A short letter submitted to ApJ by the same team who brought you the first galaxy without dark matter. This second discovery is very similar to the first : it's in the same group of galaxies, at the same distance, has a low surface brightness, is very extended, and has a similar smooth and boring-looking morphology. Its all-important velocity dispersion is even lower than the first, at a mere 6 km/s compared to 8-10 km/s. Which is again consistent with its dynamics being completely dominated by its stellar mass, with little or no additional dark matter needed.
This is very strange indeed. During tidal encounters between galaxies, it's possible for the gravity to tear off enough material to form a brand new (low mass) galaxy without its own dark matter component - that's been known for ages. But such a process ought to be messy. It shouldn't be able to form big, smooth objects that move very slowly. There ought to be debris all over the place : stellar streams and other weird-looking structures. It just shouldn't be able to make anything that looks this damn boring. Well, not quite true : after a good long while things should settle down and most of the crazier stuff ought to disperse, but to form very smooth things like these galaxies should take a very, very long time indeed because their motions are so low. And galaxies produced by this mechanism are chemically different to other galaxies, whereas this one isn't.
Could this just be a normal (though faint) galaxy observed close to face-on where we wouldn't be able to detect any rotation ? It was possible with one object, but that becomes highly unlikely with two - where are all the faint edge-on galaxies, eh ? Similarly, while tidal encounters can act to strip away large amounts of dark matter from ordinary galaxies, it seems incredibly unlikely that we'd find two such objects in a group without the expected tidal debris.
The other weird feature of these objects is that they have a large number of globular clusters given their low stellar mass. What the connection might be with the lack of dark matter is anyone's guess, but it does make it even more likely that they're part of a distinct population rather than being weird but rare exotica. Having a second object changes the picture considerably, but we need many more objects to have any kind of statistical view.
What I'm a bit surprised at is that no-one is talking much about the other (rather large !) population of objects which are known to show unusually low velocity dispersion from their gas measurements : ultra-diffuse galaxies. I e-mailed van Dokkum about that because it seems like something that should be mentioned more in the literature somewhere, but after a couple of weeks I didn't get a response so I guess I never will.
https://arxiv.org/abs/1901.05973
Tuesday, 22 January 2019
Tuesday, 15 January 2019
Missing Matter Still Even More Missing, Study Finds
Last year a galaxy that seemed to have no dark matter was doing the rounds because that's freakin' weird. Virtually all galaxies appear to be heavily mass dominated by dark matter : it's arguably the best way to define a galaxy as opposed to a giant star cluster. The whole mainstream basis of galaxy formation and evolutionary theory depends on dark matter as an integral feature. While there are some cases of dwarf galaxies formed by tidal encounters that don't have much (or any) dark matter, these tend to be still embedded in the debris associated with their formation. As far as I know there are no good cases of a dark matter free galaxy just sitting there minding its own business.
If such an object were to be found, it would raise awkward questions for the standard theories of galaxy evolution but make life even more difficult for the main alternative : modified gravity. Tidal encounters between galaxies can strip away dark matter, so it's at least possible to reduce the dark matter content in standard theories (but remove it completely ? I doubt it). For modified gravity, on the other hand, any two star systems of the same size and shape ought to have the same dynamics : gravity should work the same everywhere, more or less. A nice control test where one can compare similar objects is not so easy to find as you might think, but such systems have been found - and the results don't look good for modified gravity.
Then there is this galaxy, NGC1052-DF2. This is an ultra-diffuse galaxy, meaning it's very large but with few stars per unit area. That makes it difficult to measure how fast its stars are moving, which is what you need to work out its total mass. So previously astronomers used its globular clusters, which are much brighter and easier to measure (though there are only a few of them). They found a velocity dispersion of 8-10 km/s - so low that it's consistent with the galaxy having no dark matter at all.
This made a lot of people very upset. Claims were made that the distance measurements were wrong and that would mean the galaxy was perfectly normal, but then an independent team came along and said nope, the distance measurements are correct, this galaxy really is weird.
Still, having only 10 globular clusters has always raised concerns that the estimate of the velocity resolution is reliant on small number statistics. Other teams have questioned the rigour of the claim for such a low dispersion, though in my opinion the original van Dokkum claim always looked stronger. Now, two teams have used extremely powerful instruments to measure the velocity dispersion of the stars directly. Note that both papers are still under review.
