011 09:32:27 PM 706 Views

The Pati-Salam model was the one I had in mind. Joel - 24/05/2011 10:34:04 PM 648 Views

Re: The Pati-Salam model was the one I had in mind. Dreaded Anomaly - 24/05/2011 11:08:01 PM 856 Views

Re: The Pati-Salam model was the one I had in mind. Joel - 25/05/2011 01:27:10 AM 667 Views

Re: The Pati-Salam model was the one I had in mind. Dreaded Anomaly - 31/05/2011 09:16:18 AM 737 Views

Apologies for the delay; internet's been spotty and I've been busy lately. Joel - 10/06/2011 12:09:04 AM 988 Views

Re: Apologies for the delay; internet's been spotty and I've been busy lately. Dreaded Anomaly - 14/06/2011 03:38:18 AM 991 Views

Also, re: lensing from ordinary matter: Dreaded Anomaly - 29/04/2011 05:18:47 AM 681 Views

This seems like another example of what confuses the issue. Joel - 30/04/2011 05:25:04 PM 800 Views

Re: This seems like another example of what confuses the issue. Dreaded Anomaly - 30/04/2011 08:56:40 PM 772 Views

That discussion seems to reduce to "as little new and exotic physics as possible". Joel - 02/05/2011 01:29:03 AM 764 Views

Re: That discussion seems to reduce to "as little new and exotic physics as possible". Dreaded Anomaly - 04/05/2011 04:18:24 AM 726 Views

Re: That discussion seems to reduce to "as little new and exotic physics as possible". Joel - 07/05/2011 02:05:02 AM 902 Views

Re: That discussion seems to reduce to "as little new and exotic physics as possible". Dreaded Anomaly - 09/05/2011 11:29:36 PM 667 Views

Re: That discussion seems to reduce to "as little new and exotic physics as possible". Joel - 14/05/2011 05:35:56 AM 950 Views

Re: That discussion seems to reduce to "as little new and exotic physics as possible". Dreaded Anomaly - 17/05/2011 02:09:55 AM 575 Views

Re: That discussion seems to reduce to "as little new and exotic physics as possible". Joel - 19/05/2011 02:47:25 AM 915 Views

Re: That discussion seems to reduce to "as little new and exotic physics as possible". Dreaded Anomaly - 24/05/2011 09:46:30 PM 700 Views

Re: That discussion seems to reduce to "as little new and exotic physics as possible". Joel - 25/05/2011 12:20:10 AM 981 Views

Re: That discussion seems to reduce to "as little new and exotic physics as possible". Dreaded Anomaly - 31/05/2011 09:16:22 AM 799 Views

Re: That discussion seems to reduce to "as little new and exotic physics as possible". Joel - 10/06/2011 12:04:06 AM 1039 Views

Re: That discussion seems to reduce to "as little new and exotic physics as possible". Dreaded Anomaly - 14/06/2011 03:38:12 AM 805 Views

Re: I still think... (apparently, there is a 100 character limit on subjects, and yours was 99) Tor - 28/04/2011 11:57:15 PM 999 Views

Seems to happen to me a lot; sorry. Joel - 29/04/2011 12:56:14 AM 698 Views

None of this reflects on the actual facts of dark matter. Dreaded Anomaly - 29/04/2011 01:32:52 AM 664 Views

I concede my grasp (or grope) is a somewhat superficial laymans, yes. Joel - 30/04/2011 04:30:28 PM 780 Views

Re: I concede my grasp (or grope) is a somewhat superficial laymans, yes. Dreaded Anomaly - 30/04/2011 08:56:44 PM 614 Views

Re: I concede my grasp (or grope) is a somewhat superficial laymans, yes. Joel - 02/05/2011 01:28:58 AM 1132 Views

Re: I concede my grasp (or grope) is a somewhat superficial laymans, yes. Dreaded Anomaly - 04/05/2011 04:18:27 AM 658 Views

I don't object to changing my mind, but can take more convincing than I really should. Joel - 07/05/2011 02:05:09 AM 850 Views

Re: I don't object to changing my mind, but can take more convincing than I really should. Dreaded Anomaly - 09/05/2011 11:32:17 PM 776 Views

Re: I don't object to changing my mind, but can take more convincing than I really should. Joel - 14/05/2011 05:36:24 AM 929 Views

Re: I don't object to changing my mind, but can take more convincing than I really should. Dreaded Anomaly - 17/05/2011 02:10:03 AM 686 Views

Re: I don't object to changing my mind, but can take more convincing than I really should. Joel - 19/05/2011 04:33:06 AM 930 Views

Re: I don't object to changing my mind, but can take more convincing than I really should. Dreaded Anomaly - 24/05/2011 09:59:38 PM 679 Views

Re: I don't object to changing my mind, but can take more convincing than I really should. Joel - 24/05/2011 11:19:43 PM 648 Views

Re: I don't object to changing my mind, but can take more convincing than I really should. Dreaded Anomaly - 24/05/2011 11:33:58 PM 603 Views

Re: I don't object to changing my mind, but can take more convincing than I really should. Joel - 25/05/2011 12:55:36 AM 732 Views

