The Evolution of the Modern Milky Way Galaxy
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- čas přidán 31. 05. 2024
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When we scan the heavens with giant telescopes we see galactic cannibalism everywhere. We see moments that appear frozen on the human timescale, but are really snapshots of the incredibly violent process of galaxy formation. This is how all galaxies are made. We can piece together a pretty good understanding of this process from countless snapshots. Looking into the distance means looking into the past, so it’s possible to stitch together a Frankenstein flip book of galaxy evolution.
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Written by Matt Caplan & Matt O'Dowd
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Just in case you jump straight to the comments the moment Matt says "space time," make sure you check out: search.pbsspacetime.com/ It allows you to search the entire Space Time catalog for any word or phrase and get links to the exact time code in any episode it's mentioned. And it was built by a Space Time community member: Vegard Nossum! It's an incredible tool that we hope the entire community enjoys.
That's awesome! I was literally wanting this yesterday. Thank you Vegard!
how can you talk about the galactic habitable zone . if the Galaxy could have gotten material from magulonic clouds
Love microcephalis joke!
Ya'all, try Sci Man Dan, Sci Show, Joe Scott and UpisnotJump
for MORE SCIENCE FUN.
Wait, isn’t the moon highly involved in the rise of intelligent life on Earth, if the Earth Moon system wasn’t a highly skewed binary system, then Earth would have been tidally locked to the Sun long ago, hence preventing any life from arising anywhere except the thin ring of the twilight zone, and a totally unfavourable climate for the evolution of more complex forms of life altogether.
"Looks like this Galaxy suffered from..
* Matt takes off sunglasses *
...A light lunch."
🎶YEAAAAAAAH!🎶
Seriously underrated comment
😁🙌
It's so amazing to realize that milk way isn't ""just"" the disc we often see but a whole gigantic and dynamic system. The universe just got bigger for me
Imagine how it was like for Hubble when he learned that our galaxy wasn't the entire universe, but that the universe was comprised of countless galaxies
Feels good didn't it? It's why I love watching videos like this
Or maybe you've been shrinking?
Its even more amazing to realize its also a delicious chocolate bar.
To think that our planet is traveling thousands of miles an hour around our star and the entire star system traveling half a million miles an hour around the whole of the milky way and the entire milky way is traveling millions of miles an hour through spacetime all while we are just chilling on CZcams is mind blowing for me O.o
It’s kind of crazy thinking about how violent the motion of the galaxy is. Usually, they are seen as being pristine and unchanging due to the massive scale at which they move.
It’s a very slow process.
@@bngr_bngr Only from our point of view
usually by whom?
The most recent minuteearth video addresses something similar re: tectonic plates.
You need chaos for order to exist.
As a physics graduate, it’s nice coming back to these sorts of videos. You get a more conceptual overview of specific topics, without getting bogged down to much in the mathematics.
As a Math grad, I find this mildly offensive.
@@Iamrightyouarewrong Don’t get me wrong I love mathematics (if I didn’t I wouldn’t have majored in physics) but sometimes I just like getting a conceptual overview of a topic. If I want a deeper understanding of that said topic, then that’s a different story.
@@Iamrightyouarewrong As an art grad, I find this all mildly confusing.
@@N7_CommanderShepard the math and conceptual overview go hand in hand, one can't be without the other, if you're just throwing around tensor indicies or path integrals you dont get the full picture same goes for just looking at the concepts without the math, you need both at the same time in order to actually understand it. But that doesnt mean you can't completely understand it without the math, you definitely can get an idea of how it works.
As a business grad and science teacher im glad ppl like you are able to do the math bc thats the reason I didn’t study physics in university . So thanks
I was on a yacht in the middle of the Atlantic when I first saw the LMC/SMC. I too thought they were water vapour at first, then when the penny dropped I was moved almost to tears. They're something I had read about since childhood, and seeing them for the first time was an ephiphany.
I know exactly what you mean! My first time was a crystal-clear night on the shores of Lake Titicaca in Peru, and it was my first look at the southern night sky. Lo and behold, there they are, just like you always read about, and they're *real*.
Man... I really need to find a place that's dark enough for star gazing.
@@volbla East Coast US here, but I had the fortune of going to Haiti and Bolivia in years past. The sky at altitude in Bolivia was almost overwhelmingly beautiful and complex.
