Distances: Crash Course Astronomy #25

[@5lhunt]

I remember first watching this video when it came out, at the time I was still in school doing my exams but now I'm in the 2nd year of my PhD in astrophysics:)

[@IXPrometheusXI]

My favorite thing about this episode is that it focuses on the how, not the what. I love learning about the methods people actually used to figure these things out. It makes them seem so much... Nearer.

[@phoonhoymeng8290]

@EARTH IS seriously FLAT Non sequitur and straw man fallacy. You really are dishonest.

[@pasijutaulietuviuesas9174]

@EARTH IS seriously FLAT A stranded flat earther. You're far away from home there, lad.

[@pasijutaulietuviuesas9174]

It may seem nearer, but it's actually still far away from us mere plebs. It's like listening to Mozart and thinking, "this is so simple, I could have thought of that" _after_ the pieces have already been composed. Or realising how simple yet fundamental Boolean algebra is to information theory, surely you could have thought of it yourself, right? That's the thing. It takes truest geniuses like Mozart, Boole and Newton to come up with ideas that no one could ever think of yet seem so simple.

[@Stillow]

@EARTH IS seriously FLAT I think you are lost

[@brfisher1123]

Putting 4.2 light-years in perspective: seeing that this video was uploaded 4 years ago (July 16, 2015) we're seeing the alpha centauri system as it was around the time this video was first uploaded back when Phil Plait was giving us awesome Crash Course Astronomy videos! That is if we're viewing it on 2019. I enjoyed seeing Phil Plait on Crash Course Astronomy back in 2015!

[@godavaribhat6297]

So underrated coment

[@hornchief4839]

Phil is a great teacher, I actually found him on TV. I really hope he keeps doing more Crash Course stuff!

[@wei446]

Hornchief discovery science huh?

[@brentsander4849]

So figuring out the AU turned out to be pure gold.

[@LydiaIsSweet]

I hate school books, they're almost always written in such a difficult way as if they assume you've been studying the topic for years - and I'm talking undergrad level. So, so grateful for these crash courses that are much easier to grasp and actually try relating some of this stuff which may feel abstract to everyday life examples. And it's not even in my first language yet it's much more pedagogic and understandable than the books I have in my home language. Thanks for being creative and reminding students why they chose their field!

[@TheFireflyGrave]

This series is so great. I knew a parsec was roughly 3 lights years, but I had no idea that it was devised in a completely unrelated way. The ways scientists over the centuries came up with various measurements is fascinating.

[@juliocervantes8523]

This might be my favorite CrashCourse Astronomy lesson. Love learning how people figure stuff out.

[@LPSwimmer2011]

This series has probably become my favorite CrashCourse series. Thanks Phil!

[@viasaliha6150]

i get chills almost every time i watch this series bc DAMN the universe is so big and beautiful and just wow

[@Lowandhard06]

U like it big 😘😘

[@dekippiesip]

@@Lowandhard06 oh boy, you are onto something.

[@mcsmaria28]

5:58 - well, I never really understood math until I got older, because ironically I went into a field that required math. Even though I hated it in school. I wish I had as good math teachers as I had in the other subjects. It may not have seemed so scary.

[@scarletstar6184]

OMG THANK YOU FOR UPLOADING THIS!!!! I was sooo confused in class today!! And this helped me a lot!!!! THANK YOU THANK YOU THANK YOU THANK YOU!!!!

[@liamgurney3802]

mimiariana class? isnt it summer :p

[@scarletstar6184]

yeah, I'm in college, lol. I have classes during the summer, unfortunately...^^

[@badastronomy]

mimiariana Wow, that's fantastic! Glad to help. :)

[@Tetracarbon]

***** Thanks to you, Scott Manley, and Jebediah Kerman (i.e. Squad) I've learned so much about Astronomy & science. This is a big deal since I'm an accounting academic and science isn't something we need to deal with. Cheers Phil.

