<![CDATA[I have a bit of time on my hands, so let's do another 24h round of #AskAnAstrophysicist, but this time it's a thematic one.]]>I have a bit of time on my hands, so let's do another 24h round of , but this time it's a thematic one.

⭐ What do you want to ask an astrophysicist about stars? ⭐

(I am a professional astrophysicist, part of whose work concerns itself with high mass stars & their winds and I've also taught a variety of astro university courses)

Boosts welcome. I may not be able to reply to all in case of many questions.

]]>https://forum.fedi.dk/topic/24a2705c-a4fa-4eb4-96e2-dab4dabbd15e/i-have-a-bit-of-time-on-my-hands-so-let-s-do-another-24h-round-of-askanastrophysicist-but-this-time-it-s-a-thematic-one.RSS for NodeThu, 14 May 2026 13:21:04 GMTWed, 13 May 2026 16:49:45 GMT60<![CDATA[Reply to I have a bit of time on my hands, so let's do another 24h round of #AskAnAstrophysicist, but this time it's a thematic one. on Wed, 13 May 2026 20:59:20 GMT]]>@joxean Thorne-Zytkow objects come to mind, though they are not quiet normal stars : https://en.wikipedia.org/wiki/Thorne%E2%80%93%C5%BBytkow_object

]]>https://forum.fedi.dk/post/https://mastodon.social/users/vicgrinberg/statuses/116569273803480538https://forum.fedi.dk/post/https://mastodon.social/users/vicgrinberg/statuses/116569273803480538Wed, 13 May 2026 20:59:20 GMT<![CDATA[Reply to I have a bit of time on my hands, so let's do another 24h round of #AskAnAstrophysicist, but this time it's a thematic one. on Wed, 13 May 2026 20:57:27 GMT]]>@vicgrinberg

ah, thanks, fast rotation ist also a thing I haven't thought of.

Regarding rotation: I would guess in general very large stars have a long rotation period and the smaller the stars (or remnants like white dwarfs or pulsars) the rotation is getting faster and faster (due to conservation of momentum). Is this a general rule or are there types of stars with unusual behaviour? And ist differential rotation - like the sun - standard or are there stars with fusion processes which rotate like rigid body?

]]>https://forum.fedi.dk/post/https://social.tchncs.de/users/echopapa/statuses/116569266404022079https://forum.fedi.dk/post/https://social.tchncs.de/users/echopapa/statuses/116569266404022079Wed, 13 May 2026 20:57:27 GMT<![CDATA[Reply to I have a bit of time on my hands, so let's do another 24h round of #AskAnAstrophysicist, but this time it's a thematic one. on Wed, 13 May 2026 20:57:18 GMT]]>@glasspusher eddington limiy still a thing, yes 😊 Upper mass limit depends on metallicity, so likely much more massive stars very early in the Universe.

]]>https://forum.fedi.dk/post/https://mastodon.social/users/vicgrinberg/statuses/116569265824017138https://forum.fedi.dk/post/https://mastodon.social/users/vicgrinberg/statuses/116569265824017138Wed, 13 May 2026 20:57:18 GMT<![CDATA[Reply to I have a bit of time on my hands, so let's do another 24h round of #AskAnAstrophysicist, but this time it's a thematic one. on Wed, 13 May 2026 20:55:18 GMT]]>@confusedMiddleAgedDad funnily, one of my very first scicomm pists on mastodon was on this https://mastodon.social/@vicgrinberg/109461953352960242 - for more info see the link in the image - here a nice article by the author herself
https://www.americanscientist.org/article/a-chemical-history-of-the-universe

]]>https://forum.fedi.dk/post/https://mastodon.social/users/vicgrinberg/statuses/116569257962667865https://forum.fedi.dk/post/https://mastodon.social/users/vicgrinberg/statuses/116569257962667865Wed, 13 May 2026 20:55:18 GMT<![CDATA[Reply to I have a bit of time on my hands, so let's do another 24h round of #AskAnAstrophysicist, but this time it's a thematic one. on Wed, 13 May 2026 20:53:22 GMT]]>@vicgrinberg
Any kind of exotic/theoretical star that science says could potentially exist but haven't been observed yet?

