The takeaway from this episode is that at the centre of every galaxy there should be a sign saying "Mess Quenching Alert! Do not feed the Black Hole by order of Dr. Becky". That should restart star formation and save the universe.
For a galaxy that has been quenched by having its gas heated up, wouldn't that gas eventually cool down again and restart star formation? How long would that take? Perhaps instead of calling such galaxies dead, a better word would be dormant, just like for volcanoes.
I suspect that the timescales involved here make that very unlikely. It would take that heated gas so long to cool down to a useful level again that it's inevitable that before that happens, the galaxy will be involved in a merger or fall into a cluster and be subject to stripping and harassment and all the other effects that further disrupt and heat the gas.
@juliasophical perhaps, although what is there to cool the gas - it's not loosing any heat to other atoms or friction if it's in so much space. Equally, it's entirely possible that in moving so fast from the heat the gas will escape the galaxy's gravity and end up in inter-galaxtic space so far from other atoms that even if it cools down it is now so far from any other atoms as to be effectively separate.
@@quintuscrinis8032 Radiation will cool the gas back down (meaning that the gas will emit light of its own not that it will absorb radiation and become cooler), but that's an incredibly inefficient process.
Or emit in infrared but that might be very weak for such a dilute gas. The details are important as we cannot ”see” in IR immediately how transparent it is... I suppose a massive cloud will only lose heat from around its edges so can be small
Every week at some point during the video, I find myself thinking, “Dr. Becky must be the smartest person in the world.” Her intelligence just seems to be infinite. There’s no break in the flow. And maybe because so many other science communicators seem to be weighed down so much by ego. But she just seems to be pure immersion in and enthusiasm for the subject. What a gift.
I agree 100% I was just thinking that she might very well be the next Einstein. She's got the brains, she's got the passion, but more than anything she has a great sense of humor. Einstein inspired generations of people to become scientists. Not just because of relatively, but because he was personable. He had a great sense of humor and was known to be silly and goofy too. I could easily see, in 20 or 30 years, she will be inspiring similar amounts of scientists as Einstein did. My money is on she gets a Nobel prize in the next 10 years, maybe 2 of them. There is a chance that her discoveries will rival Einstein's,maybe surpass them.
My first thought was "why didn't she take off the backpack before turning on the camera?" And then I realized it was a vest and not the straps of a backpack.
Oooh, good titles all! Hmm, maybe instead of Brownian motion, we'll have Brindlian motion. Or Dalmatian ... Dalmatianian? motion? Oh, throw me a bone. I can't have any caffeine today.
0:49 Because the more massive the star is, the higher the FUSION RATE due to high pressure pushing the atoms together and fusing the atoms, burning the fuel much faster than smaller stars with less pressure at the core and burns a lot slower because of the fusion rate much lower.
A Bunsen flame burns blue because of emission from the chemical species present, surely. Not because it's hot enough to emit black body radiation in the blue region.
The Internet is not giving a solid answer for the maximum temperature in a methane Bunsen burner flame, but it looks like the various answers top out around 1800K. 1800 K would produce orange black body radiation.
I take it this is a deliberate mistake to make sure we're paying attention? Blue flame is due to emission lines in flame species, yellow/white candle flame is soot particles incandescing, oxy-acetylene torch flame is hotter and basically white, to incandesce blue you need to be much hotter, in an electric arc perhaps.
your talking about agn reminds me of the time i was standing under a very low fast moving & ascending funnel cloud that had just been a tornado carved a trail through a cornfield. it felt like a blow torch of hot air on my face & my ears popped
Terrific video Dr. Becky! Now I can't wait for "Quenching 102". That Dog analogy was right on point! BTW, my guess is that you are heading for one of the Telescope Observatories either in Hawaii or the one located in So. America? Anyway, wherever you are headed, have fun, be safe & learn a lot.......... 👍👍🐕🐕
This is a really interesting subject that you don't hear much about, ever. Thanks for teaching us about it!
4 ปีที่แล้ว +1
Yeah, it's not the topic that draws headlines... Those time scales are so long, and the processes so gradual that we haven't had the technology to look for long enough to see a difference happen anywhere, outside of single events like supernovae.
Question: on a long enough time scale, won't galaxies who's gas has been overly heated eventually cool down via radiation to the point that the gas begins to gravitationally collapse again and set off a second life of star formation?
That's fascinating to know about the colours of galaxy can be representative of their age and what stars are in there. I'll bare that in mind when I take photos of them! Good to know. Btw the puppy analogy? On point 👌
You were mentioned on the Philip Defranco show the other day and I smiled. ;) Always fun to see youtubers you follow mention the other one. It was in regards to your tweets about the standing brooms or something.
Dr. Becky you will have 1M subscribers at some point! This was one of my favorite shows so far!! AGN, a tempest in a teapot. This is very exciting, seeing how modeling drives observation, and observation drives modeling. It would be fascinating to see a more of these walkthroughs of the multi scale (very small to very large structures) modeling that you and your colleagues are doing! As I watched this I suddenly realized that my view of the universe felt more integrated and I almost felt aware of the dynamism happening at greater scales than I normally conceive of when I gaze at the night sky and ponder. Truly one of my favorite videos you’ve done so far.
If a Galaxy is quenched because the interstellar gas was heated too much, in the very long term could the gas cool off enough for star formation to be restarted? I would guess that either the universe isn't old enough for a galaxy to be revived in such a manner or that such a process would form stars infrequently enough that it couldn't meaningfully be called a revival, or both.
Yes, the heated gas will cool down over the course of hundred of 1000's years to billions. But, once cooled it's density will be almost uniform with variations probably a few orders of magnitude less than it was before the heating. Then, it may take several billions of years before any cloud become dense enough for star formation can resume.