[@Marce159951]

Tetracarbon (Phillip Wong) eeereereerrz ez ffrt yhe xcx x czz ds@):- z fd rzxx:8) ZD TDZ., ZR

[@ffggddss]

Handy way to remember (how to compute) what a parsec is: par-sec == parallax-second 1 parsec = 1 AU / 1 arcsecond where the arcsecond is expressed in radians: 1 arcsecond = 1º/3600 = (π/180)/3600 = π/648,000 So: 1 parsec = 1 AU · 648,000/π = 206,264.8 AU

[@Ni999]

And you can get to light years by the sun being about 499 light-seconds away. 1 parsec = 206264.8 AU × (499 light seconds/AU) × (1 yr/(365.25×24×3600 seconds)) ≈ 3.26 light years

[@HSCrimson]

When I was very young, I actually though the moon was chasing me...

[@verdatum]

Thanks to the law of universal gravitation, it technically, ever so very slightly is.

[@Hoopty91]

verdatum epic

[@SteveFrenchWoodNStuff]

It was. And now it's watching you, as you sleep. Sweet dreams!

[@Darkstar.....]

hunter cochran its still chasing you. How are u still alive?

[@elchicoreacts872]

Me too bro, aahh.......memories 😂😂😂😂😂

[@speedanderson6]

I was watching a documentary about The Sun last night, and I saw Phil Plait on there, thinking "Hey! The Crash Course guy!". I really like this guy as a host for this.

[@fffffffuckingponyfaaaaagsg3696]

Wow, I got here early. Hey, just wondering, how long will you keep up this series with astronomy? I love astronomy and these videos are great, and I hope you don't stop soon. Keep it up, guys, you're great.

[@HBMmaster]

***** good for you

[@HRCFre4k]

FFFFFFFUCKING PONYFAAAAAGS GET THE FFFFFFUUUUUCK OFF MY VIDEO! REEEEEEEEEEEEEEEE dat name doe. Well, there is still a lot to talk about. For example: Galaxies, Nebula, the Universe itself, maybe some strange phenomena, like The Great Attractor or Dark Matter. And Stars itself, their life cycle, especially Neutron Stars and Black Holes, because they are super fascinating and deserve more than just a few words!

[@Quokkat7]

Crash Course Astronomy is my favorite one of the entire crash course series! amazing job!

[@Me3stR]

I LOVE that last picture of the Andromeda Galaxy you used. I could stare at that, and its own stars, all day.

[@doraaaa0613]

I want Phil to teach me everything

[@thomaslomanno8427]

Same.

[@alexwang982]

I hope this is sarcasm, Edit:his channel looks idiotic

[@avs6362]

@EARTH IS seriously FLAT What ?

[@avs6362]

@EARTH IS seriously FLAT is it a joke or you seriously believe that?

[@bennymarshall1320]

@EARTH IS seriously FLAT If there is a book on trolling, you need to read it dude.

[@TerenceClark]

I've taken college level astronomy coursework and been a space geek my whole life, but I'd never heard how we determined the AU. That's awesome! Thanks, Phil! And thanks crash course!

[@vovasoft]

Amazing series. And I liked this guy after just 1 video. The quality is also very good.

[@toastynotes]

Love the breakdown on how we learned the relative size of our galaxy. From the size of Earth, to how far away the Moon is, to how far away the Sun is. Learning how the puzzle was put together can be just as fun as looking at the finished result.

[@dangerouslytalented]

*the Kessel Run is a smuggling route, probably through a lot of obstacles like asteroids. Something which is very tricky to do in a direct manner. So doing it under 6 parsecs or whatever means that he was able to do it in rather a direct manner, making it as short as possible.

[@perspectivedetective]

dangerouslytalented Originally, Solo's comment on the Kessel Run was intended to be pure boastful BS. He wasn't supposed to know what he was talking about ("if the ship's as fast as his boasting, we ought to do well"). It all got retconned later into the 'shortest distance' model to try and make sense of Han's bragging.

