Isaac is the David Attenborough of the space/science/futurism sphere. You can instantly recognise who is talking and know just as quickly that you are going to get premium quality.
For reals, Isaac is unique and an institution. This ‘what if’ clown talks like a cartoon character and talks down to his audience like we are 2nd graders. He sucks👎🏽
The Peter guy has a speech pattern that sounds forced and intensely patronizing. Like Isaac is doing science communication and Peter an episode of a magic school bus knockoff "isn't science neat, kids!"
@@TheReaverOfDarkness Where in the world did you find "virtue signalling" in any of the comments above? If anything, it's the exact opposite situation where we're being frank about our own visceral reactions to the sound of someone's voice.
40K is a setting in extreme regression, not stagnation, the volume of knowledge humanity has lost beyond any hope of recovery by the 31st, let alone 41st millennium, is absurd. this video explains it pretty well: ua-cam.com/video/1EqkOsERwi8/v-deo.html
@@RipOffProductionsLLC Yes, because a race of human-made Ai rebelled against it's creators - another, entirely different human-made AI race. That toppled galactic civilisation, and then FTL stopped working due to warp storms.
Opinion: A low gravity, dense atmospheric world would encourage the evolution of flying things, not giant walking ones. A low gravity, low atmospheric density world would encourage small life overall. A moderately low gravity, high density world (like earth) encourages the biggest life, as flight does not get the huge advantage it would on a lower gravity world. I don't think low gravity would lead to bigger organisms in any capacity, it would affect preference for flight (and maybe bipedalism) more. I think the 200 tons animal life can reach here is much more impressive than we give respect too.
I would disagree with low gravity, high density worlds encouraging flying creatures but not large ground creatures because, these two forms of creature take advantage of completely different niches. For example large ground creatures may take niches similar to that of elephants, and giraffes on earth, eating the leaves of trees, but due to low gravity the trees would far taller than on earth, and the leaves would be harder to get to. To solve this these large ground creatures would evolve to be as tall as possible to reach the leaves.
@@i.p.7687 So you're suggesting a setup where land-based life remains competitive with flying life that can get much larger on Earth because... it's harder to access food because the trees are taller? Did you forget your own setup or something?
Unpopular opinion: Earth basically has the perfect conditions for "giant" life, and what we consider normal is already so, so, so massive, the odds of us ever encountering something that dwarfs us is pretty low. Think about how much of our planet is made up of organisms so small you can barely see them (not even counting bacteria) and how much of the rest is made of insects, mammals, and birds, all less than an ounce or two in weight! What if we encounter alien life and the entire planets ecosystem, including the local sentient species, comes up to our knees?
That would be so awesome! - This is an apex predator of the entire ecosystem! - To be honest it looks like it could be a victim of a housecat... - Oh it actually can be, that is quite a big problem really... Fluffy disrupted entire local ecosystem.
I wreckon youd see a mix between 4ft and 8ft, any shorter and you expend too much energy just living, any larger and you run into the square root problem, at some point youre gonna need to keep all your limbs on the ground just to support yourself and you never evolve out of quadruped (assuming that alien life comes to the same evolutionary conclusion life on Earth did, that 4 legs does what 6 legs does for less energy and 2 legs is complicated coz you gotta not fall over)
@@BlackThunderRC They have 3.5 million subs in less than a year, but I guess that's because of daily uploads and so being heavily favoured by the algorithm.
Isaac: Next week’s episode is on technology that may be in the cards. Me: the title will be something like “technologies on the horizon” or “near-future technology” The Title: “New technologies that may be in the Cards” Me: ...
"Organic blimps" in gas giants fascinate me. There could be organisms the size of planets sleepily floating around Jupiter, and if they stay remotely deep in the atmosphere, they'ed be almost impossible to spot!
To be honest the guy you had on really adds an extra layer of appreciation for the way you speak, and the way you explain things without oversimplifying the concept or talking down to the viewer.
@@jamesdriscoll9405 another reason for animals or all life to be taller/bigger is more oxygen, which is why things were bigger before when earth had more oxygen than today.
Does life have to have a central nervous system based on electricity? Can one function or exist using light, sound, or something else? What would one possibly look like?
@@SangoProductions213 And yet the neuron's signals are indeed based on electrical charge differentials. Just because they're produced by chemicals doesn't make them not electrical.
Our central nervous system doesnt even use electricity. It uses gradients in the concentrations of ions across cellular membranes. And vasically all biological functions we have ever observed depend on concentrations of specific chemicals in a solution which makes up the organism.
I think the general reaction I'm seeing to peter is a bit harsh, but I definitely feel like his delivery is more infantilizing and comes off as a little insulting.
I was looking for information about simple and complex (and human) life in lower and higher gravity worlds and I found your channel after reading a comment on another video. This is amazing! Thanks for your videos!
Yeah my impression is that all tall trees are much more limited by wind than gravity from a structural standpoint. From a cohesion-tension water transpiration standpoint, low gravity would help them, but from a purely structural one, trees can face huge side loads from wind. And remember, a tree can live centuries or even millennia. So it needs to be able to survive that once in a thousand year wind storm, not just the day to day stuff. A big Douglas Fir or Coastal Redwood or any other 100-150 meter tree probably has 75 meters of foliage with an effective high speed drag coefficient of 0.5 or maybe even 1.0, 40 meters across. That's a nice big sail. 1500 square meters of it. And what's more, the center of pressure of that sail is 60 meters off the ground. In a 50 m/s wind (again, we need to at least sometimes survive once in a millennium storms here), that's 1.1-2.3 MegaNewtons (100-200 Tonnes-force) with a 60 meter lever arm for 130-260 million Newton-meters of torque! More torque than the wing of a 747 experiences under almost any conceivable situation. One study done in France suggests a fixed tree blowdown speed of 42 m/s for a variety of sizes and species, although I question if this really applies to the giant conifers of the north American west coast.
WRT Douglas firs regularly exceeding 100 m, yes, they do (or did). We cut most of the big ones down and built huge cities on the optimal habitats for maximum height. Thus why a 115 m Redwood far from an urban area and not a 140 m Douglas fir smack in the middle of Seattle holds the world record for height.