When I was in my early twenties I went to a bar in a country town to watch a friend play a set of music. This was 80kms outside of Melbourne, Australia - at about 1am the night was finishing and I was helping my friend load his gear into his car and then having a smoke and suddenly ALL the lights went off and this was on the one 'main st' in town and everything went off. Something happened to a transformer or a street pole and there was a power outage, but after a few minutes I looked up and was awestruck. It looked like a whole spiral arm of the Milky Way galaxy was visible over the sky.
There's something about seeing the night sky with your own eyes. I shed tears when I first saw the colors of Jupiter and the rings of Saturn through my telescope. I know of no equivalent in nature that so reliability bring us to tears.
oh, i didn't mean that "galaxies shrinking" thing as a hypothesis, but rather as a way to visualize what expanding space looks like, because some people have a hard time shaking the idea that if the universe is expanding it must have an absolute center somewhere to "expand away from."
Kinda mad I didn't think of this a long time ago.
That's an interesting model, and I am trying to think whether it's equivalent or not. It seems like it would be. The laws of gravitation remain the same, and matter still clumps if it's close enough.
But you can imagine that, as it shrinks, it is therefor further away from other matter - the amount of shrinking therefor "waters down" gravity's *effect*.
I wonder if that's clearer.
Is the math equivalent? If so, it doesn't matter, right? Or are the equations non -symmetric wrt expanding space / shrinking contents?
I get what you are saying. It's like the rubber sheet analogy for gravity. Even though it's not really like that, it's a way to visualize the concept so that it doesn't fry our brains.
I think that's not a good methaphor, because those systems would not be equivalent. A "srinking" space would reduce the distance between particles, that could only be compensated if particles iself srink so space distances could be RENORMALIZED. If not, quantum effects would say that's not possible (for example, distance between electrons and nuclei, or distance between quarks inside a nucleon, etc).
An expanding Universe that does not expand in gravity-ruled regions does not require such distance renormalization tricks for compensate these effects.
There's really no show, from any source, that I look forward to more than a new episode of PBS Space Time.
Esoterica is my second
Seriously. There is nothing that pleases me more than when I see that blip show up on my phone that there's a new episode!
Im always pretty happy when skylar vox drops a new show, but PBS spacetime is good too
I'm in awe about how on earth were we (humans, specifically scientists) able to know all of this, to be able to describe such an intricate and complex process to such a minute detail in space and time.
And to think we would know 100x more if no one listened to stone age troglodytes thinking dark ages were the best and wanting laws to reflect fantasies of illiterate stone age goat herders writing a book explaining why you should genocide/enslave/mass rape all the other tribes, while killing funding of education, science, healthcare and history...
@pyropulse *sigh* I'm not gonna get into a dead end discussion about this.
Go find out how scientific knowledge is brought about, the painstaking process it goes through before being generally accepted and then we can talk.
FFS.
@pyropulse if you want to know where a lot of this comes from and the specific experiments used to prove it, go check the wikipedia for general relativity. Explains a lot, the experiments are actually very simple and intuitive, and rely on telescopes to simply look and see what up
They simply made it all up to deceive idiots with a fairy tale of globe earth
Clever monkeys we are.
I had a very similar experience on my first clear night in Queenstown, New Zealand. Not a cloud in the sky except one small fuzzy whisp that wouldn't move. That was the first time I saw the large Magellanic Cloud, what an amazing sight.
42 Distinct streams? Must be the answer to the question of life, the universe, and everything.
Douglas Adams knew what was up
Kudos to Vegard Nossum!!! I’ve been craving for a tool like this for everrrrr! I even wrote it on the last survey they posted here in the channel. Thanks a lot!
This episode made me (astronomically) hungry ... of new episodes about of Milky Way, our Sun, and our Local Grop. Great content Matt !!
Related to this, I also loved the episode of how the heavy elements of our Sun originated from a nearby neutron-star collision
galactic mergers operate on such a mindboggling scale of spacetime, but they also seem so reminiscent of molecular bonding and cellular reproduction
comparing the timescale between galactic merges and atomic merges is what makes me realize how relative time really is.
micro to macro and back again.
or rinse and repeat?....
naaah that's...
Haha! "Galactic Cannibalism" what a fun turn of phrase! x)
I'm just happy I can actually understand this video. At the start of this channel I felt very in my conceptual depth but lately about half of these videos are way too deep. It's not easy to study astrophysics as a side hobby...