The first paper was by an independent group and came out just before Christmas :
http://adsabs.harvard.edu/abs/2018arXiv181207345E
I read this, but didn't bother writing about it because I found it rather badly-worded : I could not easily extract the main point about just how massive the galaxy is supposed to be. Fortunately the new paper (by the original team) is much more clearly written and comments on the Emsellem work.
The bottom line is that this galaxy does indeed seem to have very little or possibly no dark matter whatsoever. This is in conflict with the Emsellem claim in two ways : first, Emsellem claimed that the velocity dispersion could be much higher (13-27 km/s), whereas this paper says it's 8 km/s (just as the original globular cluster measurements indicated); second, Emsellem claimed the galaxy is rotating (albeit slowly) whereas this paper finds no evidence of that. The authors comment directly on the disagreement , noting that they aren't able to explain it. The only hint is that this latest study has a much greater velocity resolution than the Emesllem paper so it should be more accurate. And their fitted velocity dispersion profiles do seem to match the data extremely well.
As for how well this galaxy does or doesn't fit with modified gravity, as usual there's the complication of the external field effect. In modified dynamics, the presence of nearby galaxy can change the velocity dispersion in a very different way to conventional theories. Based on this, the earlier prediction was that the dispersion should be 13 km/s. This is not consistent with the new results, and only just about consistent with the Emsellem range which is actually more favourable to the galaxy having some dark matter than the modified gravity prediction.
I would expect a great deal of back-and-forth on this issue. My money's on the original van Dokkum team. Though a very strange result, it does seem to stand up to scrutiny so far. Watch this space.
https://arxiv.org/abs/1901.03711
If such an object were to be found, it would raise awkward questions for the standard theories of galaxy evolution but make life even more difficult for the main alternative : modified gravity. Tidal encounters between galaxies can strip away dark matter, so it's at least possible to reduce the dark matter content in standard theories (but remove it completely ? I doubt it). For modified gravity, on the other hand, any two star systems of the same size and shape ought to have the same dynamics : gravity should work the same everywhere, more or less. A nice control test where one can compare similar objects is not so easy to find as you might think, but such systems have been found - and the results don't look good for modified gravity.
Then there is this galaxy, NGC1052-DF2. This is an ultra-diffuse galaxy, meaning it's very large but with few stars per unit area. That makes it difficult to measure how fast its stars are moving, which is what you need to work out its total mass. So previously astronomers used its globular clusters, which are much brighter and easier to measure (though there are only a few of them). They found a velocity dispersion of 8-10 km/s - so low that it's consistent with the galaxy having no dark matter at all.
This made a lot of people very upset. Claims were made that the distance measurements were wrong and that would mean the galaxy was perfectly normal, but then an independent team came along and said nope, the distance measurements are correct, this galaxy really is weird.
Still, having only 10 globular clusters has always raised concerns that the estimate of the velocity resolution is reliant on small number statistics. Other teams have questioned the rigour of the claim for such a low dispersion, though in my opinion the original van Dokkum claim always looked stronger. Now, two teams have used extremely powerful instruments to measure the velocity dispersion of the stars directly. Note that both papers are still under review.
The first paper was by an independent group and came out just before Christmas :
http://adsabs.harvard.edu/abs/2018arXiv181207345E
I read this, but didn't bother writing about it because I found it rather badly-worded : I could not easily extract the main point about just how massive the galaxy is supposed to be. Fortunately the new paper (by the original team) is much more clearly written and comments on the Emsellem work.
The bottom line is that this galaxy does indeed seem to have very little or possibly no dark matter whatsoever. This is in conflict with the Emsellem claim in two ways : first, Emsellem claimed that the velocity dispersion could be much higher (13-27 km/s), whereas this paper says it's 8 km/s (just as the original globular cluster measurements indicated); second, Emsellem claimed the galaxy is rotating (albeit slowly) whereas this paper finds no evidence of that. The authors comment directly on the disagreement , noting that they aren't able to explain it. The only hint is that this latest study has a much greater velocity resolution than the Emesllem paper so it should be more accurate. And their fitted velocity dispersion profiles do seem to match the data extremely well.
As for how well this galaxy does or doesn't fit with modified gravity, as usual there's the complication of the external field effect. In modified dynamics, the presence of nearby galaxy can change the velocity dispersion in a very different way to conventional theories. Based on this, the earlier prediction was that the dispersion should be 13 km/s. This is not consistent with the new results, and only just about consistent with the Emsellem range which is actually more favourable to the galaxy having some dark matter than the modified gravity prediction.
