@SevenReads007 Do yourself a favor and look up some new worlds (moons, planets, dwarf planets, plutinos). Titan, encelidus, and Io (io) are all great places to start. Titan with its methane seas that cycle between mostly in the north and south poles depending on which is in winter Encelidus being an ocean world wrapped in a thick crust with geysers shooting out and forming an extra ring. Io is by far the most volcanically active world in the solar system with beautiful patterns of colors many of which are due to huge swings in temperatures across its surface.
Shoutout to the old dudes who said galileo was on crack, looked at some moons, and said nevermind he's right. These days people would look, see and understand what was happening, and then deny it so as to not admit defeat or being wrong
Yeah but you're equating scientists of the past with regular people of the future. Regular people of the past would deny it too as not to be wrong, and scientists of today would happily change their minds when looking at the evidence themselves
"Truth is the daughter of time, and I feel no shame in being her midwife" is probably the most elegant way I have ever heard someone say "Yeah I fucked up."
I can't express how much I need a "Hank Yells Passionately About Moons" series now. I need a series of 20-30 minute videos, each one on its own different moon or micro planet that we often don't think about
Last year I was largely ignorant of practical astronomy when I got my first telescope. When I looked at the brightest "star" I thought my lens wasn't focused right because what were those four little dots around it? I will never forget the sense of wonder and awe that filled me when I realized that was jupiter and those were the moons. I had NO idea you could see them with a casual telescope! My sense of scale of the universe SHIFTED instantly. I felt and feel now a deep connection to Galileo and the countless of curious apes before me that looked up in wonder - because I had mirror experience to them. Then a few months later I witnessed the total solar eclipse. I am now a space junky a thousand fold.
One of my favorite jokes I've ever told was when someone said "Pluto was too weird to be in the cool planets club" and I said "I think you mean 'eccentric'." Still proud of that one.
A realization I recently had about the moon eclipse timing is that if you had a clock in the vicinity of Jupiter that you could see, relative to clocks on Earth, that clock would appear to speed up and slow down. According to that clock, there wouldn't be any timing discrepancy in the eclipses. The difference is from relativistic time dilation due to the different velocity!
Hi! I’m currently studying physics at uni, and at the risk of being that guy this is actually a pretty common misconception about special relativity that I got recently cleared up for me as part of my course. Special relativity isn’t concerned at all with the time it takes for the light from an event to reach the observer; when we think about ‘events’ in special relativity we’re talking about the actual moment in time when it happened rather than the moment the light reaches the viewer. Special relativity instead describes how two events can appear to have different amounts of time between them when measured from different inertial frames (read observers travelling at different constant speeds) REGARDLESS of where or how far away the observer is. This unfortunately means I don’t think there are any relativistic effects involved in the time lags in the Galilean moons’ eclipses, but does in my opinion make special relativity far more profound. However, I believe there is a case of something similar that does happen within the solar system- precise measurements of mercury’s orbital period do not line up with predictions from classical mechanics and only make sense when considering general relativity, which was a big argument in favour of the theory when it was published. That’s not something I know a lot about though so I may be wrong. Sorry about the correction- I just thought this made special relativity make a lot more sense when I discovered it so hopefully you find it interesting too!
Tldr of other person's post: the discrepancy is not because of special relativity. It's because the speed of light makes light take longer to arrive when earth is a bit farther from Jupiter than when its a bit closer.
I once had an astronomy professor who loved to talk about the Jovian system. He once told us: “Most star systems are binary. We have Jupiter instead. And isn’t that just so much more interesting?”
I learned a ton about Ganymede from the book series "The Expanse." In the story, the economy of the colony there is in large part devoted to healthcare, because people who live primarily in space go there to have babies. This is because it's the only moon in the solar system that has it's own magnetic field to protect from radiation. Cool stuff!
Can’t express how much I loved this video. My 3 year old has autism and his special interest right now is moons and dwarf planets. Videos like this help me keep up with him! Would LOOOOVE to buy this shirt in toddler sizes if you ever come out with them ❤❤❤
Awww. My now 30 year old (on the spectrum) was into space at that same age 😅 His favorite was Pluto and still he wears tshirts with Pluto on them 😂 Its so cool
I like how I basically have to watch videos like this several times, not because I don’t understand it all, but because Hank will say something interesting and it will get me thinking about some other slightly somehow related thing, and I start thinking to myself deeply for several minutes… just to realize I missed like half of what Hank just said completely.
There's TWO missions to Jovian moons?! I've wanted this to happen my whole life. I'm telling you, these moons are going to get me through this next four years.
Hey Nerdfighters! I'm a history of science major in the last few months of my degree, and I wanted to pop in and give some context to the Galileo story. Mostly because I think his arrest is overemphasized in the discussion of heliocentrism and the Catholic Church. Galileo was working in the Papal court itself, and the Pope of the time was incredibly interested in astronomy (as many were). The Pope was aware of these Heliocentric models, but subscribed to a very popular idea that these models were useful computational tools, but probably not literally true. But the relationship between the Pope and Galileo was one of direct patronage. The Pope directed Galileo that if he was going to discuss heliocentrism he had to present the Popes position. Galileo wrote his work in the form of a dialogue and presented the Pope's position from a character literally named "Simplicio." He wrote a book where the Pope's position was presented by a literal bumkin idiot, while being employed directly by the Pope. His arrest was much more about a direct insult to the Papacy than his ideas. It should also be noted that at the trial, many did not want to see him convicted, including powerful direct family members of the Pope, and when he was convicted, he was placed on house arrest... In a lavish Italian villa. The church was very, very split on if he had done anything wrong, and in the end they decided they had to do something but gave him the absolute lightest punishment possible. Finally, I want to point out that although yes, there are biblical reasons to believe in Geocentrism, there were secular reasons too. Gravity was one - it was understood as an inward force in the universe, it's quite a leap to realize that everything is attracted to everything else. There's a bunch of others (some of which Galileo shattered with his other work!) but I'll try to refrain from writing a whole paper in a comments section lol tldr: Galileo was employed by the Pope, insulted him hard, and the church reluctantly gave him an exceedingly light sentence. It's more complicated than the way a lot of people discuss it.
Thank you for explaining! That's fascinating. Do you know why Galileo wrote the Pope like he did? Was he pressured into the job and was resentful, or did he really think the Pope was stupid, or what?
+1, really hope your comment gets some likes as there are ironic parallels between the popular version of the Galileo affair and the caricature of the Church that it portrays. Probably the best history-of-science content I've ever encountered, in any medium, is about exactly this: Michael Flynn's essay "The Great Ptolemaic Smackdown". It's incredibly detailed and nuanced, and available both as an article in "Analog Science Fiction and Fact" (scanned and Googleable) or a significantly-expanded series on Flynn's blog, with plenty of diagrams. I can't recommend it enough, please go read it. @@Khaim.m from what I've read (see above), Galileo was basically overconfident to the point of arrogance. Pope Urban was a personal fan of Galileo, and it was his suggestion to publish the arguments for heliocentrism in the first place, but Galileo decided anyway to depict Urban's (justified) interpretative caution as stupidity. As @jkebharper5905 says, he was arrested not for arguing for heliocentrism but for proclaiming it established fact when there was not yet sufficient evidence (and wouldn't be for over a century).
It is more like that time that Henry II accidentally ordered Becket to be killed. Theological differences did underpin it, but the argument was a lot more like humans arguing over who had real power and legitimacy than whether or not God was up to something.