]]>https://forum.fedi.dk/post/https://mastodon.social/users/joxean/statuses/116569250342128431https://forum.fedi.dk/post/https://mastodon.social/users/joxean/statuses/116569250342128431Wed, 13 May 2026 20:53:22 GMT<![CDATA[Reply to I have a bit of time on my hands, so let's do another 24h round of #AskAnAstrophysicist, but this time it's a thematic one. on Wed, 13 May 2026 20:52:11 GMT]]>@vicgrinberg which elements are made in which kind of stars and when during the Star lifetime?

]]>https://forum.fedi.dk/post/https://mastodon.social/users/confusedMiddleAgedDad/statuses/116569245702224818https://forum.fedi.dk/post/https://mastodon.social/users/confusedMiddleAgedDad/statuses/116569245702224818Wed, 13 May 2026 20:52:11 GMT<![CDATA[Reply to I have a bit of time on my hands, so let's do another 24h round of #AskAnAstrophysicist, but this time it's a thematic one. on Wed, 13 May 2026 20:44:30 GMT]]>@bkahn there is a lot of data, bit we are also pretty good at analysing it. The problem is more that there is a lot of additional stuff that can be learned from the same data (data collected to answer question A, can also be used for answer question B and, together with different data, possibly also C), but we don't have enough funding for professional astrophysicists to do the work.

]]>https://forum.fedi.dk/post/https://mastodon.social/users/vicgrinberg/statuses/116569215500741349https://forum.fedi.dk/post/https://mastodon.social/users/vicgrinberg/statuses/116569215500741349Wed, 13 May 2026 20:44:30 GMT<![CDATA[Reply to I have a bit of time on my hands, so let's do another 24h round of #AskAnAstrophysicist, but this time it's a thematic one. on Wed, 13 May 2026 20:41:42 GMT]]>@clonezone none at all likely. Dark matter is distributed on much, much longer scales. It does play a major role in the formation of galaxies and thus, in a way, on the stars that will be later formed in them (no galaxies, no or very little stars), but to today's very detailed knowledge, it plays zero role in birth, life or death of individual stars.

]]>https://forum.fedi.dk/post/https://mastodon.social/users/vicgrinberg/statuses/116569204462396582https://forum.fedi.dk/post/https://mastodon.social/users/vicgrinberg/statuses/116569204462396582Wed, 13 May 2026 20:41:42 GMT<![CDATA[Reply to I have a bit of time on my hands, so let's do another 24h round of #AskAnAstrophysicist, but this time it's a thematic one. on Wed, 13 May 2026 20:38:59 GMT]]>@secbox it's indeed not a star question. I discuss singularities as ideas eg in my book https://www.kosmos.de/de/schwarze-locher_1180792_9783440180792 - it would be too long for a post here.

]]>https://forum.fedi.dk/post/https://mastodon.social/users/vicgrinberg/statuses/116569193794133856https://forum.fedi.dk/post/https://mastodon.social/users/vicgrinberg/statuses/116569193794133856Wed, 13 May 2026 20:38:59 GMT<![CDATA[Reply to I have a bit of time on my hands, so let's do another 24h round of #AskAnAstrophysicist, but this time it's a thematic one. on Wed, 13 May 2026 20:37:42 GMT]]>@vicgrinberg

Oo, oo! I've got one!

If 'dark matter', whatever it is, interacts with other stuff by gravity, why do we seem not to have 'dark matter black holes'? And obvs, without any coherent theory of what 'dark matter' actually is, how would one know, or test the theory of how they behave or form?

]]>https://forum.fedi.dk/post/https://mastodonapp.uk/users/bytebro/statuses/116569188737383225https://forum.fedi.dk/post/https://mastodonapp.uk/users/bytebro/statuses/116569188737383225Wed, 13 May 2026 20:37:42 GMT<![CDATA[Reply to I have a bit of time on my hands, so let's do another 24h round of #AskAnAstrophysicist, but this time it's a thematic one. on Wed, 13 May 2026 20:37:08 GMT]]>@Bugspriet @vicgrinberg I think that question can best be anwered by @sundogplanets

]]>https://forum.fedi.dk/post/https://chaos.social/users/C3Casi/statuses/116569186500707402https://forum.fedi.dk/post/https://chaos.social/users/C3Casi/statuses/116569186500707402Wed, 13 May 2026 20:37:08 GMT<![CDATA[Reply to I have a bit of time on my hands, so let's do another 24h round of #AskAnAstrophysicist, but this time it's a thematic one. on Wed, 13 May 2026 20:34:23 GMT]]>@glc xkcd always wins 🤣

