How do we know how old the Milky Way is?
Vložit
- čas přidán 3. 05. 2024
- Go to brilliant.org/drbecky to get a 30-day free trial and the first 200 people will get 20% off their annual subscription.
#milkyway #science #astrophysics
---
REFERENCES (NO PAYWALL)
---
Xiang & Rix (2022; most recent age determination of the Milky Way with GAIA sub-giants) - arxiv.org/pdf/2203.12110.pdf
Belokurov et al. (2018; GAIA sausage discovery) - arxiv.org/pdf/1802.03414.pdf
Myeong et al. (2018; GAIA sausage globular clusters) - arxiv.org/pdf/1805.00453.pdf
Gregg et al. (2004; HST stellar spectral library) - ntrs.nasa.gov/api/citations/2...
Skumanich (1972; gyrochronology correlation) - articles.adsabs.harvard.edu/p...
Bond et al. (2013; first estimate of age for HD140283 over age of the Universe) - arxiv.org/pdf/1302.3180.pdf
Tang & Joyce (2021; revised estimate of age of HD140283 less than age of the Universe) - arxiv.org/pdf/2105.11311.pdf
My previous video on how we know the Milky Way is spiral shaped - • How do we know the Mil...
My previous video on HD140283, the "Methuselah star" - • Is the "Methuselah" st...
00:00 - Introduction
00:58 - The GAIA telescope surveying 1 billion stars
01:28 - Parallax & proper motion
02:23 - What the spectrum of a star tell us
03:46 - GAIA 3D map of the Milky Way
04:23 - How we know how long stars live (the Hertzpsrung Russel diagram)
06:12 - Stars formed earlier are made of different ratio of elements
07:07 - Fitting model spectra to get ages
07:47 - Other methods: GYROCHRONOLOGY
08:36 - Other methods: PHOTOMETRY
09:17 - The oldest star known and its uncertain age estimate HD140283 (no it's not older than the Universe)
10:03 - Let's do this with a big sample of sub-giant stars (Xiang & Rix 2022)
12:14 - Deriving the age of the Milky Way (Xiang & Rix 2022)
12:52 - Brilliant
13:26 - Bloopers
---
📚 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
Anyone with the courage to integrate photos of what they looked like as a teenager deserves a massive following. #blackholefan
Hahaha. For sure. I somehow thought that dreads that form through letting your hair be crusty and gross with no care whatsoever was a good look. I should go back and thank the person who ended up giving me lice, forcing me to cut off those abominations.
The images were just brief enough that it's not completely terrifying.
I love these types of videos that give us laymen better explanations than "because science says so".
You are not a layman.
I feel that the reason that she went into such an in-depth explanation was that this study was done pretty recently.
"Because science says so" is used when an explanation would require someone to spend hours, days, or even weeks just to bring your knowledge level up enough to understand the basics of the topic. These kinds of videos let you see a glimpse of the topic and make you feel like you understand it, but the truth is that you just learn more details about the topic without actually understanding it. That's why universities exist: to allow you to study a field until you properly understand it.
I love theese vidoes for the exact same reason. We can have an idea how the data looks and also how much effort is behind a simple claim that our Galaxy is 13 bn years old. Other channels usually provide just visualisations, and yes, the visualisation are nice and helpful, but I would also like to see how the data looks.
Trust me, astrophysicists _really_ appreciate them as well :)
Dear Becky - this is one of your very best! Those H-R animations are fantastic; so much is now explained. Thank you!
Space is hard... boys are harder. It's all relative Bec
"Space is hard, words are harder"
I like that quote
Always been a big fan of hold old. Brings a tear to my eye every time
I've personally become the worst speller. I was once quite good like in high school.
@@mdb1239 that's a great story
@@mdb1239 I was crap at spelling in high school and have only gotten worse.
@@LeftCoastStephen I loved it. It made me laugh.
@@mdb1239 I'm the best speller ever, I can spell any word hundreds of different ways
I love how science scaffolds on itself. Someone was researching the spin of stars wondering what could be gleaned from that and that eventually led to the calculations of the Milky Way's age. Awesome stuff!
I love this channel. Dr. Becky has infectious enthusiasm.