@@Kualinar It is also worth noting that as the gas cools it begins falling under gravity again which funnels much of that gas into the galaxies core where it can trigger AGN activity there are some massive galaxies which show evidence for episodic activity switching between feeding and quenching through outflows
@@Kualinar I think I understand. My thinking though is that we know the sun is at least a 4th generation star due to it's high metallicity. This means at one time it was part of a star that blew up, that gas became another star rinse and repeat until we got the gas forming what would come to be called "Sol" by the mostly harmless, not so hairy apes from a rather boring planet in a very uninteresting arm of the galaxy.
@@kingblondie7075 Did you know Ford is currently working on a city car version of the Torus. Much smaller that the original Torus it will be called the Ford Tardis. The catch line will be, "You'll sear it bigger on the inside."
Interesting video! However, there's one thing I'd like to know: You say that after the gas is heated it's not possible to be used for star formation anymore. Obviously at short timescales I will agree. But what about the long run? Couldn't the gas just cool down (e.g. by losing entropy due to photon emmission, or the like) and then when it has cooled down, form new stars, just much much later? In this picture it wouldn't seem too unlikely that even after a galaxy has fallen into a hot slumber, it could be woken up again after some cool-down period and continue producing new stars.
u make every outfit look good Becky... i hope u know that is meant as a simple compliment and nothing bad... as a nice person i enjoy complimenting people on the way they look because SOME work hard on it
Wednesday evening is the new Nature journal issue and also new Dr. Becky video. A double pleasure. By the way, today's Nature has the Galaxy-scale gas wave paper we heard first about on this channel.
So happy to have found your channel. I have felt like a black hole accreting everything that you’ve made available. Love your videos, the way you explain things, your voice and yes, even the Harrison Ford outfit. ⭐️
Two observations: (1) the puppy pile force is the strongest observed force known to man (2) 100,000 year lifetimes for really large stars is interesting when it's said that it takes about that long for photons to get out of the core of our Sun due to the density, etc etc.
Three questions: - Are stars equally distributes across the spectral types or is there a distribution curve that we know of? - Is the spin of a black hole enough to force it into a flattened-spherical shape like earth or is the gravity so overwhelming that it remains perfectly spherical? - Is the spin of the accretion disk related to the spin of the black hole or could the black hole be non-spinning and the 'stuff' just spirals in purely from the gravitational forces with no influence of the black hole spin, or are both interconnected in a way?
Question: When a star dies and its gas is recycled, isn't it poor in hydrogen? It seems to me it would be like a fire in a sealed container, eventually there isn't enough oxygen. Can a cloud poor in hydrogen but rich in helium achieve fusion?
I honestly thought only increased metallicity of stars would determine galactic quenching. Thanks Dr. Becky! Although I do want to add if supernovae can also prohibit star formation in nearby gas cloud besides just simply heating it like what happened to pillars of creation.
I was wondering about this too. I assume stars can only form out of hydrogen & helium, and these materials are constantly being fused into higher atomic number elements, so a galaxy eventually runs out of ingredients no matter what? I guess a lot of stars will go supernova long before they've used up all their hydrogen so maybe it actually doesn't deplete very fast compared to some of these other mechanisms?
So interesting to me as a cosmology geek but find it hard to fully grasp some of the concepts, I appreciate how you can explain things in an understandable way! So how hot is hot as far as the interstellar gasses? We were always told that space is an incredibly cold place.
Hot, about 1,000,000K or greater to emit x-rays. Space is incredible cold, roughly 2 - 3K. Heat is an expression of energy. If a gas molecule is highly energised it is "hot". There may only be 1 molecule in a volume of say a cubic meter so even though it is incredibly hot the empty space is frigid. Incredibly hot and also incredibly diffuse gas. If you were in the corona of our sun which is roughly 10,000,000K but were shaded from the direct effect of the sun you would freeze to death and not burn up.
Astronomy timescales are difficult. For exmaple you have galaxies rotating. But how long does that take because galaxies are giant. How many orbits do they get in a lifetime before some merger event disturbs it again? One or two maybe? Star life cycles are different as well and some longer than our universe is old so far. The whole star formation simulation you showed only takes a few thousand years.
I've got a query that came out of watching the animation of the two galaxies colliding. What absorbs the potential energy of their approach such that they end up merging? If none of the stars are, statistically speaking, going to collide, then should we not expect that the total momentum is conserved after the first collision? Then the stars would fly off in scattered directions as fast as they approached. Evidently, observations show us that this is not the case, so where does a colliding galaxy's momentum go? And thank you for your very informative videos.
If overheating is a quenching event, wouldn't it only be temporary, as things would cool over time? Or would the timescale for such cooling be past the ...end of the universe?
Really interesting description of things, but I'm left wondering how this combines with the conservation of energy... the energy cannot be destroyed, however it can be radiated away, which would mean that the "central" (yes, I know) galaxies would keep going for longer, but also where the energy heading "out" (this gets conceptually worse) actually goes - as in what is there? I have probably given myself an instant headache thinking about this.
1:30 I have to call you out on this one. The color of a flame has little to do with its temperature and more with complex photochemical and thermodynamical processes occurring during the oxidation of the fuel. Bunsen burners use propane and butane, which in ideal conditions burn at around 2000K, (although Bunsen flames rarely exceed 1500K) and acetylene torches around 2500K, all well below the black body radiation temperature corresponding to blue, around 9000K-12000K. Otherwise great video as always.