]]>https://forum.fedi.dk/post/https://mastodon.social/users/vicgrinberg/statuses/116569175733293695https://forum.fedi.dk/post/https://mastodon.social/users/vicgrinberg/statuses/116569175733293695Wed, 13 May 2026 20:34:23 GMT<![CDATA[Reply to I have a bit of time on my hands, so let's do another 24h round of #AskAnAstrophysicist, but this time it's a thematic one. on Wed, 13 May 2026 20:33:39 GMT]]>@GranVegas thank you 💚

]]>https://forum.fedi.dk/post/https://mastodon.social/users/vicgrinberg/statuses/116569172813449756https://forum.fedi.dk/post/https://mastodon.social/users/vicgrinberg/statuses/116569172813449756Wed, 13 May 2026 20:33:39 GMT<![CDATA[Reply to I have a bit of time on my hands, so let's do another 24h round of #AskAnAstrophysicist, but this time it's a thematic one. on Wed, 13 May 2026 20:33:05 GMT]]>@thomastc @bkahn they are in (binary) systems where they cannot have grown by enough and there are too many such systems for it to be a fluke.

]]>https://forum.fedi.dk/post/https://mastodon.social/users/vicgrinberg/statuses/116569170590186279https://forum.fedi.dk/post/https://mastodon.social/users/vicgrinberg/statuses/116569170590186279Wed, 13 May 2026 20:33:05 GMT<![CDATA[Reply to I have a bit of time on my hands, so let's do another 24h round of #AskAnAstrophysicist, but this time it's a thematic one. on Wed, 13 May 2026 20:31:27 GMT]]>@internic @johnnythan ah yes, xkcd forever 😂

]]>https://forum.fedi.dk/post/https://mastodon.social/users/vicgrinberg/statuses/116569164155178373https://forum.fedi.dk/post/https://mastodon.social/users/vicgrinberg/statuses/116569164155178373Wed, 13 May 2026 20:31:27 GMT<![CDATA[Reply to I have a bit of time on my hands, so let's do another 24h round of #AskAnAstrophysicist, but this time it's a thematic one. on Wed, 13 May 2026 20:31:03 GMT]]>@vicgrinberg So on 12 May 2026 at around 2000 hours to 2100 hours (GMT+5), I observed a star/celestial object in the sky which was way too on low down the horizon line and I think it was somewhere in the West (cos it was in the opposite direction where the sun rise). The geographical co-ordinates of my city are 24.860966° N and the longitude is 66.990501° E.

From where can I learn more about what it is/was ?! I don't know if this might sound like a stupid noob question but it's been bugging me

]]>https://forum.fedi.dk/post/https://mastodon.social/users/harib_murshidi/statuses/116569162634708147https://forum.fedi.dk/post/https://mastodon.social/users/harib_murshidi/statuses/116569162634708147Wed, 13 May 2026 20:31:03 GMT<![CDATA[Reply to I have a bit of time on my hands, so let's do another 24h round of #AskAnAstrophysicist, but this time it's a thematic one. on Wed, 13 May 2026 20:30:40 GMT]]>@vicgrinberg @coleenwalter

Somewhat unreliably:

https://xkcd.com/3012/

]]>https://forum.fedi.dk/post/https://mastodon.online/users/glc/statuses/116569161133305625https://forum.fedi.dk/post/https://mastodon.online/users/glc/statuses/116569161133305625Wed, 13 May 2026 20:30:40 GMT<![CDATA[Reply to I have a bit of time on my hands, so let's do another 24h round of #AskAnAstrophysicist, but this time it's a thematic one. on Wed, 13 May 2026 20:30:03 GMT]]>@liklyhood not a question about stars and no. Physics is not something done by single with help of AI. And you need to really understand you data to compare it with models, just getting it from online repos isn't enough. I know you will not listen, but I want others to read this. No.

]]>https://forum.fedi.dk/post/https://mastodon.social/users/vicgrinberg/statuses/116569158680441888https://forum.fedi.dk/post/https://mastodon.social/users/vicgrinberg/statuses/116569158680441888Wed, 13 May 2026 20:30:03 GMT<![CDATA[Reply to I have a bit of time on my hands, so let's do another 24h round of #AskAnAstrophysicist, but this time it's a thematic one. on Wed, 13 May 2026 20:26:28 GMT]]>@palaress ah, thanks for the question! Stellar wind (our Sun also has a wind, called solar wind) is not something that happens in an atmosphere, but rather a thin stream of particles blown away from the star from its uppermost layers. Stellar wind is what makes Aurorae (when there is an especially strong bit of it) and that makes comets have nice tails (the tail is pretty mucbtan interaction result of the comet with the wind).