I would expect a great deal of back-and-forth on this issue. My money's on the original van Dokkum team. Though a very strange result, it does seem to stand up to scrutiny so far. Watch this space.
https://arxiv.org/abs/1901.03711
Friday, 11 January 2019
Who watches the watchers ?
Interesting. In general I like the idea of a more open review process. After acceptance, it would be helpful to see the referee reports to be able to track the changes to the paper (everyone forgets when the reviewers provide extremely helpful suggestions, while everyone remembers those times when the reviewer made the paper worse - yet both do occur). But posting the reviews of rejected papers ? That doesn't sit right : the point of rejecting a paper should be that there's no need for more discussion on it. Of course you can post whatever you want on a blog, but that doesn't mean you should : it will only attract more attention anyway.
The biggest change I would make to the review system would be to have a more clearly-defined set of guidelines as to what the reviewer can/should do, e.g. how much control they have compared to the authors. The amount of transparency should be explicit and up-front - different levels may be appropriate in different cases, particularly when public preprint services are used. I don't see a good underlying principle to follow; neither total transparency nor total opacity seem sensible to me. I favour an "if in doubt, accept" approach - rejection should only be used when the paper is fundamentally flawed.
https://neuroneurotic.net/2019/01/10/an-open-review-of-open-reviewing/
The biggest change I would make to the review system would be to have a more clearly-defined set of guidelines as to what the reviewer can/should do, e.g. how much control they have compared to the authors. The amount of transparency should be explicit and up-front - different levels may be appropriate in different cases, particularly when public preprint services are used. I don't see a good underlying principle to follow; neither total transparency nor total opacity seem sensible to me. I favour an "if in doubt, accept" approach - rejection should only be used when the paper is fundamentally flawed.
https://neuroneurotic.net/2019/01/10/an-open-review-of-open-reviewing/
Wednesday, 9 January 2019
Space dragons are officially serious science
I'm in a press release based on a Nature paper and I talk about space dragons. Because that's how I roll.
"As we rotated the data cube, we got our first glimpse of the structure that we've nicknamed Orion's Dragon," said Rhys Taylor, a scientist at the Astronomical Institute of the Czech Academy of Sciences and a consultant to the SOFIA team, in a press release. "A few people have said it looks like a sea horse or a pterodactyl, but it looks like a dragon to me."
A bit more of my own explanation and more images (including a VR video) can be found here.
http://astronomy.com/news/2019/01/orions-dragon-revealed-in-3d-by-nasas-airborne-observatory
"As we rotated the data cube, we got our first glimpse of the structure that we've nicknamed Orion's Dragon," said Rhys Taylor, a scientist at the Astronomical Institute of the Czech Academy of Sciences and a consultant to the SOFIA team, in a press release. "A few people have said it looks like a sea horse or a pterodactyl, but it looks like a dragon to me."
A bit more of my own explanation and more images (including a VR video) can be found here.
http://astronomy.com/news/2019/01/orions-dragon-revealed-in-3d-by-nasas-airborne-observatory
Monday, 7 January 2019
I am an artist now
The visitor's office now features a ginormous (~3x2 m) print of one my artsy-farsty data visualisation projects. Original with explanations here :
https://astrorhysy.blogspot.com/2018/06/h-one.html
The landscape is an intensity map of the hydrogen content of M33, where intensity generates height rather than colour (landscape colours are completely arbitrary and were added by someone else to make things prettier, and rightly so). The background colours are derived from the frequency and intensity of Milky Way hydrogen. They're a bit washed out in the final print version compared to the original, but they get the job done.
The original digital version of this image looks like this :
https://astrorhysy.blogspot.com/2018/06/h-one.html
The landscape is an intensity map of the hydrogen content of M33, where intensity generates height rather than colour (landscape colours are completely arbitrary and were added by someone else to make things prettier, and rightly so). The background colours are derived from the frequency and intensity of Milky Way hydrogen. They're a bit washed out in the final print version compared to the original, but they get the job done.
The original digital version of this image looks like this :
Saturday, 15 December 2018
Undergraduate students in Cardiff now get to build Rube Goldbergmachines at the final lab session of the year.