[@Arkalius80]

dangerouslytalented That's what's called a retcon. The line was likely written by someone who thought "parsec" was a unit of time. People have "retconned" the line to be what you have described. Retcon = retroactive continuity - suggesting a different meaning than originally intended for a plot or story element to fit with information discovered after it was written/presented.

[@dangerouslytalented]

***** ... fast and manoeverable. If you can go straight through an asteroid field, you can cut a lot from your journey.

[@MeepChangeling]

Arkalius80 Who cares? lol

[@SV67943]

***** This. The original line was about speed. There's no way to retcon that. Stop trying to "fix" Star Wars, people. Lucas did enough of that shit on his own, and look where that got us!

[@herpsenderpsen]

this whole video basically summed up my physics class and it was hell!

[@chrissame]

I love these videos: Its like getting my drivers licence, but in Astronomy!

[@B4brenda]

This is,by far, my favorite video of the astronomy series.

[@burpilicious9687]

"Curiosity can lead us to great great distances" True.

[@lemonfridge5119]

this is the best channel ever. Great teacher like john green and this guy who are funny and very good at teaching us for school in a enjoyable way. always will watch their videos for school

[@oChaoticBlitzx]

This video was insanely helpful in understanding space distance! Great job!

[@zedasilva3]

Gotta say you guys managed to make a series just as good as Crash Course History,and I freaking love Crash Course History! Good job,guys! You make learning fun!

[@spectre111]

I read some where that a lot of the Greek calculations were off because they assumed the Earth was a perfect sphere, which it is not. It's not flat by any means but it's not perfectly round and that threw off their sums a little bit.

[@tonyreyes8190]

Wow one of my favorite crash course videos of all time. I wanna learn about this so much right now. Very cool.

[@Azivegu]

Suddenly there was a terrible roar all around us and the sky was full of what looked like huge bats, all swooping and screeching and diving around the car.

[@ryangoldade4561]

We can't stop here, it's bat country

[@joshpwner8818]

Lol. I was watching this and wondered if anybody noticed it.

[@petertimowreef9085]

I think I all ready knew about 80% of all the things you say, but they were just random bits of knowledge floating through endless mind-space. Like when you say them I go "oh right I knew that, I heard that before". But when I actually need the knowledge in a pinch I can't get to it fast enough because there aren't enough connections. This series is perfect for constructing a mental lattice-work, connecting the facts into a bigger understanding of Astronomy and making the individual tidbits of info much easier to remember. And it's very enjoyable too, thanks a lot!

[@simplename000]

YES. Exactly this! It's linking everything I'd learnt too!

[@rahulvinodroy1518]

thank you sir i have now understand whole concept about parallax

[@tuomaskristola8441]

So I have ADD. Today is one of those days I'm having a hard time focusing on the subject at hand without slipping into my imagination to extrapolate on the ideas I'm receiving. I could only take in approximately a third of the information in this video on a single watch - but thanks to your videos being so pleasant to watch, I'm poised to watch this again. And again. So, thank all you CrashCourse people for making learning easier and more fun for a somewhat challenged person like me.

[@mikeseay8053]

This show has helped me with my answer to the "what do you want to do in college?" question

[@josephcasey9280]

Well it's been four years...how that work out for you?

[@Bushcraft-xz6xd]

Glad that there are much smarter people out there that have figured out all this so I can watch KZbin videos on the subject!

[@Balin_James]

it still baffles me to think that, despite how many stars there are in our galaxy alone and all that, a lot of them are in the order of light years apart. it's crazy

[@hogdog6525]

Even if life exists somewhere else (which if you ask me it has to considering how vast the universe is), the enormity of space means we probs won't ever get to encounter them. I really wish I was born maybe 200 or 300 from now so that I could see advancements in space travel.

[@davidk1308]

Hog Dog Just help fund and support these projects so they can get done faster, like a Mars mission, a Moon colony, a eel on Euorpa, a sub on Titan, a cloud city on Venus, a telescope that will look for life, all of these things will happen between now and 2040 if we support them.

