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:)
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.
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.
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!
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.
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!
***** 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.
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.
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.
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.
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!
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!
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!
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.
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
*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.
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.
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.
***** 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!
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
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
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.
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!
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.
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.
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.
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.
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.
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.
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!🙂
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.
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
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.
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.
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.
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.
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!
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.
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.
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.
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.
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.
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
@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.
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
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.
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.
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.
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.
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.
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.
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
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.
This is a super episode!! I have long knew the sizing of the Earth in ancient times, but I did not know they had gone on to estimate the distance to the moon and the sun. Whoot!
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?
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".
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
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
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.
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.
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 ?.
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.
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
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?
I just found your channel. Excellent in every respect. Teaching -- conveying information so that it hits the target brain and sticks -- is a true art, and you appear to have nailed it. I'd like to make one suggestion, however. I know that the UA-cam gurus tell you to aim for a higher degree of animation and expressivness than you would in everyday conversation, to keep people engaged. It's possible to go overboard to the point of making the presentation distracting rather than entertaining or educational. Specifically, scrunching your face into a parody of joy, waggling your fists and proclaiming "YAAYYY!!" rings the bell on the Dork-O-Meter, and the distraction overwhelms the content. I guess a good rule of thumb is "Anything that would get you a wedgie in middle school should probably be edited out." Your content and ability to explain will stand on their own. Otherwise, really excellent. Please keep it up.
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
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:)
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.
@EARTH IS seriously FLAT Non sequitur and straw man fallacy. You really are dishonest.
@EARTH IS seriously FLAT A stranded flat earther. You're far away from home there, lad.
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.
@EARTH IS seriously FLAT I think you are lost
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!
So underrated coment
Phil is a great teacher, I actually found him on TV. I really hope he keeps doing more Crash Course stuff!
Hornchief discovery science huh?
So figuring out the AU turned out to be pure gold.
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.
This might be my favorite CrashCourse Astronomy lesson. Love learning how people figure stuff out.
This series has probably become my favorite CrashCourse series. Thanks Phil!
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!
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!!!!
mimiariana class? isnt it summer :p
yeah, I'm in college, lol. I have classes during the summer, unfortunately...^^
mimiariana Wow, that's fantastic! Glad to help. :)
***** 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.
Tetracarbon (Phillip Wong) eeereereerrz ez
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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.
I LOVE that last picture of the Andromeda Galaxy you used. I could stare at that, and its own stars, all day.
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.
i get chills almost every time i watch this series bc DAMN the universe is so big and beautiful and just wow
U like it big 😘😘
@@Lowandhard06 oh boy, you are onto something.
Amazing series. And I liked this guy after just 1 video. The quality is also very good.
Crash Course Astronomy is my favorite one of the entire crash course series! amazing job!
I want Phil to teach me everything
Same.
I hope this is sarcasm,
Edit:his channel looks idiotic
@EARTH IS seriously FLAT What ?
@EARTH IS seriously FLAT is it a joke or you seriously believe that?
@EARTH IS seriously FLAT If there is a book on trolling, you need to read it dude.
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.
***** good for you
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!
I love these videos: Its like getting my drivers licence, but in Astronomy!
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!
this whole video basically summed up my physics class and it was hell!
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!
When I was very young, I actually though the moon was chasing me...
Thanks to the law of universal gravitation, it technically, ever so very slightly is.
verdatum epic
It was. And now it's watching you, as you sleep. Sweet dreams!
hunter cochran its still chasing you. How are u still alive?
Me too bro, aahh.......memories 😂😂😂😂😂
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.
"Curiosity can lead us to great great distances" True.
Wow one of my favorite crash course videos of all time. I wanna learn about this so much right now. Very cool.
This video was insanely helpful in understanding space distance! Great job!
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
*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.
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.
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.
*****
... fast and manoeverable. If you can go straight through an asteroid field, you can cut a lot from your journey.
Arkalius80 Who cares? lol
***** 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!
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
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
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.
We can't stop here, it's bat country
Lol. I was watching this and wondered if anybody noticed it.
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!
thank you sir i have now understand whole concept about parallax
I'm re falling in love with this channel all over again!
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.
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.
This show has helped me with my answer to the "what do you want to do in college?" question
Well it's been four years...how that work out for you?
0:58 His response to the ufo-hypothesis: 'mheh'. Priceless xD.
I just fell in love with astronomy, trigonometry, geometry, maths or spectroscopy and any kind of nerdy shit
This is,by far, my favorite video of the astronomy series.
So how did we figure out the speed of light?
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.
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.
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.
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.
Arwis HellFrost That's interesting. Thanks
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!🙂
Flat earthers quacking at the Greeks
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.
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
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.
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.
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.
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.
ALL, of them, are light years apart.
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!
YES. Exactly this! It's linking everything I'd learnt too!
Omg I love the Fear and Loathing reference!!! 😸👏🏼
Love the little Kerbals you put on your desk ^^
"Next Episode - 26: Stars"
Thanks for this week of torture!
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.
100,000,000,000,000 kilometers? What is that, like, 400 miles?