Just a couple of pictures from my traditional, "spend-Christmas-in-the-Cardiff-Physics-Department-because-that's-how-I-roll" trip...
First, undergraduate students in Cardiff now get to build Rube Goldberg machines at the final lab session of the year. We never got to do anything fun like that back in my day...
And second, this notice board attests to the very important research being done in this student office.
First, undergraduate students in Cardiff now get to build Rube Goldberg machines at the final lab session of the year. We never got to do anything fun like that back in my day...
And second, this notice board attests to the very important research being done in this student office.
New review process for the HST
Last year, despite efforts made to reduce bias, proposals for medium and large programs on the Hubble Space Telescope had an acceptance rate of 24% for programs led by men and 13% for programs led by women, an imbalance largely in keeping with the telescope's history. This year, in one of the most competitive cycles ever, that suddenly changed to a near-equivalent 8.7% acceptance rate for women and an 8.0% acceptance rate for men, reversing the trend seen over the past 15 cycles. What happened? Anonymized proposals.
Interesting but unsurprising. I'd be more interested to see what happens with regards to prominent researchers versus novices. Are people being awarded time essentially because they've already been awarded time, or are they more successful simply because they write better proposals ? My guess would be more variability in the proposal quality of famous researchers. That is, if you're well-known, you probably do have a better chance of getting a lower-quality proposal accepted, but on average your proposals tend to be better.
https://www.metafilter.com/178225/Focus-on-the-Science-Not-the-Scientist
Interesting but unsurprising. I'd be more interested to see what happens with regards to prominent researchers versus novices. Are people being awarded time essentially because they've already been awarded time, or are they more successful simply because they write better proposals ? My guess would be more variability in the proposal quality of famous researchers. That is, if you're well-known, you probably do have a better chance of getting a lower-quality proposal accepted, but on average your proposals tend to be better.
https://www.metafilter.com/178225/Focus-on-the-Science-Not-the-Scientist
Wednesday, 12 December 2018
We're hiring !
Just when I thought I was finally done for the year, I end up giving a seminar to some visiting PhD students yesterday morning. With a flight in the afternoon I wasn't planning to come it at all that day, but oh well... they enjoyed it anyway. One of them said it was one of the best talks they'd ever had !
[Readers will have to imagine me in a suitably heroic pose of the non-Blackadder variety at this point]
Seminars are now extremely useful though, as due to a surfeit of riches at the Czech Academy of Sciences they decided to fund all three of our group's grant applications. So I get a higher salary and the group is now searching for three (!) new postdocs : one in star formation in the galactic centre, one in star formation in clusters, and one in optically dark hydrogen clouds that don't do anything (you can guess which one is mine). Anyone want to become my assistant andfetch me tea on demand carry out important research in galaxy evolution ? Starts mid 2019, guaranteed funding until the end of 2021 with a healthy travel budget. We're also looking for an additional postdoc for ALMA-related things. More details to follow should we have trouble finding people (obviously I am not relying on blog posts to find postdocs because that would be completely mad).
In other news I won this year's institutional Jan Fric (the founder of the institute) award, so I get another shiny award ceremony in January (and another seminar...). And my position is now, if not exactly tenure track, on a rather more permanent basis that a postdoc position. Must be doing something right... of course, I expect Brexit will completely bugger the whole thing up, and then I will be sad. Until then I shall be enjoying Christmas.
[Readers will have to imagine me in a suitably heroic pose of the non-Blackadder variety at this point]
Seminars are now extremely useful though, as due to a surfeit of riches at the Czech Academy of Sciences they decided to fund all three of our group's grant applications. So I get a higher salary and the group is now searching for three (!) new postdocs : one in star formation in the galactic centre, one in star formation in clusters, and one in optically dark hydrogen clouds that don't do anything (you can guess which one is mine). Anyone want to become my assistant and
In other news I won this year's institutional Jan Fric (the founder of the institute) award, so I get another shiny award ceremony in January (and another seminar...). And my position is now, if not exactly tenure track, on a rather more permanent basis that a postdoc position. Must be doing something right... of course, I expect Brexit will completely bugger the whole thing up, and then I will be sad. Until then I shall be enjoying Christmas.
Friday, 7 December 2018
Who needs dark matter when you can have... negative matter !
"This implies that our Universe is just one of those things that happen on occasion..."