[@pdc023]

CaptainCat 15 Equally as astounding are globular clusters, where collections of 70,000 stars or more are concentrated into a volume of roughly 50 light-years diameter.

[@doraaaa0613]

It's also baffling to know that there are around a hundred BILLION galaxies, and 70 sextillion (70 x 10^21 if I'm not wrong) stars in the universe. Just.. Wow.

[@judsonkr]

ALL, of them, are light years apart.

[@thesilverfox06]

I'm writing an Astronomy curriculum from scratch for the upcoming school year, and these videos are just amazing. My students will have seen every one of them by semester's end.

[@TalhaBedir]

I just fell in love with astronomy, trigonometry, geometry, maths or spectroscopy and any kind of nerdy shit

[@fyk1117]

I wish I'd be years younger that could've seen such courses in school ages, but never too old to learn, thanks for the great share of wisdom and knowledge.

[@Majoofi]

So how did we figure out the speed of light?

[@MeepChangeling]

Majoofi By standing on two hills a known distance apart an timing how long it took to see the light from a lantern lit on each hill. Then later by using devices to detect laser pulses from longer strait line distances.

[@360Freaks]

Meep Changeling Nope. The problem there is that the speed of light is simply too fast to be measured this way. Light takes only .000005 seconds to travel one mile. There's no way Galileo could have accurately measured that.

[@TheCardiffMafia]

Majoofi Well it is relatively new, basically a laser is shone over a known distance into a detector and a computer uses the speed = distance/time equation to work out it's speed, the better the computer got the more accurate it could measure the time and so our degree of accuracy increased. It is 299,792,458 m/s . That is in a vacuum (the more air the more the light gets distorted and less accurate to measure) - DISCLAIMER i did this of the top of my head so don't complain if the Wikipidia says something different.

[@Arwiiss]

Majoofi First rough estimate was made in 17 or 18 hundreds by observing one of the Jupiters moons. Some guy was writing down times when one of Jupiters moons appears and hides and noticed that there's a delay between expected appearance when earth orbited away from or closer to Jupiter. Than he plugged in orbital values and calculated speed of light with astonishing degree of accuracy. He was off by 30% or something but given technology of the time it was amazingly accurate.

[@Majoofi]

Arwis HellFrost That's interesting. Thanks

[@bigkkm]

I didn’t realize until the end that the host was Phil Plait. Read a lot of his stuff but never had seen or heard him. A great explanation of parallax and distances.

[@fernandoschuindt1665]

Best KZbin series or best KZbin series?

[@jamescain2141]

Yes

[@BumpyFly]

I watch a lot of crash course, and I think this may be the best video I've ever seen on this channel! Thank you so much for taking such an important fundamental concept and boiling it down to where I can explain it to anyone who asks me!

[@Goreuncle]

As always, great lesson, Phil. Just one thing, it seems that the Kessel run parsec thing from Episode IV actually makes sense, Han was talking about distance after all. YES, I know, it doesn't seem possible, but hear me out and you'll see how it can make sense. Take a look at this description (read the "History" section) > starwars.wikia.com/wiki/Kessel_Run It seems that the Kessel run isn't exactly a race, it actually consists in smuggling "Glitterstim spice" from Kessel (hence the name) to a location close to a cluster without being caught by imperial patrols... So it's literally a run... It appears that Han was crazy enough to bring the Falcon very close to the black holes in the area, he basically took a shortcut, so to speak. So he made the Kessel run in less than 12 parsecs because of that shortcut... or perhaps he was able to shake off those imperial patrols at a point that was closer to Kessel than normal, so there you have two possible explanations. 1-He got to the delivery point following a shorter route of 12 parsecs instead of the typical one of 18 parsecs. (it doesn't account for speed, though) 2-He was able to shake off those imperial patrols when he was just 12 parsecs away from Kessel (after just 12 parsecs of pursuit, instead of 18, that is)...so you can say that he made the Kessel run, and made it faster than most (this explanation does account for speed indirectly, so it's more valid, imho). The shortcut explanation was probably made up by some SW fan, but it's not a bad one, I think, XD The "shake off" explanation is mine, I think it's a better alternative since it also conveys the idea of speed, which is the point Han wanted to make in that cantina conversation with Luke and Obi.