I love hearing how science was working exactly the way it's supposed to even back then. Not "oh he said this so he's right," or "that sounds wrong, so he's wrong." It's "hmm, seems weird. Now I'LL test it too" followed by seeing the evidence and changing your mind based on the evidence, with no pride getting in the way of the truth
I’m a big fan of the Galliliean moons, as an aside I’m also a big fan of The Expanse books 😅. They’ve featured in so many works of Science Fiction and it seems that they are more special than we could ever imagine
Arthur Clarke's sequels¹ to _2001,_ _2010_ and _2063,_ were what permanently cemented my fascination with the Galilean moons and the idea of Jupiter as a "failed star"-"All these worlds are yours, except Europa. Attempt no landing there." ¹technically "sequels" should be in quotes, as Clarke stated they're part of separate continuities (read: "don't @ me about plot contradictions")
I was introduced to Ganymede by an old Robert Heinlein book called Farmer in the Sky. I'm a little older than most of you. But science fiction is awesome.
I built an optical replica of Galileo's original telescope a few years ago, and it was really enlightening to see just how easily the moons could be observed. I really need to get back to that project and try grinding my own lenses for it, for the full experience. (My main conclusion of that project is that we're lucky Galileo lived in a sunny, Mediterranean climate. Had he lived in the Seattle area, we might never have had a scientific revolution. It took me *months* to get 5 days of observations in a row!)
I happen to live in Padua, which is where Galileo made his observations and spent most of his carreer. Let me tell you: it's not a place where a clear sky is the norm, like people imagine Italy 😉
I used to volunteer at a lot of astronomy nights and one of my "entertain these people while they're waiting in line to look through a telescope" strategies was to talk about how the Galilean moons have been revolutionizing science, using the same points you describe! Cool to hear it from you and learn more about the other moons that aren't Europa.
My thoughts on Pluto: I remember, when I was a child first seeing the illustration of the orbits of the nine planets, recognizing that Pluto was _off._ All the other planets had nearly circular orbits well separated from each other and all on the same flat plane - and then there's Pluto, with its orbit tilted way off of that plane and so elliptical that it spent a good deal of time *closer to the Sun than Neptune.* It put me in mind of a song I heard on my favorite TV show (brand-new at the time), _Sesame Street_ - "One of these things is not like the others..." So, when folks started finding lots of other objects out there with weird orbits like Pluto's, and realized that Pluto was actually one of _those,_ I didn't think of it as a "demotion" the way everyone reacting online does. Instead of the oddball runt of the planets like I'd been taught to see it, we now know it as the King of the Kuiper Belt - yay Pluto! Not to speak of how silly the plea to "don't be mean to Pluto!" objectively is ... as if a non-sentient mass orbiting the Sun between ~30-40 AU out cares at all how we Earthlings classify it. All of which speaks more about how important certain people think their own opinions are, than about Pluto.
The problem I have with decisions made by the IAU about Pluto is not that Pluto is being discriminated against(I'm actually fine with it's designation as a dwarf planet) so much as according to the current IAU definition of a planet(the decision that 'demoted' Pluto) there are only 8 "planets" in the entire cosmos. That may seem nonsensical(which it is) as we have made a big deal about detecting planets orbiting distant stars, but those are all classified as exoplanets. In order for a body to be a "real planet" it MUST orbit Sol. And because of that the IAU has thrust us backward to the days of 'special designation' for the Earth and it's buddies. Rather than do the sensible thing and adopt a more inclusive definition of planet, then designate subcategories such as gas giant, terrestrial, dwarf, etc.. we get a narrow definition that is not universally applicable. Makes me wonder what Galileo would think about the IAU.
@@shannonlawhorn1674 It should be that there are planets and some of them are exoplanets and some are endoplanets. Also nepioplanets like Pluto - baby planets. And for normal planets kopodeplanet - boring planets.
@@shannonlawhorn1674 Another problem with the IAU definition is that Pluto is a dwarf planet but not a planet which causes a lot of confusion. There are a lot of people who think that being a dwarf planet still makes it a planet and they're right for thinking that. A dwarf star like the sun is still a star and a dwarf galaxy is still a galaxy. One of the common arguments for 'demoting' Pluto actually is discriminating against it. That line of argument goes that we shouldn't be preserving Pluto's status as a planet just because it was considered one historically and that it's so different from the others that it should have a separate categorization. But by that same logic, Mercury and Jupiter are incredibly different and the only reason they're both considered planets is because they were historically considered planets. Looking at the relative sizes and masses of the planets, even Earth is just a dwarf compared to Jupiter. I think that adopting a more inclusive definition of planet with subcategories is definitely more sensible. Of course, there's still a lot we don't know about how star systems form and the definition of planet might have to be amended multiple times as we learn more.
6:30 The Cool Worlds bit got me. Wanting to be as cool and collected as David Kipping on the mic is a relatable feeling for many science communicators, I’m sure!
I envy you! Especially right now with Jupiter up. (And Venus & Mars) My first sight of Jupiter was in the early 90s through a rickety little refractor. I was beyond excited and immediately bought a 10" Dob. (Odyssey Compact) Man, I loved that thing so much! Must have spent 3x the cost of the scope on eyepieces & filters. Fun times!
My dream growing up was always to be an astronomer because of exactly this type of excitement. I went a different way but thank you for making that sense of wonder and excitement accessible to me anyway. And the shirt is gorgeous, might have to grab one as an early birthday gift for myself!
Love you hank been watching you for longer than I can remember. you've taught me alot from being a kid till now as a 25 year old man. hope I'm early enough for you to see this man. Best science teacher ever.
0:31 *THANK YOU!* How the hell is the only actual image of Haumea a *deep fried blurry dot???* You're telling me there's a *squashed* dwarf planet *with a ring* out there, and no one wants to *see* it???? *WHAT??????* How is it *not* already an astronomical celebrity? *Make it make sense!!!*
13:49 1963 novel "Cat's Cradle" has a substance called "ice-nine." It has a melting point around 40C, where water is at 0. If ice-nine comes in contact with water, it acts as a seed and freezes the entire body of water. Glass, tub, pool, lake, ocean, it freezes the whole thing. If it gets in contact with a human body's moisture, it'll freeze the person, ice-nine kills --- where the band Ice Nine Kills got their name
I am always glad to see another human with just as much enthusiasm for the complexities of planetary and celestial systems and bodies as I have :D I'm a big fan of Red Rising and other works based on the human expansion into other worlds, particularly since we tend to categorize those worlds through the lens of our systems, which simply exist within separate limits and forces than the ones currently beyond our reach. When people capture and explain those differences, we learn to conceptualize the world around us more thoughtfully.
It is amazing to me that even being alive for almost 50 years and spending so much of that time on the internet - yes, wasting time, but also learning tons and tons and tons of random things... it is amazing to me how much I still learn. Things that are sort of fundamental and important, but I learned a large part of what was said in this video. Awesome
Yes! Another fun bit of history about the Galilean moons not mentioned in the video: Galileo created timetables of eclipses of the moons of Jupiter, called ephemerides. His predictions of the timings of eclipses were accurate enough that mapmakers used them to determine the longitude on land. "King Louis XIV of France, confronted with a revised map of his domain based on accurate longitude measurements, reportedly complained that he was losing more territory to his astronomers than to his enemies." -Longitude by Dava Sobel Galileo also designed a funky navigation helmet called the celatone, with a telescope attached to one of the eyeholes.
#JusticeForPluto (The Disney dog, not the planetary body. Why can Goofy just hyucking walk around like nothings wrong while his canine brethren are not free?)
@@Spacemongerrdoes this imply goofy is no longer considered human adjacent when changing clothes? or that the clothes are what allows them to have consciousness?? or rather that the clothes act as the consciousness and possess the characters? so many questions
I’ve read this before. Animals with no clothes are animals, and animals wearing clothes are thought of as people. It’s why even sapient animals like Bambi still live in the forest and other animals (that wear clothes ie Mickey or Minnie and friends) live in a more modern society.
