A few months ago I came across an intriguing contrarian theory: Hydrogravitional-dynamics (HGD) cosmology … predicts … Earth-mass planets fragmented from plasma at 300 Kyr [after the big bang]. Stars promptly formed from mergers of these gas planets, and chemicals C, N, O, Fe etc. were created by the stars and their supernovae. Seeded gas planets reduced the oxides to hot water oceans [at 2 Myr], … [which] hosted the first organic chemistry and the first life, distributed to the 1080 planets of the cosmological big bang by comets. … The dark matter of galaxies is mostly primordial planets in proto globular star cluster clumps, 30,000,000 planets per star (not 8!). (
In the post I linked in my "via" it is claimed that cold dark matter also predicts more small satellite/dwarf galaxies than are actually observed (further discussed in this post ). What do you think?
I'm a physics major but I'm having difficulty reading this but I do have some remarks. Cyan is on to something, baryonic dark matter is unlikely to make up a large percentage of dark matter. Also, the "abundance" of large planets, in low orbits is generally regarded as selection bias by astronomers, because planets that are smaller and/or locked in higher orbits are simply more difficult to detect.
I didn’t understand turbulence well enough to judge these theories, so I set it all aside. But over the last few months I’ve noticed many reports about puzzling numbers and locations of planets:What has puzzled observers and theorists so far is the high proportion of planets — roughly one-third to one-half — that are bigger than Earth but smaller than Neptune. … Furthermore, most of them are in tight orbits around their host star, precisely where the modellers say they shouldn’t be.
There's a heavy amount of selection bias here: because of the way our current methods of detecting planets work, we can basically only detect massive planets close to stars. Of course most of the planets are in tight orbits around stars: planets close to stars move quicker, which make them detectable faster -- we're looking for changes in the stars appearance. Of course most of the planets are fairly massive: they have a bigger impact on their parent star, so we can detect them easier.
The planets we discovered so far are certainly not what we would expect from a random sample of planets in the galaxy (at least, what we think a random sample of planets would look like). But they aren't a random sample of planets in the galaxy. They do look roughly like we would expect planets detectable by the methods we're using to look like.
Also, cold dark matter seems to have been falsified (nearly concurrently with the date on the paper you link) by observations of the dark matter distribution in dwarf galaxies.
The cusp problem is a real one for the simplest models of cold dark matter, but the general idea has hardly been falsified. With strong theoretical support in several places---and no distinctly better alternatives---cold WIMPs remain the leading contender for dark matter. The difficulty (as always, with this sort of stuff) is the strongly model-dependent connection between observation and theory. There are many plausible mechanisms to evade the cusp problem while preserving the key aspects of cold WIMPs, and our limited observations don't tell us whether any of them are right.
Just passing by; "Comparing face-to-face meetings, nominal groups, Delphi and prediction markets on an estimation task" Graefe & Armstrong 2011 http://dl.dropbox.com/u/531...
We recruited 227 participants (11 groups per method) who were required to solve a quantitative judgment task that did not involve distributed knowledge. This task consisted of ten factual questions, which required percentage estimates. While we did not find statistically significant differences in accuracy between the four methods overall, the results differed somewhat at the individual question level. Delphi was as accurate as FTF for eight questions and outperformed FTF for two questions. By comparison, prediction markets did not outperform FTF for any of the questions and were inferior for three questions. The relative performances of nominal groups and FTF were mixed and the differences were small. We also compared the results from the three structured approaches to prior individual estimates and staticized groups. The three structured approaches were more accurate than participants’ prior individual estimates. Delphi was also more accurate than staticized groups. Nominal groups and prediction markets provided little additional value relative to a simple average of the forecasts...The participants rated personal communications more favorably than computer-mediated interactions. The group interactions in FTF and nominal groups were perceived as being highly cooperative and effective. Prediction markets were rated least favourably: prediction market participants were least satisfied with the group process and perceived their method as the most difficult.
The dark matter of galaxies is mostly primordial planets in proto globular star cluster clumps, 30,000,000 planets per star (not 8!)
