JWST shows the early Universe is DIFFERENT than we thought (that's a good thing!)
Vložit
- čas přidán 20. 05. 2024
- Go to ground.news/drbecky to stay fully informed. Subscribe through my link to get 30% off the Vantage plan for unlimited access this month only.
Remember those overmassive galaxies that JWST found that people claimed proved "the big bang never happened?" when in reality it was just that we couldn't explain how they'd got so big? Well, turns out those galaxies probably aren't that massive after all. In this video we're chatting about how new JWST observations have found evidence that galaxies in the early Universe form different types of stars at different rates to in the Milky Way (called the Initial Mass Function of stars). This then has knock on effects on the calculation of the masses of these distant galaxies...
#jwst #astrophysics #bigbang
My previous video on these massive galaxies when they were first found: • JWST has found MASSIVE...
My previous video on changing the IMF in the distant galaxies: • JWST's "too massive" g...
** REFERENCES **
Cameron et al. (2023; top-heavy IMF evidence in early Universe) - arxiv.org/pdf/2311.02051.pdf
Steinhardt et al. (2023; idea proposed for bottom-heavy IMF for early universe) -arxiv.org/pdf/2208.07879.pdf
Boylan-Kolchin (2023; massive galaxies tension with λ CDM) - arxiv.org/pdf/2208.01611.pdf
Labbé et al. (2023; 6 massive galaxies in JWST data) - arxiv.org/pdf/2207.12446.pdf
Rana (1987; the initial mass function of stars) - articles.adsabs.harvard.edu/p...
JWST observing schedules: www.stsci.edu/jwst/science-ex...
JWST data archive (with public access!): mast.stsci.edu/portal/Mashup/...
Twitter bot for JWST current observations: / jwstobservation
00:00 - Introduction
01:46 - Ground News AD
03:19 - How we calculate the masses of galaxies & what's an IMF
07:02 - What's a top-heavy IMF and why it solves JWST's "over-massive" galaxy problem
08:48 - Evidence for a top-heavy IMF in the early Universe
12:51 - Some caveats and what's next...
15:56 - Bloopers
Video filmed on Sony ⍺ 7 IV
---
📚 My new book, "A Brief History of Black Holes", out NOW in hardback, e-book and audiobook (which I narrated myself!): hyperurl.co/DrBecky
---
📚 "The Year In Space" celebrating all things space in 2022 from me and the rest of the Supermassive Podcast team: geni.us/jNcrw
---
👕 My new merch, including JWST designs, are available here (with worldwide shipping!): dr-becky.teemill.com/
---
🎧 Royal Astronomical Society Podcast that I co-host: podfollow.com/supermassive
---
🔔 Don't forget to subscribe and click the little bell icon to be notified when I post a new video!
---
👩🏽💻 I'm Dr. Becky Smethurst, an astrophysicist at the University of Oxford (Christ Church). I love making videos about science with an unnatural level of enthusiasm. I like to focus on how we know things, not just what we know. And especially, the things we still don't know. If you've ever wondered about something in space and couldn't find an answer online - you can ask me! My day job is to do research into how supermassive black holes can affect the galaxies that they live in. In particular, I look at whether the energy output from the disk of material orbiting around a growing supermassive black hole can stop a galaxy from forming stars.
drbecky.uk.com
rebeccasmethurst.co.uk - Věda a technologie
Go to ground.news/drbecky to stay fully informed. Subscribe through my link to get 30% off the Vantage plan for unlimited access this month only.
Thank you Dr۔ Becky۔
Isn't it obvious that on the path of discovery، there will be missteps by one generation and which will be corrected by the next generation۔
May you live in interesting times in Astronomy 😊
Just curious @DrBecky who wrote your script for the Ground News Ad?
It's dark matter with dark gravity pushing dark particles at dark light speeds. There. i just invented for 'astronomers' the required BS. to explain the failure of BBT*
Fewer stars not "less stars"
@@Audion Ah, the audacious astronomers, those celestial maestros who, in their cosmic symphony, have now composed a sonata of avoidance for the electric and plasma models of the universe. Their fear of these alternatives has grown so profound that they've resorted to verbal contortions, performing linguistic ballets to divert attention from the cosmic outcast - plasma.