Potential completion of the Periodic Table of the Elements: I currently believe that there are 120 chemical elements in this universe. If a person were to look at how electrons fill up the shells in atoms: 2, 8, 18, 32, 32, 18, 8 (seven shells), and realizing that energy could freely flow in this universe if nothing stopped it from doing so, then a natural bell shaped curve might occur. An eighth energy shell might exist with a maximum of two elements in it, chemical element #119 (8s1) and chemical element #120 (8s2). Chemical Element #119 (8s1): #119 I put at the bottom of the Hydrogen group on the Periodic Table of the Elements. It only has one electron in it's outer shell with room for only one more electron. Energy might even enter the atom through the missing electron spot and then at least some of the energy might get trapped inside of the atom under the atom's outer shell. Chemical Element #120 (8s2): #120 I put at the bottom of the Helium group since it's outer shell is full of electrons. It might have some of the properties of group two, Beryllium group (Alkali Earth Metals group) since it has two electrons in it's outer shell; as well as some of the properties of the Helium group (Noble Gases group) since it's outer shell is full of electrons; and if you look at the step down deflection of the semi-metals and where #120 would be located on the chart, it's possible #120 might even have some semi-metal characteristics. #120 would be the heaviest element in this universe. I believe chemical element #120 could possibly be found inside the center of stars. When a neutron split inside of this atom, it would give off one proton, one electron, neutrinos and energy. The proton and electron would be ejected outside of the atom since all their respective areas are full. One proton and one electron are basic hydrogen, of which the Sun is primarily made up of, and the Sun certainly gives off neutrinos and energy. And note, it's the neutron that split, not a proton. So even after the split, there are still 120 protons inside of the atom and the atom still exists as element #120. The star would last longer that way.
Questions: Do all galaxies eventually collapse in upon themselves, possibly go nova, to eventually generate a new galaxy? And 'if' so, is our determination of the age of the universe really only based upon the maximum age of galaxies? Does the universe truly eternally exist without any beginning and possibly never having an actual end?
Isn't the heating by quasars thought to be why things calmed down to a rate that isn't going to drive life extinct through frequent bursts of radiation from supernovas, like they are looking a very old/distant galaxies? And also, that quasars went out because they cut off their own food supply by heating it? That must be what you mean by the models needing it to work out correctly.
Okay, question about the “pristine” galaxy falling into a cluster that is surrounded by energetic, x-ray emitting gas: Why is that x-ray emitting gas stationary relative to the infalling galaxy? Why isn’t the gas also falling towards the cluster, such that it does not cause all these effects on the infalling galaxy?
The other analogy, rather than puppies, is trying to collect pre-school age kids after they have eaten too much chocolate cake at a birthday party! Great video. A fascinating and complex subject that you made understandable.
Dr. Becky: a very good explanation as always, but... ... you mention several times the word "gas". That let me in doubt because if the gas is hydrogen, it will be usable to form a star. If it is helium resulting from hydrogen fusion on a dead star then it will not be easily usable on a new star. So, besides the four quadrant explanation I missed some clarification about what gas you were thinking of.
May I point out a Bunsen burner, in contrast to both a candle flame and a star, does not radiate like a black body. The blue colour is a particular electronic transition.
Beat me to it Argus. Noticed the same error. Still love your videos regardless of a little mislabeled galaxy, Dr. Becky! I’m sure M33 didn’t lose any sleep over the error. 😊
Knowledge for the sake of knowledge with zero practical purpose? Doesn't matter. You are so charming I would watch your videos just for the pleasure of watching someone talk about subjects they obviously love. Everyone should have a career that excites them. What a wonderful world that would be 😁👍👍
Those old galaxies have reached a gravitational equilibrium with its parent singularity thus countering one another's forces and leaving a net zero that essentially stops any pulling action by the gravity pit of the singularity leaving the rest of the galaxy rotating under its own momentum although still gravitationally bound as whole complete entity. It takes the energy to compete away and everything stays as is and dies.... At least that's what I think.
151 comments already! Not fair, I am still watching this interesting video/lecture slowly and carefully. Wait me up guys ... @Dr. Becky, I am working on a video about how the mass of stars decide their number of years to live @AstroGate بوابة الفضاء if you are interested in a Cameo
Maybe as it becomes defuse it gets trapped in the gravity of individual star systems all across the galaxy? In which case how/why would it ever manage to leave these systems to become massive clumping clouds again?
Just had an idea about FRBs. Could it be as simple as gravitational lensing of radio waves? When a radio wave source lines up with a massive object from our perspective. Would love to hear your thoughts.