A quick peek at Wikipedia suggests that baryonic dark matter is not plausible because it implies far less deuterium than is actually observed. Do the authors address this issue?
Also, cold dark matter seems to have been falsified (nearly concurrently with the date on the paper you link) by observations of the dark matter distribution in dwarf galaxies. Cold dark matter is predicted to clump in the center; actual dark matter distributions are far too smooth. (via)
In the post I linked in my "via" it is claimed that cold dark matter also predicts more small satellite/dwarf galaxies than are actually observed (further discussed in this post ). What do you think?
I'm a physics major but I'm having difficulty reading this but I do have some remarks. Cyan is on to something, baryonic dark matter is unlikely to make up a large percentage of dark matter. Also, the "abundance" of large planets, in low orbits is generally regarded as selection bias by astronomers, because planets that are smaller and/or locked in higher orbits are simply more difficult to detect.
I didn’t understand turbulence well enough to judge these theories, so I set it all aside. But over the last few months I’ve noticed many reports about puzzling numbers and locations of planets:What has puzzled observers and theorists so far is the high proportion of planets — roughly one-third to one-half — that are bigger than Earth but smaller than Neptune. … Furthermore, most of them are in tight orbits around their host star, precisely where the modellers say they shouldn’t be.
There's a heavy amount of selection bias here: because of the way our current methods of detecting planets work, we can basically only detect massive planets close to stars. Of course most of the planets are in tight orbits around stars: planets close to stars move quicker, which make them detectable faster -- we're looking for changes in the stars appearance. Of course most of the planets are fairly massive: they have a bigger impact on their parent star, so we can detect them easier.
The planets we discovered so far are certainly not what we would expect from a random sample of planets in the galaxy (at least, what we think a random sample of planets would look like). But they aren't a random sample of planets in the galaxy. They do look roughly like we would expect planets detectable by the methods we're using to look like.
Also, cold dark matter seems to have been falsified (nearly concurrently with the date on the paper you link) by observations of the dark matter distribution in dwarf galaxies.
The cusp problem is a real one for the simplest models of cold dark matter, but the general idea has hardly been falsified. With strong theoretical support in several places---and no distinctly better alternatives---cold WIMPs remain the leading contender for dark matter. The difficulty (as always, with this sort of stuff) is the strongly model-dependent connection between observation and theory. There are many plausible mechanisms to evade the cusp problem while preserving the key aspects of cold WIMPs, and our limited observations don't tell us whether any of them are right.
Just passing by; "Comparing face-to-face meetings, nominal groups, Delphi and prediction markets on an estimation task" Graefe & Armstrong 2011 http://dl.dropbox.com/u/531...
We recruited 227 participants (11 groups per method) who were required to solve a quantitative judgment task that did not involve distributed knowledge. This task consisted of ten factual questions, which required percentage estimates. While we did not find statistically significant differences in accuracy between the four methods overall, the results differed somewhat at the individual question level. Delphi was as accurate as FTF for eight questions and outperformed FTF for two questions. By comparison, prediction markets did not outperform FTF for any of the questions and were inferior for three questions. The relative performances of nominal groups and FTF were mixed and the differences were small. We also compared the results from the three structured approaches to prior individual estimates and staticized groups. The three structured approaches were more accurate than participants’ prior individual estimates. Delphi was also more accurate than staticized groups. Nominal groups and prediction markets provided little additional value relative to a simple average of the forecasts...The participants rated personal communications more favorably than computer-mediated interactions. The group interactions in FTF and nominal groups were perceived as being highly cooperative and effective. Prediction markets were rated least favourably: prediction market participants were least satisfied with the group process and perceived their method as the most difficult.
The dark matter of galaxies is mostly primordial planets in proto globular star cluster clumps, 30,000,000 planets per star (not 8!)
A quick peek at Wikipedia suggests that baryonic dark matter is not plausible because it implies far less deuterium than is actually observed. Do the authors address this issue?
Also, cold dark matter seems to have been falsified (nearly concurrently with the date on the paper you link) by observations of the dark matter distribution in dwarf galaxies. Cold dark matter is predicted to clump in the center; actual dark matter distributions are far too smooth. (via)