Such a fun video😊 watched a compilation of all the reunion videos recently and the "planets donˋt exist" and "there are other planetary bodies which should count as planets" was still tumbling around in my head. Getting this as basically a part two ❤ so excited for the things we will get to know about those orbs. Also: I just love me a nerdy explosion of interest and excitement on the universe, I'd watch this series 😊
I prefer to think of Jupiter as an incredibly successful planet rather than a failed star. As for the Jovian moons, I can't think of any moons that are more appreciated other than our own, and they're still underappreciated. That's how amazing they are.
Ceres always stands out to me. Mass driver launch point loaded with water, and pointing to the outer worlds. A tech testing ground for the cluster of similar-mass objects in our Solar system. Worlds where we'd float more than moon hop. Even just arbitrarily between 1.5% and 4.5% Earth Gravity, we've got Vesta, Pallas, Amalthea, Rhea, Dione, Iapetus, Tethys, Titania, Oberon, Ariel, Umbriel, Charon, Makemake, Eris, Haumea... Nothing soon nearby, but if we're investing in something we want to iterate upon, yanno? Mars is more unique than a key to further beyond, it feels like, with a deep gravity well compared to the numerous.
Plutonium is named after the Planet Pluto! Just like Uranium (after Uranus) and Neptunium (after Neptune)! And if Pluto was discovered 10 years later - or Plutonium 10 years earlier - that naming standard would have fallen apart! Am I the only one that cares about this?!
Watching you makes me glad I,m alive! Sum good stuff is rubbing off of you and onto me. And on a serious note, I’m so glad you survived your big health challenge. You make this world a better place
I love, LOVE, when someone smart like Hank gives an aside to explain something like a palimpsest, and I'm all "you don't need to explain it, I know what you meant, dude!". But at the same time, we're smart, Hank, teach us NEW things!
As someone who lives in the town with the observatory that FOUND PLUTO (Common school field trip) Bold of Hank to assume I don't also love these moons and read about them in my free time like a huge NERD. They're SO cool.
As soon as Hank said "failed star" Tomy Cardy's "H.S" started playing in my head :D Actual science question regarding the fact that light has a speed and looking farther away means we're looking back in time: can anyone please explain how we know that light from distant galaxies is stretched because the universe's expansion is accelerating, instead of because it got stretched out due to earlier faster expansion and just hasn't been re-compressed because even if expansion slowed down it's still not contraction? i feel like this idea must be the result of me having an incomplete understanding of the phenomenon.....
Because we have light from every direction at a variety of distances, we see a pretty observable pattern that matches our theory of expanding space continuing over time. Some of this comes from how light itself is stretched out to lower wavelengths, but another part is that stuff like galaxies and pulsars are spread out farther from each other the farther out we go. There could be some weird uneven stretching going on, but it would have to be way more complicated to somehow still match our observations.
if we only had one Galaxy to look at, we wouldn't know when the stretching of light happened, and what you said could be correct. But, good news, there's lots of galaxies! So we can graph the amount of redshift that we see from various stars galaxies at various distances, and what we see is that the close galaxies, the ones "only" a couple million light years away, still have redshift. That tells us that it's happening close-ish to us, and in the recent-ish past (relatively speaking), it wasn't just at the beginning of the universe. Then we look at galaxies that are further away, and see more red-shift, which tells us that it has been happening for a long time too, it wasn't just a one time event, and light that travels for longer gets shifted more. Then, finally, we look at how *much* more red the far galaxies are, is light that traveled 2x as far 2x as shifted? And that's where we see the most surprising answer, no, light that traveled 2x as far *isn't* 2x as shifted, it's less, maybe only 1.9x. Which means that recent shifting is stronger than old shifting, and the universe's red shift is getting stronger over time. so the expansion of the universe that is causing that shifting is speeding up. What you're suggesting is basically "what if red-shift was just a short term thing at the beginning", if that was the case, all of the light that was traveling before the expansion happened would be redshifted, and none of the light that shined out into the void after the expansion would be shifted. But, all of the light that we can see, even recent light, seems to be red shifted, so we know expansion is probably still happening
IDK if you look at comments after the first few hours, but this video made me feel a way that I haven't in maybe a decade. I remember being a kid and being fascinated by the solar system, and physics, and science, and everything. But at some point my encroaching adult responsibilities and lack of science communication beyond the simplistic made me lose faith in the wonders of the universe. But this video... this is it. It makes me remember what watching Bill Nye felt like, what early SciShow felt like. I've been so beaten down by the delays in modern NASA programs that I forgot Europa Clipper actually *did* launch and **holy shit** we're going to have a flyby in 5 years. Science can be so *fucking* cool, and I don't know when I forgot that. "Strange Charm" helped me love science 14 years ago, and even though we're both wildly different people today, you're still doing it.
paused immediately to look for discussion of this. my first thought was that Mercury had been demoted somehow? or maybe Hank likes some hypothesis about planetary *capture* like Expanse's Phoebe idea?
@@FrelanceEQ Seconded on Mercury. I strongly feel that giving Pluto back to its family of dwarf planets after kidnapping it for over three quarters of a century was the morally correct choice, but Mercury is quite lonely that close to the Sun. I have mixed feelings about Mercury not being a planet.
You know, I've been feeling lately like there are so many things that are not ideal about inhabiting this particular time and place in our universe, but getting to be alive at the same time as Hank Green, as he gleefully geeks out about our solar system--we're all pretty lucky.
I love the enthusiasm! This is great timing, too, because I've been binging RUclips videos about these moons for the last week. Planets are great, I'm especially fond of one in particular, but don't forget about these incredible moons!
The while video is wonderful, but one thing that made me particularly happy was when you referred to Jupiter as a failed star and its "moons" as its would-have-been planets. I first heard that idea as a teenager, when I read it in a short story (by Larry Niven, IIRC) and it sparked in my brain forever after. Then, maybe a decade or two ago? I read somewhere that Jupiter was no longer considered a failed star, for reasons I don't remember. This made me sad, because I loved the idea that we almost had another solar system this!close to us. So thank you for reviving Jupiter-was-almost-another-star idea!
My favorite planetary body is Titan. It was famously postulated by Randall Munroe that the combination of dense atmosphere and low surface gravity could in theory allow a human being to flap their arms and fly like a bird, which I just think would be sweet.
Titan is awesome, but if you're already in the orbit of Saturn, you gotta find out what's going on with Iapetus. The ridge going around the whole planet, the distinct difference in albedo of the two halves, that weird monolith...
Goddamnit Hank I cannot express in words how deeply satisfying it is to watch someone very smart and very informed talk for almost 20 minutes straight about one of my fave special interests (the geology of non-Luna moons). Brain itch inCREDibly scratched 😌😌
I'm glad to see more people appreciating how wonderful moons are! I forget who said it, but moons are the laboratory experiments of the universe given how many there are and how incredibly diverse they are. Once we can start cracking exomoons, the universe is gonna look even weirder!
They're planets, same as Pluto and Charon and Luna. If it's massive enough to be* round and it isn't in the process of fusing hydrogen to helium (or formerly have done so) then they're a planet. ...and no I will not be elaborating
That would mean that we have around 40 planets in our solar system. Would include Haumea, Makemake, Eris, Orcus, Salacia, Quaoar, Gonggong, Sedna, plus ~20 moons like Io, Titan, Oberon, Callisto, Tethys etc.