I recently started my kids on home school and we do a class on astronomy and we use your videos. We watch them and I have a short test for them at the end and they love it. They are so mesmerized and at the same time perplexed at the size of the galaxy. Thank you for what you do
I can recommend SciShow and CrashCourse videos too, many teachers use them in their classes! (There’s also a separate SciShow Kids channel you might like, depending on the ages of your kids!) Much love
Anton Petrov is amazing too! And 3D size comparisons are insane! I prefer the longer ones and definitely newish ones.... More than a few months old is just ancient in my opinion. Have a good day and keep on learnin'!! 🍻🌎❤️🚀🤯
@@juliaspoonie3627
I wouldn't use SciShow, though. Especially not for teaching, considering how often they are simply wrong.
@@juliaspoonie3627 nooo not scishow
For some reason, I never realized how old the Milky Way is. I'm so used to thinking in terms of the age of our Solar System.
Relatable 🥑🗣️
I agree with Melvyn Davis -- this was one of the best presentations of significant astronomical research I've ever seen. Great job, Becky.
Gotta say thanks for such cool information all the time! Your videos helped me pick an awesome galaxy for my science presentation, and helped me get an awesome grade on it :)
Best explanation I've seen. Can't wait for the book to arrive next week. Looking forward... and upward.
Very well explained, Dr. Becky you are such a great science educator!
Thank you for another and enjoyable video. I especially appreciated your presentation of a HR Diagram. I found it more visually pleasingcand informative than others ive seen in textbooks.
Thanks! Those links to the appropriate papers are cool. Useful while reviewing & replaying this lecture.
The amount of work put in each of your videos is incredible. I have watched this one like 10 times because it is a very good summary and I did not want to miss any details. My research is on estimating the ages of globular clusters so I found your video very helpful.
Ah, HD 140283. That was the subject of the first video I ever saw by you. Almost two years later and I'm still here watching your videos every week. Here's to the next two and beyond. 😀
Excellent explanation of a complex subject!
Thanks for another clear, concise explanation of important discoveries! Wrapping my head around all that the Gaia recording leads to is not easy. I imagine the sheer, raw data it's collected has to be staggering. Then, very bright people reach into that data set to find so much useful information. Thrilling stuff!
excellent video, Dr B! of course, they all are! loved your most recent book, too! now, i need to read the other one. thanks and.......Happy St Pat's Day😃👍
Thank you Dr. Fantastic description and intuitive breakt. You continue to inform me in ways I understand. Cheers. ❤
My brain put a period after fantastic
The rest of the sentence made no sense. I had to reread it to make sense
But I'd say she is Doctor Fantastic.
@@christianheichel 😂 that does change it. I re-read as you did. 😆
Sooo, the word "bigger." Would you possibly think about using either more massive or having more or less volume (voluminous?) when describing stars. I teach physics and astronomy and I've run into this misinterpretation too many times, because I, too, inadvertently use the word bigger. Your videos are wonderful, many of my students watch them. It goes without saying (but I'm going to say it anyway), I never miss one, I enjoy them, so much. Thank you.
Great explanation! Space is hard, words are harder. I might have to borrow that.
Kudos! Eminently clear. Thank you.
It was nice to hear and see you again.
As always, great content for non-scientists.
Beautiful Bloopers!
Nice work, thank-you!
yet again you have done it again so wonderful i only understand a small percentage of the video but its mind-blowing
I'm a big fan of all your videos but this one was really outstanding. Extremely well explained
Thank you!
Thanks Dr. Becky! As a current astronomy student these videos are a lot more informative and realistic as opposed to the media’s out of context headlines. I appreciate your work. I’m getting into the coding aspects of the kind of work astronomers/astrophysicists do.
You’re very welcome! All the best with your studies 🥳
@@DrBecky It is hard to believe that the Wealthy are wasting money on stuff like those you talk about instead of focusing on organising a prosperous society.
Brilliant ! You have just about encompassed the theories of everything in your interesting explanation. So determining the age of our galaxy has not at all been a simple task though challenging and knowledgeably rewarding.
That was super informative, thank you! It's weird, a friend of the family was asking only 2 days ago about how do we work out the age of the stars and galaxies... i'll send her this way!
Always a good day when we get to spent a little time in Dr. Awesomeness's class. Thanks Doc.
Pretty awesome stuff! Great video!
Hi Doctor Becky. Enjoy your content and it answers many of my questions. If I had a few more in-depth ones, could you recommend a resource for communicating one-on-one with an astrophysicist/cosmologist?
I was feeling under the weather today - even lost track of what day it is. Then this popped up. Now I feel much better. Thank you.