Hey Dr. Becky, here's a question might be interesting: Does Dark Matter influence the 'ignition' of new stars? And if so, could 'ripples' in the patterns of ignition of new stars in a galaxy be used to help 'see' where dark matter might be more concentrated or less concentrated in a galaxy (or anywhere stars might form)? I ask because I know that when two clumps/masses of Hydrogen collide, the increased density triggers star ignition. So maybe a clump of dark matter 'colliding' with a mass of Hydrogen could likewise trigger new star ignitions where otherwise left alone, the H cloud would *not* have ignited (as many) stars. For example, suppose a big, enormous, but 'invisible' blob of dark matter just so happened to be plunging through a certain portion of the Milky Way right now, at relatively high speed (in my mind's eye, I'm picturing the famous Bullet Galaxy photo showing how DM might form such 'free-floating' high-speed blobs). Perhaps its leading edge might cause a measurable increase in the rate of star formation in the disk of the MW, which, as it passes through, would expand into a circle or disc, and then as it passes all the way through it would shrink or just fade away. Two things that it reminds me of: 1) The phenomenon of Fairy Rings, which are literally expanding rings of mushroom formation (say, on a patch of forest floor), over time, as the underlying fungal mass of rhizomes (within the soil, and thus 'invisible', thus paralleling DM) grow and spread out from a central origin, using up all the nutrients along the way, such that night after night, the centre of the Fairy Ring doesn't have enough nutrients (paralleling Hydrogen gas) to form mushrooms (paralleling star ignitions), but on the edges of the fungal mass there's still enough nutrients to form new mushrooms. Hence, you see a nearly perfectly circular ring of mushrooms that at first glance seems to have been arranged by 'someone' (Fairies, obviously!) to be that way. Maybe a similar pattern could be detected within galaxies or nebulae to spot the movement of 'clumps' of dark matter? Does DM even form clumps? It must, at *some* scale, right? Do we know if it can form smaller-scale clumps? 2) The analogy of a 3D entity interacting with a 2D Flatland, where the '3D entity' in this case might be a blob of DM, and the '2D flatland' would be the basic disk/spiral shape of a galaxy. As the 3D enters the 2D, suddenly a 2D object pops into existence, from the POV of any flatlander. Then the 2D manifestation grows and morphs its shape, as the 3D entity passes through flatland, then it shrinks and finally disappears. Here the analogy is that the appearance of a 2D manifestation (or projection, in geometrical terms) would be the equivalent of observing a sudden (in cosmic time scales anyway) increase in star ignitions, then that starburst region expands, then shrinks and disappears. Any of this make sense in terms of the actual physics of DM? Could such an observation actually be made to spot more 'structure' and motion within otherwise very 'fuzzy'-seeming 'halos' of dark matter? Or maybe the lack of such effects might be indicative that DM truly is very fuzzy, maybe something like how electron clouds are inherently fuzzy, and that it actually is physically *unable* to form small-scale structures?
Also, as stars die don't they make heavier elements, up to iron? The darker, harder to see elements would theoretically never be formed into stars again. Each successive death would produce smaller amounts of available fuel, right?
![[LIVE] : ONE ลุมพินี 80 | คู่เอก "รักษ์ vs ยอดนำชัย"](http://i.ytimg.com/vi/ckLMRorsMeY/mqdefault.jpg)
The takeaway from this episode is that at the centre of every galaxy there should be a sign saying "Mess Quenching Alert! Do not feed the Black Hole by order of Dr. Becky". That should restart star formation and save the universe.
For a galaxy that has been quenched by having its gas heated up, wouldn't that gas eventually cool down again and restart star formation? How long would that take? Perhaps instead of calling such galaxies dead, a better word would be dormant, just like for volcanoes.
I suspect that the timescales involved here make that very unlikely. It would take that heated gas so long to cool down to a useful level again that it's inevitable that before that happens, the galaxy will be involved in a merger or fall into a cluster and be subject to stripping and harassment and all the other effects that further disrupt and heat the gas.
@juliasophical perhaps, although what is there to cool the gas - it's not loosing any heat to other atoms or friction if it's in so much space.
Equally, it's entirely possible that in moving so fast from the heat the gas will escape the galaxy's gravity and end up in inter-galaxtic space so far from other atoms that even if it cools down it is now so far from any other atoms as to be effectively separate.
@@quintuscrinis8032 Radiation will cool the gas back down (meaning that the gas will emit light of its own not that it will absorb radiation and become cooler), but that's an incredibly inefficient process.
Or emit in infrared but that might be very weak for such a dilute gas. The details are important as we cannot ”see” in IR immediately how transparent it is... I suppose a massive cloud will only lose heat from around its edges so can be small
Harrison Ford? My first thoughts were, "Why is Dr. Becky wearing a backpack?"
I thought this exact thing but backpack first, then Han Solo
Every week at some point during the video, I find myself thinking, “Dr. Becky must be the smartest person in the world.” Her intelligence just seems to be infinite.
There’s no break in the flow. And maybe because so many other science communicators seem to be weighed down so much by ego. But she just seems to be pure immersion in and enthusiasm for the subject.
What a gift.
A gift from Allah
@@fazlishah8996 A gift from her parents, actually :P
I agree 100%
I was just thinking that she might very well be the next Einstein. She's got the brains, she's got the passion, but more than anything she has a great sense of humor.
Einstein inspired generations of people to become scientists. Not just because of relatively, but because he was personable. He had a great sense of humor and was known to be silly and goofy too.
I could easily see, in 20 or 30 years, she will be inspiring similar amounts of scientists as Einstein did.
My money is on she gets a Nobel prize in the next 10 years, maybe 2 of them. There is a chance that her discoveries will rival Einstein's,maybe surpass them.
I wish her a long and healthy life filled with accomplishment. 😸
You've got your Becky Solo vest on. Haha.
Edit: Wrote that before your outtakes at the end.
My first thought was "why didn't she take off the backpack before turning on the camera?" And then I realized it was a vest and not the straps of a backpack.
The best quote ever “ you don’t need Galaxy Collision insurance yet”. LMAO 🤣
@@OlettaLiano : That's galactic-scale engineering, so NASA doing interstellar stuff, so _do_ push it.
Right - brace for impact!
Try telling that to the car hire mob!
That did actually calm me down though xD I am super interested in astronomy but also super scared of big space things going boom xD
These videos make every Wednesday exciting
Dr. Becky, I bet you could do the Kessel run in eleven parsecs, by sciencing the crap out of it! Take that Han Solo!
Ah, kudos on fixing the focus issues :) Might I suggest using bounce lighting off the ceiling to hide the shadow?
A side light would also help
I find your lectures absolutely fascinating and you are utterly charming in your delivery. Thank you
You owe the universe an expansion of your puppy based cosmological theories.