@@SpacemongerrThe current situation is that there are 8 "planets" in the entire universe. Which makes more sense? There are 8 planets in the whole universe, or there are lots in the solar system and lots more to be found?
i've been a massive Jovian Moons Enjoyer for a while now. so glad they finally got some recognition. personally, i'm betting they all revolutionize our thinking at least another 3 more times when those orbiters finally reach them
3:56 Hank it’s really disappointing that you did the classic “i dont know how to pronounce this name” thing. its literally never been easier in history to go to wikipedia find the ipa characters next to his name and paste them into a website that tells you how to say it. no need to be perfect but you could at least get an idea instead of using a disappointing common excuse
So happy to see other people excited about the Galilean moons, absolutely love the Jovian system. As soon as Hank showed the shirt I went to the description to check for a link before he even said one was there.
i’ve been listening to all of dear hank and john chronologically and i’m in the 240s now and i’ve been so invested in the progress of the mars drill that hank was talking about at the time and i can’t believe he just spoiled the ending for me at 14:26 ;_;
Your passion and energy for subjects you care about comes across, to me, as unhinged and I am here for all of it. I love it. Keep that passion and education flowing. Teach me more Hank!
The time lapse of Juno’s photos of The Galilean moons as it approached Jupiter is really cool. The moons are just floating there and moving around Jupiter. It’s just gravity, but invisible force acting from a distance is eerie to see.
9:05 It was at thus point that Hank's love for Europa seemed to have cancelled out his ability to understand that it's not, in fact, a planet, but an interesting moon.
You hit the nail on the head. People keep making a fuss about Pluto no longer being a planet because they feel like it was wronged. But Pluto is not a person. There’s no point in feeling like it was wronged. But unfortunately, it is human nature to want to ascribe human attributes to inanimate objects.
Oddly depressing to imagine the possibility of life in an ocean so far under the surface of Ganymede, just stuck in darkness between two impenetrable layers of ice, just living things killing and eating each other in the dark without ever even seeing each other - which is I guess basically all microscopic life and lots of deep sea life, but the fact that the ones on Ganymede would never even be able to be known to us somehow makes it so much worse
Its fun to see how your style for videos has changed after becoming a professional stand up comedian. I'm sure it's also just an artifact of lifez but the evolution of your storytelling has been a joy to witness.
I want to point out at 10:28 that that is a SpaceX Falcon Heavy. EC was supposed to launch on SLS and get there more quickly with fewer maneuvers, but given the pace of SLS development, it was decided to put it on the underpowered -- for EC''s mass and intended trajectory -- FH because it is reliable and readily avaliable; better to get it on its way and know when it will arrive than wait indefinitely.
I'm a geology student, specializing in paleontology, but I took an astrobiology class because that's fun. Also the professor works for NASA on astrobiology and geo stuff. Important note: we have NO evidence of life outside of Earth currently!! However. There are a number of places that are considered 'good' candidates, that if we were to find other life in the solar system it would most likely be there or at least would tell us about potential conditions that life could form/survive in extrasolar places (ex: Venus, NOT a good candidate. Basically hell, next). The Galilean moons, particularly Europa are some of those notable candidates! Saturn also has a moon with a water ocean covered in ice, Enceladus. So Enceladus and Europa are very very interesting to astrobiologists bc microbes (whats basically the most likely kind of life form to find) love a good liquid water ocean. Depending on the chemistry of those oceans, they could be very good candidates. (Also cryovolcanism is very very cool). Most of what we have now are bits and pieces of the conditions for life scattered around. We've found amino acids, water, hydrocarbons, etc. in places around the solar system. A lot of the field of astrobiology is studying how life originated on Earth and its earliest forms, as that can help us understand what it would take for life to take hold in other places. It's a really cool field (even if we haven't found any actual aliens) and yes, the moons are very cool!
This is the most Hank video I've ever seen. Like slap this in a gold record for the aliens. Ps. Listening to Dear Hank and John. It's fun to see Hank's progression from obsessed ❤with Mars to obsessed with Jupiter's moonw 😂
"Jupiter is tugging on it" is actually how most Roman myths start
Words cannot express how much I love this comment.
😂😂
😂
Io go boingy boingy boingy
nice
"Maybe I should have had a series where I talked about each of these moons"
You still can.
This video got me so interested in astronomy, I’m desperate for a new series 💪
Yes, please! 😂💙💙
+
@SevenReads007
Do yourself a favor and look up some new worlds (moons, planets, dwarf planets, plutinos). Titan, encelidus, and Io (io) are all great places to start. Titan with its methane seas that cycle between mostly in the north and south poles depending on which is in winter
Encelidus being an ocean world wrapped in a thick crust with geysers shooting out and forming an extra ring.
Io is by far the most volcanically active world in the solar system with beautiful patterns of colors many of which are due to huge swings in temperatures across its surface.
100% would watch
Shoutout to the old dudes who said galileo was on crack, looked at some moons, and said nevermind he's right. These days people would look, see and understand what was happening, and then deny it so as to not admit defeat or being wrong
You’re crazy, people wouldn’t do that, I’d never do that, I dare you to prove me wrong /j
I'm certain plenty did it at the time too
Those were scientists of course, and this is still how scientists are today.
Yeah but you're equating scientists of the past with regular people of the future. Regular people of the past would deny it too as not to be wrong, and scientists of today would happily change their minds when looking at the evidence themselves
As far as time goes, Galileo was not completely wrong. We are the center of our own time of space.
"Truth is the daughter of time, and I feel no shame in being her midwife" is probably the most elegant way I have ever heard someone say "Yeah I fucked up."
You delivered the baby of Time from Truth? I don't get it
@@Broken_robot1986I think roughly that with enough Time, the truth will emerge, so he’s saying he helped it along
I've been revising my resume recently. This is going on it
I can't express how much I need a "Hank Yells Passionately About Moons" series now. I need a series of 20-30 minute videos, each one on its own different moon or micro planet that we often don't think about
Last year I was largely ignorant of practical astronomy when I got my first telescope. When I looked at the brightest "star" I thought my lens wasn't focused right because what were those four little dots around it? I will never forget the sense of wonder and awe that filled me when I realized that was jupiter and those were the moons. I had NO idea you could see them with a casual telescope! My sense of scale of the universe SHIFTED instantly. I felt and feel now a deep connection to Galileo and the countless of curious apes before me that looked up in wonder - because I had mirror experience to them. Then a few months later I witnessed the total solar eclipse. I am now a space junky a thousand fold.
Hank has a lot more feelings in a day than I have in a month.
Also Pluto is hot shit.
@@windowdoog I love that song
@@Marcaline99 S tier song
And you know Pluto knows it!
That song has been stuck in my head this entire video
@@chiliwithonel I won’t ever be a planet it don’t matter cuz I know that I’m still worth it babay
One of my favorite jokes I've ever told was when someone said "Pluto was too weird to be in the cool planets club" and I said "I think you mean 'eccentric'."
Still proud of that one.
Incredible
i,,,,dont get it
you should be proud
@@VioletRM Pluto's orbit is highly eccentric. It is a very good joke.
🥁🥁📀
“In fact the Galilean moons and other dwarf planets have been wronged!”
Ive been thinking this FOREVER! Glad to see I wasn’t alone.
yay heart, cant edit but i also LOVE the Galilean moons, im gona need that shirt
Count Ceres in with that group too
Right?? Haumea does *not* deserve this disrespect!
given the them of the Video Titan got wronged by Hank.
YESSS. There are SO MANY awesome planetoids in our solar system that don't get the appreciation they deserve!
A realization I recently had about the moon eclipse timing is that if you had a clock in the vicinity of Jupiter that you could see, relative to clocks on Earth, that clock would appear to speed up and slow down. According to that clock, there wouldn't be any timing discrepancy in the eclipses. The difference is from relativistic time dilation due to the different velocity!