[@SapphireCrook]

Goreuncle I knew at least ONE person would step up with this argument to defend it.

[@Goreuncle]

Sapphire Crook Actually, somebody below did it before me, LOL. Btw, like Phil, I always thought that SW screenwriters just didn't know what they were talking about (that's probably the case anyway, XD). I just did a little bit or google magic and I saw this explanation, which isn't that bad...I improved it a little and I'm pleased with the result.

[@Meatman8089]

I'm re falling in love with this channel all over again!

[@HigherPlanes]

... and from Hunter S. Thompson's persepective, he didn't travel to Vegas, as much as Vegas arrived in him.

[@onair141]

Astronomers are a gift to the world!

[@yawzheek6722]

"Next Episode - 26: Stars" Thanks for this week of torture!

[@craydenrosario7847]

Your teaching methods are greatly fascinating..... It didn't allow me to blink or even get distracted while watching. Keep up this good work and thanks for such amazing videos!🙂

[@heliosdelsol]

Omg I love the Fear and Loathing reference!!! 😸👏🏼

[@TunaFreeDolphinMeat]

Glad to know I am not the only one who drives down the road as trees fly past and with the moon following me. From content and host to visuals and sound, an interesting and well produced series.

[@cpob2013]

its amazing how much knowledge was lost when the church got all witch-burny

[@KimShailee]

the big bang theory finder was a priest xD but it all went downhill after that

[@ednelson2501]

They burnt anything or anyone that disagreed. Im surprised there is anything left. They are guarders of the holy secret.

[@TheBaMMboozle]

Are you guys acting or are you actually stupid?

[@Luxalpa]

Probably still not as much as was lost when the Great Library burned down.

[@wesmo_]

@Connor O'Brien - How do you people have interest in science and ignore history? Church had huge interest in science and financed hundreds of scientist priests. The disagreement was with Galileo because the Church had his own astronomers hired to control the calendar. The gregorian calendar used to this day, the most accurate possible, was founded by the church that had interest that universal christian feast to be celebrate in the correct time. So yes, when Galileo, who was looking for fame, used Copernicus theory, Church astronomers disagree, so the Pope went with their own people. A mistake, but in any fact or form church was against science.

[@ptl763]

Really liking these newer videos that focus on the methods of astronomy. Much better paced and consistently interesting than the 'objects of our solar system' videos which had their moments but felt like a bit of a slog when watched all in a row

[@TheBonzobonzo]

FEAR AND LOATHING IN LAS VEGAS !!

[@Ronenlahat]

Can I suggest a chapter about an overview of the history and the misconceptions of astronomy? This series is wonderful.

[@wheezyplaylists7993]

Speed of Earth's orbital velocity: 30 km/sec

[@surya8891]

I don't know how others think about this , but in my opinion it's really cool how we can use both the concept of luminosity and parallax method to how far the stars are away from us !!!!!!!!!!!

[@gloobark]

crazy that they got the camera man that far. respect

[@th3sand7]

"Curiosity can take us to great, great distance". As a curious, it's very touching to hear 😊😊😊

[@justgonnastay]

100,000,000,000,000 kilometers? What is that, like, 400 miles?

[@MarCuseus]

Chris Moore "miles"? *facepalm*

[@ffggddss]

+Chris Moore (100 trillion km) It's about 62,000,000,000,000 miles (62 trillion mi) About 10 or 11 lt-yr

[@justgonnastay]

+ffggddss It was a joke, man.

[@ffggddss]

Well it would sure make the stars more accessible! You could literally *drive* to Alpha Centauri in an afternoon! Wouldn't that be neat?

[@dudz1055]

+Chris Moore it would be 621371192237.334 miles

[@TheGuyWhoIsSitting]

Really enjoying this series! I hope this doesn't end too soon. I suppose there is also your own channel(s) and everything, but I've really enjoyed this course.