You said that it's hard to think the Milky Way became this beautiful through such a violence, and I just went through such a crazy though-train. I thought immediately that it's not really violent because the stars don't touch. Then I went back, emergent phenomenon by emergent phenomenon, first galaxies, then stars and planets, then rocks and trees and animals (including people), then molecules and atoms, then quarks and electrons, and I realized how we consider things to be violent even though nothing ever touches. What we call "touch" is basically "interact with the EM field". So yeah, galaxy interactions are "violent", or, at least, are as violent as anything else we consider to be violent.
This is incredible, I had no idea we knew the history of the Milky Way in such detail. The animations you guys do are stunning, you can sense the cosmic scale of it all in the simulated motions, thank you for making this research accessible to everyone!
Well said! This ep blew me away too.
14:10 Thank you, Vegard Nossum! That's really cool, amazing work!!!
Great time to learn more about our Galaxy! Happy Towel Day, you Hoopy Froods!
Happy birthday, Star Wars!
I used to observe Towel Day, but it's becoming more difficult over time.
This year I had to... throw in the towel.
Always keep a towel with you, it could mean life or death if you plant is being destroyed for a intergalactic highway.
I usually love the snark; heck, I love snark in general! Unfortunately the last comment response this week felt a bit heavy, especially since I’ve actually wondered the same thing as Evelyn and Jonathan Rose. After all, if the infinite universe is getting even more infinite while islands of matter within it stay fixed in size, why not think of the infinite universe as a fixed size and everything else inside it as shrinking? The fact that relativity is a thing should mean there’s effectively no difference between the two, right?
But it turns out the answer is a resounding “wrong,” and for a very simple, Relativity-resistant reason. That reason is that there are certain dimensionless values (such as the fine structure constant) that are … well, constant … in an expanding universe that would have to be variable in a fixed universe with shrinking matter. Since those values are constant in our universe, we know that the universe has to be expanding instead of the stuff inside it shrinking.
The correlation between these constants and the non-shrinking of the universe wasn’t obvious to me at all, and this isn’t the first time I’ve seen other people pose the same question. I honestly think this idea is common enough m that it might deserve a couple minutes of serious screen time.
Couldn't the constants also be adjusting themselves continously so that from one frame of reference they remain similar but from the outside frame they're decreasing? An easy one to consider is c. C would actually be decreasing from an outside frame as you progressed in the time dimension but inside of it it that is canceled by the amount of shrinking?
I actually don't know and am not a physicist so genuinely curious if there's any hard reason that couldn't be true. Because otherwise the "universe isn't shrinking because of constants" argument isn't very strong to me.
Matter doesn’t shrink
@@SigmundDali I think his point is that if the constants were changing, then we would be able to know since relativity would demand that fast moving objects have their constants change slower. Furthermore, the 3 fundamental forces would have to change in sink with the Planck length and probably the masses of all the fundamental particles, despite all of these constants appearing in different places in MULTIPLE different equations. All of these constants would need to be determined by a single shrinking or expanding value (that changes without breaking the equations).
That being said, is it really impossible for that to be the case?
That catalog search tool is awesome! Thanks Vegard!! ;O)-
Of course, thanks to Matt and the Space Time team for making these educational materials.
Tq PBS spacetime. I hope you guys use more illustrations like these. Today's was awesome. Tnx to the guys in the studio.
A searchable catalog of all Space Time episodes? I've been waiting for this for a long time.
Glad we get to see these awesome Magellanic galaxies in the SH. The Tarantula nebula is just my favourite of all time. It's utterly mind blowing.
Comment on comment response: A professors once mentioned that the moon and tides could be important for the migration of life onto land, since it sort of blurs the boundary. Is it really easier for life to adapt to a dynamic beach than a static one? Where do we find the most amphibian fish today?
For that matter, how likely is it for a rocky planet to have a surface of both water and land? It doesn't matter if a planet can support liquid water if it has no water. Conversly, technology would be hard to get started without a large supply of land fauna. It intuitively seems like a very fine balance. Enough water for multicellular life to evolve and flourish. Enough land to evolve an intelligence-centered tool user.
