8 ms·
Are the “missing baryons” simply too hot to see?
- messe 3y ago[flagged]
- _Microft 3y agoThis seems to be a special form of article: "Mostly Mute Monday tells an astronomical story in images, visuals, and no more than 200 words." (from the end of the article)
- messe 3y agoWell, whichever ET it's targeting, I hope they enjoyed it; I'm pretty sure no human did.
- willcipriano 3y agoI think the text is perfunctory and you are supposed to listen. It is horrible.
- irrational 3y agoThe text in the sidebar is using such a washed out color that I didn't even see it until you mentioned it and I went back and looked for it. What is wrong with plain black text?
- nonameiguess 3y agoThe plain Wikipedia article about this is way clearer: https://en.wikipedia.org/wiki/Missing_baryon_problem https://en.wikipedia.org/wiki/Missing_baryon_problem
- ars 3y agoThe theory is that only 1 billionth of the original matter/antimatter mixture survived as matter. The rest annihilated. But when something annihilates the energy doesn't vanish - so where did that energy go??? One person I asked told me it bacame the CMB, but that seems far too weak for the amounts we are talking about.
- marginalia_nu 3y agoIf you stretch out the CMB across the volume of the entire universe, it seems plausible it would be pretty faint. That r^-3 term on the energy density is pretty small when r is of order ~100 billion ly or more.
- pfdietz 3y agoAnd there's another factor of r from the redshift of those photons.
- scotty79 3y agoMy personal pet theory is that it's in the kinetic energy of relative motion of galaxies. The standard way of looking at things is that galaxies are roughly locally stationary and spacetime between them just inflates. But you could take the opposite look, which someone told me has exactly the same mathematical representation, that galaxies are moving away due to their kinetic energy and sort of drag along the spacetime between them, stretching it. Also I'm not sure about matter-antimatter asymetry. We might be just in a place that locally had a little more matter than antimatter initally. This place might even be the size of the observable universe but we don't know how small part of entire universe is the observable universe. The thesis about matter and matter asymetry comes from the fact that we kinda assume that initially universe was pure energy. But we really can't tell. And everything that doesn't check out in cosmology might be the result of initial conditions being slightly different than the simplest ones we assume.
- gpderetta 3y ago> that galaxies are moving away moving away from what? The reason inflation works is that it doesn't require a privileged frame of reference.
- scotty79 3y agoFrom each other. Bigbang that has a center is perfectly consistent with Hubble law. Imagine that the spacetime is flat, there's no gravity and clumps of matter (galaxies) initially had random velocities. The faster the galaxy was, the further is went till now. What is a bit surprising, is that if you do the math in such universe and compare distances from any galaxy to others and their relative velocities you'll get Hubble law exactly. For every galaxy the distance to any other galaxy is directly proportional to relative velocity between them and they appear to be moving directly away from each other. So even though this big bang had epicenter you can't really tell that it had it or where it was if you can't see the edge. And if our observable universe is small when compared with the size of the entire universe we have a low chance of being near the edge. Try it. You can do it on paper or do a little computer simulation and measure. I did it few years ago. I was quite surprised with the results. Especially with the direction of the relative velocity vectors. They always face directly away from one galaxy to any other.
- zeroimpl 3y agoThe article was interesting but didn't explain why hot atoms would be invisible.
- amelius 3y agoI think pop-sci articles should be (peer) reviewed by lay-people so questions like these can be addressed before the article is published.
- TheRealPomax 3y agoWhere is the actual article though? It's basically a million captioned images without any kind of article between them...?
- messe 3y agoThank you! My comment below got flagged for saying this. I can't understand why the fuck anybody upvoted this.
- _Microft 3y agoNeither their nor your or my taste for content is universal? They might like this form and instead hate Youtube Shorts, long form articles or scientific papers instead.
- _Microft 3y ago"Mostly Mute Monday tells an astronomical story in images, visuals, and no more than 200 words.", from the end of the article. Maybe you'd want to consume different content if that's not for you? Edit: beside that, they are cheating a bit with all these detailed image captions ;)
- TheRealPomax 3y agoI probably do, hence checking "hacker news", not "hacker visual novels".
- obblekk 3y agoThis is the most exciting science event to follow recently. Just wait until the normal media picks up on it. A story made for TV.
- kridsdale3 3y agoAre you sure you didn't mean to write that in one of the Superconductor articles?