Big fan aspiring astrophysicist myself !! Absolutely love love love your channel ! Thank you for your videos your explanations are great 👍🏼
Am I the only one who wants to see a paper titled the "Over-excited Puppy Distribution of ..." at some point? I am? Okay, I'll see myself out...
"Analysis of the Over-excited Puppy temperature regime of the Interstellar Medium".
The Mathematical Properties of Organising Energised Puppies and Factors of Canine Entropy.
“The Fluid Dynamics and Strange Attractor States of Over-Excitable Puppies in The Bayesian Probability of Star Formation”
Oooh, good titles all! Hmm, maybe instead of Brownian motion, we'll have Brindlian motion. Or Dalmatian ... Dalmatianian? motion? Oh, throw me a bone. I can't have any caffeine today.
I really want to see the video on this now!
0:49 Because the more massive the star is, the higher the FUSION RATE due to high pressure pushing the atoms together and fusing the atoms, burning the fuel much faster than smaller stars with less pressure at the core and burns a lot slower because of the fusion rate much lower.
Love your outtakes makes me feel more normal
A Bunsen flame burns blue because of emission from the chemical species present, surely. Not because it's hot enough to emit black body radiation in the blue region.
Yes. They aren't anywhere near hot enough to be blue hot. There just isn't any soot to glow yellow because you have complete combustion.
That is my understanding.
The Internet is not giving a solid answer for the maximum temperature in a methane Bunsen burner flame, but it looks like the various answers top out around 1800K. 1800 K would produce orange black body radiation.
I take it this is a deliberate mistake to make sure we're paying attention? Blue flame is due to emission lines in flame species, yellow/white candle flame is soot particles incandescing, oxy-acetylene torch flame is hotter and basically white, to incandesce blue you need to be much hotter, in an electric arc perhaps.
@@markholm7050 It is just barely possible to melt a copper wire in a small methane flame, if that helps you.
Great video!!! Could the hot gas created in these events ever get cold again in any sort of realistic time frame?
12:00 This portrays one of the reasons why I love your videos so much.
your talking about agn reminds me of the time i was standing under a very low fast moving & ascending funnel cloud that had just been a tornado carved a trail through a cornfield. it felt like a blow torch of hot air on my face & my ears popped
Haha, the Indiana Jones of physics... "It belongs in a laboratory!" ;)
Terrific video Dr. Becky! Now I can't wait for "Quenching 102". That Dog analogy was right on point! BTW, my guess is that you are heading for one of the Telescope Observatories either in Hawaii or the one located in So. America? Anyway, wherever you are headed, have fun, be safe & learn a lot.......... 👍👍🐕🐕
The Universe isn’t old enough...
for galaxies to have lived long enough, to die.
Wow, loved it
Whirlpool galaxies are particularly worrying though...and they can't be recalled either...
If the gas is heated, can it eventually radiate enough light that it will cool enough that it will form stars again?
This is a really interesting subject that you don't hear much about, ever. Thanks for teaching us about it!
Yeah, it's not the topic that draws headlines... Those time scales are so long, and the processes so gradual that we haven't had the technology to look for long enough to see a difference happen anywhere, outside of single events like supernovae.
Question: on a long enough time scale, won't galaxies who's gas has been overly heated eventually cool down via radiation to the point that the gas begins to gravitationally collapse again and set off a second life of star formation?
That's fascinating to know about the colours of galaxy can be representative of their age and what stars are in there. I'll bare that in mind when I take photos of them! Good to know.
Btw the puppy analogy? On point 👌
AstroFarsography
Kittens could also work, especially since we already have the metaphor “it’s like herding cats” in the English language.
You were mentioned on the Philip Defranco show the other day and I smiled. ;) Always fun to see youtubers you follow mention the other one. It was in regards to your tweets about the standing brooms or something.
I saw! So cool 😂
Standing brooms???
this probably wont get the most views, but imo this is the best video you've ever made, I really learned a lot and it's such a fascinating topic
Dr. Becky you will have 1M subscribers at some point! This was one of my favorite shows so far!! AGN, a tempest in a teapot. This is very exciting, seeing how modeling drives observation, and observation drives modeling. It would be fascinating to see a more of these walkthroughs of the multi scale (very small to very large structures) modeling that you and your colleagues are doing! As I watched this I suddenly realized that my view of the universe felt more integrated and I almost felt aware of the dynamism happening at greater scales than I normally conceive of when I gaze at the night sky and ponder. Truly one of my favorite videos you’ve done so far.
Becky. You are an absolute joy to watch and to listen to. Thank you
Wouldn't a dead galaxy be composed of mostly heavier elements making fusion more difficult and much less efficient?
Older galaxies will have more heavier elements, but will still be mostly hydrogen.
If a Galaxy is quenched because the interstellar gas was heated too much, in the very long term could the gas cool off enough for star formation to be restarted?
I would guess that either the universe isn't old enough for a galaxy to be revived in such a manner or that such a process would form stars infrequently enough that it couldn't meaningfully be called a revival, or both.
I love your Hon Solo outfit and I love that you talked about it.
So good to see you again Becky. Hope you had a great Christmas and New Years.
Can't the gas eventually cool down again? Even if it's a very long "eventually"
Yes, the heated gas will cool down over the course of hundred of 1000's years to billions. But, once cooled it's density will be almost uniform with variations probably a few orders of magnitude less than it was before the heating. Then, it may take several billions of years before any cloud become dense enough for star formation can resume.
Sounds like Dr Who time scales. Easy for a TARDIS.