Thanks for being one of the channels I use to find out the actual space news behind the headline daftness
I'm wandering how much of The James Webb's targets are suggested from Gaia data (or other intereractions between the two projects) if that would be a useful topic for your channel
Great video dr. Becky
You are fantastic. Love your videos. Learn much from you. Thank you very much. Live long and prosper 🖖
The Hertzsprung-Russell diagram is gold
It makes a good song, too: czcams.com/video/xN7U8VPd9_U/video.html
Thank you for this video. Very informative
Great video. I enjoyed the changing Becky montage.
To summarise, we can age astrophysicists by looking at their baby pictures (awwww), while we age stars in galaxies by looking at their retirement party pictures (awwwwww).
Tanks Dr Becky, así Google traduce bien los textos , pero lo mejor es que se escucha el timbre de tu voz, que yo opino que es bonito😊
Dear Becky - Excellent Video with great visual and excellent explanations, very well done. Please keep up the good work. I like how you explained about the Gaia mission and how crucial it is, however you missed to mention the LAMOST spectroscopic survey. The Xiang&Rix 2022 study relies on spectroscopic data from the LAMOST survey - the stellar parameter, radial velocities and the chemical abundances come from these spectra, without which accurate ages and this kind of study is not possible.
3:30 and if you put a wall of certain materials between you and the ambulance, sound gets altered in different ways also.
kinda like the light that goes through different materials as well :)
Numbers are actually the main problem in astronomy . But they are the one who excites us the most . The enormity of the universe is an amazing aspect .
this video left me very impressed, very good, thank you....
I was there. Gawd, I feel old. LOL!
Thanks for the video, Dr. Becky!
9:23
Reminds me of Sheldon from the BBT "singing" star names hopping down the stairs.
I love these videos when you explain how the scientists got to a certain discovery. We can have an idea how the data looks and also how much effort is behind a simple claim that our Galaxy is 13 bn years old. Other channels usually provide just visualisations, and yes, the visualisation are nice and helpful, but I would also like to see how the data looks.
Thanks Dr. Becky. Keep looking up.✨🌟⭐️. Martin from the Emerald Isle ☘️🇬🇧👍
Such good explanations. Instant sub
Welcome! And thanks 🥳
Great Presentation. Wise girl
Taylor opened her tour in my town last night! 💓
You're the best astrophysicist I've ever known, yet have never met. That's a strange paradox. Eh, I still appreciate everything you do for your audience. This was a great topic. Thank you for tackling subject matter like this. Cheers, Dr. Becky. Oh, and what did we learn today? Methods used to measure the age of our galaxy, but more importantly, Dr. Becky is a Swiftie. I'd glitter up and go to the concert with ya. It looks fun.
Great explanation
I can always rely on Dr Becky for answering questions of the universe I've had for years.
Thank you Becky 😘🙏
Gaia is one of the most important astronomy missions around. Its information will be used for decades to understand the Milky way.
Title typo...
Like Dr Becky says, 'Space is hard, words are harder.' LOL.
Whoops!
I missed it, and now I feel like I’ve been left out of something fun.
Edit: just figured it out
Wonderful! Thank you
Thank you so much for all your content. I learn so much from every video. You may have answered somewhere else. Do we know if our star was formed in the Milky Way or the Sagittarius dwarf galaxy as I have heard suggested?
a full 1hr of bloopers from your sow would make my evening.
I literally love each your each n every vdo Ma'am Love from a Lil Fan from India ❤❤
0:21 - Baby Dr. Becky! ;-) And those star animations at 1:37 and 2:15! Thanks for the great work and explanation for all of this, Dr. Becky. Much appreciated!
I really enjoy videos like this; videos that explain how certain measurements of celestial bodies are measured. I hope information like this gains more virality.
I love the look of Baby Becky there 🙂
Good videos, keep them coming !
Seeing an accomplished astrophysicist spontaneously break out in song gives me hope for mankind every time.
Awesome! Thanks!
So cool that Gaia caught Webb out there. :)
I'm thinking about making a spectroscope of my own. Using an old cheap refractor and a prism, with a camera attached. Not sure how to pull it off yet though.
czcams.com/video/fW4aMOSVv_8/video.html
CZcams for you, enjoy
Caught Webb? It's in space since 10 years :o
@@Saidor570 Caught Webb in a capture. Hence the word "caught". That's what telescopes do. Catch light.
Such a clear and easily understandable presentation. Excellent graphics. You rock!