Enter the grand illusion: once-humble plasma filaments, those wisps of ionized matter, have now ascended to the lofty title of "objects." Yes, you heard it right - objects. Because, naturally, uttering the P-word might provoke a cosmic uprising, shaking the very foundations of astronomical dogma.
It's as if astronomers are participants in a cosmic charades game, tactfully replacing "plasma" with the ambiguous "objects," hoping that the cosmic audience won't catch on. "Look over here at these mysterious objects," they declare, with a conspiratorial wink, trying desperately to divert attention from the heretical idea that perhaps, just perhaps, electricity plays a starring role in the cosmic drama.
But why the cosmic shyness, esteemed astronomers? Is it the terror of challenging established doctrines, the apprehension of acknowledging that the universe might be a bit more electrically charged than the textbooks dictate? Or is it simply easier to conjure cosmic charlatanry, renaming plasma currents as elusive "objects" and hoping no one will notice?
And now, a cosmic twist in this grand performance: astronomers, driven by an apparent disdain for scientific credibility, have birthed a menagerie of mythical entities from the cosmic void - dark photons, dark ions, dark sectors, dark voids, and the newly discovered ultra-diffuse galaxies. It's as if they're pulling these cosmic rabbits out of a hat, or perhaps from a location less glamorous.
In this cosmic masquerade, astronomers, once heralded as seekers of truth, now perform linguistic acrobatics to sidestep inconvenient words. It's like discussing the solar system without whispering the word "Sun," an act of linguistic gymnastics that distorts the very essence of scientific inquiry.
So here's a cosmic encore for these linguistic illusionists, seamlessly conjuring "dark" entities and ultra-diffuse galaxies from the cosmic shadows. The theater of astronomy may be dimming, but the spectacle of linguistic escapades continues, skillfully performed under the watchful eyes of the old guard. Bravo, for turning the pursuit of knowledge into a cosmic vaudeville act, complete with dark photons, fantastical wordplay, and galaxies that seem to exist in the celestial realm between substance and sheer imagination.
I love that Dr. Becky shows us the actual graphs with measured data and models. It helps me understand astronomy better. Thanks!
And she's sporting a Yosemite shirt! I live near Yosemite and have visited more than 200 times in my life, including participating in 16 public star parties at Glacier Point with my astronomy club. 🙂
Yeah, and that she explains things so concrete is amazing. I really like how she explained the redshifting. So clear and concise.
@@skysurfer5cva I'm a little bit south of Yosemite, about an hour south on 99.
@@almostfm Fresno, here.
I appreciate that she picks out the graphs that make sense and/or explains.
In my experience staring at the graphs in desperation alone went cut it 😅
I mean, imagine if we spent a billion dollars on a space telescope ahd it didn't show us anything new. How boring would that be?
Underrated comment
Imagined, felt like cheated, won't recommend, 0/10 😂
Image spending trillions on blowing things up. 😢
How about 11 billion
It wouldn’t just be boring, it would be a modern particle accelerator
My dad always used to get me so hyped for the James web space telescope. Saying things like how much of the distant early universe we would see and how it would flip our understanding upside down. Unfortunately he never got to see the results of his prediction but its pretty cathartic to see it come true.
This is the beauty of it, science is a team project involving everybody from every generation. I think our ancestors would be proud of what their labor amounted to, just as people generations from now will say the same of us, and they will be right :)
@@euclidesribeiro8810 Remarkable view ! 👍👍👍
It's comments & communities like this that Should give All of us Hope for a Better Wold @@euclidesribeiro8810
ps
I'd slip in "from All Around the World".
Happy for you that someone so awesome was in your life!
This is wonderful when dad and son share similar passions. I'm so lucky I have such relatoinship with my dad too, and although he sometimes says my interests in physics and topics I choose is a bit beyond him now, I can always get him curious on many other things which are not so recent. For example, a couple months ago I sent him a wonderful lecture of prof. David Rickets on high voltage physics, and he said he watched it with a help of a translator (thanks to AI for better and better live translations). He was sitting till 3am to finish the lecture 😊
It is my way to say "thank you" to him, for giving me that passion to fix things when he was teaching me basic math and physics when I was at school. And also for countless hours spent in the garage with him, tinkering and fixing his car, taking a part in a lot of house refurbishing. A young boy watching dad at work, usually takes that as a good example which will pay off heavily in the future 😊
That passion later turned into my job path and I never regreted becoming a service tech. Perheaps I stayed a bit too long in visiting maintenance division, but I'm just changing it now to something more stationary, so I can pursue other goals in life and be closer to family.
