When The Stars Turned On | Crash Course Pods: The Universe #4

[@oO0catty0Oo]

Katie: Space is just sooo cool. John: But, like, free will's not an illusion, right? RIGHT?!

[@fang_xianfu]

Katie: err..... I'm not sure you're ready for that level of existential crisis yet John, maybe let's circle back to that in the next season?

[@SnappyWasHere]

I just feel lucky that I live right now. With the technology and knowledge to be here looking at the sky and listening to this podcast. This moment will never happen again and is totally unique to me. ❤❤

[@Jackson09]

And me...jk...I get it😅

[@nentendomofo]

I love that John was able to enrich that Head of Player Operations' life lol

[@sohinidutta97]

THESE ARE THE PERIODS IN THE HISTORY OF THE UNIVERSE I AM RESEARCHING ON! Finally some visibility for CD-EoR!!!!! Thanks Katie and John for the lovely episode!

[@planclops]

I’m not an astronomer by any means (preschool teacher), but it’s great to hear about people like you doing such important and fascinating work 😊

[@jamesmoehle9882]

Every time I listen to a new episode, I can't help thinking about "The Total Perspective Vortex" from the Hitchhikers Guide series.

[@adpirtle]

It's absolutely liberating to know we are almost entirely insignificant, that our whole species has come and will go without the rest of the universe noticing.

[@ponyote]

We are big bang stuff.

[@reallydoe2052]

😂

[@TeethToothman]

❤❤❤

[@mrpearson1230]

Yes, thank you for not being so.. Earthcentric

[@strooom546]

True

[@sarahleonard7309]

I had a moment of confusion when she said that the photons from electron spin transition are low energy enough to be detected as radio waves, because the experiments I do in the lab result in much higher energy microwaves. Then I remembered that she's talking about a spin transition in just an atom minding its own business in space. In my experiments, I put the atoms in a strong magnetic field first. So that forces the electrons to behave differently, and makes the flip a higher energy transition. So, mystery solved. Phew! I feel better.

[@The_Pope_real]

This show was my childhood, i remember binge watching US/World history back in 2014. Thank you, Crashcourse.

[@LawTaranis]

Childhood... 2014... Gods I'm old.

[@yourbuddyunit]

Fun fact: if you go watch crash course philosophy (while you wait between episodes), you can hear about the long line of existential crisis mankind had when thinking about thinking. So really, John isn't alone. There's a little existential crisis patiently waiting for all of us.

[@Spikeawe]

Just want to say thank you for making this. This has been my favorite podcast

[@Inthemains]

This podcast is so so so good and only a little bit existentially upsetting. Thank you John, Katie, and the rest of the CrashCourse team!

[@jonah4196]

I still can't get over the genius of giving us all this existential dread and the advertising life insurance to us XD

[@3bingust]

We are so small and insignificant😔 We are so small and insignificant😄

[@Surax]

11:13 I disagree with you that rainbow trouts aren't observing the universe. Sure, they aren't observing the formation of galaxies and stars and attempting to quantify the creation of the universe as a whole. But to treat their river as if it were somehow not part of the universe is inaccurate. They know how a small part of the universe, their river, impacts them.

[@3bingust]

That’s so true, we know we are small and insignificant, yet we put ourselves above other animals based on perception

[@MakeMeThinkAgain]

While I think the concept of "spin" is as annoying as the colors of quarks, Katie did a great job of explaining how neutral hydrogen can generate radio waves. Going back to something in the first episode, it does still seem like we are mostly made of star stuff -- except for the hydrogen. Also, it's always worth mentioning that if this series only covered what was known over a hundred years ago it would only have taken a few minutes. If that.

[@jas9friend]

Well I think the point was that we're mostly H20, and since H20 is mostly Hydrogen, and most Hydrogen comes from the big bang, we're not mostly made of star stuff. Lol. Just also made of star stuff.

[@reaper96789]

Perhaps Cosmic Clarity for when the universe became transparent to visible light? Absolutely excellent podcast thanks so much to Dr Katie, John and the crash course team for bringing so much knowledge to so many people ❤

[@Pfhorrest]

7:45 John you are a pretty good question-asker, that's like most of your job in this project right here and you're doing it alright.

[@JordanLeigh]

This podcast is the highlight of my entire Subscription feed. Thank you Katie for sharing your knowledge with us in a digestible way for those of us who didn't get an astrophysics degree.

[@AndreBehrens]

The most humane science content I know of.