@@Kualinar It is also worth noting that as the gas cools it begins falling under gravity again which funnels much of that gas into the galaxies core where it can trigger AGN activity there are some massive galaxies which show evidence for episodic activity switching between feeding and quenching through outflows
@@Kualinar I think I understand. My thinking though is that we know the sun is at least a 4th generation star due to it's high metallicity. This means at one time it was part of a star that blew up, that gas became another star rinse and repeat until we got the gas forming what would come to be called "Sol" by the mostly harmless, not so hairy apes from a rather boring planet in a very uninteresting arm of the galaxy.
@@kingblondie7075 Did you know Ford is currently working on a city car version of the Torus. Much smaller that the original Torus it will be called the Ford Tardis. The catch line will be, "You'll sear it bigger on the inside."
Very good. Even a little easier to understand than Anton, whom I love. The outtakes are a riot.
Interesting video!
However, there's one thing I'd like to know: You say that after the gas is heated it's not possible to be used for star formation anymore. Obviously at short timescales I will agree. But what about the long run? Couldn't the gas just cool down (e.g. by losing entropy due to photon emmission, or the like) and then when it has cooled down, form new stars, just much much later? In this picture it wouldn't seem too unlikely that even after a galaxy has fallen into a hot slumber, it could be woken up again after some cool-down period and continue producing new stars.
I was thinking along the same lines. I expect things were pretty hot at the big bang yet galaxies did eventually form.
> losing entropy
More like gaining entropy, and _losing energy._
Dr. Indiana Smethurst, adventure astrophysicist. Has a nice ring to it. :)
u make every outfit look good Becky... i hope u know that is meant as a simple compliment and nothing bad... as a nice person i enjoy complimenting people on the way they look because SOME work hard on it
Does the hydrogen thrown off from dead stars eventually cool down so that it can form stars again? Maybe from the energy lost from emitting radiation?
Many times, but not always.
Wednesday evening is the new Nature journal issue and also new Dr. Becky video. A double pleasure.
By the way, today's Nature has the Galaxy-scale gas wave paper we heard first about on this channel.
So happy to have found your channel. I have felt like a black hole accreting everything that you’ve made available. Love your videos, the way you explain things, your voice and yes, even the Harrison Ford outfit. ⭐️
Such a great video! Once again, thank you for all of these! My guess for your undisclosed trip destination: The Royal Observatory?
Dr. Becky I love your outtakes at the end of your videos.
Ah! Will your puppies become dog stars like Sirius?
You cannot be Sirius, Maaan!
> puppies become dog stars?
To see that would be _the cat's meow!_
Love how you plugged the blue flame Bunsen into the blue tap
Two observations: (1) the puppy pile force is the strongest observed force known to man (2) 100,000 year lifetimes for really large stars is interesting when it's said that it takes about that long for photons to get out of the core of our Sun due to the density, etc etc.
Well, there is a French movie called, "Blue is the warmest color."
Puppy analogy was on point 👌
"Bender event". Technical terminology, write it down
Another awesome video! ❤️
How much does the temperature of the gas raise before it becomes unusable for star formation?
Three questions:
- Are stars equally distributes across the spectral types or is there a distribution curve that we know of?
- Is the spin of a black hole enough to force it into a flattened-spherical shape like earth or is the gravity so overwhelming that it remains perfectly spherical?
- Is the spin of the accretion disk related to the spin of the black hole or could the black hole be non-spinning and the 'stuff' just spirals in purely from the gravitational forces with no influence of the black hole spin, or are both interconnected in a way?
Question: When a star dies and its gas is recycled, isn't it poor in hydrogen? It seems to me it would be like a fire in a sealed container, eventually there isn't enough oxygen. Can a cloud poor in hydrogen but rich in helium achieve fusion?
I honestly thought only increased metallicity of stars would determine galactic quenching. Thanks Dr. Becky! Although I do want to add if supernovae can also prohibit star formation in nearby gas cloud besides just simply heating it like what happened to pillars of creation.
I was wondering about this too. I assume stars can only form out of hydrogen & helium, and these materials are constantly being fused into higher atomic number elements, so a galaxy eventually runs out of ingredients no matter what?
I guess a lot of stars will go supernova long before they've used up all their hydrogen so maybe it actually doesn't deplete very fast compared to some of these other mechanisms?
Thanks Dr Becky, I enjoy the logic and simplicity of your presentation. Keep the videos coming please.
So interesting to me as a cosmology geek but find it hard to fully grasp some of the concepts, I appreciate how you can explain things in an understandable way!
So how hot is hot as far as the interstellar gasses? We were always told that space is an incredibly cold place.
Hot, about 1,000,000K or greater to emit x-rays. Space is incredible cold, roughly 2 - 3K. Heat is an expression of energy. If a gas molecule is highly energised it is "hot". There may only be 1 molecule in a volume of say a cubic meter so even though it is incredibly hot the empty space is frigid. Incredibly hot and also incredibly diffuse gas. If you were in the corona of our sun which is roughly 10,000,000K but were shaded from the direct effect of the sun you would freeze to death and not burn up.
"Galaxies can die?"
Not on my watch damn it!!!
We learn a lot from astronomy & cosmology, like how barbecuers follow the motto of red stars:
"Low and Slow!"
"He who controls the Spice Girls, controls the Universe."
Do they play Arrakis Roll?
It's official Dr. Becky. You are the most adorable TH-camr on the net! And with all those smarts?!? Simply Irresistible !
Can we clone a few million of her?
The Excited Puppy star formation model and Galaxy Benders. I sense a paper coming.
You had a shout out on Philllip defranco's show yesterday....just FYI!
Astronomy timescales are difficult.