I really appreciate how well you are able to take mind-bendingly complex material and present it in a way that mere humans like me can actually understand it. Thank you for the huge effort you put into enlightening and delighting your viewers.
This is great news honestly. It’s doing exactly as planned. Seeing these early galaxies and star formations will help us to understand so much more.
I love the level at which you pitch your content. I'm very much learning and you walk the line between entertainment, interest and challenge perfectly. Thank you :)
yeh,,one day soon,, you can go to these stars, 6 ly away,, who give a sht.. people are dying here.. not there.....
This science news and explanation channel rises a parsec above most others, for showing the actual science data plots, papers, making technical concepts understandable while not dumbing things down so much that real scientists laugh.
The universe is so incomprehensibly vast and we have explored so very little of it... not even sat foot on another planet in our own solar system. It is amazing to me how much scientists can figure out just from watching tiny dots of light, but it is hardly surprising to me that these calculations turns out to be less than accurate sometimes.
Thank you for the video Doctor Becky!
Your outtakes are delightful.
As someone who is not deeply versed in any of this (but has a reasonable familiarity with science), thank you for explaining it so cogently!
So exciting to follow Dr.Becky’s analysis of these new papers about JWST observations. This one was a lot harder for me to follow., but Dr. Becky is just great at pointing out the salient ideas and telling us what needs to come next.
I'm so glad to be alive at a time that we can study phenomena so unfathomably far across time and space. Ever since I was a small kid I loved astronomy and if life went differently I might of made it my proffession. Sometimes I think about how some people do or used to think of the world coming out of some kind of primordial 'chaos' and I'm like hey y'all that's literally outer space. I don't think enough people really appreciate how astrophysics stares directly into the nature of reality. I never imagined as a kid we would be learning nearly all the things we have in the last few years let alone since JWST went up.
So well explained. Every time a question pops up in my mind about something you just said, you adress it less than a minute later. Your videos are extremely well made. Thanks
I appreciate the depth of your reporting. I’m sure some viewers (including me sometimes, I’ll admit) might glaze over. But when you take the time to go into fine points and caveats, you give me the opportunity to understand the research at a much deeper level. Thanks for all your effort.
I really appreciate this channel. Sometimes you want more information on a subject but you don't want to read papers. Becky does a great job at picking out very interesting topics to cover.
For me, early universe data is easily the most exciting thing about JWST, and why I put Christmas on hold to watch the launch. THANK YOU for taking time to break this down so well. Super cool that a colleague of yours is publishing work with the potential to break so much stuff. Best of luck with all the model adjustment should it come to that.
Loving the way you lay out the steps of what you're gonna go over in the video - really helps understand the amazing information you provide
Seeing how at 15:15 you practically start to glow in excitement about the implications of this research is heartwarming and exactly the reason why I love to watch your videos. They show how exciting astrophysics can be. thanks for that!
Yeah, that's the best part of a video like this. More exciting than any raw research paper.
If this new data and technology shows that we've been wrong in our understanding of the universe, we should celebrate that our science is good enough to prove us wrong.
Good point
being wrong about “early” Universe is not exactly being wrong about the Universe
Thanks dr becky! For your hard work and the energy with which you present your passion for the field! I feel privileged (like many here I'm assuming) to absorb your educational content. It has been years at this point. Your videos are part of the routine here 🎉 and the kids love you even though they're as of yet unable to grasp most of the concepts and topics you discuss here. 😉 It gives us the oppertunity to find out if we actually understood it ourselves when they start asking difficult questions.
The early universe is a fascinating place. Also, contemplating how old the universe is makes me feel young again.Total bonus there.
Thank you for these wonderful videos. No re-crapping possible , they were never crap to begin with.
I love watching scientists get excited about being wrong and getting to do more science
Excellent video. Thank you for your clear presentation of the information. As an aside, I remember a video saying that higher mass stars were supposed to be more common in the early universe due to the absence of 'metals.'