That's one of the memorable lines in this very interesting paper that tries to replace conventional dark matter with something more exotic : negative matter. The other wonderful line is the extremely astute remark, "Observations clearly indicate that the Universe is not empty." That's one thing we can surely all agree on. But is regular dark matter too mainstream for you ? Is doing away with dark matter too contrarian ? Then this is the paper for you !
The press release was quite interesting but left me very puzzled so I decided to read the paper, even though this kind of thing is well outside my area. Here's my take on it for whatever that's worth.
I get the distinct impression that the author was having great fun writing this. The overall tone is - by the standards of academic research at any rate - frivolous and playful. I doubt it's supposed to be taken entirely seriously; he's clearly not saying that he's definitely overturned all of physics. Taken as a curious piece of speculation I wholeheartedly approve - taken as anything more than that and the guy's a nutter. Which is a nice summary of the some of the very best papers, really.
Anyway, the key point is figure 1, which illustrates how matter with negative mass accelerates due to gravity. As everyone's familiar with, normal (positive) matter accelerates towards other normal matter under gravity. Negative matter would accelerate away from itself. Weird, but okay. That might leave you wondering how in the world negative matter could possibly be a substitute for dark matter : observations indicate the presence of large amounts of unseen positive mass. How could stuff which tends to push itself apart possibly be a substitute for stuff that's supposed to be pulling everything together ?
Well, where it gets really strange is the interaction between positive and negative matter. Positive matter would accelerate away from negative matter, but negative matter would accelerate towards positive matter. Stick a mass of negative matter at the end of an equal mass of positive matter in free space and in principle they both accelerate forever, eventually reaching - says Farnes - lightspeed. He's quite explicit about equalling lightspeed, not just merely coming close to it. Conservation of energy is not violated; I'm guessing (but only guessing !) because a moving negative mass has negative kinetic energy. He notes that such claims have been labelled as "preposterous", however.
My guess is that if you have negative matter instead of positive matter, you don't need an equal amount of it to reproduce the effects of "ordinary" dark matter. It only has to provide that extra push to reproduce the apparent effects of unseen positive mass (e.g. galaxy rotation and motions in clusters). In very hand-waving terms I can sort-of see how negative matter could then act as a replacement for conventional, positive-mass dark matter : it wouldn't be a direct substitution.
A lot of the paper describes how this model can unify dark matter and dark energy. The latter is much easier to see (though I won't for a second claim to understand the maths) : if you've got some substance pushing everything apart, then sure, that could drive the acceleration of the expansion of the Universe. It's more difficult to understand how negative matter could be responsible for the evidence typically interpreted as large amounts of missing positive matter, at least in an intuitive way.
Farnes presents code, simulations and analytic formulae to address all of the major underlying objections one might raise. He notes that negative mass may or may not equate with antimatter; at least in principle the two need not annihilate each other. He shows that structures can form in a negative matter-dominated universe, even more rapidly, in face, than in one dominated by positive matter. Runaway accelerating particles do not occur, presumably because random motions dominate (also gravity is a very weak force). And he demonstrates how negative mass may lead to flat rotation curves, although to be honest I didn't really understand how that works.
He doesn't address gravitational lensing though (God knows how that would work with negative mass) or say much about the CMB power spectrum, which IIRC has been interpreted as very strong evidence for dark matter independent of galaxy rotation curves. Also, this theory requires a continuous creation of negative matter.
So as I said, don't get too excited. It's an interesting bit of speculation but it's also bloody weird. To mind mind a constant amount of missing positive mass, plus some other, unrelated component for dark energy, still feels like a simpler explanation. I hope there will be more serious and detailed responses from more knowledgeable people. It is Christmas, after all...
I haven't tried the code provided but I hope someone will.
https://arxiv.org/abs/1712.07962
That's one of the memorable lines in this very interesting paper that tries to replace conventional dark matter with something more exotic : negative matter. The other wonderful line is the extremely astute remark, "Observations clearly indicate that the Universe is not empty." That's one thing we can surely all agree on. But is regular dark matter too mainstream for you ? Is doing away with dark matter too contrarian ? Then this is the paper for you !
The press release was quite interesting but left me very puzzled so I decided to read the paper, even though this kind of thing is well outside my area. Here's my take on it for whatever that's worth.