"....a bigger planet is likely to have a stronger magnetosphere to hold on to those gasses." I've heard a planetary scientist say something very interesting about that. She said that larger rocky planets would have greater pressure in their cores, which would tend to compress more of their iron content into a solid state, causing them to have weaker magnetic fields than Earth's, or even no magnetic field at all past a certain size.
Atmosphere retention is related to the temperature and the escape velocity. Temperature tells you how fast the molecules are going and escape velocity tells you whether that means they will escape the gravity well. You can have a low-g world with a high escape velocity if it is large but made of less dense stuff.
I play a game called Tau Station. It’s a sci-fi text-based RPG. It’s a pretty cool little game. It has a lot of extra features as well, like a “council” of temporary moderators who are elected by players. One feature, called Cinema, picks a somewhat relevant UA-cam video every so often and features it to all players as “old-Earth media” (the game takes place in the far future). Today, this was the featured video. Tl,dr: in the far future, this video is one of the few remaining relics of 20th-century humanity. Also, go play Tau Station.
SFIA : Here’s the colonization report, ship telemetry, fusion drive specs, and AI subroutines for self replication and hull repair. Grab a drink and a snack and you’ll be at Tau Ceti in 500 years. What If: What if we all held hands to astral project to Tau Ceti?
@@FLPhotoCatcher No I don't think any dates are given in the Space Trilogy, rather the events of the books are simply presented in as happening in more or less present day, present day being the time the books were written/published. You should definitely read the trilogy, it's every bit as good as the Chronicles of Narnia, but written with adults as the intended audience rather than being designed to be accessible and enjoyed by both children and adults the way Narnia was.
Its important to note that all these changes would be on an evolutionary time scale. Usually in science fiction humans being taller in lower gravity is not because they have evolved that way but because normal human growth is accelerated with less gravitational resistance. If anything humans transplanted to a lower gravity planet would at first be tall and willowy but slowly evolve to a more practical shape.
Awesome video! As someone obsessed with imagining new worlds, I hope you continue this sort of speculation on what alien life will be like on distant planets. Prehaps a complementary video on life on High gravity worlds? I always imagined human colonists on a super earth would adopt quadrupedalism.
11:35 Megafauna such as large dinosaurs or mammals did not live during a time with a higher oxygen concentration in the atmosphere. The animals did grow to larger sizes because of higher oxygen concentration were land arthropods like insects, arachnids, and myriapods in the Carboniferous.
Very true. This is an especially important point, because the largest known animal is still going about today with the current oxygen levels (The blue whale) and because the dinosaurs in particular had extremely efficient lungs which well permitted thriving in conditions with relatively lower oxygen concentration.
Clearly we should expect a strong evolutionary push towards large heads, green skin, 4 digits, and the propensity to start as many words as possible with a 'K'.
12:00 what's this guy got against birds 😂😂😂 I'd like to think he was thinking of something different to the displayed image and the guy editing it all just thought it would be funny.
I sure love your channel. I cant believe it took me so long to find. I truly appreciate the work and effort you must have to put into the videos you make. Amazing content. Thank you for all the hard work.
Big issue with small high CO2 atmosphere planets, especially far from the sun, is that as soon as you get plants they use up the CO2 and the temperature drops. You could end up with a permanent snowball or one that alternated between lush and tundra frozen for decades.
Only just now realizing how much I appreciate Isaac Arthur’s approach to audio compression hearing it juxtaposed with What If (Dubstep Were A Voiceover) here.
I dispute Pete's assertion about low gravity not holding onto lighter gasses. Titan has a very low gravity, but has a thick nitrogen atmosphere heavier than earth's.
But that's exactly the point. Diatomic nitrogen is a fairly heavy gas, heavier than helium and hydrogen at any rate. Titan's atmosphere consists almost completely of the heavier gases because it loses the light ones fast. Earth is a bit more capable of holding onto the light gases.
A lot of the need for muscle mass comes from gravity and muscle or bone mass costs in terms of the food required to grow and maintain it. Stuff still has the same inertia, but friction is lower and less work is required to lift things against lower gravity. If there's an evolutionary arms race towards melee you could get hulking giants, but herbivores pursuing not pursuing a combat strategy don't have that incentive and if the lesser strength required to just be ambulatory at a reasonable size is lower predators may not need to be as strong either.
Jesse Mulder why is this book not discussed more often? There’s almost nothing about it on the internet. I first read it back i the early 80’s and Its one of my all time favourites and way better than ringworld IMO. I also think it would make an Awesome movie with modern day CGI Mo/cap techniques, either that or “Hothouse” by Brian Aldiss. That too, would be some eye popping stuff....
Thanks for the book suggestion. I really enjoy your book selections. I read this CS Lewis Trilogy in college. I have to admit, it was the first time I needed a dictionary to understand an author's vocabulary.
Krzysztof Świderski There would be an entire scene showing the struggle of just trying to lift a pencil that is as heavy as a watermelon on some massive planet with high gravity!
@@wackyruss In my opinion your example is a bit exaggerated . Planets with solid crust like Earth would have only 2-3 times higher gravity, at max something about 5x higher if Kepler 145b is really a massive terrestrial planet. It's mean that object would weigh only 5 times more than on Earth.