Thank you for another in depth video Dr Becky. The early universe is fascinating stuff and I agree it's exciting regarding how much is being discovered. But also countless questions are being raised at each stage of our advancement in our quest for knowledge and understanding of all aspects of the universe. These are indeed exciting times.
Love this video!❤ What a time we live in. So exciting! So many of the cosmological models and attendant models for phenomena at different scales have adjustable parameters. We can tweak these and see what predictions are made and how these comport with observation. JWST and related efforts give us bounds on these adjustable parameters. The key thing here is to watch the scientific method flowering in this field. More money and effort for these efforts please!
These are your best videos. The ones where you explain the details which allows us to understand what the "controversies" are and why they're not so sensational as they're made out to be in the media.
You know this is media as well?! Calling all major media “the media” is a slap for good journalism. Putin (and Trump) loves you.
its a boys club,,they all agree so they get paid.. tell the truth, ousted.. like say,,.... the big bang never happened..
One of my favourite and consistent reviewers of scientific data coming out of the astrophysics realm. I hope Dr. Becky keeps this up for her entire career.
I'm with you. Her presentations are a very generous gift to all of us who don't have her resources, or perhaps the ability to understand the raw data. I am always tremendously grateful when people who make real money in their profession give it away for free to the masses. Clearly she values an educated public, and she obviously puts a lot of work into teaching us these challenging topics in a way that most of us can understand. Maybe not completely, but certainly to our satisfaction.
Man, do I love your content. I was a physics/astronomy major in college, and spent years afterward aching to nerd out about this stuff. And you are such an excellent presenter.
Always appreciate your TLDR of research papers and bottle-feeding me the info
Astrophysicist: Hey, this equation is slightly off.
Media: EVERYTHING WE KNOW IS WRONG!!!
Insightful as always Professor Becky😁
Thank you Dr. Becky. I finally understand the redshift distance calculation. Even though I've had it explained to me before, you're the first one who made it make sense for me.❤
I love watching these videos to find out just how much I don’t know. I learn something new every time. Thank you.
Thanks, Dr. Becky. It's a lot of fun to see other people prove your hypothesis. I thought this was the most likely solution all along, but the way they proved it was superb. There are very improbable other reasons, and the whole idea of using the IMF we currently do is based on speculation. This provides structure to start a basing an IMF on real data.
It was probably a well known explanation. Just a lot of dishonest people published papers without actually caring about the truth, in the rush for publicity.
@@tbird81True. At universities it's "publish or perish."
Thank you so much, you make all these scientific papers approachable. I always got frustrated while reading them because I have trouble reading longer and more difficult texts with my adhd but thanks to you I can finally keep up with what's going on is astrophysics.
I can relate!
Indeed. A very logical and honest analysis. Averaging and extrapolating on assumptions. Good for a start, bad for a finish! lol As I mentioned before, proximity/density is an obvious mitigating state.
Great presentation on light emission spectrum from distant galaxies. This topic is very interesting and intriguing to see unfold in near real time.
Very elegant presentation! Good explanations!
Love the way three quarters of the video explains the context needed to understand the science. Excellent video. Succinctly explains a key paper in astrophysics.
Amazing content by a professional in the field. Keep it up Dr. Becky!
With each new space telescope we are learning more and realize we know so little. Just wow...
Early Universe galaxies would obviously have a different ratio of star types compared to the MW now. I mean they would be mostly first gen stars. The stars currently in the MW would include stars with more elements available to be included during their formation. So why would we assume they have the same ratio?
I think it was a simple case of ... we had nothings else to compare to.
@@MrBizteck fair point
Thanks for this video, Dr. Becky~ The stellar evolution nerd over here is happy with new data and new hypotheses.
"That's funny." A great start to what hopefully will become some great science!
I wonder whether Dr Becky or the electrons were more excited?
Wow. This is 1 hour old and there are 188 comments already. And Dr.Becky as usual cuts right thru the smoke and mirrors. I love this stuff. My niece said "you really get excited about it" . I have (only) a BS Physics but who would not like it - 188 people in front of me sure did ! !