For exmaple you have galaxies rotating. But how long does that take because galaxies are giant. How many orbits do they get in a lifetime before some merger event disturbs it again? One or two maybe?
Star life cycles are different as well and some longer than our universe is old so far. The whole star formation simulation you showed only takes a few thousand years.
emoji galaxies were a great visual aid!
I've got a query that came out of watching the animation of the two galaxies colliding. What absorbs the potential energy of their approach such that they end up merging? If none of the stars are, statistically speaking, going to collide, then should we not expect that the total momentum is conserved after the first collision? Then the stars would fly off in scattered directions as fast as they approached. Evidently, observations show us that this is not the case, so where does a colliding galaxy's momentum go? And thank you for your very informative videos.
It goes into the changing of the stars orbit from the ordered slower rotation to the more chaotic “beehive” like orbits I mentioned
@@DrBecky Much appreciated. Thank you.
If overheating is a quenching event, wouldn't it only be temporary, as things would cool over time? Or would the timescale for such cooling be past the ...end of the universe?
Really interesting description of things, but I'm left wondering how this combines with the conservation of energy... the energy cannot be destroyed, however it can be radiated away, which would mean that the "central" (yes, I know) galaxies would keep going for longer, but also where the energy heading "out" (this gets conceptually worse) actually goes - as in what is there?
I have probably given myself an instant headache thinking about this.
1:30 I have to call you out on this one. The color of a flame has little to do with its temperature and more with complex photochemical and thermodynamical processes occurring during the oxidation of the fuel. Bunsen burners use propane and butane, which in ideal conditions burn at around 2000K, (although Bunsen flames rarely exceed 1500K) and acetylene torches around 2500K, all well below the black body radiation temperature corresponding to blue, around 9000K-12000K.
Otherwise great video as always.
Potential completion of the Periodic Table of the Elements:
I currently believe that there are 120 chemical elements in this universe. If a person were to look at how electrons fill up the shells in atoms: 2, 8, 18, 32, 32, 18, 8 (seven shells), and realizing that energy could freely flow in this universe if nothing stopped it from doing so, then a natural bell shaped curve might occur. An eighth energy shell might exist with a maximum of two elements in it, chemical element #119 (8s1) and chemical element #120 (8s2).
Chemical Element #119 (8s1):
#119 I put at the bottom of the Hydrogen group on the Periodic Table of the Elements. It only has one electron in it's outer shell with room for only one more electron. Energy might even enter the atom through the missing electron spot and then at least some of the energy might get trapped inside of the atom under the atom's outer shell.
Chemical Element #120 (8s2):
#120 I put at the bottom of the Helium group since it's outer shell is full of electrons. It might have some of the properties of group two, Beryllium group (Alkali Earth Metals group) since it has two electrons in it's outer shell; as well as some of the properties of the Helium group (Noble Gases group) since it's outer shell is full of electrons; and if you look at the step down deflection of the semi-metals and where #120 would be located on the chart, it's possible #120 might even have some semi-metal characteristics. #120 would be the heaviest element in this universe. I believe chemical element #120 could possibly be found inside the center of stars.
When a neutron split inside of this atom, it would give off one proton, one electron, neutrinos and energy. The proton and electron would be ejected outside of the atom since all their respective areas are full. One proton and one electron are basic hydrogen, of which the Sun is primarily made up of, and the Sun certainly gives off neutrinos and energy. And note, it's the neutron that split, not a proton. So even after the split, there are still 120 protons inside of the atom and the atom still exists as element #120. The star would last longer that way.
NEEEEERD ALERT!! Im joking ofc...Very Impressive!
Questions: Do all galaxies eventually collapse in upon themselves, possibly go nova, to eventually generate a new galaxy? And 'if' so, is our determination of the age of the universe really only based upon the maximum age of galaxies? Does the universe truly eternally exist without any beginning and possibly never having an actual end?
Isn't the heating by quasars thought to be why things calmed down to a rate that isn't going to drive life extinct through frequent bursts of radiation from supernovas, like they are looking a very old/distant galaxies? And also, that quasars went out because they cut off their own food supply by heating it? That must be what you mean by the models needing it to work out correctly.
"RAM pressure stripping" is what my computer does, if im too much into "stuff" he doesnt care for...
Are these same processes what keep globular clusters from continuing to form new stars? (except for the smbh)
Okay, question about the “pristine” galaxy falling into a cluster that is surrounded by energetic, x-ray emitting gas: Why is that x-ray emitting gas stationary relative to the infalling galaxy? Why isn’t the gas also falling towards the cluster, such that it does not cause all these effects on the infalling galaxy?
The other analogy, rather than puppies, is trying to collect pre-school age kids after they have eaten too much chocolate cake at a birthday party! Great video. A fascinating and complex subject that you made understandable.
Can you make a video about radiative and convective cooling in stars. (Bonus points if you talk about the CNO cycle)
Dr. Becky: a very good explanation as always, but...
... you mention several times the word "gas". That let me in doubt because if the gas is hydrogen, it will be usable to form a star. If it is helium resulting from hydrogen fusion on a dead star then it will not be easily usable on a new star.
So, besides the four quadrant explanation I missed some clarification about what gas you were thinking of.
HAHAHA The Puppy Metaphor is everything!
A new addition to the spice girls...
Brainy spice! 😍
What? The Milky War and Andromeda are in a void, but we're STILL heading for collision and galaxy death? This is an injustice!
May I point out a Bunsen burner, in contrast to both a candle flame and a star, does not radiate like a black body. The blue colour is a particular electronic transition.
Oops, I think you mislabeled M81 as M33.