There is some problematic misinformation from your guest What if while Venus is losing Nitrogen it relatively isn't a significant amount (though it is significant on longer timescales and part of the evidence suggesting the current Venus is a relatively recent phenomenon) Venus does hold onto Nitrogen it even has over 3 times the Nitrogen that Earth does he does say it has "some nitrogen" but the Nitrogen in Venus's atmosphere is about the same amount as Earth has in its atmosphere+biosphere so there doesn't appear to be appreciable losses. Of course the gravity differences between Earth and Venus are quite small relatively speaking so I don't think the differences there should be significant
There are a handful of big errors in this video when it comes to how the biology behind it stacks up, and I feel like with this one specifically you didn’t really care much on actual biomechanics and instead decided to wing it without considering how it would affect the end product. 10:28 “tall is only advantageous in nature if it makes a critter look more threatening or reach food that’s higher up” … what about the innumerable other uses for a tall physique? Dispersing seeds or spores over a wider area, seeing farther away, displaying or fighting for potential mates? And what’s worse the sentence that comes after is a complete non-sequitur. No, the lack of megafauna in the modern world has nothing to do with how tall is a beneficial trait, the lack of modern megafauna seems to be caused by human hunting and climatic shifts, not tallness no longer being favoured. 11:14 What exactly is he talking about? Hopefully someone can clarify this one for me. 11:36 “we can look at megafauna in the past who also benefited from higher oxygen levels” what on earth does higher oxygen have to do with lower gravity? As I noted on the Space Habitat Environment video, we aren’t even sure if oxygen levels led to larger body sizes for Insects, let alone Dinosaurs where we know for sure higher oxygen didn’t affect their body size. Actually, there is a school of thought that believes that gravity was lower in prehistoric times, that being the Expanding Earth, a now disproven notion that touts that Earth was smaller in the past and that it somehow added mass to itself to grow to its modern size, gravity increasing with it. 12:24 Leopards already exist buddy. They are large predators that live in trees. Indeed we already have animals that parachute and ones with wings; just look at literally any animal that can fly and you’ll see it’s got wings, same for gliding animals like Draco lizards or Flying squirrels. 16:10 The main reason you’re ignoring why lifeforms in low gravity would become fragile and frail is because muscle and bone are both very energetically demanding both to carry around and maintain. Skeletons are still something the body must repair and heal even if it doesn’t contain live cells, and muscle even more so since it needs electrolytes (salts) to maintain its function. This is why not using a muscle weakens it, the muscle in question becomes obsolete for survival of the cell colony (you) and therefore atrophies, freeing up the proteins and lipids to be better used; a similar mechanism happens to cause reduced bone density in astronauts as the calcium in the skeleton can be reclaimed because it is no longer needed for support. The main takeaway is that lower gravity wouldn’t necessarily mean thinner musculature would be a given, but it would still be favourable over very thick bones and muscles for a given size class. 16:25 You do know that’s just a myth, right? Camels don’t store water in their humps, the adipose tissue in humps acts as a larder for food, not water. I know I definitely came off as uncouth here, and although I still admire your content, I think you should try to update this video specifically; the Fermi Paradox compendium also needs an update. Good luck mate.
One qualifier you likely need to add in, size is relative. Therefore, saying something is tall, or massive, doesn't actually make sense unless it's compared to something. We are potentially a massive, or microscopic creatures compared to those living on other planets of different gravity. Love your work. Keep it up
saying that oxygen levels were higher during the age of dinosaurs is not true. the oxygen levels had become as low as they are today over 100 million years before the dinosaurs ever existed.
21:40 - congrats! The book should at least grace your shelves again soon when your lovely bride merges in her bibliography;). Seriously though awesome man, so happy for you both!
Isaac, you are your s/o are both adorable. I love this channel so much and it’s gotten me through some tough times. I hope if you read this it makes your day a bit brighter. Be safe.
Me, beginning of this episode, used to the rest of UA-cam: He'll probably only talk about the gravity issue and not evolutionary competition. I'll prep a comment explaining that kind of stuff. Me, middle of this episode, remembering that this is Isaac Arthur: Oh, right, this guy's actually thorough.
I Love your videos BUT I would really prefer if you didn't sneak other peoples voices into them I come here for you and I don't mind being pointed to other channels but I don't like being forced into them.. Its been a real pleasure to see the channel grow over the years and see yourself grow as a person and the quality of your content always improve! I have watched every video on your channel some of them dozens of times and I have thousands of total hours of watchtime here. You give myself and many others a reason to hope for the future when everyone says how bad things are I always hear your words in my head reminding us all truly how great the human race could be if we really get ourselves together and work on a brighter future! Thank you for the years of fantastic content and making this world a better place. Congrats on your engagement!
Pretty much this. Could not write it better myself. Been here for about 4-5 years. And what a great journey it was. Always have to chuckle when rewatching the older episodes, where he says "If you told me a year ago, when the channel had 100 subscribers, ..., that thousands of folks would be tuning in every week, to listen to a guy with speech impediment..." like here ua-cam.com/video/_Kt7883oTd0/v-deo.html while he has almost 500k subscribers now. I do not really mind the occasional Fraser Cain or even John Michael Godier. But I think these collaborations would be better of as specials, rather than in place of regular Arthursday content. As I often play these as audio before falling asleep, the host voices are rather disturbing. Nevertheless it is his choice and I respect it. Dear Isaac, thank you for all the amazing content and peaks into our possible future. I'm glad I have learned english, because now I can listen to great works like yours. Congratulation to your marriage, wish to you and your wife bright and happy future.
You said that trees on a more massive planet could grow taller due to being able to produce lighter-than-air pockets inside of themselves, but weight isn't really the main factor in how tall a tree can get, they can just pack on more width, to an extent. But the real limiting factor on tree growth on Earth is the limits of capillary action, which drives the vascular system of trees and is responsible for getting water from the roots to the leaves, where part of it is used in photosynthesis, and the rest is transpired out to pull up more water through adhesion. Granted, the equation for capillary action scales linearly with gravity, while the volume of wood required to support a tree of the same height would scale faster than that, there may be a point where the limiting factor would be compression of the wood, but it definitely isn't a factor on Earth, since the redwoods of California don't even hit the theoretical limits of capillary action at 400 feet. The main reason all trees don't grow that tall is due to lack of nutrients and water, stresses like pests, and mostly cause they don't need to. No point in being 50 feet taller than your neighbor when being 5 feet will suffice. Edit: source for the 400 feet number comes from a 2004 article by George Koch in the journal Nature and it's free to view.
You should do a video about life specifically on high gravity worlds, focusing on combating high gravity on a planet itself and how a civilization would accomplish that or how they'd terraform the planet or bioform themselves to be suited to the planet.
Isaac is the David Attenborough of the space/science/futurism sphere. You can instantly recognise who is talking and know just as quickly that you are going to get premium quality.
What if one day we totally terraform Mars and were able give it a breathable Earthlike atmosphere and pressure. The gravity would still be low, but you could go outside without a spacesuit! You could jump really high and bounce around under blue skies and breathable air! Imagine riding dirt bikes or playing basketball on such a world!