Hi! I’m currently studying physics at uni, and at the risk of being that guy this is actually a pretty common misconception about special relativity that I got recently cleared up for me as part of my course. Special relativity isn’t concerned at all with the time it takes for the light from an event to reach the observer; when we think about ‘events’ in special relativity we’re talking about the actual moment in time when it happened rather than the moment the light reaches the viewer. Special relativity instead describes how two events can appear to have different amounts of time between them when measured from different inertial frames (read observers travelling at different constant speeds) REGARDLESS of where or how far away the observer is. This unfortunately means I don’t think there are any relativistic effects involved in the time lags in the Galilean moons’ eclipses, but does in my opinion make special relativity far more profound. However, I believe there is a case of something similar that does happen within the solar system- precise measurements of mercury’s orbital period do not line up with predictions from classical mechanics and only make sense when considering general relativity, which was a big argument in favour of the theory when it was published. That’s not something I know a lot about though so I may be wrong. Sorry about the correction- I just thought this made special relativity make a lot more sense when I discovered it so hopefully you find it interesting too!
Tldr of other person's post: the discrepancy is not because of special relativity. It's because the speed of light makes light take longer to arrive when earth is a bit farther from Jupiter than when its a bit closer.
9:27 Hank accidentally calling Europa a planet, when it is, in fact, a continent
What is this, is this a Twitter thing?
Europe=continent
Europa=Moon
@@erlannderrantem6972 On the other hand, Europa = continent in German, so I'd argue my joke still works
@@The8BitPianist as a german I didn't even notice😂
LMAO
I once had an astronomy professor who loved to talk about the Jovian system. He once told us:
“Most star systems are binary. We have Jupiter instead. And isn’t that just so much more interesting?”
I learned a ton about Ganymede from the book series "The Expanse." In the story, the economy of the colony there is in large part devoted to healthcare, because people who live primarily in space go there to have babies. This is because it's the only moon in the solar system that has it's own magnetic field to protect from radiation. Cool stuff!
The expanse is so good!!
Was about to also talk about The Expanse. Saw the TV series, now I'm reading the books. So good!
Ganymede, the breadbasket of the solar system! I love these books. I'm only on book 3 but man, they are engaging.
to bad the Expanse did not tell a story about Titan. there is even more fascinating stuff there.
@@MusikCassette In Book 7, Naiomi and Holden announce that they're retiring and settling on Titan, which is a luxe resort planet.
Can’t express how much I loved this video. My 3 year old has autism and his special interest right now is moons and dwarf planets. Videos like this help me keep up with him! Would LOOOOVE to buy this shirt in toddler sizes if you ever come out with them ❤❤❤
Awww. My now 30 year old (on the spectrum) was into space at that same age 😅 His favorite was Pluto and still he wears tshirts with Pluto on them 😂
Its so cool
I like how I basically have to watch videos like this several times, not because I don’t understand it all, but because Hank will say something interesting and it will get me thinking about some other slightly somehow related thing, and I start thinking to myself deeply for several minutes… just to realize I missed like half of what Hank just said completely.
Ah, hello fellow ADHD-haver (lighthearted)
Pluto adds 1 Mult and 10 Chips to my High Card score, idk how I could be wrong about that
This guy gets it.
balatro gang !!
real shit
There's TWO missions to Jovian moons?! I've wanted this to happen my whole life. I'm telling you, these moons are going to get me through this next four years.
refreshed at the exact right time
Same, lol.
Hey Nerdfighters! I'm a history of science major in the last few months of my degree, and I wanted to pop in and give some context to the Galileo story. Mostly because I think his arrest is overemphasized in the discussion of heliocentrism and the Catholic Church.
Galileo was working in the Papal court itself, and the Pope of the time was incredibly interested in astronomy (as many were). The Pope was aware of these Heliocentric models, but subscribed to a very popular idea that these models were useful computational tools, but probably not literally true. But the relationship between the Pope and Galileo was one of direct patronage.
The Pope directed Galileo that if he was going to discuss heliocentrism he had to present the Popes position. Galileo wrote his work in the form of a dialogue and presented the Pope's position from a character literally named "Simplicio." He wrote a book where the Pope's position was presented by a literal bumkin idiot, while being employed directly by the Pope. His arrest was much more about a direct insult to the Papacy than his ideas.
It should also be noted that at the trial, many did not want to see him convicted, including powerful direct family members of the Pope, and when he was convicted, he was placed on house arrest... In a lavish Italian villa. The church was very, very split on if he had done anything wrong, and in the end they decided they had to do something but gave him the absolute lightest punishment possible.
Finally, I want to point out that although yes, there are biblical reasons to believe in Geocentrism, there were secular reasons too. Gravity was one - it was understood as an inward force in the universe, it's quite a leap to realize that everything is attracted to everything else. There's a bunch of others (some of which Galileo shattered with his other work!) but I'll try to refrain from writing a whole paper in a comments section lol
tldr: Galileo was employed by the Pope, insulted him hard, and the church reluctantly gave him an exceedingly light sentence. It's more complicated than the way a lot of people discuss it.
Thank you for explaining! That's fascinating. Do you know why Galileo wrote the Pope like he did? Was he pressured into the job and was resentful, or did he really think the Pope was stupid, or what?
+1, really hope your comment gets some likes as there are ironic parallels between the popular version of the Galileo affair and the caricature of the Church that it portrays.
Probably the best history-of-science content I've ever encountered, in any medium, is about exactly this: Michael Flynn's essay "The Great Ptolemaic Smackdown". It's incredibly detailed and nuanced, and available both as an article in "Analog Science Fiction and Fact" (scanned and Googleable) or a significantly-expanded series on Flynn's blog, with plenty of diagrams. I can't recommend it enough, please go read it.
@@Khaim.m from what I've read (see above), Galileo was basically overconfident to the point of arrogance. Pope Urban was a personal fan of Galileo, and it was his suggestion to publish the arguments for heliocentrism in the first place, but Galileo decided anyway to depict Urban's (justified) interpretative caution as stupidity. As @jkebharper5905 says, he was arrested not for arguing for heliocentrism but for proclaiming it established fact when there was not yet sufficient evidence (and wouldn't be for over a century).
Thank you, I appreciate the details.
It is more like that time that Henry II accidentally ordered Becket to be killed. Theological differences did underpin it, but the argument was a lot more like humans arguing over who had real power and legitimacy than whether or not God was up to something.
Galileo just liked insulting people, I think (OP to check me on that).
He alienated people even when they agreed with him and would have helped.
I love hearing how science was working exactly the way it's supposed to even back then.
Not "oh he said this so he's right," or "that sounds wrong, so he's wrong."
It's "hmm, seems weird. Now I'LL test it too" followed by seeing the evidence and changing your mind based on the evidence, with no pride getting in the way of the truth
I mean, it took decades and lots of people kept not believing it for a full century after that. It's basically the same now.
Hank, I in fact was sleeping on the moons of Jupiter. Thank you for enlightening me
After learning from _The Expanse_ that fact about Ganymede's magnetosphere, I honestly dream of sleeping there.
I was sleeping with Io
I love going back to my dorm from my astronomy class and then opening up my phone and happening across more astronomy in the form of this video
Nuh uh. Pluto is the dog from Mickey Mouse. I’m 100 percent on that. How could I be wrong
You are not wrong.
Nah Goofy is the dog, nobody knows what Pluto is
No, she is the keeper of the door of space and time.
I’m a big fan of the Galliliean moons, as an aside I’m also a big fan of The Expanse books 😅. They’ve featured in so many works of Science Fiction and it seems that they are more special than we could ever imagine
The Expanse is the main reason I got into astronomy and all the sick moons in the solar system. It’s great!
The Expanse books definitely set me up to think of Ceres, Ganymede, etc as already being prime settlement candidates.
Arthur Clarke's sequels¹ to _2001,_ _2010_ and _2063,_ were what permanently cemented my fascination with the Galilean moons and the idea of Jupiter as a "failed star"-"All these worlds are yours, except Europa. Attempt no landing there."
¹technically "sequels" should be in quotes, as Clarke stated they're part of separate continuities (read: "don't @ me about plot contradictions")
I was introduced to Ganymede by an old Robert Heinlein book called Farmer in the Sky. I'm a little older than most of you. But science fiction is awesome.