I wonder if this was also true for Earth's atmosphere -- too much atmosphere and you get Venus, but too little atmosphere and you get Mars, both of which are unfriendly to life (even if Mars turns out to have a few remnant microbes). With Earth being as massive as it is, it would seem to be a candidate for having an even thicker atmosphere than Venus. So maybe the Moon-forming impact was needed to splash off most of that atmosphere to get the remaining atmosphere down to a manageable thickness.
@@Lucius_Chiaraviglio Venus has a thick atmosphere due to its closeness to the Sun and a run-away greenhouse effect releasing co2 due to heat, and then trapping it. Mars lost its atmosphere over billions of years after it lost its magnetic shield and magnetosphere - causing the Sun to slowly strip/blast away what was once an atmosphere akin to Earth's billions of years ago. Not sure if there even was enough of an atmosphere on Earth when the Moon formation theory is thought to have happened to it making a difference. The amount of nitrogen in Earth's atmosphere, our placement in relation to the Sun, and our magnetosphere is more likely the reason why life could evolve here? I think?
But I'm no scientist.
@@LateralTwitlerLT You are correct about Venus, but what I am saying is that Earth might have ended up the same way even with half the solar radiation if it hadn't been partially depleted of carbon dioxide. Not clear if Earth's minerals would have been able to absorb all that carbon dioxide like what Venus has.
I think the magnetosphere importance is overblown, because Venus doesn't have a magnetosphere, and it has no trouble holding onto all that carbon dioxide. Mars is just too small, although arguably a magnetosphere might have helped it to hold its atmosphere longer, or at least done so for a planet that would otherwise be on the edge of being able to do so.
@@Lucius_Chiaraviglio Uhm.... Venus has a magnetic field, tho. And it generates a de facto magnetosphere for the planet. The interaction of the Sun’s solar wind with Venus' ionosphere produces or generates a "full-fledged" magnetosphere around the planet.
So your "hypothesis" does seem to be in need of a bit of refinement, me thinks.
But nice try.
(edit) cleaning up sentences, and grammar
@@LateralTwitlerLT The interaction of the solar wind with the atmosphere is the ONLY magnetic field it has, and it is much weaker than Earth's magnetic field. If this induced magnetic field was really what was keeping Venus from losing its atmosphere, it should have also worked for (and still be working for) Mars.
That sound effect at 9:31 almost killed me lol
Same here! lol
Same. My ears will take a wile to recover. Bad editing.
Perfect timing with this video, right before a major physics examination to calm my nerves
I really enjoy these episodes where I actually understand at least half of what's being said . . . thanks! 🧐
I love your episodes on astrophysics like this one.
I really appreciate the work of PBS Space Time. It’s why I was able to notice a minor mistake in the video clip of stars orbiting in the galaxy’s halo. As the galaxy rotated, the “randomly” moving stars all rotated uniformly around an invisible vertical axis instead of being influenced by the center of the galaxy’s gravity. Still, these videos are super informative. Thanks :)
It’s just so beautiful how everything is interconnected and interdependent.
The graphics department had way too much fun with this episode 😂
By far this is the best channel I’ve found for this kind of content. Fantastic channel.
Try the Fermilab channel, especially the series hosted by Dr. Don Lincoln. Less spectacular in its presentation than PBS SpaceTime but he's great at explaining complex concepts to the layman.
Sabine Hossenfelder's channel is also worth a check.
@@mugwump7049 I will check them both out. Appreciate the recommendations. Thank you.
@@guyfromnj You're welcome.
The closing comments to the questions: 11/10
The distances between objects in a galaxy is so great that galactic collisions are not actual collisions. However, there is a non-zero chance that collisions between star-sized objects could occur. What are the calculations of the probability that a collision could occur? How would these events be characterized? Have any of these events or the aftermath of the events ever been observed?
Please answer this!
Why do you make alt accounts to spam these questions?
A _very_ big star is still less than a light day or so in diameter; almost all stars are less than five light seconds across. Typical distances between stars are (dozens of) light years - and that order of magnitude is maintained as two galaxies move right through one another. From this you may extract a crude back of the envelope "exceedingly rare" that is borne out by more detailed calculations. Note also that the event of a head-on collision would be much rarer still. TV represents gravity as making things smash into each other, but gravity actually tends to make things swish past each other. The mathematical reason for this is that a straight line is a degenerate conic and the initial conditions that would put you on that trajectory have measure zero. It is possible, I guess, that two hitherto isolated stars capture one another and become a double star.