Drinking ferrofluid won't be enough I think. But with metal bodies it should work. Except everything non-magnetic would still float. Air flow would still be different. So it only acts like gravity on certain objects. That is a very poor artificial gravity effect. Also magnetising the floor might create quite a sticky gravity that is much stronger at your feet than at your hips for example. Maybe the magnets would work better when they are a certain distance below the floor. But I do not understand magnetism well enough. It might be possible with a magnetic floor.
At present, our only means of leaving the planet or launching satellites are chemical rockets. Launching a rocket from a smaller than earth body is much easier. Launching a rocket from larger than earth body gets exponentially difficult. If there is intelligent space-faring life, they might technologically mature in that role more rapidly coming from a smaller planet than a large one. Larger planets might have more developed societies but lack the means of leaving their planet?
Seems right. Civilizations on high-G worlds might be less hesitant to use nuclear rockets though (Andromeda project). So the limit for gravity that still allows space travel would be a bit higher. Not much though. Railguns and lasers might push space ships off of even more massive super earths. But as you said: that would mean a civ on such a world would have to be more advanced before it could leave. If that is still possible.
Near the center of an O'Neal cylinder, the gravity gradient goes to zero. If the ends of the cylinder are hemispheres, there may be some unique local ecologies that are adapted to low-gravity. Insects and birds that eat insects may quickly adapt to that part of the cylinder's atmosphere that has a low gradient creating a peculiar "ecological cloud" near the axis.
Hey Issac, is it possible to have multiple earth sized planets in the same orbit? And what would be the max before the planet's gravity begins to have an affect on each other.
Oh dear! Please don’t have that guest speaker on again. I felt like I was listening to an AM radio morning show. He seemed to dumb down your show to a grade four science class.
Isaac is the David Attenborough of the space/science/futurism sphere. You can instantly recognise who is talking and know just as quickly that you are going to get premium quality.
Like James Earl Jones, Issac has turned his speech impediment into an strength.
Your voice is a significant reason I listen to this channel. (Sorry but I didn’t like switching to another UA-camr in the middle.)
For reals, Isaac is unique and an institution. This ‘what if’ clown talks like a cartoon character and talks down to his audience like we are 2nd graders. He sucks👎🏽
Reminds me of Barry Kripkey lol
I hope he talks about life on gas giants
Nothing against Peter, but this episode made me appreciate Issacs voice a good bit more and how much it has grown on me.
I'm curious as to what accent Isaac has. It almost has a "southern gentleman" type feel to it. Easy enough to understand nonetheless.
The Peter guy has a speech pattern that sounds forced and intensely patronizing. Like Isaac is doing science communication and Peter an episode of a magic school bus knockoff "isn't science neat, kids!"
@@kyrrekausrud5960 I hate to agree but I totally agree. Tbf, his delivery is probably good for younger audiences but definitely not my cup of tea.
This virtue signalling makes me sick.
@@TheReaverOfDarkness Where in the world did you find "virtue signalling" in any of the comments above? If anything, it's the exact opposite situation where we're being frank about our own visceral reactions to the sound of someone's voice.
Isaac: technological stagnation
My mind: Warhammer 40K
Ave Imperator!
Wow
The Emprah Proteks!
40K is a setting in extreme regression, not stagnation, the volume of knowledge humanity has lost beyond any hope of recovery by the 31st, let alone 41st millennium, is absurd.
this video explains it pretty well:
ua-cam.com/video/1EqkOsERwi8/v-deo.html
@@RipOffProductionsLLC Yes, because a race of human-made Ai rebelled against it's creators - another, entirely different human-made AI race. That toppled galactic civilisation, and then FTL stopped working due to warp storms.
Opinion: A low gravity, dense atmospheric world would encourage the evolution of flying things, not giant walking ones. A low gravity, low atmospheric density world would encourage small life overall. A moderately low gravity, high density world (like earth) encourages the biggest life, as flight does not get the huge advantage it would on a lower gravity world. I don't think low gravity would lead to bigger organisms in any capacity, it would affect preference for flight (and maybe bipedalism) more. I think the 200 tons animal life can reach here is much more impressive than we give respect too.
I would disagree with low gravity, high density worlds encouraging flying creatures but not large ground creatures because, these two forms of creature take advantage of completely different niches. For example large ground creatures may take niches similar to that of elephants, and giraffes on earth, eating the leaves of trees, but due to low gravity the trees would far taller than on earth, and the leaves would be harder to get to. To solve this these large ground creatures would evolve to be as tall as possible to reach the leaves.
@@i.p.7687 So you're suggesting a setup where land-based life remains competitive with flying life that can get much larger on Earth because... it's harder to access food because the trees are taller? Did you forget your own setup or something?
Unpopular opinion: Earth basically has the perfect conditions for "giant" life, and what we consider normal is already so, so, so massive, the odds of us ever encountering something that dwarfs us is pretty low. Think about how much of our planet is made up of organisms so small you can barely see them (not even counting bacteria) and how much of the rest is made of insects, mammals, and birds, all less than an ounce or two in weight! What if we encounter alien life and the entire planets ecosystem, including the local sentient species, comes up to our knees?
That would be so awesome!
- This is an apex predator of the entire ecosystem!
- To be honest it looks like it could be a victim of a housecat...
- Oh it actually can be, that is quite a big problem really... Fluffy disrupted entire local ecosystem.
This idea was done on the Twilight Zone😃
Yeah but there was also 30-50% more O2 and CO2 in the atmosphere than after the meteor hit
I wreckon youd see a mix between 4ft and 8ft, any shorter and you expend too much energy just living, any larger and you run into the square root problem, at some point youre gonna need to keep all your limbs on the ground just to support yourself and you never evolve out of quadruped (assuming that alien life comes to the same evolutionary conclusion life on Earth did, that 4 legs does what 6 legs does for less energy and 2 legs is complicated coz you gotta not fall over)
Thank you, Isaac, for featuring us in your episode!
I found your channel from this video. Thanks indeed, Isaac!
Yo I watched what if the earth was as big as the sun and I doesn't even make sense. No science. Just some editing.