I get the distinct impression that the author was having great fun writing this. The overall tone is - by the standards of academic research at any rate - frivolous and playful. I doubt it's supposed to be taken entirely seriously; he's clearly not saying that he's definitely overturned all of physics. Taken as a curious piece of speculation I wholeheartedly approve - taken as anything more than that and the guy's a nutter. Which is a nice summary of the some of the very best papers, really.
Anyway, the key point is figure 1, which illustrates how matter with negative mass accelerates due to gravity. As everyone's familiar with, normal (positive) matter accelerates towards other normal matter under gravity. Negative matter would accelerate away from itself. Weird, but okay. That might leave you wondering how in the world negative matter could possibly be a substitute for dark matter : observations indicate the presence of large amounts of unseen positive mass. How could stuff which tends to push itself apart possibly be a substitute for stuff that's supposed to be pulling everything together ?
Well, where it gets really strange is the interaction between positive and negative matter. Positive matter would accelerate away from negative matter, but negative matter would accelerate towards positive matter. Stick a mass of negative matter at the end of an equal mass of positive matter in free space and in principle they both accelerate forever, eventually reaching - says Farnes - lightspeed. He's quite explicit about equalling lightspeed, not just merely coming close to it. Conservation of energy is not violated; I'm guessing (but only guessing !) because a moving negative mass has negative kinetic energy. He notes that such claims have been labelled as "preposterous", however.
My guess is that if you have negative matter instead of positive matter, you don't need an equal amount of it to reproduce the effects of "ordinary" dark matter. It only has to provide that extra push to reproduce the apparent effects of unseen positive mass (e.g. galaxy rotation and motions in clusters). In very hand-waving terms I can sort-of see how negative matter could then act as a replacement for conventional, positive-mass dark matter : it wouldn't be a direct substitution.
A lot of the paper describes how this model can unify dark matter and dark energy. The latter is much easier to see (though I won't for a second claim to understand the maths) : if you've got some substance pushing everything apart, then sure, that could drive the acceleration of the expansion of the Universe. It's more difficult to understand how negative matter could be responsible for the evidence typically interpreted as large amounts of missing positive matter, at least in an intuitive way.
Farnes presents code, simulations and analytic formulae to address all of the major underlying objections one might raise. He notes that negative mass may or may not equate with antimatter; at least in principle the two need not annihilate each other. He shows that structures can form in a negative matter-dominated universe, even more rapidly, in face, than in one dominated by positive matter. Runaway accelerating particles do not occur, presumably because random motions dominate (also gravity is a very weak force). And he demonstrates how negative mass may lead to flat rotation curves, although to be honest I didn't really understand how that works.
He doesn't address gravitational lensing though (God knows how that would work with negative mass) or say much about the CMB power spectrum, which IIRC has been interpreted as very strong evidence for dark matter independent of galaxy rotation curves. Also, this theory requires a continuous creation of negative matter.
So as I said, don't get too excited. It's an interesting bit of speculation but it's also bloody weird. To mind mind a constant amount of missing positive mass, plus some other, unrelated component for dark energy, still feels like a simpler explanation. I hope there will be more serious and detailed responses from more knowledgeable people. It is Christmas, after all...
I haven't tried the code provided but I hope someone will.
https://arxiv.org/abs/1712.07962
Saturday, 1 December 2018
Science is not fake news
The key word here is "best". The consensus isn't, and shouldn't, claim to be the Absolute Truth. Such a thing may well not even exist. All it can claim is to be the best possible approximation to such a truth given the current state of the understanding of the evidence at any time. That can and frequently does change, such that you get some people lambasting scientists for not being able to make up their minds, while others insist that they're all dogmatic and never change their minds at all. Or worse, they say that when they do shift, they rewrite history so it looks like everything was fine and that they were ignoring legitimate criticism.
In reality, what usually happens is that contrarians remain contrarian because their arguments simply lack sufficient power. If and when they accumulate more evidence, the consensus position shifts. What you have to remember is that there's usually a plethora of available contrarian positions to choose from, a sort of "dial a theory" if you like. This results in a survivorship bias when the consensus changes, when in fact the new position was previously rejected for what were, at the time, very good reasons.
https://astrorhysy.blogspot.com/2016/07/they-said-i-was-maaaaad.html
http://astrorhysy.blogspot.com/2015/06/consensus-and-conspiracy.html
You may be extremely intelligent and capable in a whole slew of ways, but you can immediately recognize the limits to your own knowledge and expertise. There are some things you know extremely well; possibly as well as the top few dozen people on Earth know it. But when it comes to most issues, there are people who have far greater levels of knowledge and expertise than you do.