Exactly how much time does it take you to collect the information and graphs to take info I would NEVER have access to and convert it to an understandable, friendly talk between to friends. You are brilliant and a gifted teacher. Thank you for your time and efforts. Much appreciated.
Very interesting indeed! Thanks, dr. Becky! 😃
Stay safe there with your family! 🖖😊
And happy holidays!
This channel is the prime example that you don't need to "dumb it down" to teach people. You don't have to be familiar with astronomy to follow along, because the core concept is intuitive even if the terms escape the viewer.
Dr. Becky does "dumb it down." Try reading the actual papers she's provided links to.
@@douglaswilkinson5700 I do read them. I am a geologist and study multiple fields of science...
@@terrafirma5327 I did not mean you. Her audience in-general needs these research papers in astrophysics, cosmology, etc. simplified and summarized. (If she were to review the mathematics used -- e.g. differential geometry and tensor calculus -- even PhDs in biology, chemistry, etc. would run for the hills.)
@@douglaswilkinson5700 Quite true, math is a great divider in advanced fields of study. I work primarily with conceptual science rather than hard science but it is still science.
That sounds really exciting. I always wonder whether the compostion of the stars, like mostly hydrogen in the early universe vs (still mostly) hydrogen but also other heavier elements in the older universe, does influence the spectrum of light they give of. It feels like it should (similar to stars changing colour when burning other elements in later stages of their lifecycles), but there might not be enough "other stuff" to influence the spectrum when stars still burn hydrogen to a point where we cant actually detect that. That being said, if there is an influence would that influence any of the data, since these stars will have coniderably less "other stuff"?
I think Hydrogen and Helium still make up 99% of the mass of the universe.
Dr. Becky has the best presentation I've seen of any 'tuber. I always enjoy catching up on Cosmological news and updates here more than any other channel! 2 questions for Dr. Becky:
1) Did you have a blast at Yosemite? I've been there a few times, it's absolutely stunning.
2) Did you paint your nails like that for any particular reason?
Thanks!
This is incredibly exciting! If these new calculations hold up to peer review and ongoing scrutiny, l cannot even imagine all the amazing things which we will soon learn!
I've read that time was accelerated immediately after the "big bang". I'd imagine that time period was relatively short-lived and long before star formation but could that have any impact on stars like this forming "earlier" than we thought?
You might be thinking of inflation, which is more conventionally characterised as a rapid expansion of space. That probably prushed back the time it took stars to form, though the models of what actually happened during inflation are still very theoretical as we haven't got many measurements that shed light on that time period.
Thanks again for your analysis. Looks like astrophysics is going to be kept busy for a while longer. Great stuff, for youngsters to keep an eye on. ;)
You are so good at explaining the incredibly complicated.
I love that science embraces doubt, something anti-science people don't understand.
You celebrate the potential unknown wonderfully!
Cool! Might this have an impact on the question of dark matter?
Rhetorical right? 😂. Great comment. (Dark matter🙄)
It likely won't have a big impact. Most measurements of dark matter content are made in the more local universe where the IMF has more evidence of holding, or in the distant universe and don't rely on any light mass ratio measurements.
i love watching your vids, u and your team keep up the amazing work
Love Ground News, so thankful that so many "trusted" CZcamsrs are advertising their service!
It is wild they'd use the distribution of stars in our galaxy as a baseline to determine the mass of a galaxy that formed at the beginning of the universe.
Well the Milkyway also formed approximately 13 billion years ago so at around the same time 🤷
It's all they have. We're still struggling to count individual stars in other galaxies.
I thought that a top heavy (relative to our galaxy) early universe was the dominant model? i.e the first stars were much larger on average than today and further generations had more moderate/closer to a modern star mass distribution.
There have been a lot of proposed models for first gen stars, but none have been conclusively proven. And as far as I'm aware, even for current stars that we understand comparitively extremely well we haven't been able to generate the IMF strictly from first principles. So we've still got a long way to go with predicting stellar populations, but this paper is a great step in that direction.
You can't form a working IMF model from an unobserved stellar population.
Nice job, Dr. Becky! You made that very understandable ... and interesting. Thanks!
Love your work. I routinely share it with my 10yo even if he doesn't get every single detail. Thanks!
You are a fantastic educator you explain things so beautifully wish I could grasp all of this better
well done, as always, doc. love your channel.