I sometimes miss power metal stance Matt. if galaxies colliding and being eaten wasnt enough to bring him back, I fear he may truly be gone.
Enceladus was a Giant, not a Titan. Same "parents" but the Giants were created due to the castration of Uranos by the Titan Cronos.
I didn't think he was a Titan, but was too lazy to look up. Thanks for mentioning.
This complicated business of multiple generations with Giants, Titans, etc. inflicting castrations, devourings, and what have you on one another is also found in Nordic myths. One could attempt to reconstruct the broad outlines of the original Indo-Europeans' mythical system, at least in broad outline. Also strange, isn't it, that we now all regard this as "obvious" nonsense, our cultures having been for the last two millennia side-tracked into Mesopotamian-Canaanite fairytales, which apparently it is offensive to regard as ridiculous.
Just the one parent as from the blood lf uranus' castration. Titans were Gaia+Uranus (mother+son) children, except by most accounts Aphrodite who was born or Uranus' genitals including progenitive contents falling into the sea!
(For every greek myth there are AT LEAST two contradictory versions, and that's just the written-down stories that survived, often not written during their inception centuries or millenia before Athens' heyday in some cases)
@@DrWhom Oh, no worries, the level headed among us refer to those modern religions by the correct nomenclature and accept them as the most recent in a long line of mythologies. Anyone with any idea of religious history can see the parallels between Canaanite myths and the Greco-Roman religions they usurped. It's clearly a case of one fiction becoming more popular than another while consuming the traditions of the former.
Vegard Nossum you are an absolute Madlad
Many thanks for the space time search engine Vegard! It is just what I needed,
So I guess the Milky Way's "dessert" by combining with Andromeda will be comparable to a pie in the face
It hurts my mind that gravity travels at the speed of light; we see that clump of 10 billion stars orbiting the galaxy and affecting it. To us the pull from that clump is coming from the direction where we see it, but with the galaxy being 100k light years across every other star feels it from a different location/time. And even with that our galaxy still ends up keeping a nice shape, or maybe that's just how it looks to us.
In a hypothetical system with 2 small masses, one being us, if a large mass that wasn't there before suddenly appeared forming a triangle, with it being a hypotenuse away from us but only a side length away from the other small mass. Would we see the other small mass moving toward something we don't know is there yet? Or does it just work itself out that no matter the geometry of the triangle, by the time the effect of the large mass hit the other small mass and it moved and its new movement became apparent to us, the large mass would already be visible to us? Or am I thinking about this wrong?
@@ZGorlock what you can "see" can also travel no faster than c
This video is easily in the top 10 of PBS Space Time.
8:30
Damn Milky Way, you got a THICC DISK...just sayin'...Imma collide wit dat!
-Andromeda Galaxy...probably...
Interesting. Questions:
Does the fact that the universe is expanding mean that galaxies will one day no longer merge? Hypothetical: If the universe WASN'T expanding, would all galaxies in the universe eventually merge into one galaxy?
Yes! And its even worse! At a very future point in time, our sun (well whatever is left from it anyway) will be a part of some super galaxy, and this gravitationally bound object will be the ONLY thing that could be seen. Past the edges of this super galaxy there will be void, and future intelligent beings will have NO WAY of knowing there is ANYTHING except their tiny (compared to whole universe) super-galaxy - and thus possibly no way of confirming that the universe is indeed expanding.
The expansion of the universe acts at scales where galaxies aren't gravitationally bound. It will divide the universe into 'lumps' of bound galaxies. Within these lumps dynamical rearrangement shows us everything must eventually merge or be ejected. So at some point all galaxy clusters will collapse into a single large galaxy and one day a single supermassive black hole.
If the universe were NOT expanding then its fate depends on how much kinetic energy matter has. Too much and things will flay apart forever, much like the expanding universe. Too little and everything must collapse in a /big crunch'. It was while investigating which of these applied that we discovered dark energy.
@@garethdean6382 "Too much and things will fly apart forever" Wouldn't things just fly into each other (and that would calm things down)?