[@anomienormie8126]

I'd've liked more details on the Standard candle methods.. not just a mention of the cepheid stars

[@liliesstarlight]

I love how Crash Course teaches for a few minutes like I can understand straight away. My teacher teaches for a week and I can't understand the basics

[@Cryogenian]

It sad that the Ancient Greeks knew more about astronomy, math and science than most people do today.

[@rickkwitkoski1976]

Yeah, but did the "average" ancient greek know this stuff? Most likely not. They were more interested in screwing their ewes...

[@gagan4012]

@@rickkwitkoski1976 agreed

[@khadijafatma4532]

@@gagan4012 Bro Please tell what your profile photo is ? As far as I think 10% people have same profile photo as you🤔🤔

[@dekippiesip]

No, only the intellectual elite knew this stuff. And the current intellectual elite knows much much more than they did. The ancient Greeks are very impressive when you compare them to the middle ages though. We could have had starships and several colony planets by know if it wasn't for the fall of the roman empire and the church blocking progress for centuries.

[@americansmark]

Im pretty sure I watched this the exact minute it was posted. Was browsing the astronomy Playlist on the video page afyer seeing you on my tv (science channel) and it popped up on my auto refresh. Great as always. Next to the old cosmos, this is my favorite science series. I'd love to see you do some full length stuff.

[@liliesstarlight]

Flat earthers quacking at the Greeks

[@cakedreviews2811]

these never cease to amaze me.

[@ayushsharma9270]

And people think that the earth is flat.....

[@bingo4519]

Ayush Sharma Fortunately, they are only in a very small minority, and most of them are in America. Get your education system together America!

[@LD-qj2te]

Ayush Sharma mostly NBA players. But that is to be forgiven , their college degrees are for show, they don’t have to study or go to school they just have to dribble and shoot a ball ! Oh yeah and talk trash

[@SteveFrenchWoodNStuff]

Not "people", "idiots".

[@tyhggb]

EARTH IS seriously FLAT I have researched flat earth. It's only for full blown fucktard clowns

[@tyhggb]

EARTH IS seriously FLAT says the fucktard that doesn't understand that if something get too far away to see, it shrinks in size

[@stevendemaree4282]

I really like all of these episodes. Very informative. I just completed a text book "Mathematics of Astronomy" and this was very useful.

[@rebelyell1983x]

Don't astronomers use Type 1 Supernova's as a "Standard candle" to measure distances as well?

[@kuronosan]

rebelyell1983x He sort of mentions them at 10:02

[@BullShitThat]

rebelyell1983x Yes, he never said they didn't :?

[@foobargorch]

rebelyell1983x search "How Far Is It" by David Butler on youtube, it's a series of videos that works up from parallax to standard candles to z very nicely

[@frankschneider6156]

rebelyell1983x Yeah, sort of disappointing, that in an episode on distances he leaves out the standard candle and the doppler shift out.

[@foobargorch]

Frank Schneider as long as it's just an episode on distances and not the episode on distances I wouldn't worry about it =)

[@AndreyKitsa]

The best way to explain this subject so far! Well done!

[@Canma890]

Thank you for using kilometers ! :D

[@phoonhoymeng8290]

@I know you are right, And I just got owned but: no it is simply stupid to use miles.

[@phoonhoymeng8290]

@I know you are right, And I just got owned but: Non sequitur and ad hominem fallacy.

[@phoonhoymeng8290]

@I know you are right, And I just got owned but: It is funny that I can convert easily but find it rather inconvenient.

[@fugginnice]

Solo was not referring directly to his ship's speed when he made this claim. Instead, he was referring to the shorter route he was able to travel by skirting the nearby Maw black hole cluster, thus making the run in under the standard distance. By moving closer to the black holes, Solo managed to cut the distance down to about 11.5 parsecs. Love the show, cheers!