[@chillsahoy2640]

Regular matter and energy are like the items on a store window, looking nice and teasing about what might be inside. Once you go into the store and see the aisles and tables filled with stuff, all of this dark matter and dark energy that you couldn't see from the street.

[@nickfcarter]

The new york knicks can afford to feed exactly one sandwich to each of their players? There wasn't a single extra sandwich on that tray? Sounds like dude skimped out on his job and blamed his shortcomings whatever novelist or video blogger happened to be near by

[@thewrens_]

We don't know that for certain lmao. There could've been a few spare sandwiches in case of hungry novelists, but if every reporter in that room had a snack break? i mean, at that point you may as well hold the conference in a subway

[@DatedReference]

I was thinking the same thing! Athletes got APPETITES, there should always be a surplus of food for athletes to the point where NY Times Best Selling author and internet sensation John Green can accidentally weasel his way into stealing one without anyone caring

[@semaj_5022]

I adore this series ❤️

[@raiseer]

This is my favourite CrashCourse since CrashCourse World History.

[@154jorge154]

I was wondering if I had missed this weeks episode, then remembered it's wednesday today. So happy to be on time🥰

[@Alice_Walker]

I'm loving these so so much. Such an interesting and moving collaboration and the theme music is just perfectly haunting ✨

[@crashcourse]

Thank you for supporting our channel!

[@juliegolick]

Katie: [says something she thinks is neat] John: "Oh no" [has existential crisis[

[@ellenguseman8708]

I love John and Katie and this crash course is the best!

[@evilparkin]

It's strange that we call 5% of the universe "regular" matter. It's like calling strawberry milk "regular" milk.

[@thewrens_]

to the strawberry cow, strawberry milk is for sure regular milk

[@AndrewTBP]

Historical reasons. Fritz Zwicky coined the term in German in 1933.

[@Binarynova]

Loving this, and I just have to say the soundtrack is very reminiscent of the soundtrack from Myst.

[@schelsullivan]

This is a type of content.I feel confident in giving a thumbs up at the beginning of the video

[@stecky87]

"We're the universe observing it self" somehow made the existential crisis worth it John Green, trying not to laugh at the ridiculousness of having an insurance ad in the middle of this podcast

[@JiroTheFro]

I love this podcast. I’m learning so much more about space than I ever thought was even researched

[@krellend20]

I know he's going to do an ad read, and yet every time I'm still surprised that the ad read is the ad read, and I still listen to the ad read because John somehow manages to make it sound profound anyway.

[@crackle2262]

So interesting to zoom out so far to think that we have and never will have enough power as human beings to be physically capable of harnassing the power of the universe and controlling the cosmic effects. We can only do so much in our little bubble but the cosmos expands on its own terms and we can't do anything to change that outcome.

[@Beryllahawk]

Inevitable and yet against literally astronomical odds, that I should live in this time, this space, this place. That I should have the immense arrogance to think that I matter, and yet at the same time being constantly humbled by every single moment I spend gazing at the night sky. If every one of us is a miracle, what miraculous things can we accomplish...

[@malkum77ify]

"Free will" is expensive....

[@CliffSedge-nu5fv]

_Impossibly_ expensive.

[@maryandrews6338]

This is my favorite series in the whole universe !!!

[@SunlightHugger]

See now, THIS is the stuff that makes life worth living!

[@Bjorndri]

The matters of matter do not matter.

[@laurachapple6795]

Really enjoying both Katie's wonderful explanations and John's ongoing existential crisis.

[@chillsahoy2640]

Could the Hydrogen v Metal thing be fixed by renaming them pre-stellar and post-stellar elements? Or just hydrogen and post-stellar elements.

[@AbrielMcPierce]

I believe in a truth about reality that I try and forget as soon as I remember that I believe it.

[@Davlavi]

Great episode thanks.

[@TatianaBoshenka]

I can't love this series enough!

[@Enn-]

Dr. Mack, is it possible that the Universe isn't accelerating apart, but only appears to be? For example, what if what we're seeing is compression on a molecular level, where local objects are all being reduced in size and energy, so things close to us seem unchanged, but things distant from us appear to recede at an increasing pace as everything is compressed... just as bubbles shrink and vanish when compressed in resin.

[@misslayer999]

People who think law of attraction is a real thing need to hear this LOL 😆 Also, since John's so interested in free will/determinism he needs to talk to a neuroscientist, like Patrick Haggard, or read some of Benjamin Libet's research. Or Robert Sapolsky. I'm reading his book Determined right now and it pretty much covers all talking points on the matter. I'm guessing the research will give him a full on existential crisis though lol. I'm a neuroscience student, and like most of my peers, I do not believe in free will because of the overwhelming evidence against it. You still have to live like you have it tho, since we don't have another choice (pun intended haha 😆)

[@adamdymke8004]

Free will has never been in the equations. What would free will even mean mathematically?