I see the same problem as Mariam. What the hell? Go away please.
@@BlackThunderRC
They have 3.5 million subs in less than a year, but I guess that's because of daily uploads and so being heavily favoured by the algorithm.
space 1999 Isaac Arthur talks facts
Imagine ridiculous sizes like 9m to 12m reevaluated to be *normal*
I wanna hollow out the skull and replace it with a control panel
Specify the context, lest minds descend to the gutter and off-colour jokes commence.
@@annoyed707 I didn't think that way till you mentioned it 🤣
@@annoyed707 Don't you think it upsets you a lot more than it should?
Ants have been having this debate for thousands of years.
SFIA > What if.
Never change Isaac... your science content is some of the best around.
(I don't recommend going to what if lol.)
Isaac: Next week’s episode is on technology that may be in the cards.
Me: the title will be something like “technologies on the horizon” or “near-future technology”
The Title: “New technologies that may be in the Cards”
Me: ...
Thank you for such an in-depth analysis, as always. Stay safe.
This has to be one of the only channels where I actually watch the sponsor section every single time, because Isaac transitions into it so seamlessly.
"Organic blimps" in gas giants fascinate me. There could be organisms the size of planets sleepily floating around Jupiter, and if they stay remotely deep in the atmosphere, they'ed be almost impossible to spot!
Thanks for that image of Lovecraftian horrors I have in my mind now.
To be honest the guy you had on really adds an extra layer of appreciation for the way you speak, and the way you explain things without oversimplifying the concept or talking down to the viewer.
your content on youtube is a diamond among an ocean of coal
That would make the legacy media an ocean of ___________
Just take a look at the Trending page if you want to lose a few billion brain cells 🤦
@@poggyfroggy4156 oil is more valuable
@@sidgar1 It's all just mindless BS I only saw one good video there from minute physics.
@@sidgar1 Drew gooden somehow made it to #3 on trending. that gives me hope
One other reason for an animal to be taller: seeing farther.
Longer stride, possibly better Navier-Stokes performance in fluids?
@@jamesdriscoll9405 another reason for animals or all life to be taller/bigger is more oxygen, which is why things were bigger before when earth had more oxygen than today.
What does height have to do with that?! Personally, I saw my father more as a child than I do now that I am a fully grown man. ;)
Agree
Climbing and picking fruit too.
Congrats on your engagement!
Tomorrow my wife and I will celebrate our tenth anniversary.
Congrats on a decade! That's an achievement to be proud of!
Congrats! Today is the day you will celebrate yer tenth anniversary :D
Does life have to have a central nervous system based on electricity? Can one function or exist using light, sound, or something else? What would one possibly look like?
Underrated question.
Silicon based life or carbon-silicon based life are possibly use light computing or pure electrical computing as the nervous system.
Considering single cell life. And the fact that not even our life is "electricity based". Yes.
@@SangoProductions213 And yet the neuron's signals are indeed based on electrical charge differentials. Just because they're produced by chemicals doesn't make them not electrical.
Our central nervous system doesnt even use electricity.
It uses gradients in the concentrations of ions across cellular membranes.
And vasically all biological functions we have ever observed depend on concentrations of specific chemicals in a solution which makes up the organism.
I was thinking of writing a novel about how living on different planets would change human physiology so this has been a very useful video.
Yes, still in quarantine having a stressful week, and now I'm feeling better now this video popped up
Until it reaches the part where it mentions audio books for "going to the gym", and that seems like ages ago.
@annoyed707, well if it makes you feel better, I have a home gym, but it's not the best thing compared to a regular gym. But it's better than nothing
@annoyed707 I’m sure that when Isaac recorded this episode it was before quarantines for reduction of spread of this virus was a common thing.
Been very curious about this! Thanks for making this :)
I think the general reaction I'm seeing to peter is a bit harsh, but I definitely feel like his delivery is more infantilizing and comes off as a little insulting.
I was surprised to even see him on here and the video that he was promoting was terrible
12:05 If pigs could fly, everyone would carry an umbrella!
I was looking for information about simple and complex (and human) life in lower and higher gravity worlds and I found your channel after reading a comment on another video. This is amazing! Thanks for your videos!
Yeah my impression is that all tall trees are much more limited by wind than gravity from a structural standpoint. From a cohesion-tension water transpiration standpoint, low gravity would help them, but from a purely structural one, trees can face huge side loads from wind. And remember, a tree can live centuries or even millennia. So it needs to be able to survive that once in a thousand year wind storm, not just the day to day stuff. A big Douglas Fir or Coastal Redwood or any other 100-150 meter tree probably has 75 meters of foliage with an effective high speed drag coefficient of 0.5 or maybe even 1.0, 40 meters across. That's a nice big sail. 1500 square meters of it. And what's more, the center of pressure of that sail is 60 meters off the ground. In a 50 m/s wind (again, we need to at least sometimes survive once in a millennium storms here), that's 1.1-2.3 MegaNewtons (100-200 Tonnes-force) with a 60 meter lever arm for 130-260 million Newton-meters of torque! More torque than the wing of a 747 experiences under almost any conceivable situation.
One study done in France suggests a fixed tree blowdown speed of 42 m/s for a variety of sizes and species, although I question if this really applies to the giant conifers of the north American west coast.
Woops. 70-130 MN*m of torque, not 130-260
WRT Douglas firs regularly exceeding 100 m, yes, they do (or did). We cut most of the big ones down and built huge cities on the optimal habitats for maximum height. Thus why a 115 m Redwood far from an urban area and not a 140 m Douglas fir smack in the middle of Seattle holds the world record for height.
Love how you speak just realy suits the types of vids you make
Isaac! "Never lend a book" - Captain Adama. Congrats on the engagement!
🎉
Wait... wasn't he an Admiral when he said that? And... In the Colonial Fleet, Commander has higher than Captain. Lee was a captain, y'know.
"....a bigger planet is likely to have a stronger magnetosphere to hold on to those gasses." I've heard a planetary scientist say something very interesting about that. She said that larger rocky planets would have greater pressure in their cores, which would tend to compress more of their iron content into a solid state, causing them to have weaker magnetic fields than Earth's, or even no magnetic field at all past a certain size.
the corona quarantine just got a little bit better, thanks isaac!