Re: I don't object to changing my mind, but can take more convincing than I really should. Dreaded Anomaly - 31/05/2011 09:16:24 AM 642 Views

Re: I don't object to changing my mind, but can take more convincing than I really should. Joel - 10/06/2011 12:09:13 AM 825 Views

Re: I don't object to changing my mind, but can take more convincing than I really should. Dreaded Anomaly - 14/06/2011 03:38:05 AM 802 Views

Might help if you clarified where your skepticism is at Isaac - 29/04/2011 02:32:07 AM 636 Views

Potentially either, or a combination of the two. Joel - 30/04/2011 02:36:50 PM 700 Views

It's hard to discuss without knowing your objections a bit more clearly Isaac - 30/04/2011 04:58:03 PM 615 Views

My primary objection is that alternatives to dark matter seem to have been ruled out prematurely. Joel - 02/05/2011 01:29:14 AM 752 Views

Well, they weren't, not really sure how else to put that Isaac - 10/05/2011 03:19:57 AM 789 Views

Alright then, objection withdrawn (cautious skepticism intact). Joel - 14/05/2011 05:34:17 AM 907 Views

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<quote id="206270">
<quote id="205747">With so much matter unaccounted for, how is it certain a more distant gravity source isn't pulling the superclusters (and everything else)? I'm not saying that's the case, I'm just curious how we can KNOW that's not the case.</quote>

<quote id="205747">Yeah, but I'm a lot more comfortable with that. We know no theory perfectly explains all the evidence, so there's a known but undefined amount of inaccuracy in every theory. Reducing that inaccuracy through observation, hypothesis and experimentation is what I hope is occurring, up to and including completely abandoning any theory with as much or more evidence against it as for it. Maybe I am just giving into the sensationalism again, but it seems like dark energy is more than just a wrinkle of the cosmological constant. That's not necessarily a bad thing; if it becomes a complete revision justified by the evidence then I have no complaint with it--provided it IS justified by the evidence, not just a desire to replace an existing theory.</quote>

<quote id="205747">The distinction was that we'd expect a unique fundamental particle to have unique properties, but positing multiple particles with most or all of the same properties would make the properties no longer unique. That's what I meant by comparing them to neutrons and protons: They were recognized as different particles due to different properties; had they possessed all or most of the same properties with slightly different masses they would not have been considered different particles (and, in the sense of both being baryons, no longer are) but variations of a single particle. The notion of multiple fundamental particles with only a few slight but critical variations reminds me of how we were tipped to the existence of quarks in the first place.</quote>

This entire paragraph is gibberish. Particles with all of the same properties but slightly different masses are recognized as different particles, as you could see by looking at the hadronic "particle zoo." The same combinations of quarks can exist at different levels of total angular momentum and isospin, and therefore different rest masses. Compare, for example, with the Delta particles, some of which have the same valence quark content as the proton and neutron but are ~30% more massive.

Basically, you've come up with some mental model of particles that isn't well grounded in the Standard Model or quantum field theory, and therefore makes meaningless distinctions. None of this is in any way a reasonable objection to dark matter being a new exotic particle.

<quote id="205747">I find your surplus of faith disturbing. ;) Professional communities, the scientific among them, can and have made mistakes, sometimes big ones. I'm confident any such error will be caught eventually, but can't help remembering that "eventually" is the word Wikipedia uses to describe how other scientists ultimately vindicated Vera Rubins findings on gravitational rotation, which it also says were met with skepticism until then. Institutional errors happen, and thus no discipline is infallible collectively or individually. EVENTUALLY quarks were hypothesized (and also met a fair amount of skepticism) and eventually they were found, but prior to the former particle physics went through a period where list of new "fundamental" particles never stopped growing. Not centuries ago, but about fifty years ago. Certainty that "science marches on" and never needs to retrace its steps except briefly is, once again, less than reassuring since it's reminiscent of the same certainty that has led down many blind alleys.</quote>

<quote id="205747">OK, I'll wait and see. I still can't help thinking about the proton decay GUTs predict. Perfect Symmetry contained the statement that "we know in our bones" protons have a half-life>10^30 years because our bodies own radioactivity would kill us if they didn't. Neutrino detectors had recently established their half-life had to be>10^31 years because we hadn't seen any decay, so the GUT creators revised their theories to more complicated particles that only required a half-life of 10^32 years. Then bigger detectors ruled that out; more revision, more complexity, more observation. Recently crusing through Wikipedia I saw that the minimum estimate is up around 10^34 years and there's a real prospect we'll NEVER be able to build a detector large enough to reproducably observe proton decay, and still the revision and increased complexity continues. The possibility the theory might just be WRONG doesn't seem to have ever been on the table; there's too much fame to be had from achieving what Einstein attempted and failed.

But, OK, I know I'm out of my depth. I'll see what happens and hope that if any observer bias exists it's corrected sooner rather than later.</quote>

...what? The vast majority of physicists have discarded the viability of traditional GUTs and don't consider proton decay worth a second thought. Yeah, there are still a few people trying to find it, but so what? The field is not one solid monolith, taking only one step in one direction at a time. I'm not sure why you have that impression, but you should revise it.
</quote>

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