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These kind of facts always blow my mind. For instance, the Sun orbits the milky way once every 212m years. That means that if the sun existed from the big bang
by p-o 3y ago
These kind of facts always blow my mind. For instance, the Sun orbits the milky way once every 212m years.
That means that if the sun existed from the big bang to now, it would have only done ~63 complete revolutions around Sagittarius A*. If you account for the Milky Way's creation, that number gets even lower. I'm no expert, so maybe this makes sense to someone who knows more about this, but it definitively feel weird to me.
- mihaitodor 3y agoI wondered the same thing and I asked Sean Carroll about it [1]. He didn’t go into much detail, but here is his answer: > I guess my only insight is, I'm not sure why you relate the number of revolutions that the Milky Way has made to its complex and symmetric structure. The spiral arms that you see in a galaxy like the Milky Way do not rigidly rotate with it, they are more like... This is complicated, but they are more like regions where star formation is going on, and therefore the galaxy is brighter rather than regions where there's more density or anything like that. So if you're worrying how the spiral structure forms. It can form pretty easily in one or two revolutions, I don't see why it would take even 68, much less, but need more than that. [1] https://www.preposterousuniverse.com/podcast/2023/10/09/ama-october-2023/ https://www.preposterousuniverse.com/podcast/2023/10/09/ama-...
- firebot 3y agoProblem with Sean and most cosmologists is they are proliferate regurgitates with little independent thought.
- ben_w 3y agoEven before LLMs were dismissed as "stochastic parrots" (and even more so since then), I find myself noticing when people dismiss the intellectual capacity of entire groups. "Mickey Mouse degrees", https://xkcd.com/793/ https://xkcd.com/793/, the attitude displayed by the bully in "Zero for Conduct" and similar IRL dismissals of the entire ME area in the post 9/11 discourse, mid-Brexit politicians saying the country had had enough of experts, some of my fist girlfriends' anecdotes from her childhood, town v gown, …
- ryanklee 3y agoI really don't understand how you can put forth a criticism like this and be so vague at the same time. It really undermines your credibility. Be specific or why bother.
- firebot 3y agoI have no credibility. Sean jumps on the hype train all day long. I'm skeptical. I don't think this illustrious dark matter or big bang mean anything. So it's like that telephone game where Sean is the last person and gets to tell you what the first person said and he's always very excited but baseless. Really do like his energy. I just don't think he's much of an independent thinker.
- wholinator2 3y agoWell, as someone with a shred of credibility, he really does have strong theoretical evidence for the things he's saying. The difficulty here is that theoretical physics is really fucking hard. Way too hard to distill down into a paragraph. I'm sure the man could do a lecture series on star formation in spiral galaxies to convince you but you're going to need a bachelor's at minimum to even start that. I think he's easy to dismiss because much of his exposition deals in philosophical physics, it's really his specialty. There's levels of solidity. Experimental physics is reality. Theoretical physics is an explanation of reality, sometimes attempting to extend to predict the next experiment. Philosophical physics takes theoretical tools and expands them to explain everything in the Universe, including the Hard questions. I don't think it's a problem that they do it, someone should be thinking of this stuff. Do you have much experience with theoretical physics or cosmology. I have some and the math really helps make these things comprehensible and reasonable. Theoretical physics without math is indeed just continuous excited, but baseless assertions. The math fixes this
- firebot 3y agoI don't believe you. I prefer alternative theories. Plasma physics. Electric universe models. There's Gareth Samuel on YouTube, See The Pattern. He just explores various theories. Treats them as merely theories (instead of facts) and I like that approach. It's very historic and really fleshes out ideas. Then you got the Lerner himself, author of The Big Bang Never Happened, which I think has been overwhelmingly falsified so you mean you can take Sean and his amazing fantastic firework singularity that blew up from a dimensionless point and yeah blah blah blah blah blah inflation blah blah blah acceleration blah blah blah and it makes no fucking sense whatsoever. I'm really good at math. At least compared to most people. I'm 38 and really only started questioning the big bang maybe in the last decade, and then I found Eric Lerner and well, now I can firmly say the big bang never happened.
- gitaarik 3y agoI think your story is about the spiral structure of the milky way, whereas the parent is about the amount of revolutions of our solar system around the milky way. So 2 different things I think. That might be the confusion here. Regarding the spiral arms: the arms itself do not really move, but stars move through the arms. The arms contain a lot of gas and when stars move through them, they can collect more gas and result in supernovas creating new stars.
- mihaitodor 3y agoFair enough, it's a bit of a tangent. Thanks for the extra insight! I kinda' assumed that stars wouldn't move across a galaxy, like from one arm to another. I'll have to look into that.
- gitaarik 3y agoYes, stars move through the arms, and circle around the center of the galaxy. The arms actually also "move", but not in the way you would maybe expect. They are actually density waves - areas of greater density of gas & dust, similar to a traffic jam on a highway. These waves also "move" along with the gas & dust. But this wave-movement is illusory, because they are formed by these traffic jams. The stars move through these waves (traffic jams), and in these high density areas new star formation and supernovas happens mostly (because there is more stuff to collect). The stars move through the gas & dust faster than the gas & dust themselves, because the stars are more massive and need more velocity to stay in stable orbit. The illusory movement of the waves is also slower than the stars, because the illusory waves move as slow as the dust & gas that forms them, and the stars are faster. Apart from that, you also have dark matter which influences the rotation speed of objects based on it's distance from the galaxy center. It causes objects at the end of the spiral arms of the galaxy to rotate at the same speed as the ones close to the center, or anywhere. That is a mysterious area, and actually caused the requirement of dark matter into the equation. Because in Einstein's relativity theory, objects with same mass that are farther away from the galaxy center, need to move slower to have a stable orbit, which is the case in our solar system and other solar systems we observe. But in galaxies the case seems to be different. That is why dark matter was introduced, and makes it more complicated.
- gattr 3y agoAnother fun fact: there are more trees on Earth (3×10¹²) [1] than stars in the Milky Way (1-4×10¹¹). [1] "Mapping tree density at a global scale" https://www.nature.com/articles/nature14967 https://www.nature.com/articles/nature14967
- dataflow 3y agoThat fact sounds like it will become fiction very very soon. :\
- fukpaywalls2 3y agoOn the postive side, there's probably more microplastics in our oceans than there are stars in all of the galaxies summed together.
- sp332 3y agoOcean microplastics were probably overestimated. https://phys.org/news/2023-08-plastic-litter-oceans-overestimated-persist.html https://phys.org/news/2023-08-plastic-litter-oceans-overesti... Most plastic in the oceans is in larger chunks… so far anyway.
- joshuahedlund 3y agoMaybe not. Deforestation rates peaked in the 80’s https://ourworldindata.org/global-deforestation-peak https://ourworldindata.org/global-deforestation-peak
- tamimio 3y agoHave another fact since we are talking about trees, wood is the rarest element in the universe, even more rare than diamonds, in fact, wood can only be found on earth! A piece of me dies every time I see someone cutting a tree for useless reasons.
- Solvency 3y agoWood isn't an element?
- defaultcompany 3y agoAgreed. Another surprising one to me is that the earth itself has been around for about 1/3 the age of the universe. I always assumed that the timescale of the universe was vastly longer than the life of the earth.
- k7sune 3y agoWow it’s amazing that we could somehow time the orbit period.