I built an optical replica of Galileo's original telescope a few years ago, and it was really enlightening to see just how easily the moons could be observed. I really need to get back to that project and try grinding my own lenses for it, for the full experience. (My main conclusion of that project is that we're lucky Galileo lived in a sunny, Mediterranean climate. Had he lived in the Seattle area, we might never have had a scientific revolution. It took me *months* to get 5 days of observations in a row!)
I happen to live in Padua, which is where Galileo made his observations and spent most of his carreer. Let me tell you: it's not a place where a clear sky is the norm, like people imagine Italy 😉
At least Galileo would not have been fighting the light pollution we have now.
I used to volunteer at a lot of astronomy nights and one of my "entertain these people while they're waiting in line to look through a telescope" strategies was to talk about how the Galilean moons have been revolutionizing science, using the same points you describe! Cool to hear it from you and learn more about the other moons that aren't Europa.
0:07 "the moons of Jupiter have exploded" Oh no! "...our understanding" I think I have emotional whiplash now.
My thoughts on Pluto:
I remember, when I was a child first seeing the illustration of the orbits of the nine planets, recognizing that Pluto was _off._ All the other planets had nearly circular orbits well separated from each other and all on the same flat plane - and then there's Pluto, with its orbit tilted way off of that plane and so elliptical that it spent a good deal of time *closer to the Sun than Neptune.* It put me in mind of a song I heard on my favorite TV show (brand-new at the time), _Sesame Street_ - "One of these things is not like the others..."
So, when folks started finding lots of other objects out there with weird orbits like Pluto's, and realized that Pluto was actually one of _those,_ I didn't think of it as a "demotion" the way everyone reacting online does. Instead of the oddball runt of the planets like I'd been taught to see it, we now know it as the King of the Kuiper Belt - yay Pluto!
Not to speak of how silly the plea to "don't be mean to Pluto!" objectively is ... as if a non-sentient mass orbiting the Sun between ~30-40 AU out cares at all how we Earthlings classify it. All of which speaks more about how important certain people think their own opinions are, than about Pluto.
The problem I have with decisions made by the IAU about Pluto is not that Pluto is being discriminated against(I'm actually fine with it's designation as a dwarf planet) so much as according to the current IAU definition of a planet(the decision that 'demoted' Pluto) there are only 8 "planets" in the entire cosmos.
That may seem nonsensical(which it is) as we have made a big deal about detecting planets orbiting distant stars, but those are all classified as exoplanets. In order for a body to be a "real planet" it MUST orbit Sol. And because of that the IAU has thrust us backward to the days of 'special designation' for the Earth and it's buddies. Rather than do the sensible thing and adopt a more inclusive definition of planet, then designate subcategories such as gas giant, terrestrial, dwarf, etc.. we get a narrow definition that is not universally applicable.
Makes me wonder what Galileo would think about the IAU.
THANK YOU @dwc1964. I've been thinking the same thing for years.
@@shannonlawhorn1674 It should be that there are planets and some of them are exoplanets and some are endoplanets. Also nepioplanets like Pluto - baby planets. And for normal planets kopodeplanet - boring planets.
@@shannonlawhorn1674 Another problem with the IAU definition is that Pluto is a dwarf planet but not a planet which causes a lot of confusion. There are a lot of people who think that being a dwarf planet still makes it a planet and they're right for thinking that. A dwarf star like the sun is still a star and a dwarf galaxy is still a galaxy.
One of the common arguments for 'demoting' Pluto actually is discriminating against it. That line of argument goes that we shouldn't be preserving Pluto's status as a planet just because it was considered one historically and that it's so different from the others that it should have a separate categorization. But by that same logic, Mercury and Jupiter are incredibly different and the only reason they're both considered planets is because they were historically considered planets. Looking at the relative sizes and masses of the planets, even Earth is just a dwarf compared to Jupiter.
I think that adopting a more inclusive definition of planet with subcategories is definitely more sensible. Of course, there's still a lot we don't know about how star systems form and the definition of planet might have to be amended multiple times as we learn more.
Pilot episode for "Bizarre heavenly bodies". Can't wait for my Ganymede pin.
YESSSSSSSS
+
YOOOOOO YES
6:30 The Cool Worlds bit got me. Wanting to be as cool and collected as David Kipping on the mic is a relatable feeling for many science communicators, I’m sure!
I have a 6" dobsonian that I LOVE to look at Jupiter with!! Seeing the moons' motion is mind blowing.
I envy you! Especially right now with Jupiter up. (And Venus & Mars)
My first sight of Jupiter was in the early 90s through a rickety little refractor. I was beyond excited and immediately bought a 10" Dob. (Odyssey Compact) Man, I loved that thing so much! Must have spent 3x the cost of the scope on eyepieces & filters. Fun times!
@Splucked Saturn too! It's a great time for viewing! Clear skies 🤞
Hank yelling about things he's passionate about is one of the most entertaining and loveable things about Hank. Hank, keep being Hank. 😄💖
My dream growing up was always to be an astronomer because of exactly this type of excitement. I went a different way but thank you for making that sense of wonder and excitement accessible to me anyway. And the shirt is gorgeous, might have to grab one as an early birthday gift for myself!
Love you hank been watching you for longer than I can remember. you've taught me alot from being a kid till now as a 25 year old man. hope I'm early enough for you to see this man. Best science teacher ever.
0:31 *THANK YOU!* How the hell is the only actual image of Haumea a *deep fried blurry dot???* You're telling me there's a *squashed* dwarf planet *with a ring* out there, and no one wants to *see* it???? *WHAT??????* How is it *not* already an astronomical celebrity? *Make it make sense!!!*
13:49 1963 novel "Cat's Cradle" has a substance called "ice-nine." It has a melting point around 40C, where water is at 0. If ice-nine comes in contact with water, it acts as a seed and freezes the entire body of water. Glass, tub, pool, lake, ocean, it freezes the whole thing. If it gets in contact with a human body's moisture, it'll freeze the person, ice-nine kills --- where the band Ice Nine Kills got their name
That Vonnegut guy sure could write
I went there immediately too! That book messed me up, honestly
I am always glad to see another human with just as much enthusiasm for the complexities of planetary and celestial systems and bodies as I have :D I'm a big fan of Red Rising and other works based on the human expansion into other worlds, particularly since we tend to categorize those worlds through the lens of our systems, which simply exist within separate limits and forces than the ones currently beyond our reach. When people capture and explain those differences, we learn to conceptualize the world around us more thoughtfully.
i took an introductory astrobiology course in college as an elective and we spent a lot of time talking about these moons. they’re so cool.
It is amazing to me that even being alive for almost 50 years and spending so much of that time on the internet - yes, wasting time, but also learning tons and tons and tons of random things... it is amazing to me how much I still learn. Things that are sort of fundamental and important, but I learned a large part of what was said in this video.
Awesome
Me: My brain is tired and I just want to watch a Hank Green video.
RUclips: I gotchu
Yes! Another fun bit of history about the Galilean moons not mentioned in the video: Galileo created timetables of eclipses of the moons of Jupiter, called ephemerides. His predictions of the timings of eclipses were accurate enough that mapmakers used them to determine the longitude on land. "King Louis XIV of France, confronted with a revised map of his domain based on accurate longitude measurements, reportedly complained that he was losing more territory to his astronomers than to his enemies." -Longitude by Dava Sobel
Galileo also designed a funky navigation helmet called the celatone, with a telescope attached to one of the eyeholes.
#JusticeForPluto
(The Disney dog, not the planetary body. Why can Goofy just hyucking walk around like nothings wrong while his canine brethren are not free?)
Because he wears clothes.