Atmosphere retention is related to the temperature and the escape velocity. Temperature tells you how fast the molecules are going and escape velocity tells you whether that means they will escape the gravity well. You can have a low-g world with a high escape velocity if it is large but made of less dense stuff.
Thumper that is a good point but the density can only drop so much before it turns into a gas world without a solid surface for life to arise on.
Congratulations on your engagement!
Thank you so much 😀
I never had ever anticipated that peter and Issac would work together. Two voices of curiosity, imagination and hypothesis
I play a game called Tau Station. It’s a sci-fi text-based RPG. It’s a pretty cool little game. It has a lot of extra features as well, like a “council” of temporary moderators who are elected by players. One feature, called Cinema, picks a somewhat relevant UA-cam video every so often and features it to all players as “old-Earth media” (the game takes place in the far future). Today, this was the featured video.
Tl,dr: in the far future, this video is one of the few remaining relics of 20th-century humanity. Also, go play Tau Station.
SFIA : Here’s the colonization report, ship telemetry, fusion drive specs, and AI subroutines for self replication and hull repair. Grab a drink and a snack and you’ll be at Tau Ceti in 500 years.
What If: What if we all held hands to astral project to Tau Ceti?
Last time I was this early people still thought we'd have a colony on Mars by 1990.
Did C. S. Lewis mention 1990 in his books? ..I had no idea that he wrote sci-fi. Far out!
@@FLPhotoCatcher No I don't think any dates are given in the Space Trilogy, rather the events of the books are simply presented in as happening in more or less present day, present day being the time the books were written/published. You should definitely read the trilogy, it's every bit as good as the Chronicles of Narnia, but written with adults as the intended audience rather than being designed to be accessible and enjoyed by both children and adults the way Narnia was.
XD
Your videos are consistantly amazing and you've got an incredible voice to go with it
The last time I made the leap this early, low gravity didn't hold me down.
Another fantastic video Isaac, reminding me that my preconceptions are still narrow and that vast possibilities exist.
A good Arthursday as always.
Making my quarantine so much better, many thanks from a future astronaut
Its important to note that all these changes would be on an evolutionary time scale. Usually in science fiction humans being taller in lower gravity is not because they have evolved that way but because normal human growth is accelerated with less gravitational resistance. If anything humans transplanted to a lower gravity planet would at first be tall and willowy but slowly evolve to a more practical shape.
Awesome video! As someone obsessed with imagining new worlds, I hope you continue this sort of speculation on what alien life will be like on distant planets. Prehaps a complementary video on life on High gravity worlds? I always imagined human colonists on a super earth would adopt quadrupedalism.
I am glad to hear about the interesting realistic things that life and people would have to deal with. Hope you are doing good.
Ah wonderful, more for the Isaac Art playlist running constantly, even in sleep. Good to dream😴
I want to live on a world with a sulfur hexafluoride atmosphere so everyone will speak like Darth Vader.
PhazonSouffle it’s great for Pars: non toxic, greenhouse gas to help terraform, and also obviously increases air density.
11:35 Megafauna such as large dinosaurs or mammals did not live during a time with a higher oxygen concentration in the atmosphere. The animals did grow to larger sizes because of higher oxygen concentration were land arthropods like insects, arachnids, and myriapods in the Carboniferous.
Very true. This is an especially important point, because the largest known animal is still going about today with the current oxygen levels (The blue whale) and because the dinosaurs in particular had extremely efficient lungs which well permitted thriving in conditions with relatively lower oxygen concentration.
Dude you couldn’t know just how badly I needed this today. Somehow helped me keep it together. Thanks for being you sir.
Clearly we should expect a strong evolutionary push towards large heads, green skin, 4 digits, and the propensity to start as many words as possible with a 'K'.
12:00 what's this guy got against birds 😂😂😂 I'd like to think he was thinking of something different to the displayed image and the guy editing it all just thought it would be funny.
I sure love your channel. I cant believe it took me so long to find. I truly appreciate the work and effort you must have to put into the videos you make. Amazing content.
Thank you for all the hard work.
Big issue with small high CO2 atmosphere planets, especially far from the sun, is that as soon as you get plants they use up the CO2 and the temperature drops. You could end up with a permanent snowball or one that alternated between lush and tundra frozen for decades.
glad you got to have fun doing a collab, but I hate sharing your voice time with other, less relaxing voices.
"We don't know yet" applies yet again. | Second
For anything we don’t understand. “I don’t know” is the only honest answer
I've been waiting for you to do this one.
Isaac Arthur, you are collaborate with What if channel. I am surprised and impressed.
They reached out to me about a month back, was quite a lot of fun, but collabs usually are :)
Your the David Attenborough of space! Love your channel so much! Your accent just makes it even more better.
Only just now realizing how much I appreciate Isaac Arthur’s approach to audio compression hearing it juxtaposed with What If (Dubstep Were A Voiceover) here.
I dispute Pete's assertion about low gravity not holding onto lighter gasses. Titan has a very low gravity, but has a thick nitrogen atmosphere heavier than earth's.
But that's exactly the point. Diatomic nitrogen is a fairly heavy gas, heavier than helium and hydrogen at any rate. Titan's atmosphere consists almost completely of the heavier gases because it loses the light ones fast. Earth is a bit more capable of holding onto the light gases.
Yeah, 200kg tiger gliding around like a flying squirrel. Gonna be fun trying to climb up the evolutionary free for all once those show up.
A lot of the need for muscle mass comes from gravity and muscle or bone mass costs in terms of the food required to grow and maintain it. Stuff still has the same inertia, but friction is lower and less work is required to lift things against lower gravity. If there's an evolutionary arms race towards melee you could get hulking giants, but herbivores pursuing not pursuing a combat strategy don't have that incentive and if the lesser strength required to just be ambulatory at a reasonable size is lower predators may not need to be as strong either.
Life on Tidally-Locked Planets?
Please...?
I think that was episode 6 or 7, waaaaaayyyyy back, though I've been considering redoing it as Life under a Red Sun.