Good luck, Dr. Becky. I hope it fixes some of the Physics problems.
I've said for a while that you can't compare galaxies from so long ago with what we have now. Back then, hydrogen was even more abundant than it is now. Plus we still lack tons of data that's essential to our understanding.
Yeah, a lot of work will need to be reevaluated. But that's what happens when you use shortcuts that don't actually fit what you're observing.
Thanks for the great content, always relatable and interesting
Another stellar video, Doctor B. Thank you!
Exciting stuff. Thanks for the run-down. So nice to see cool scientific reasoning taking the hysterical heat out of all the JWT conspirifying that has been going on. (Nice too to see mention of my old mate Pavel Kroupa. 🙂 )
absolutely wonderful video again Dr Becky!
I've been watching your videos for quite some time now, and have gotten to the point of the discussion the sentence descirinb the IMF as "all added together". And as soon as item 1 was complete I understood what a "top-heavy IMF" is.
Thank you for literally years of astronomy and astrophysics education for those who enjoy learning about the universe without being professionals in the field.
Always appreciate your videos and the amount of work that goes into them! Sometimes I wish I had gone a different way in school and stuck to a physical science, your videos help me to attempt to keep up with the road not traveled. ... BUT WHO'S JAKE ..s !!! You should bring him on the channel... LOL
Given the number of admittedly informed and educated assumptions necessary for scientists in astronomy/cosmology to make just to begin understanding this magnificent universe, it is hardly surprising that along the path of greater and greater technology and the resultant better and more detailed data obtained, some of those basic assumptions will necessarily be found to be in error and in need of revision. We live in an exciting time for astronomical and cosmological research and such times are frequently disruptive.
Keep it coming Dr. Becky, you're doing great things here.
Very good video, Dr. Smethurst.
It would be interesting if all the model fitting (not the super computer simulations, more the stuff that can be run on a workstation in a few minutes) could be put together as one big computer program where new data and assumptions could be patched in and re-run to see what knock-on assumptions change significantly when low level models change.
It would be a really laborious process to get it built (i.e. lots of undergrads in astrophysics and computer science getting paid a bunch of peanuts), but it would be really powerful to have it compete.
9:00
So cool that Dave Franco portrays him in the film adaptation
good stuff Dr. B.
JWST affecting research even more than we all thought. Amazing.
Merry Christmas Doc!
Thanks I am greatful for the input!! Aloha's stay safe ,,you Rock Doc!!! 🤘👍⭐️💙🤙
I love astronomy.
And you are a superstar, Becky! ❤️⚜️✨️
Love your content. Great balance between layman and budding expert. Reckommended to neice and nephew.
As an aside Good Lock>Keyscafe on Samsung devices lets you remap the whole keyboard (main and symbol) to get your needed characters easily.
I put all maths long press on top row, symbols mid, punctuation bottom.
Not messed with the symbol pad yet as I am layman.
thanks for the information dr becky
Dr. Becky is a wonderful expressive rare human being, full of excitement on each sliver of potential discovery, She is a true space intellectal space traverler not just an academic. I'm learning as fast as her facial expressions with teaching descriptions are revealed! I find her discovery tutorials a wonderfully refreshing experience. I know nothing I'm learning about a subject I have a great interest in which is far outside my field.
Your Ground News ad was great. When I was doing a paper on Ridiculous Instruction Set Computers (RISC), I found 26 articles on the project. None were technical publications (probably because they do fact-checking). One article said we did not have enough evidence to draw a conclusion. A second said it was complete garbage. The other said it was the greatest idea since sliced bread. While typing the bibliography, I noticed that every positive article was written by the same instructor. RED FLAG! I reread his papers. The real results were the following:
1) There was no functional hardware.
2) The "performance" information was obtained from assembly programs run through a simulator and then the results were multiplied by 7 (to make them look better?)
3) Only non-technical publications would publish the articles (no fact-checking?).
This is an example of "Proof by massive publication". We are still burdened by the Advanced Ridiculous Instruction Set Computer Microprocessor (ARM). (Many ARM chips cannot do simple integer division.)