9:30 PTSD is back,
Love the movie posters! You are a true star in your own right! 😃
Just imagine the spectacular night sky views of a civilization in the Magellanic Cloud
As someone who's always been in the U.S. I've always wanted to be able to look at the night sky in the southern hemisphere
I’ve been to Peru several times but had no luck seeing them. They are very low in the horizon. You have to go down into Chile or Argentina to seem them.
this is one dream you can make true!
@@bngr_bngr Eh? Just wait a few hours for them to get higher.
I really like this macro-scale astronomy and cosmology in PBS Space time so much more than theoretical subatomic particles and speculative quantum physical phenomena. Great episode!
To each his own.
I mean, it's basically all the same thing. We just haven't figured out the golden thread, so to speak.
@@jezlawrence720 you assume there has to be a golden thread.
@@bngr_bngr well, the way I see it I'm assuming a hundred years of physicists riffing on Einstein and thinking the idea has enough promise to build giant supercolliders to figure it out probably know more than me!
To be clear yes it is possible they'll be wrong (science!!! :) ), I'm not an idiot. But at this point it's very much like claiming it *might* be the case that humans aren't amplifying and accelerating climate change.
Violence isn't the answer, its the question and the cosmos always answers with slow but enthusiastic "yes."
It’s my belief that our moon helps the Earth’s core remain molten, by pulling on the planet with tidal forces. A molten, rotating core means a strong magnetic field, and a good strong field gives protection from the suns radiation that could be harmful to the formation of life. Add the fact we are the perfect distance from the sun, and our star is stable (not variable light, or too massive). Also add the fact that we have planets like Jupiter to draw away the larger meteors that would have impacted us and stalled evolution. All of this together makes us very, very lucky in our circumstances.
These videos are always amazing! Keep up the great work PBS Space Time team!
19:40 Wait, accepting wrong scientific explanations makes your brain shrink? wow, mind blown! I can feel it shrinking as I jump to conclusions about this already!
Haha nice
Its shrinks to the power of x with this one. What does irony do to brains? Too much can cause rotational transformations of the prefrontal cortex for sure
Thank you for this marvellous episode PBS Space Time! I always thought that the Milky Way was a somewhat calm galaxy but this episode opened my eyes. I wonder what our galaxy looks like to astronomers of other galaxies. The Fermi Bubbles like a crown, the Small and Large Magellanic Clouds like satellite galaxies and last but definitely not the least - the shredded galaxies with which we collided all looking like heavenly rivers bathing the Milky Way galaxy from over and under. Also, the scientists who used the data from GAIA telescope are so smart! They deduced almost the entire history of our Milky Way Galaxy just by observing the stars in it!
Nice. Vegard Search is such a good idea put into practice. Well done!
It is so amazing how we are able to figure out how the modern milky way come to be. I know we are using equations and super computers. All this clever work before we see it.must be enormous.respect! By the way, a clever way to tell people to be fact oriented.
_"By the way, a clever way to tell people to be fact oriented."_
If you mean the comment at the end directed at Jonathan Rose and Evelyn, I thought it was a tongue-in-cheek way of telling them to stop talking sh*t. 😁
@@nagualdesign Six one, half dozen the other 😅
@@nagualdesign exactly what I meant!
I guess you exactly know what I meant. I'm not here to shoot the breeze ☺️
Could the passing of a galactic core through the Milky Way, such as with Sagittarius Dwarf Spheroidal Galaxy, affect the orbits and positions of stars that had formed in the same stellar nursery enough that we couldn't, using our current criteria, conclude that they formed in the same stellar nursery? If so, what are the chances that this might help explain why we haven't had much luck finding stars that formed in the same stellar nursery as the Sun?
Not all stars are formed in a stellar nursery.
@@bngr_bngr Some are born at home 😉
@@bngr_bngr Some are born at home 😉
Aside from globular clusters, stellar nurseries don't hold together well, even without extragalactic perturbation. Most stars should see their siblings scattered across the galactic disc because a small difference in orbital speed adds up over time. It's quite difficult to spot stellar twins of any star we know of that's not in a cluster massive enough to avoid disruption.
Really fun episode! I'm doing my PhD on Galactic Archaeology, happy to get some spectral analysis discussion on SpaceTime 😄
Way to go Vegard Nossum!
I hope someone from the Andromeda is also freaking out about this merger, like i am right now!!