@@isaacarthurSFIA on the side note - I like your early episodes very much. Don't mess with them, please.
ua-cam.com/video/K7OloPuLMpA/v-deo.html
Great episode, but I was hoping you'd mention larry niven's integral trees. Maybe life in a gas torus could be a future episode?
Jesse Mulder why is this book not discussed more often? There’s almost nothing about it on the internet. I first read it back i the early 80’s and Its one of my all time favourites and way better than ringworld IMO. I also think it would make an Awesome movie with modern day CGI Mo/cap techniques, either that or “Hothouse” by Brian Aldiss. That too, would be some eye popping stuff....
That book was good.
Thank you for showing us a picture, you guys are an adorable couple. You deserve it man, you are an incredible human being.
Thanks for the book suggestion. I really enjoy your book selections. I read this CS Lewis Trilogy in college. I have to admit, it was the first time I needed a dictionary to understand an author's vocabulary.
I would be glad to see film about life on high gravity worlds too.
Krzysztof Świderski There would be an entire scene showing the struggle of just trying to lift a pencil that is as heavy as a watermelon on some massive planet with high gravity!
@@wackyruss In my opinion your example is a bit exaggerated . Planets with solid crust like Earth would have only 2-3 times higher gravity, at max something about 5x higher if Kepler 145b is really a massive terrestrial planet. It's mean that object would weigh only 5 times more than on Earth.
omg i am reading the word "worlds" in isaac's voice.
There is some problematic misinformation from your guest What if while Venus is losing Nitrogen it relatively isn't a significant amount (though it is significant on longer timescales and part of the evidence suggesting the current Venus is a relatively recent phenomenon) Venus does hold onto Nitrogen it even has over 3 times the Nitrogen that Earth does he does say it has "some nitrogen" but the Nitrogen in Venus's atmosphere is about the same amount as Earth has in its atmosphere+biosphere so there doesn't appear to be appreciable losses. Of course the gravity differences between Earth and Venus are quite small relatively speaking so I don't think the differences there should be significant
Also the video he was promoting is awful I couldn't even get through it
There are a handful of big errors in this video when it comes to how the biology behind it stacks up, and I feel like with this one specifically you didn’t really care much on actual biomechanics and instead decided to wing it without considering how it would affect the end product.
10:28 “tall is only advantageous in nature if it makes a critter look more threatening or reach food that’s higher up” … what about the innumerable other uses for a tall physique? Dispersing seeds or spores over a wider area, seeing farther away, displaying or fighting for potential mates? And what’s worse the sentence that comes after is a complete non-sequitur. No, the lack of megafauna in the modern world has nothing to do with how tall is a beneficial trait, the lack of modern megafauna seems to be caused by human hunting and climatic shifts, not tallness no longer being favoured.
11:14 What exactly is he talking about? Hopefully someone can clarify this one for me.
11:36 “we can look at megafauna in the past who also benefited from higher oxygen levels” what on earth does higher oxygen have to do with lower gravity? As I noted on the Space Habitat Environment video, we aren’t even sure if oxygen levels led to larger body sizes for Insects, let alone Dinosaurs where we know for sure higher oxygen didn’t affect their body size. Actually, there is a school of thought that believes that gravity was lower in prehistoric times, that being the Expanding Earth, a now disproven notion that touts that Earth was smaller in the past and that it somehow added mass to itself to grow to its modern size, gravity increasing with it.
12:24 Leopards already exist buddy. They are large predators that live in trees. Indeed we already have animals that parachute and ones with wings; just look at literally any animal that can fly and you’ll see it’s got wings, same for gliding animals like Draco lizards or Flying squirrels.
16:10 The main reason you’re ignoring why lifeforms in low gravity would become fragile and frail is because muscle and bone are both very energetically demanding both to carry around and maintain. Skeletons are still something the body must repair and heal even if it doesn’t contain live cells, and muscle even more so since it needs electrolytes (salts) to maintain its function. This is why not using a muscle weakens it, the muscle in question becomes obsolete for survival of the cell colony (you) and therefore atrophies, freeing up the proteins and lipids to be better used; a similar mechanism happens to cause reduced bone density in astronauts as the calcium in the skeleton can be reclaimed because it is no longer needed for support. The main takeaway is that lower gravity wouldn’t necessarily mean thinner musculature would be a given, but it would still be favourable over very thick bones and muscles for a given size class.
16:25 You do know that’s just a myth, right? Camels don’t store water in their humps, the adipose tissue in humps acts as a larder for food, not water.
I know I definitely came off as uncouth here, and although I still admire your content, I think you should try to update this video specifically; the Fermi Paradox compendium also needs an update. Good luck mate.
One qualifier you likely need to add in, size is relative. Therefore, saying something is tall, or massive, doesn't actually make sense unless it's compared to something. We are potentially a massive, or microscopic creatures compared to those living on other planets of different gravity. Love your work. Keep it up
Congratulations on your engagement, I wish you both harmony.
saying that oxygen levels were higher during the age of dinosaurs is not true. the oxygen levels had become as low as they are today over 100 million years before the dinosaurs ever existed.
21:40 - congrats! The book should at least grace your shelves again soon when your lovely bride merges in her bibliography;). Seriously though awesome man, so happy for you both!
Isaac, you are your s/o are both adorable. I love this channel so much and it’s gotten me through some tough times. I hope if you read this it makes your day a bit brighter. Be safe.
Me, beginning of this episode, used to the rest of UA-cam: He'll probably only talk about the gravity issue and not evolutionary competition. I'll prep a comment explaining that kind of stuff.
Me, middle of this episode, remembering that this is Isaac Arthur: Oh, right, this guy's actually thorough.
A low gravity world would probably be a nice place to have flying cars. At least, it would be easier.
@Please Complete All Fields I'm doubtful about the human-powered flight but I do see flying bicycles being a thing
Happy Arthursday! Stay safe
I Love your videos BUT
I would really prefer if you didn't sneak other peoples voices into them
I come here for you and I don't mind being pointed to other channels but I don't like being forced into them..
Its been a real pleasure to see the channel grow over the years and see yourself grow as a person and the quality of your content always improve!