-official disney canon (afaik)
@@Spacemongerrdoes this imply goofy is no longer considered human adjacent when changing clothes? or that the clothes are what allows them
to have consciousness?? or rather that the clothes act as the consciousness and possess the characters? so many questions
I’ve read this before. Animals with no clothes are animals, and animals wearing clothes are thought of as people. It’s why even sapient animals like Bambi still live in the forest and other animals (that wear clothes ie Mickey or Minnie and friends) live in a more modern society.
No #JusticeForMoons
Goofy is just a human with animal characteristics (a furry) and Pluto is a dog CHANGE MY MIND.
"ALL THESE WORLDS ARE YOURS EXCEPT EUROPA
ATTEMPT NO LANDING THERE
USE THEM TOGETHER USE THEM IN PEACE"
-- HAL, 2010
8:37 the exact feeling you have at 3am waking up with a dry mouth.
lmao this is so underrated
one of the 7 planets of the solar system? was there another demotion? 😮
No one else seemed to be mentioning that, I was about to google the planets to check I hadn't made one up lol
Since he said just before to consider Jupiter as a failed star he might have excluded Jupiter from the count, or he could have just misspoke.
Earth wasn't a planet. "Planete" meant "wanderer", as they moved through the sky. It wasn't clear Earth was the same kind of object for a long time
I thought the same, but these replies bring up some good points.
@@vivid_oblivion if he misspoke then we can forgive him just this once.
Such a fun video😊 watched a compilation of all the reunion videos recently and the "planets donˋt exist" and "there are other planetary bodies which should count as planets" was still tumbling around in my head. Getting this as basically a part two ❤ so excited for the things we will get to know about those orbs.
Also: I just love me a nerdy explosion of interest and excitement on the universe, I'd watch this series 😊
I prefer to think of Jupiter as an incredibly successful planet rather than a failed star. As for the Jovian moons, I can't think of any moons that are more appreciated other than our own, and they're still underappreciated. That's how amazing they are.
Hank: I love these moons so much and I feel like we ignore them
Also Hank: *calls a video about Galilean moons after Pluto*
Ceres always stands out to me. Mass driver launch point loaded with water, and pointing to the outer worlds. A tech testing ground for the cluster of similar-mass objects in our Solar system. Worlds where we'd float more than moon hop. Even just arbitrarily between 1.5% and 4.5% Earth Gravity, we've got Vesta, Pallas, Amalthea, Rhea, Dione, Iapetus, Tethys, Titania, Oberon, Ariel, Umbriel, Charon, Makemake, Eris, Haumea... Nothing soon nearby, but if we're investing in something we want to iterate upon, yanno? Mars is more unique than a key to further beyond, it feels like, with a deep gravity well compared to the numerous.
6:30 And I absolutely equally love his calm demeanor AND your chaotic enthusiasm! 😁
Plutonium is named after the Planet Pluto! Just like Uranium (after Uranus) and Neptunium (after Neptune)! And if Pluto was discovered 10 years later - or Plutonium 10 years earlier - that naming standard would have fallen apart!
Am I the only one that cares about this?!
i care
Why not just change it t be about celestial bodies? Then we could get europtionium or something similar if we produce heavier elements.
Watching you makes me glad I,m alive! Sum good stuff is rubbing off of you and onto me. And on a serious note, I’m so glad you survived your big health challenge. You make this world a better place
You should absolutely make a series of videos about these moons! Made me excited about them again :)
I love, LOVE, when someone smart like Hank gives an aside to explain something like a palimpsest, and I'm all "you don't need to explain it, I know what you meant, dude!". But at the same time, we're smart, Hank, teach us NEW things!
Behold my name.
I share your enthusiasm.
Hank, at 6:40 you made my day. Thank you for being you, you wonderful bean.
Make Pluto a dog again
Pluto is a dwarf dog!
MPDA
As someone who lives in the town with the observatory that FOUND PLUTO (Common school field trip)
Bold of Hank to assume I don't also love these moons and read about them in my free time like a huge NERD.
They're SO cool.
As soon as Hank said "failed star" Tomy Cardy's "H.S" started playing in my head :D
Actual science question regarding the fact that light has a speed and looking farther away means we're looking back in time: can anyone please explain how we know that light from distant galaxies is stretched because the universe's expansion is accelerating, instead of because it got stretched out due to earlier faster expansion and just hasn't been re-compressed because even if expansion slowed down it's still not contraction? i feel like this idea must be the result of me having an incomplete understanding of the phenomenon.....
Because we have light from every direction at a variety of distances, we see a pretty observable pattern that matches our theory of expanding space continuing over time. Some of this comes from how light itself is stretched out to lower wavelengths, but another part is that stuff like galaxies and pulsars are spread out farther from each other the farther out we go. There could be some weird uneven stretching going on, but it would have to be way more complicated to somehow still match our observations.
if we only had one Galaxy to look at, we wouldn't know when the stretching of light happened, and what you said could be correct. But, good news, there's lots of galaxies! So we can graph the amount of redshift that we see from various stars galaxies at various distances, and what we see is that the close galaxies, the ones "only" a couple million light years away, still have redshift. That tells us that it's happening close-ish to us, and in the recent-ish past (relatively speaking), it wasn't just at the beginning of the universe.
Then we look at galaxies that are further away, and see more red-shift, which tells us that it has been happening for a long time too, it wasn't just a one time event, and light that travels for longer gets shifted more.
Then, finally, we look at how *much* more red the far galaxies are, is light that traveled 2x as far 2x as shifted? And that's where we see the most surprising answer, no, light that traveled 2x as far *isn't* 2x as shifted, it's less, maybe only 1.9x. Which means that recent shifting is stronger than old shifting, and the universe's red shift is getting stronger over time. so the expansion of the universe that is causing that shifting is speeding up.
What you're suggesting is basically "what if red-shift was just a short term thing at the beginning", if that was the case, all of the light that was traveling before the expansion happened would be redshifted, and none of the light that shined out into the void after the expansion would be shifted. But, all of the light that we can see, even recent light, seems to be red shifted, so we know expansion is probably still happening
IDK if you look at comments after the first few hours, but this video made me feel a way that I haven't in maybe a decade. I remember being a kid and being fascinated by the solar system, and physics, and science, and everything. But at some point my encroaching adult responsibilities and lack of science communication beyond the simplistic made me lose faith in the wonders of the universe. But this video... this is it. It makes me remember what watching Bill Nye felt like, what early SciShow felt like. I've been so beaten down by the delays in modern NASA programs that I forgot Europa Clipper actually *did* launch and **holy shit** we're going to have a flyby in 5 years. Science can be so *fucking* cool, and I don't know when I forgot that. "Strange Charm" helped me love science 14 years ago, and even though we're both wildly different people today, you're still doing it.
1:44 aren't there 8 planets?
Earth is not a Planet, it’s the loony bin of the galaxy 😅
Thank you! I thought we'd lost another one 😅
paused immediately to look for discussion of this. my first thought was that Mercury had been demoted somehow? or maybe Hank likes some hypothesis about planetary *capture* like Expanse's Phoebe idea?
@@FrelanceEQ Seconded on Mercury. I strongly feel that giving Pluto back to its family of dwarf planets after kidnapping it for over three quarters of a century was the morally correct choice, but Mercury is quite lonely that close to the Sun. I have mixed feelings about Mercury not being a planet.
You know, I've been feeling lately like there are so many things that are not ideal about inhabiting this particular time and place in our universe, but getting to be alive at the same time as Hank Green, as he gleefully geeks out about our solar system--we're all pretty lucky.