Hi dr Becky I love you so much videos are grate learning experience I’m glad to have you as a teacher
Fun to watch and learn as usual, nice and dependable Thursday event. Seems like the most logical is Top Heavy, but can we take just a moment to wonder at just how "much" is out there... mjb
In the chaotic sea of sensationalized videos on this topic, you are the only channel I believe. Amazing stuff!
I love your videos Dr Becky! I'm a big space nerd but I'm not great at searching out the new information and discoveries for myself, so I'm so glad you're covering papers from JWST data.
When you were discussing the IMF curves we use to relate mass and brightness, there's one extra thing that I want to understand. Were astronomers assuming 1 billion year old galaxies had the same distribution of stars as the Milky Way, or were they rewinding that distribution so that there are fewer old stars? It sounded like the first option was the norm, but surely it's an obvious adjustment to make to say our Milky Way has been accumulating long-lasting, dim stars.
That's exactly the part I had trouble believing. Why would we ever assume a Milky Way-like distribution of stars, much less interpret observations - billions of light-years away - on that basis? Maybe before rubbing their hands in anticipation at all of the "new science" to be done, astronomers should first reflect on how they came to rely on such a simplistic approach.
@@destiny1004 Its the usual story of going with what your data suggests. The IMF appears to be approximately the same in every galaxy we can successfully measure it in, although that really means just nearby galaxies, but of course nobody is sure that the IMF is the same everywhere. In high redshift galaxies we expect the IMF to be different since the environment must have been different in the past (e.g. lower metallicity) but we just cannot measure it accurately enough, but new measurements are now indicating that the IMF is different in the early universe (but it can't be TOO much different). More observational evidence is needed before astronomers can come to a better conclusion, as always. There may also be other explanations for why these galaxies appear brighter than they are and slightly different IMF may actually only be a small part of that.
Dr. Becky gets the same expression talking about how much research this study will impact, as I do when thinking about how much DIY I've got to do round the house! 😆
Keep up the good work make more videos, enjoy the holiday spirit😊
Absolutely fascinating. 😯
I did some research in the '70s on the Jeans Mass gravitational collapse of gas clouds. Fragmentation towards stellar masses can continue so long as the clouds can cool themselves, and in clouds dominated by hydrogen and helium and modest temperatures there are surprisingly few radiative mechanisms available (e.g. blackbody radiation from dust grains, rotational and vibrational modes of carbon monoxide) to cool the clouds.
It seemed to me that a "metal-poor" population III era would produce very high stellar masses and it would take a lot of supernovas throwing out dirt before we would see the kind of Initial Mass Function deduced locally.
Thanks for your videos :-)
Dr. Becky and Sabina Hoffman - both making Science interesting, fun, and presenting accurate data as well in a very understandable way,. Women make the best teachers!
You have good content, you are knowledgeable and you have tons of data and cross-references (I am also reading your book). I wish (my unsolicited suggestion), to make your content more user friendly, maybe reduce the speed of talking.. let folks watching get some moments to digest what is shown in visuals and what you are talking. I know YT provides speed change settings for playback and we can always pause and then proceed further but that's not so ideal and convenient. Try speaking in a bit slower pace, see how it goes (you can poll people or some people will recognize and appreciate). Thanks.
Cool. Nice to have an insight into the science of measurement.
Great vid as always! I’m confused by one thing though: you mentioned big hotter stars and smaller cooler ones. But I think of red giants and blue dwarfs, which is the opposite relationship between mass and temperature. Did you just mean brighter rather than hotter?
Really excellent as always, I’m not generally into astrophysics, but watch everything you put out 👍😁
Red giants and white dwarves are dead stars so the rules are a bit different. For active stars, the speed at which fusion reactions happen is basically limited by the outward radiation pressure from the generated light. The more fusion you have, the more you push the star apart, the less dense it is, the less fusion you get. A more massive star has more gravity and can keep the fusioning plasma packed tighter and therefore fusioning faster.
@@MD-pg1fhShe said "blue dwarfs" which are main sequence spectral type *O* stars such as bi253 which is O2V. Red giants are not "dead stars." They are stars that have evolved off the main sequence and are fusing elements heavier than hydrogen.
Just love the questions you pose in the science. So different to others who really believe they know it all..
Thanks, brilliant work Dr Becky 💜🌈🦄