[@tarabates7088]

Sooooo good. Really enjoying this podcast!

[@somethingforsenro]

metal? i think you mean ✨polyprotonal matter✨

[@paulthew2]

Fantastic podcast! Learning so much, and it's really helping my understanding of our existence. Many thanks.

[@fede22081]

Just because there is a lot that we don't know about the greater purpose of the universe, doesn't mean that we (as in life) don't matter. Sure you can believe that, but the two things are unrelated

[@STMoody6]

I hope this continues into more series or a regular podcast channel

[@johnfrancis7687]

I think space is less significant than we are, certainly less significant to me than my family and friends. Still significant, and very interesting.

[@SnappyWasHere]

I hope he asks here in this series to put the scale of these distant measurements in common terms. Most people don’t understand just how crazy measuring this stuff is.

[@oposkainaxei]

Katie ❤

[@TheDanielscarroll]

Yaaaaa!!!

[@JAKempelly]

That sandwich story was so funny

[@_maybe13]

really loving this series!

[@Jacob-sb3su]

pretty sure ive listened to the other 3 podcasts about 5 times over now

[@ponyote]

The sun is a miasma of incandescent plasma. At least according to an update from They Might Be Giants. I remember when it was a mass of incandescent gas, but we have learned.

[@fromulaon]

I learnt a lot and so much more confused right now. If gravity affects flow of time, how fast was time during the big bang? Are those fractions of seconds way faster than the fractions of seconds we experience today? Were light years shorter back then? Aaaaaaaaaaaaaaaaaaahhhhh

[@mantra4ia]

In the theme of looking at "different" forces as the same force seen from varying angles, I actually feel kinda lucky that of all the mass in there is in the grand scheme, I'm made up of an infinitesimal speck of the 5% of baryons in the universe so that I can sit here in contemplative fascination of the other 95%. We're the rarified percent along for the ride.

[@BraedenMyers]

I live for these episodes I need more

[@CyborusYT]

I feel like "dirt" would be a better name for the heavier elements. Better than "metals", that's for sure

[@Thr3leven]

I have my mind set on free will. The universe may be laws and forces clashing against one another to the level of explaining all reality, but we are agents of the universe enacting its own destiny. We might not be free, but we ARE will.

[@ponyote]

We still don't matter in the scheme of things, but we're the only observers we know of. Humbling, aggrandizing, needing insurance. Yep.

[@azkon7975]

I vote for "Recession of Cosmic Fog" instead of "Reionization"

[@garrettfuller3642]

That feeling of being an observer rather than being a participant is probably the felt experience of autism. Personally, i love being autistic. I highly recommend it. The PTSD flashbacks to moments of social mistakes and the anxiety, i could do without. - _ -

[@s33wagz]

38:14 did that star become a quasar for everybody else too? lol

[@Ultimate_Hater75]

The brilliant thing about language is that since dark matter and energy is so mysterious, we can literally just replace the term with "magic" and it won't matter. It's literally so unknown.

[@OluwaToyinAdewa-Faboro]

Hi . This video is very cool

[@davetoms1]

*PolicyGenius:* _"Because you're not significant... but your loved ones are. Well, at least to you."_

[@salvestrom]

How about we refer to re-ionisation as "the parting of the veil"

[@flytape8490]

I need a short of just that sandwich Anecdote

[@albertosalazar7968]

If the gas was so dense after recombination that light couldn’t pass through where was the room for the dark matter? Does that not take up space? Could light pass through that?

[@AndrewTBP]

Light photons do not interact with dark matter at all, except for how light is affected by spacetime.

[@PalmHeal]

Wonder. It's all.about.wonder.

[@sarcasmo57]

It's strange that any of it exists.

[@sclair2854]

Yet another reason to end TB. So John can go "I'm John Green I spearheaded the effort to eradicate TB from the planet" when he is caught eating sandwiches he isn't allowed to eat.

[@danielpaulson8838]

We are emergent in the flotsam of quantum foam.