17:10 You always wanna make sure that, if you pronounce an acronym, you also display it on screen, lest you end up with the ESA's "Jews" mission
He definitely pronounced it like Juice
AUDIBLY SCREAMING CRYING YEEHAWING AT THE IO SPEED OF LIGHT DISCOVERY GOD I LOVE SCIENCEEE 😭😭😭😭😭😭😭
the entire ganymede section sounds like a very, very weird innuendo
"Salty, hot and with multiple rocky layers below" sounds like my ex for sure.
I love the enthusiasm! This is great timing, too, because I've been binging RUclips videos about these moons for the last week. Planets are great, I'm especially fond of one in particular, but don't forget about these incredible moons!
5:34 3blue1brown just put out a video explaining all that with visuals. What a coincidence!
The while video is wonderful, but one thing that made me particularly happy was when you referred to Jupiter as a failed star and its "moons" as its would-have-been planets. I first heard that idea as a teenager, when I read it in a short story (by Larry Niven, IIRC) and it sparked in my brain forever after. Then, maybe a decade or two ago? I read somewhere that Jupiter was no longer considered a failed star, for reasons I don't remember. This made me sad, because I loved the idea that we almost had another solar system this!close to us. So thank you for reviving Jupiter-was-almost-another-star idea!
My favorite planetary body is Titan. It was famously postulated by Randall Munroe that the combination of dense atmosphere and low surface gravity could in theory allow a human being to flap their arms and fly like a bird, which I just think would be sweet.
Titan is awesome, but if you're already in the orbit of Saturn, you gotta find out what's going on with Iapetus. The ridge going around the whole planet, the distinct difference in albedo of the two halves, that weird monolith...
3Blue1Brown is currently running a series on how they calculated the distances in the universe, starting with Earth and working out.
Agree. Was always so fascinated by these 4 moons (especially io because of it's colors). Looking forward to the images!
YES I would love for you to do a series talking about Moons!!!!
9:44 hank, we've been over this. ice is rock and water is lava.
Hank... 6:30 I am sorry to say this, but you started this particular video off at a solid 8 outta 10. Time travel was at like a 12 😂
Goddamnit Hank I cannot express in words how deeply satisfying it is to watch someone very smart and very informed talk for almost 20 minutes straight about one of my fave special interests (the geology of non-Luna moons). Brain itch inCREDibly scratched 😌😌
We should advocate for calling the moons of Jupiter "Jovian planets."
Hank, I am also a massive Galilean moon lover. So glad to see you're on the right side of history.
7:33 Now I know why I have such a revulsion to that ride at Disneyland.
6:30 Calm and cool Hank (such as on Journey to the Microcosmos) is always appreciated, but enthusiastic and excited Hank is an absolute delight.
Taxonomy is sexy, guys. Don't let anyone tell you otherwise
Pluto's status, ahh yes. I love watching people get so upset about something that could not possibly matter less
GALILEO🎶
Galileo's head was on the block
The crime was lookin' up the truth
I'm glad to see more people appreciating how wonderful moons are! I forget who said it, but moons are the laboratory experiments of the universe given how many there are and how incredibly diverse they are. Once we can start cracking exomoons, the universe is gonna look even weirder!
They're planets, same as Pluto and Charon and Luna. If it's massive enough to be* round and it isn't in the process of fusing hydrogen to helium (or formerly have done so) then they're a planet.
...and no I will not be elaborating
That would mean that we have around 40 planets in our solar system. Would include Haumea, Makemake, Eris, Orcus, Salacia, Quaoar, Gonggong, Sedna, plus ~20 moons like Io, Titan, Oberon, Callisto, Tethys etc.
No need to elaborate, you're obviously correct.
@@SpacemongerrThe current situation is that there are 8 "planets" in the entire universe.
Which makes more sense? There are 8 planets in the whole universe, or there are lots in the solar system and lots more to be found?
i've been a massive Jovian Moons Enjoyer for a while now. so glad they finally got some recognition. personally, i'm betting they all revolutionize our thinking at least another 3 more times when those orbiters finally reach them
3:56 Hank it’s really disappointing that you did the classic “i dont know how to pronounce this name” thing. its literally never been easier in history to go to wikipedia find the ipa characters next to his name and paste them into a website that tells you how to say it. no need to be perfect but you could at least get an idea instead of using a disappointing common excuse
Give me a break! Seriously?
So happy to see other people excited about the Galilean moons, absolutely love the Jovian system. As soon as Hank showed the shirt I went to the description to check for a link before he even said one was there.
i’ve been listening to all of dear hank and john chronologically and i’m in the 240s now and i’ve been so invested in the progress of the mars drill that hank was talking about at the time and i can’t believe he just spoiled the ending for me at 14:26 ;_;
It's okay, I'm sure your Perseverance will pull you through 💜
the first time I saw these moons through my telescope on my front porch, I fell in love with the sky.
Your passion and energy for subjects you care about comes across, to me, as unhinged and I am here for all of it. I love it. Keep that passion and education flowing. Teach me more Hank!
The time lapse of Juno’s photos of The Galilean moons as it approached Jupiter is really cool. The moons are just floating there and moving around Jupiter.
It’s just gravity, but invisible force acting from a distance is eerie to see.
9:05 It was at thus point that Hank's love for Europa seemed to have cancelled out his ability to understand that it's not, in fact, a planet, but an interesting moon.
and this, when im literally wearing my Europa Clipper mission shirt. top tier post as always Hank
You hit the nail on the head. People keep making a fuss about Pluto no longer being a planet because they feel like it was wronged. But Pluto is not a person. There’s no point in feeling like it was wronged. But unfortunately, it is human nature to want to ascribe human attributes to inanimate objects.
Oddly depressing to imagine the possibility of life in an ocean so far under the surface of Ganymede, just stuck in darkness between two impenetrable layers of ice, just living things killing and eating each other in the dark without ever even seeing each other - which is I guess basically all microscopic life and lots of deep sea life, but the fact that the ones on Ganymede would never even be able to be known to us somehow makes it so much worse
Its fun to see how your style for videos has changed after becoming a professional stand up comedian. I'm sure it's also just an artifact of lifez but the evolution of your storytelling has been a joy to witness.
I want to point out at 10:28 that that is a SpaceX Falcon Heavy.
EC was supposed to launch on SLS and get there more quickly with fewer maneuvers, but given the pace of SLS development, it was decided to put it on the underpowered -- for EC''s mass and intended trajectory -- FH because it is reliable and readily avaliable; better to get it on its way and know when it will arrive than wait indefinitely.
I'm a geology student, specializing in paleontology, but I took an astrobiology class because that's fun. Also the professor works for NASA on astrobiology and geo stuff. Important note: we have NO evidence of life outside of Earth currently!! However. There are a number of places that are considered 'good' candidates, that if we were to find other life in the solar system it would most likely be there or at least would tell us about potential conditions that life could form/survive in extrasolar places (ex: Venus, NOT a good candidate. Basically hell, next). The Galilean moons, particularly Europa are some of those notable candidates! Saturn also has a moon with a water ocean covered in ice, Enceladus. So Enceladus and Europa are very very interesting to astrobiologists bc microbes (whats basically the most likely kind of life form to find) love a good liquid water ocean. Depending on the chemistry of those oceans, they could be very good candidates. (Also cryovolcanism is very very cool).
Most of what we have now are bits and pieces of the conditions for life scattered around. We've found amino acids, water, hydrocarbons, etc. in places around the solar system. A lot of the field of astrobiology is studying how life originated on Earth and its earliest forms, as that can help us understand what it would take for life to take hold in other places.
It's a really cool field (even if we haven't found any actual aliens) and yes, the moons are very cool!
This is the most Hank video I've ever seen. Like slap this in a gold record for the aliens.
Ps. Listening to Dear Hank and John. It's fun to see Hank's progression from obsessed ❤with Mars to obsessed with Jupiter's moonw 😂
this video singlehandedly has given me reason to keep going until 2030 just so i can learn more about these silly moons