Way, way more probable was that abiogenesis started in the muddy atmosphere of the Hadean eon, what with all the ash in the atmosphere and a very large volume of liquid water in tiny droplets overcasting the Earth in a giant cloud (maybe containing all the water that now occupies the oceans) over the water-vapor-saturated lower atmospheric layer. All kind of variable parametres there, much energy gradient, and zillions of droplets, each a tiny lab to experiment with abundant nucleic bases and catalytic clay substrates to form an immense variety of self-catalytic polynucleotides and no need of cell membranes, which UV radiation would even increase. Compare this huge volume to that of hydrothermal vents where chemicals dilute in a short distance.
This is probably my favorite video on PBS-SPT so far! Really mind blowing stuff, and new to me, so thanks so much for this episode!!
That search website is absolutely amazing
I've seen the Milky Way shown as a barred spiral, but not with consistency. Do we know how big our bar is and when it was formed in our galaxy's evolution?
I believe the understanding that it's a barred galaxy is a recent thing. So you may be viewing older literature before that determination was made.
We've had solid evidence for the bar for about 20 years, and some hints before that. But even now we don't know exactly how big it is and a lot of our galaxy's structure is hidden from us. So an inconsistent portrayal is expected.
Let’s learn something 🧐
Brilliant as always. You show stars above the galaxy orbiting some strange center axis. That Can't be right. They have to orbit the center of mass. Your simulation is clearly 2D
Matt and PBS Spacetime are the greatest gems on youtube.
The moon causes some tidal heating of the earth's interior. Back when life was starting, the moon was closer and the tidal effect was a *lot* greater. Our oversized moon probably did contribute heat to the geothermal vents at the ocean bottom.
That’s one wacky idea.
Doesn't most of the internal Earth's heat and volcanism come from nuclear processes that happen in the Earth's core?
@@ThatCrazyKid0007 Yes, that is now the case. But the moon used to be much, much closer.
i am not capable of doing the math, but i intuitively (lol, at least) disagree. first of all, tidal heating should be greatest at the surface, because that's where the moon's gravitational "lever arm" is strongest, and then its strength should decrease rapidly with depth due to the inverse-square law. secondly, currently half the earth's heat is due to the decay of radioactive isotopes, and thus _that_ must have been far higher in the distant past, due to the fact there would have been much much more radioactive material present, and which has since decayed leaving us with what we have today. lastly, the earth-moon distance increased logarithmically, so most of the distance was created very quickly (from earth/moon's perspective) after the initial consolidation of fragments into the moon, and again, the inverse square law.
@@ThatCrazyKid0007 From what I understand both are still important processes.
When you talk about mergers as meals, it kind of puts a shadow on the possible fact that these meals are in the vicinity because our galaxy group is maturing into possible a single-like entity or let's say its final form. How vast is the distance between galaxies? Was it likely for our galaxy to run into another galaxy when it met sagit dwarf or gaia 5 bn years ago, or were they always in the vicinity, fulfilling their very slow motion of becoming one. Is there such a distinction of mature galaxies that have gathered every galaxy in its vicinity?
Not counting the smallish satellites of the Milky Way, the nearest major galaxy is Andromeda. That's two million light years. Both are about 0.1 million lightyears across, so the distance would be about 20 diameters. Close! There are regions in the universe where major galaxies are even closer together, and there are sparser regions. By the way, yes, we are on a collision course with Andromeda.
I don't know if we have a word for a galaxy made of many galaxies, since the galaxy doesn't seem to care very much about the exact size of itself, but perhaps one that is significantly larger by some order of magnitude would be called a supergalaxy? It's entirely possible sometime in the future a galactic supercluster could om nom nom it's way into a single hypergalaxy.
Wow Matt, you were savage when you made your last remark about Science Communication. I have never seen your fierce side.
I was just thinking of watching space time and voila, a new upload!
So don't most galaxies have black holes at their centre? Does that mean there are errant black holes floating around the Milky Way? Not freaking out just wondering.
Yes, there are free-range black holes I've heard 😄
It seems likely that the MW's SMBH swallowed the BH's of the other galaxies, assuming they all had them.
Yepo. The James-Webb discovered a galactic collision in which the bigger galaxies black hole yeeted the smaller galaxies black hole away
@@ESL-O.G. rouge? Like...red holes?
@@jorriffhdhtrsegg Or it was mistyped. You decide
"The more we know the less we know"
Reason is, when we learn more about confusing topics, we still have more questions then answers coming up.
