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Triton Station

Triton Station
A Blog About the Science and Sociology of Cosmology and Dark Matter
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Dark MatterData InterpretationDwarf Satellite GalaxiesMONDPhilosophy Of SciencePhysical Sciences
Published

Previously, we discussed non-equilibrium dynamics in tidal dwarf galaxies. These are the result of interactions between giant galaxies that are manifestly a departure from equilibrium, a circumstance that makes TDGs potentially a decisive test to distinguish between dark matter and MOND, and simultaneously precludes confident application of that test.

Dark MatterData InterpretationDwarf Satellite GalaxiesGalaxy FormationMONDPhysical Sciences
Published

There are a number of galaxies that have been reported to lack dark matter. This is weird in a universe made of dark matter. It is also weird in MOND, which (if true) is what causes the inference of dark matter. So how can this happen?

MONDPhysical Sciences
Published

A strange and interesting aspect of MOND is the External Field Effect (EFE). If physics is strictly local, it doesn’t matter what happens outside of an experimental apparatus, only inside it. Examples of gravitational experiments include an Eötvös-style apparatus in a laboratory or a dwarf galaxy in space: in each case, test masses/stars respond to … Continue reading The minimum acceleration in intergalactic space →

CosmologyPhysical Sciences
Published

My colleague Jim Schombert pointed out a nifty new result published in Nature Astronomy which you probably can’t access so here is a link to what looks to be the preliminary version. The authors use the Deep Synoptic Array (DSA) to discover some new Fast Radio Bursts (FRBs), many of which are apparently in galaxies … Continue reading The baryons are mostly in the intergalactic medium. Mostly.

Personal ExperiencePoliticsPhysical Sciences
Published

Currently, English is the lingua franca of science. It wasn’t always that way, and there’s no reason to expect it always will be. A century ago, all the great physicists who wanted to be part of the quantum revolution went to study in Germany.

CosmologyData InterpretationLCDMPhysical Sciences
Published

There are many tensions in the era of precision cosmology. The most prominent, at present, is the Hubble tension – the difference between traditional measurements, which consistently obtain H0 = 73 km/s/Mpc, and best fit* to the acoustic power spectrum of the cosmic microwave background (CMB) observed by Planck, H0 = 67 km/s/Mpc.

CosmologyLCDMPhysical Sciences
Published

I set out last time to discuss some of the tensions that persist in afflicting cosmic concordance, but didn’t get past the Hubble tension. Since then, I’ve come across more of that, e.g., Boubel et al (2024a), who use a variant of Tully-Fisher to obtain H0 = 73.3 ± 2.1(stat) ± 3.5(sys) km/s/Mpc.

CosmologyLCDMPersonal ExperiencePhysical Sciences
Published

I took the occasion of the NEIU debate to refresh my knowledge of the status of some of the persistent tensions in cosmology. There wasn’t enough time to discuss those, so I thought I’d go through a few of them here. These issues tend to get downplayed or outright ignored when we hype LCDM’s successes.

CosmologyDark MatterLCDMMONDPhysical Sciences
Published

This is a quick post to announce that on Monday, April 7 there will be a virtual panel discussion about dark matter and MOND involving Scott Dodelson and myself. It will be moderated by Orin Harris at Northeastern Illinois University starting at 3pm US Central time*. I asked Orin if I should advertise it more widely, … Continue reading Dark Matter or Modified Gravity?