[@richardnixon2567]

I just discovered Astronomy and to be honest, its rather overwhelming. Thinking about outer space almost makes me want to cry. I learned that it will take 300 years for Voyager 1 to reach the oort cloud. And another 30,000 to pass through it. WTF. I'l be lucky to live til 2100, i can't even begin imagine what we'll learn from here to then, let alone in those 300 years. Then there's the fact that there might be as many as 100 billion solar systems in the milky way galaxy alone. hfs, i'm not even trying to get into clusters and superclusters. Yet here we are letting our planet go to shit with pollution. People will never understand that there's more to it.

[@DarkAngelEU]

The Universe doesn't care whether we exist or not anyway so it's entirely up to ourselves to make something out of it.

[@robert_wigh]

Thank you very much, Phil Plait and the rest of _CrashCourse_ Astronomy, for making this video! The universe really is big, immense, gigantic, humongous, infinite! That’s great and all, but it really is a big problem for space boomers. I wonder how we will travel to the nearest solar system and deal with those big distances in the future....

[@ethanboyd6885]

Pause it at 4:54 ! :))

[@ikuzolightskin]

Ethan Boyd lol I know

[@nicholasc3905]

Ethan Boyd I don't see it??

[@SV67943]

I like your Sound Designer. I've never noticed any audio mistakes in any Crash Course video, though to be fair, I'm yet to watch Biology or Economics. That's a bigger accomplishment than it might seem to anyone who's never so much as seen a soundboard, much less mixed or mastered audio.

[@drink15]

Anyone else think Green Lantern?

[@tmason995]

Yup, I did

[@krishnamshinde5589]

What!why?

[@joshn2564]

Good clarification of the distances of our observable universe & how we measure them with light.

[@danamuise4117]

size of the earth - math = flat earth theory

[@YawnGod]

This video is so full of information. Mighty.

[@godavaribhat6297]

Flat earthers left the chat

[@joseforappangal6169]

This is my favourite video because amaizing distances are what attracted me to astronomy!

[@JabberCT]

Any way you guys can put miles as text on the screen whenever you use kilometers for us lowly non-metric people?

[@Goreuncle]

JabberCT Are you serious? Just use a calculator... Introduce the amount in kilometers and multiply it by 0.62, that will give you a pretty close approximation in miles. I usually convert cm to inches with the calculator (dividing by 2.54), you definitely can do it on your own.

[@unvergebeneid]

JabberCT To be honest, I have as little of a notion how long a million kilometers are as I have for a million miles. So do you really care? Distances in astronomy are so large that you have to build up new intuitions anyway. And when you're not doing it in AUs and light-years, you might as well do it in kilometers.

[@24680kong]

Goreuncle Everybody complains when someone uses US customary units. When you have an American show in an American country with a mostly American audience, it makes sense to include both.

[@hardcard254]

Penny Lane True, but I bet (s)he also has problems with small distances/sizes given in km... So just remember the 0.62 thingy.

[@unvergebeneid]

Hard Card I didn't remember that there were any small distances in this episode.

[@razorintube]

awesome...you have incited a little astronomer inside me by explaining how parallax and spectroscopy are combined

[@alien9279]

yo darth vader on the millennium falcon:)

[@benaaronmusic]

He's going the distance, He's going for speed, He's all alone (all alone) on Crash Course Astronomy I love these videos. thanks to everyone involved.

[@SuperZarrabal]

Meanwhile, in religion...

[@bobshortforkate2364]

People went crazy....

[@tiagocampos9824]

Gabriel Zarrabal Stop judging religion by what idiot people do with it. That makes you an even bigger idiot

[@notchjohnson2540]

Tiago Campos you take offense because you know that his comment strikes true ;)

[@tiagocampos9824]

Notch Johnson I took no offense. I'm not religious but if you believe you're smarter because you call yourself an atheist then you're no better than a stupid cult yourselves. You'd expect better in this comment section actually. Disappointing

[@KinginCanada]

Tiago Campos you sure sound defensive, regardless, you're making someleaping assumptions. Afterall, the very principle of science would be agnosticism and curiosity in all things.