[@Pfhorrest]

"On a cosmological scale, we don't matter at all..." ...Yet. And precisely *because* we are so unusual; it's the unusual phenomena that matter the most, that make the biggest differences. And we are, so far as we can tell, an unprecedentedly weird thing that the universe has never done before -- the hottest and coldest places in the universe are both here on this mote of dust we call Earth, because we made that happen, out of curiosity -- so it's a very open question how enormous of an cosmological impact we might snowball into. As John says, we are part of the universe observing itself, and to that I would add also *controlling* itself, in the manner of a conscious agent, so we are the very beginning of the universe becoming self-aware and self-controlled, having mind and will. Now imagine if we can keep that going, and the whole of the cosmos could awaken, as though it were a pantheistic god...

[@KitChesh]

Theoretically, is the fog still around us, only completely transparent?

[@luciel2428]

so all the matter in the universe doesnt matter

[@DampeS8N]

Thing about free will: Folks that believe in it seem to struggle with the idea of determinism. But, the things that we think aren't determined are _random._ Things like quantum probabilities and stuff. If there is stuff in my brain that makes me decide things a certain way, that's determinist. The alternative would be that _nothing_ determines my actions - that they are random. I get the idea that if my actions are predictable, that you could somehow know what choice I would make 100 years before I am born, that my actions aren't free. But, and this is important, none of us actually can do that. I can't say if we are anything more than robots. But nobody knows how these robots were programmed and what they are going to do. So, there is no difference between free will and determinism that isn't just word salad.

[@jenloves4260]

I feel small in a good way. Sort of.

[@trainyoumust]

We do matter because we can create knowledge that will eventually transform the cosmos

[@jamesonpace726]

Free will? Don't panic....

[@jrpipik]

Whether or not we have free will, we have to act like we do. We wake up and have to decide between cereal or pancakes, blue shirt or white, pack a lunch or stop for a sandwich. The question of free will is literally academic, something for philosophers and theologians to ponder while we get on with making the choices that shape our lives.

[@romajimamulo]

Wait you don't know anything about black holes? That might be the most surprising thing in the episode

[@Newfster]

John is always a little too gleeful when he makes a good segue to selling life insurance.

[@perrid13]

I truly hate arguments about free will, they always devolve into arguments about semantics, what counts as "you" or hell what even "free will" means. We all make choices and those choices are made for reasons, conscious and unconscious. Having reasons for making our choices doesn't negate free will. Not being in absolute control of all of the inputs into our decision making does not mean we are not making decisions, and I will absolutely die on this hill.

[@josephclayson2714]

The thing about the free will debate is that science can’t really handle the idea of free will. Science deals with cause and effect, but free will implies that humans are able to make decisions without anything causing them to make it. The ultimate question though is where does that will come from? It must come from some unmeasurable consciousness or intellect within us that has no cause. This contradicts most of what science has to say, and yet most of our social systems are built on the idea that we have free will!

[@brockgan8941]

There is utility in that discussion though. If the universe is near deterministic nobody could have ever acted differently and therefore moral punishment is wrong

[@warriorscholar41]

Isn't it kind of wild to call the matter that is 5% of the universe REGULAR matter? She said dark matter and dark energy are called dark because we can't interact with it. Given how rare "regular" matter is, to me, it feels like we are the incorporeal ghosts haunting the rest of the universe.

[@AndrewTBP]

No, we’re corporeal because we feel the electromagnetic force. 😉

[@lilyrooney]

first

[@RenayEmond]

🥇 ❤

[@LawTaranis]

You are going to be attacked by an angry goose now.

[@exeggcutertimur6091]

This will get buried but... If dark matter is 85% of regular matter, am I experiencing it right now??? Is the Earth 85% dark matter??? Where is it?

[@timlister177]

No, 85% of the universe is dark matter but you, the Earth, all of the other planets and stars and galaxies we can see in the Universe makes up the 5% that is regular matter

[@AndrewTBP]

We don't consider dark matter when discussing Earth. It's considered when discussing galaxies, and large scale structures in the universe. There could be dark matter streaming through you right now. You'd never know, because you can't see it or touch it. There _are_ neutrinos streaming through you right now, but that's not dark matter.

[@danielpaulson8838]

Dark matter is not known or understood to be any kind of matter that we know. It’s just a name given because the gravitational effects of something is in play, causing large scale, galaxy sized motion we cannot otherwise explain. This is in Newtonian physics. The effects of what is presumed to be unseen matter, in the percentage they calculate, is what is referred to as dark matter.

[@somebody.2know839]

Okay, okay.

[@oopsy444]

4:24 we're not affecting the cosmos do we really want humans to be able to affect the cosmos? look what we're doing to own planet. imagine that damage to the cosmos. it's horrorfying to even contemplate a tiny bit