sight19 t1_jdx0z40 wrote on March 27, 2023 at 8:29 PM

Reply to comment by arcanum7123 in Black holes may be swallowing invisible matter that slows the movement of stars by trevor25

For structure to form, you need to compress gas in a small volume. As gas is compressed, it's temperature increases and so do the random motions of the theoreticized WIMPs. That means that at a certain point, the gas cloud stops collapsing (this is also called 'virialization'). The only way to collapse further is if the gas cloud would leak out temperature somehow, and that can only happen via radiation. And dark matter can't radiate, so it can't cool further

sight19 t1_jc9u6zv wrote on March 15, 2023 at 9:34 AM

Reply to comment by the_JerrBear in In defence of dark energy | Nobel Laureate and dark matter pioneer James Peebles answers critics of dark energy. by IAI_Admin

And BAO. And CMB anisotropy. And the Bullet Cluster. And DM free galaxies. And early -universe structure formation. DM works on a huge range of scenarios. Even MOND requires DM to function properly...

sight19 t1_jamz7jm wrote on March 2, 2023 at 4:20 PM

Reply to comment by ilikedmatrixiv in Royal Astronomical Society announces all journals to publish as open access from 2024 by magenta_placenta

Yeah, Harvard hoste ADS which helps - but for e.g. Nature (astronomy) you still rely on arXiv publications for a year at least. Luckily, A&A and MNRAS don't have similar restrictions. But still, a good move on their part

sight19 t1_jahaf7h wrote on March 1, 2023 at 12:57 PM

Reply to comment by New_Poet_338 in Satellite Constellations Are an Existential Threat for Astronomy by ChieftainMcLeland

Jwst isn't a replacement for ELTs though, good luck putting METIS in orbit

sight19 t1_ja2d6vp wrote on February 26, 2023 at 9:09 AM

Reply to comment by Anomaly-Friend in A mysterious object is being dragged into the supermassive black hole at the Milky Way’s center by TradingAllIn

The article says that it is a molecular cloud though

sight19 t1_ithl319 wrote on October 23, 2022 at 6:31 PM

Reply to comment by bk15dcx in James Webb revisited gravitational-lensing cluster Abell 2744 this week - and I spent hours processing and cleaning hundreds of cosmic ray artifacts to reveal the faintest details, yet unseen, in glorious six-color 4k+ by Riegel_Haribo

Dark matter of the galaxy cluster is causing lensing. It actually warps background galaxies even on relatively large angular distances from the cluster (what we call 'weak lensing'). This only produce a small effect, but if we stack this effect, we can effectively 'draw in' the shape and location of the DM in the cluster. This has been done before, in for example the Bullet cluster or the Toothbrush cluster (I know, we are really creative with names here...)