[@CyberSystemOverload]

What a wonderful video. Why dont vids like this have billions of views? Why?! Why do do pop stars and influencers pull the crowds when amazing material like this about the very science that makes our lives tick are disregarded by so many? So glad Im subbed to this channel!

[@geraldellis1177]

who remembers watching zooboomfoo

[@addisonm8286]

Oh my gosh, this just made that semester in astronomy make so much more sense. I could use and figure out parallax, but I sure did not comprehend it. Now I do, and everything seems so much easier! :D

[@fredro4901]

We Americans do not use metric. When he says X number of Kilometers, could there be a caption that states what it is in miles?

[@hogdog6525]

The metric system is used within most areas of science world wide. Just google a measurement translator program and alter the form of measurement yourself?

[@alucardwhitehair]

Hog Dog I can smell the arrogance in the air. All these metric users reek of it. We aren't in a damn university. This is a fun way for the layman to learn more about our universe. If they were using imperial units you wouldn't want to "just google it".

[@fredro4901]

Amen!

[@DrHotep]

Fred Roach deal with it, imperial peasant :P

[@alucardwhitehair]

Dr. Ny Har Rut Hotep And I rest my case. Yet, Americans are the obnoxious and ignorant ones.

[@maic991]

Give this man a medal ! I love the way he teaches

[@RushiScorpin]

I just want to tell , speaking ancient thinker you forgot about east, india, chin etc. Pls think today and yesterday world is not a place just around Greeks

[@qu33n0fh3arts08]

CRASH COURSE ASTRONOMY IS THE BEST!!!

[@Faarax96]

Pretty disappointed that Al biruni was not mentioned when it came to calculating the earths circumference with trigonometry , he had a much closer estimate for earths circumference (16 KM off) than Eratosthenes but he's not "European" so never mind.

[@mitahenare8901]

qaadirowayne lol 1000 years after

[@Faarax96]

Hunter Koester I'm not implying that crash course intentionally glossed over Al birunis achievements , but that bias that is rooted in racism is very common among western academics and this leaks into the psyche of western students who are otherwise oblivious to the racial agenda and so they unknowingly propagate European supremacy. Crash course is a victim of this effect and i also would have been if i hadn't studied history. Ever noticed how science always "begins" in Greece ? , when discussing the history of science it always starts in Greece and comes to the modern times in western Europe. You never hear about the Babylonians , Indians , Persian and Arabs , it's like after Greece collapsed science just disappeared and it was rediscovered during renaissance lol smh. Why do you think that is ? racism obviously. I challenge you to come up with a sound reason as to why all non European scientific achievements are downplayed and given secondary importance to European achievements , even though they are both equally significant ?.

[@Faarax96]

Mita TeTai It doesn't matter who did it first , what matters is who got it right , Biruni got the most accurate result , while Eratosthenes was off by alot , that's why i think Biruni deserves more credit. It's like discrediting Copernicus's solar system model because Ptolemy did it first even though he got it wrong lol.

[@mitahenare8901]

qaadirowayne Actually it does matter who did it first, Eratosthenes was NOT off by alot, That's like me discrediting Biruni's discovery because we have far accurate data now (down to a few yards) than Biruni's As time goes on, people are going to be more accurate with their measurements

[@senhox970]

qaadirowayne 1-Does it matter who did it first, as this would have fewer resources, and as the first, was a major milestone, I repeat it is not a mark of equal size. 2-In this case it is not racism, Eurocentrism is, is totally different. 3_The science was not born in Greece, Philosophy was born in Greece, the science, and the knowledge gained by it, formed with the work of several pessoas.Por example, Gracia was one of the places that have emerged geometry in Mesopotamia was the Algebra. 4-This guy you mentioned did it after the Greeks, if I make an electric light bulb without a manual, my merit is iguaal to the thomas edson?

[@tinylol]

Our teacher made us watch this and I learnt more about this topic in 11 minutes than I did in multiple lectures