Beat me to it Argus. Noticed the same error. Still love your videos regardless of a little mislabeled galaxy, Dr. Becky! I’m sure M33 didn’t lose any sleep over the error. 😊
Knowledge for the sake of knowledge with zero practical purpose? Doesn't matter. You are so charming I would watch your videos just for the pleasure of watching someone talk about subjects they obviously love. Everyone should have a career that excites them. What a wonderful world that would be 😁👍👍
I love how clever Dr Becky is making me, I love your videos they have so much information☺️
If Dr. Becky was my teacher I would never want to go home. Because I would love to continue hearing her in my class.
I guess you have never seen "pinwheel puppies enjoying dinner" ? It is worth seeing by all and is not unique but looks just like a galaxy, @Dr.Becky.
Hey Becky, the sun has a heliossphere, do galaxies have a galaxysphere around them from all the combined starsystems?
I am a complicated man. When I see Dr. Becky's video, I go through all the 21 minutes of it and then I hit like.
Explaining the ?. This is why I like your channel.
Those old galaxies have reached a gravitational equilibrium with its parent singularity thus countering one another's forces and leaving a net zero that essentially stops any pulling action by the gravity pit of the singularity leaving the rest of the galaxy rotating under its own momentum although still gravitationally bound as whole complete entity. It takes the energy to compete away and everything stays as is and dies.... At least that's what I think.
151 comments already! Not fair, I am still watching this interesting video/lecture slowly and carefully. Wait me up guys ... @Dr. Becky, I am working on a video about how the mass of stars decide their number of years to live @AstroGate بوابة الفضاء if you are interested in a Cameo
9:15 NEVER? :o
Why not? Wouldn't it cool and condense eventually?
I came down here to make a comment like this. I hope she addresses this question.
Exactly my thoughts. It is glowing, therefore radiating heat, and hence must cool down.
Maybe as it becomes defuse it gets trapped in the gravity of individual star systems all across the galaxy? In which case how/why would it ever manage to leave these systems to become massive clumping clouds again?
@@realityvanguard2052 interesting idea, but I have never heard an astrophysicist talk about this type of effect.
Just had an idea about FRBs. Could it be as simple as gravitational lensing of radio waves?
When a radio wave source lines up with a massive object from our perspective. Would love to hear your thoughts.
Thanks doc -- you are intellectually stimulating -- humorous -- and quite lovely -- take care -- stay safe and -- don't stop!!!!!
Any analogy with puppies is a good analogy.
Looking forward to the live q and a 100k subscribers celebration!
Hey Dr. Becky, here's a question might be interesting: Does Dark Matter influence the 'ignition' of new stars? And if so, could 'ripples' in the patterns of ignition of new stars in a galaxy be used to help 'see' where dark matter might be more concentrated or less concentrated in a galaxy (or anywhere stars might form)?
I ask because I know that when two clumps/masses of Hydrogen collide, the increased density triggers star ignition. So maybe a clump of dark matter 'colliding' with a mass of Hydrogen could likewise trigger new star ignitions where otherwise left alone, the H cloud would *not* have ignited (as many) stars.
For example, suppose a big, enormous, but 'invisible' blob of dark matter just so happened to be plunging through a certain portion of the Milky Way right now, at relatively high speed (in my mind's eye, I'm picturing the famous Bullet Galaxy photo showing how DM might form such 'free-floating' high-speed blobs). Perhaps its leading edge might cause a measurable increase in the rate of star formation in the disk of the MW, which, as it passes through, would expand into a circle or disc, and then as it passes all the way through it would shrink or just fade away.
Two things that it reminds me of:
1) The phenomenon of Fairy Rings, which are literally expanding rings of mushroom formation (say, on a patch of forest floor), over time, as the underlying fungal mass of rhizomes (within the soil, and thus 'invisible', thus paralleling DM) grow and spread out from a central origin, using up all the nutrients along the way, such that night after night, the centre of the Fairy Ring doesn't have enough nutrients (paralleling Hydrogen gas) to form mushrooms (paralleling star ignitions), but on the edges of the fungal mass there's still enough nutrients to form new mushrooms. Hence, you see a nearly perfectly circular ring of mushrooms that at first glance seems to have been arranged by 'someone' (Fairies, obviously!) to be that way.
Maybe a similar pattern could be detected within galaxies or nebulae to spot the movement of 'clumps' of dark matter?
Does DM even form clumps? It must, at *some* scale, right? Do we know if it can form smaller-scale clumps?
2) The analogy of a 3D entity interacting with a 2D Flatland, where the '3D entity' in this case might be a blob of DM, and the '2D flatland' would be the basic disk/spiral shape of a galaxy. As the 3D enters the 2D, suddenly a 2D object pops into existence, from the POV of any flatlander. Then the 2D manifestation grows and morphs its shape, as the 3D entity passes through flatland, then it shrinks and finally disappears.
Here the analogy is that the appearance of a 2D manifestation (or projection, in geometrical terms) would be the equivalent of observing a sudden (in cosmic time scales anyway) increase in star ignitions, then that starburst region expands, then shrinks and disappears.
Any of this make sense in terms of the actual physics of DM? Could such an observation actually be made to spot more 'structure' and motion within otherwise very 'fuzzy'-seeming 'halos' of dark matter? Or maybe the lack of such effects might be indicative that DM truly is very fuzzy, maybe something like how electron clouds are inherently fuzzy, and that it actually is physically *unable* to form small-scale structures?
'Go BIG or go home bender' now you're talking. Absorbing as ever Dr B.
Also, as stars die don't they make heavier elements, up to iron? The darker, harder to see elements would theoretically never be formed into stars again. Each successive death would produce smaller amounts of available fuel, right?