]]>https://forum.fedi.dk/post/https://mastodon.social/users/vicgrinberg/statuses/116569144599611975https://forum.fedi.dk/post/https://mastodon.social/users/vicgrinberg/statuses/116569144599611975Wed, 13 May 2026 20:26:28 GMT<![CDATA[Reply to I have a bit of time on my hands, so let's do another 24h round of #AskAnAstrophysicist, but this time it's a thematic one. on Wed, 13 May 2026 20:25:19 GMT]]>@vicgrinberg Fair, I guess it's a question along the lines of "what if G had a different value": not something one can answer except with "in this universe it doesn't".

Thanks for taking the time!

]]>https://forum.fedi.dk/post/https://hachyderm.io/users/Two9A/statuses/116569140069190611https://forum.fedi.dk/post/https://hachyderm.io/users/Two9A/statuses/116569140069190611Wed, 13 May 2026 20:25:19 GMT<![CDATA[Reply to I have a bit of time on my hands, so let's do another 24h round of #AskAnAstrophysicist, but this time it's a thematic one. on Wed, 13 May 2026 20:23:59 GMT]]>@vicgrinberg Do you think it is possible to verify models in theoretical physics using publicly available data from repositories such as https://researchguides.gonzaga.edu/physics/data only ? Just order this data around some N real world physical experiments and check your theoretical physics model for each of the N experiments. My idea is developing new models in theoretical physics using AI (new geometries in general relativity for example) and check them against the public data repos.

]]>https://forum.fedi.dk/post/https://mastodon.social/ap/users/116307245093704299/statuses/116569134793261990https://forum.fedi.dk/post/https://mastodon.social/ap/users/116307245093704299/statuses/116569134793261990Wed, 13 May 2026 20:23:59 GMT<![CDATA[Reply to I have a bit of time on my hands, so let's do another 24h round of #AskAnAstrophysicist, but this time it's a thematic one. on Wed, 13 May 2026 20:23:34 GMT]]>@draNgNon this is not a question about stats, so very short answer: gas clouds are far too thin to carry sound in the meaning of the sound on Earth - the densest gas clouds are as dense as some of the most extreme vacuums we can create on Earth. The Universe is very, very empty.

]]>https://forum.fedi.dk/post/https://mastodon.social/users/vicgrinberg/statuses/116569133182033492https://forum.fedi.dk/post/https://mastodon.social/users/vicgrinberg/statuses/116569133182033492Wed, 13 May 2026 20:23:34 GMT<![CDATA[Reply to I have a bit of time on my hands, so let's do another 24h round of #AskAnAstrophysicist, but this time it's a thematic one. on Wed, 13 May 2026 20:20:13 GMT]]>@DaveNelson it's not a about stars, but I'll answer (I like neutron stars & black holes): the densest objects of normal matter are neutron stars - pretty much the density of an atomic nucleus but as a star or the mass of 1.4 suns squeezed into a ball of 10 km radius. Denser doesn't work - if we pile up more than 3 sun masses together at neutron star density or squeeze the neutron star further, we end up with a black hole, where things collapse to endless density in a singularity in the middle.

]]>https://forum.fedi.dk/post/https://mastodon.social/users/vicgrinberg/statuses/116569119994981492https://forum.fedi.dk/post/https://mastodon.social/users/vicgrinberg/statuses/116569119994981492Wed, 13 May 2026 20:20:13 GMT<![CDATA[Reply to I have a bit of time on my hands, so let's do another 24h round of #AskAnAstrophysicist, but this time it's a thematic one. on Wed, 13 May 2026 20:11:26 GMT]]>@Two9A to be honest, I don't know what you mean by a deeper reason here. There is no reason why things are the way they are - except that we would not exist as we are if they weren't.

For atoms, you can roughly imagine that the more (positivly charged) protons there are, the harder it is to squeeze them together. So the larger the atom, the less energy is left over to be released when it is created, until at some point you need go add energy to make them instewd of releasing.

]]>https://forum.fedi.dk/post/https://mastodon.social/users/vicgrinberg/statuses/116569085473524303https://forum.fedi.dk/post/https://mastodon.social/users/vicgrinberg/statuses/116569085473524303Wed, 13 May 2026 20:11:26 GMT