Reminds me of what one of my Computer Science Professors told me about Novices, Intermediates, and Experts/Masters of a field think.
Novice: "I have sooo much to learn..."
Intermediate: "I know everything there is about this."
Expert: "I have sooo much to learn..."
@@rvaughan74 dunning kruger effect!
All answers can be questioned
Not all questions can be answered
@@mastershooter64 Wouldn't that be more of the novice going "I know everything there is about this" ?
A gorgrous, revelatory, unforgettable episode. I live in the Sierra Foothills and am blessed to see the Milky Way regularly and photograph it sometimes (in the warmer weather!). The splendor of what you folks have put forward here will transform my MW watching moments since I will now know much better the complexity of the cosmic dance before my eyes. Thank you!
I envy your luck. I live in a rainy city, except in summer, when it's smoky ...
@@thehellyousay Thank you for taking my memory back to this amazing PBS ST episode -- I'm now about half way thru watching it again and equally as impressed as b4 by all the distant-past galactic sleuthing they're able to do. We actually have that darn smoke problem here too, and sometimes straight-up terrifying close calls (with evac) from wildfires, though I'm grateful to report that this year we've had a rare smoke-free, nearly threat-free summer. The wet winter and smarter, more-assertive fire surveillance by CALFIRE seem to be benefitting us. Clear sky's to you!
Marvellous video. Pretty easy to follow with simple physics that is not too wacky, but great exposition of our complex space-time neighbourhood. Mind expanded.
I like how mysterious is our universe rather I should say parallel universe or multiverse. The way he explains these things spark curiosity for everyone.
Big bang first
When Matt said "Find a dark (k)night in the Southern Hemisphere and you'll see it too" the first thing that came to my mind was "Australian Batman"
He doesn't fight Australian Joker, just the wildlife is challenge enough.
Thank you! Appreciate the poetic nature of the video.
Brilliant scripts, and great delivery Matt, keep them coming!
I just wanted to say thank you! What a fantastic episode!
The sound effect at 9:31 scared the crap out of me.
Wow that PBS Space time search website is amazing! I frequently reference Space Time's videos when I'm learning a new physics topic and it sometimes takes a while to find the episode I'm looking for. Amazing tool!
Fellow Australian here. A minor point: atmospheric clouds are not water 'vapour' - they are either liquid or solid (ice) water in upwards air current suspension. I'm sure you know this 🙂 Gaseous water is invisible.
The orbiting streams are mesmerizing!
The existence of these streams satisfies me deeply.
New to the channel. Really enjoyed this video. Ty for the upload.
Thanks for this video; most of this stuff is new to me. My understanding of the importance of tidal pools is that their transient nature helped drive evolution toward animals that could survive out of the water even briefly. That sounds like a bigger deal than undersea geothermal vents with respect to being an evolution driver, but that’s just my intuition talking. Also, having a persistent magnetic field, even if slight, helped us keep an atmosphere and keep the surface from being pulverized by cosmic rays and the solar wind.
Loved you on metaphysical milkshake!
Milky Way having breakfast: Yum yum, snackies!
Milky Way having lunch: Gulp!
Vegard Nossum: How the heckers do I tag this?
Search algorithm: Yum yum, snackies!
That was a lovely burn at the end there.
Would love it if you could do an episode on the local void, KBC Void, local under density and its effects on the Hubble tension.
That spicy last jab made me chuckle
You make Earth sound so young. 14BYA the big expansion takes place. 9BYA we start swallowing other galaxies. 4BYA Earth forms. It’s like the universe has only just begun.
There are stars today who would hope to burn well into their 10 trillionth year. We exist in the brief afterglow of the big bang, the flash before everything settles down.
Thanks for all the amazing content and interesting sciency stuff.
Hoping for an episode on mandelbrot blackhole theories? I'll go back through your other videos but I cant remember seeing one on this, hope your all doing well.
9:30 this made me jump for some reason
vegard you’re the mvp!
I love your stab at science misinformation at the end! Can you do a video on debunking science misinformation in astrophysics?
An extremely interesting video. Thank you!
I loved this episode. It was easy to follow and so interesting! Some episodes about relativity or quantum mechanics are hard for me.
I wish you could collaborate with Netflix or National Geographic to produce a documentary on the history of the Vía Lactea...