I have watched every video on your channel some of them dozens of times and I have thousands of total hours of watchtime here.
You give myself and many others a reason to hope for the future when everyone says how bad things are I always hear your words in my head reminding us all truly how great the human race could be if we really get ourselves together and work on a brighter future!
Thank you for the years of fantastic content and making this world a better place.
Congrats on your engagement!
Pretty much this. Could not write it better myself.
Been here for about 4-5 years. And what a great journey it was. Always have to chuckle when rewatching the older episodes, where he says "If you told me a year ago, when the channel had 100 subscribers, ..., that thousands of folks would be tuning in every week, to listen to a guy with speech impediment..." like here ua-cam.com/video/_Kt7883oTd0/v-deo.html while he has almost 500k subscribers now.
I do not really mind the occasional Fraser Cain or even John Michael Godier. But I think these collaborations would be better of as specials, rather than in place of regular Arthursday content. As I often play these as audio before falling asleep, the host voices are rather disturbing. Nevertheless it is his choice and I respect it.
Dear Isaac, thank you for all the amazing content and peaks into our possible future. I'm glad I have learned english, because now I can listen to great works like yours.
Congratulation to your marriage, wish to you and your wife bright and happy future.
You said that trees on a more massive planet could grow taller due to being able to produce lighter-than-air pockets inside of themselves, but weight isn't really the main factor in how tall a tree can get, they can just pack on more width, to an extent. But the real limiting factor on tree growth on Earth is the limits of capillary action, which drives the vascular system of trees and is responsible for getting water from the roots to the leaves, where part of it is used in photosynthesis, and the rest is transpired out to pull up more water through adhesion. Granted, the equation for capillary action scales linearly with gravity, while the volume of wood required to support a tree of the same height would scale faster than that, there may be a point where the limiting factor would be compression of the wood, but it definitely isn't a factor on Earth, since the redwoods of California don't even hit the theoretical limits of capillary action at 400 feet. The main reason all trees don't grow that tall is due to lack of nutrients and water, stresses like pests, and mostly cause they don't need to. No point in being 50 feet taller than your neighbor when being 5 feet will suffice.
Edit: source for the 400 feet number comes from a 2004 article by George Koch in the journal Nature and it's free to view.
You should do a video about life specifically on high gravity worlds, focusing on combating high gravity on a planet itself and how a civilization would accomplish that or how they'd terraform the planet or bioform themselves to be suited to the planet.
"We have Peter, the voice of What If"
This is somehow gonna end badly
Wow, this reminds me of speculative evolution, the works of Wayne Barlowe and such. Very interesting!
Isaac: humans will have to use armors to keep itself on the ground.
Me: *Power Armor flashbacks intensify.*
Videos get better and better this is why IA Needs to consult on games and movies.
The most outrageous accent in all science entertainment today
One of the best science shows on Orth.
Isaac is the David Attenborough of the space/science/futurism sphere. You can instantly recognise who is talking and know just as quickly that you are going to get premium quality.
Mowas is my fav planet
1:21
Thanks for the nightmares. I wasn't planning on sleeping ever again, anyway.
11:54 This is why I set the gravity of Aegis to 80%. It’s so giant flyers don’t have ridiculously large wings
Merry Issac Arthur Thursday guys and gals!
ive been looking forward to this
Imagine being able to use your army of 472K people to get your book back from your fiance.
Isaac doesn't have to. Isaac just did it.
Wait what happened
Finally a topic suggested by UA-cam that is not COVID-19.. GOOD LUCK TO YA ALL!
What if one day we totally terraform Mars and were able give it a breathable Earthlike atmosphere and pressure. The gravity would still be low, but you could go outside without a spacesuit! You could jump really high and bounce around under blue skies and breathable air! Imagine riding dirt bikes or playing basketball on such a world!
Happy Arthursday!
Thanks Isaac, stay safe and well.
This is a bit tongue in cheek but could you create an artificial gravity effect by getting someone to drink a ferrofluid and magnetising the floor?
Drinking ferrofluid won't be enough I think. But with metal bodies it should work. Except everything non-magnetic would still float. Air flow would still be different. So it only acts like gravity on certain objects. That is a very poor artificial gravity effect.
Also magnetising the floor might create quite a sticky gravity that is much stronger at your feet than at your hips for example. Maybe the magnets would work better when they are a certain distance below the floor. But I do not understand magnetism well enough. It might be possible with a magnetic floor.
I love the Space Trilogy. Thank you so much for mentioning it.
At present, our only means of leaving the planet or launching satellites are chemical rockets. Launching a rocket from a smaller than earth body is much easier. Launching a rocket from larger than earth body gets exponentially difficult. If there is intelligent space-faring life, they might technologically mature in that role more rapidly coming from a smaller planet than a large one. Larger planets might have more developed societies but lack the means of leaving their planet?
Seems right. Civilizations on high-G worlds might be less hesitant to use nuclear rockets though (Andromeda project). So the limit for gravity that still allows space travel would be a bit higher. Not much though.
Railguns and lasers might push space ships off of even more massive super earths. But as you said: that would mean a civ on such a world would have to be more advanced before it could leave. If that is still possible.
Near the center of an O'Neal cylinder, the gravity gradient goes to zero.
If the ends of the cylinder are hemispheres, there may be some unique local ecologies that are adapted to low-gravity. Insects and birds that eat insects may quickly adapt to that part of the cylinder's atmosphere that has a low gradient creating a peculiar "ecological cloud" near the axis.
Hey Issac, is it possible to have multiple earth sized planets in the same orbit? And what would be the max before the planet's gravity begins to have an affect on each other.
Well, formal definition of planet requires the object to have cleared its orbit of other significant bodies (that gives you stable orbit)
Is the Earth spinning backwards at 4:40?
Yes, nice catch
Time to learn. Thank you sir.
The Integral Trees books by Larry Niven were interesting as an exploration of an ecosystem without a planet at all, just a dense torus of atmosphere.
Oh dear! Please don’t have that guest speaker on again. I felt like I was listening to an AM radio morning show. He seemed to dumb down your show to a grade four science class.
I haven't watch the whole thing yet but here is my obligatory comment that, yes, I'm here.