I remember reading something on stars a long while back on something called black dwarf stars. The idea was that star start out as yellow giant expand into a red giant eventually collapse into a white dwarf which at this point is basically a small very dense piece of rock slowly cooling over millions of years Like a hot piece of cooal taken out of a fire. The part that interested me was it's estimated to take so many billions of years of for a star to go through it's yellow red white and eventually black phases that it'd be more time than the universe has actually existed for.
I think becky is related to Jay Leno on some blood line or something!
You should check into that. You were such a cute kid!
She has so much style and confidence!
Interesting way of touching on the use of H-R diagrams in deducing the age of a group of stars. If I understood it correctly, the lower left hand corner of the diagram is initially populated by fast-dying stars, they blow up and then their elements form main sequence stars, and these in turn blow up and their matter make up stars in the upper right quadrant, e.g. subgiant, red giant, or super giants. A very pedagogical explanation to be sure.
Hi Prof. Dr. Becky ! Which desktop/laptop cosmology or Astrophysics applications is best for learning computational Astrophysics or Cosmology for programming?
Thank you for another enlightening video. You often talk about Gaia taking stellar spectra and even show samples, but does Gaia have a list showing spectral types? Like star X = G2 v, or A6 i. I keep looking and I can't find any so I continue depending on Simbad for such info. If gaia does have such a list, how do I access it? Thank you.
Have you read this Reddit thread?
"How to figure out spectral type from SIMBAD/GAIA data?"
(Not linking directly in case my comment is automoderated.)
I found the formation of time is what only life can perceive and having current knowledge with an open mind that feels free, so see Dr. Becky
You are exceptional to be able to independently close your eyes one at a time.
So cool the video starts with different ages of Becky in photos, so cute
5:24 oh, this animation was incredible
How does Dr. Becky not have a million subscribers by now?
Dr. Becky, have you seen the strange object(?) in the latest JSWT images? It's at the very top of the composite image and about 1/4 of the way across the image starting at the left. Would be curious to see what you think it is. Cheers!
Flashback to you demonstrating parallax on sixty symbols and confusing Brady
wow, the graphics are amazing, thanks for the extra editing work!!!
So, there is about 16 minutes light distance between the two points used to determine the distance to a star like Betelgeuse which is about 642.5 light-years. Wow, 16 light-minutes wide and 642.5 light-years long…amazing that the distance a star is can be measured with such a tiny distance between two points. I’m sure there’s something I’m not getting about this, but still, amazing!
Becky, a general question.
1: do 'we' know if the strength of space-time is the same everywhere? I can imagine it being weaker where it gets stretched?
2: Do I get this right?
Lightspeed is a constant, but as space gets stretched by mass (x speed?), light has to travel a longer distance through that stretched space, which logically takes more time?
First off, great video as always. The simulation in the first minute of the video shows what looks like explosions or bullet trails that do not seem to be directly related to mergers. Is that just an artifact of the simulation, or is there a cause for these outbursts? Are they just delayed results of bursts of star formation due to mergers?
Thanks!
Thanks Dr. Becky! Is there any problem with using a unit (the year) for measuring the age of something that existed an enormous amount of time before our earth and sun ever existed?
The stuff GAIA is doing sounds unreal. That is so cool. 🤩
fascinating
Came back to have another look at this, one of my faves.
Epic Spaceman has just released an incredible vid about the size of the galaxy and our place in it, a truly beautiful explanation and I highly recommend watching it.
Is it possible for stars and other structures start forming before re-ionization?
The baby pictures alone deserve a thumbs-up.
The definition here seems to be a question for a whole thesis already?
When is an object a galaxy? Mass boundary? Rotation threshold? AGN? Local Magnitude (not brightness). Star generation?
that would mean the galaxy as a whole has only rotated 65 times in its lifetime, it rotates once every 200 million years, I think we underestimate it somewhat
Great video, I really needed to learn this and you nailed it (as usual).
However, I know this isn't essential to the story that is told, but the illustrative animation at 3:12-3:27 doesn't show the right movement of the spectrum. For example, when the star is at its furthermost position it shifts from moving away to moving towards us, and thus the spectrum wouldn't be moving at that moment, rather it would change direction.
(I'm also extremely funny at parties 🙂)
Hmm, measuring the wavelength of light through color differential adjustments may also help determine time over distance. Yeah um size of a sun "taps chin with head tilted sideways". Surprises me that they don't use other filters pertaining to other subjects that like to overlap.
Hello Lovely Dr Becky, another wonderful video. How did the book sales go? I am really attracted to watching your mouth and eyes when you talk because you are so excited and happy about your passion. Coffee and Biscuits????