This isn't a failing on your part, mind you. This is a result of the fact that, as human beings, we only get one life to live. However we've spent our time in this world — whatever we've studied, practiced, worked on, researched, etc. — that's where our greatest expertise lies. And this extends beyond ourselves as well: the expertise of others, particularly when we're lacking in that expertise, is something we need to rely on when we're out of our depths.
Which is why it's so dangerous and delusional to proclaim that you, when you're a non-expert, are better equipped to assess an expertise-requiring problem than the experts themselves.
You are not.
That doesn't mean the experts are always right. That doesn't mean there aren't frauds, charlatans, fools, cronies, and unimaginitive followers among the experts. That doesn't mean that people aren't corrupt, and it doesn't mean that the expert consensus won't change as more and better data comes in.
But that's why we not only have experts, it's why we have the enterprise of science.
Of course, that's not to say that you aren't allowed to question the experts or that they're entitled to pronounce judgement upon you. It's more a case of "you can ignore them if you like, but it's your own bloody fault if you get it wrong". Which you are far, far more likely to do than if you'd just accepted the consensus view. Doesn't mean you can't have hobbies or that amateurs can't be valuable, but if you actually want to make progress, it's worth considering the mainstream ideas first. Lots of people seem to think it's fine to debunk things they've never actually looked into in the slightest.
One of my favourite pieces on assessing credibility [REPLACE LINK !]:
https://plus.google.com/u/0/+RhysTaylorRhysy/posts/ExUtrBorfWs
https://www.forbes.com/sites/startswithabang/2018/11/29/science-is-not-fake-news/
In reality, what usually happens is that contrarians remain contrarian because their arguments simply lack sufficient power. If and when they accumulate more evidence, the consensus position shifts. What you have to remember is that there's usually a plethora of available contrarian positions to choose from, a sort of "dial a theory" if you like. This results in a survivorship bias when the consensus changes, when in fact the new position was previously rejected for what were, at the time, very good reasons.
https://astrorhysy.blogspot.com/2016/07/they-said-i-was-maaaaad.html
http://astrorhysy.blogspot.com/2015/06/consensus-and-conspiracy.html
You may be extremely intelligent and capable in a whole slew of ways, but you can immediately recognize the limits to your own knowledge and expertise. There are some things you know extremely well; possibly as well as the top few dozen people on Earth know it. But when it comes to most issues, there are people who have far greater levels of knowledge and expertise than you do.
This isn't a failing on your part, mind you. This is a result of the fact that, as human beings, we only get one life to live. However we've spent our time in this world — whatever we've studied, practiced, worked on, researched, etc. — that's where our greatest expertise lies. And this extends beyond ourselves as well: the expertise of others, particularly when we're lacking in that expertise, is something we need to rely on when we're out of our depths.
Which is why it's so dangerous and delusional to proclaim that you, when you're a non-expert, are better equipped to assess an expertise-requiring problem than the experts themselves.
You are not.
That doesn't mean the experts are always right. That doesn't mean there aren't frauds, charlatans, fools, cronies, and unimaginitive followers among the experts. That doesn't mean that people aren't corrupt, and it doesn't mean that the expert consensus won't change as more and better data comes in.
But that's why we not only have experts, it's why we have the enterprise of science.
Of course, that's not to say that you aren't allowed to question the experts or that they're entitled to pronounce judgement upon you. It's more a case of "you can ignore them if you like, but it's your own bloody fault if you get it wrong". Which you are far, far more likely to do than if you'd just accepted the consensus view. Doesn't mean you can't have hobbies or that amateurs can't be valuable, but if you actually want to make progress, it's worth considering the mainstream ideas first. Lots of people seem to think it's fine to debunk things they've never actually looked into in the slightest.
One of my favourite pieces on assessing credibility [REPLACE LINK !]:
https://plus.google.com/u/0/+RhysTaylorRhysy/posts/ExUtrBorfWs
https://www.forbes.com/sites/startswithabang/2018/11/29/science-is-not-fake-news/
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ChatGPT Is A Competent Source Extractor
This builds on my post from two years ago, ChatGPT Is Not A Source Extractor . My, how things change. Last time I wrote : They're still ...