Chris Moore "miles"? *facepalm*
+Chris Moore
(100 trillion km)
It's about 62,000,000,000,000 miles (62 trillion mi)
About 10 or 11 lt-yr
+ffggddss It was a joke, man.
Well it would sure make the stars more accessible!
You could literally *drive* to Alpha Centauri in an afternoon!
Wouldn't that be neat?
+Chris Moore it would be 621371192237.334 miles
Love this guy!! Excellent teacher!!
Best UA-cam series or best UA-cam series?
Yes
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.
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.
Goreuncle I knew at least ONE person would step up with this argument to defend it.
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.
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.
Don't astronomers use Type 1 Supernova's as a "Standard candle" to measure distances as well?
rebelyell1983x He sort of mentions them at 10:02
rebelyell1983x Yes, he never said they didn't :?
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
rebelyell1983x
Yeah, sort of disappointing, that in an episode on distances he leaves out the standard candle and the doppler shift out.
Frank Schneider as long as it's just an episode on distances and not the episode on distances I wouldn't worry about it =)
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.
its amazing how much knowledge was lost when the church got all witch-burny
the big bang theory finder was a priest xD but it all went downhill after that
They burnt anything or anyone that disagreed. Im surprised there is anything left. They are guarders of the holy secret.
Are you guys acting or are you actually stupid?
Probably still not as much as was lost when the Great Library burned down.
@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.
I really like all of these episodes. Very informative. I just completed a text book "Mathematics of Astronomy" and this was very useful.
... and from Hunter S. Thompson's persepective, he didn't travel to Vegas, as much as Vegas arrived in him.
Great episode, and the icing on the cake was the Han shout-out when discussing what a parsec is :)
And people think that the earth is flat.....
Ayush Sharma
Fortunately, they are only in a very small minority, and most of them are in America. Get your education system together America!
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
Not "people", "idiots".
EARTH IS seriously FLAT I have researched flat earth. It's only for full blown fucktard clowns
EARTH IS seriously FLAT says the fucktard that doesn't understand that if something get too far away to see, it shrinks in size
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.
Pause it at 4:54 !
:))
Ethan Boyd lol I know
Ethan Boyd I don't see it??
The best way to explain this subject so far! Well done!
Flat earthers left the chat
Astronomers are a gift to the world!
I'd've liked more details on the Standard candle methods.. not just a mention of the cepheid stars
these never cease to amaze me.
FEAR AND LOATHING IN LAS VEGAS !!
Glad that there are much smarter people out there that have figured out all this so I can watch UA-cam videos on the subject!
Speed of Earth's orbital velocity: 30 km/sec
"Curiosity can take us to great, great distance". As a curious, it's very touching to hear 😊😊😊
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.
The Universe doesn't care whether we exist or not anyway so it's entirely up to ourselves to make something out of it.
Can I suggest a chapter about an overview of the history and the misconceptions of astronomy? This series is wonderful.
crazy that they got the camera man that far. respect
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.
Thank you for using kilometers ! :D
@I know you are right, And I just got owned but: no it is simply stupid to use miles.
@I know you are right, And I just got owned but: Non sequitur and ad hominem fallacy.
@I know you are right, And I just got owned but: It is funny that I can convert easily but find it rather inconvenient.
This video is so full of information.
Mighty.
Any way you guys can put miles as text on the screen whenever you use kilometers for us lowly non-metric people?
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.
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.
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.
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.
Hard Card I didn't remember that there were any small distances in this episode.
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
It sad that the Ancient Greeks knew more about astronomy, math and science than most people do today.
Yeah, but did the "average" ancient greek know this stuff? Most likely not. They were more interested in screwing their ewes...
@@rickkwitkoski1976 agreed
@@gagan4012 Bro Please tell what your profile photo is ? As far as I think 10% people have same profile photo as you🤔🤔
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.
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
size of the earth - math = flat earth theory
This is my favourite video because amaizing distances are what attracted me to astronomy!
Anyone else think Green Lantern?
Yup, I did
What!why?
This is a super episode!! I have long knew the sizing of the Earth in ancient times, but I did not know they had gone on to estimate the distance to the moon and the sun. Whoot!
yo darth vader on the millennium falcon:)
CRASH COURSE ASTRONOMY IS THE BEST!!!
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?
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?
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".
Amen!
Fred Roach deal with it, imperial peasant :P
Dr. Ny Har Rut Hotep And I rest my case. Yet, Americans are the obnoxious and ignorant ones.
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
who remembers watching zooboomfoo
Phil plait has a unique way of teaching love this
Meanwhile, in religion...
People went crazy....
Gabriel Zarrabal Stop judging religion by what idiot people do with it. That makes you an even bigger idiot
Tiago Campos you take offense because you know that his comment strikes true ;)
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
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.
Good clarification of the distances of our observable universe & how we measure them with light.
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.
qaadirowayne lol 1000 years after
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 ?.
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.
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
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?
I just found your channel. Excellent in every respect. Teaching -- conveying information so that it hits the target brain and sticks -- is a true art, and you appear to have nailed it. I'd like to make one suggestion, however. I know that the UA-cam gurus tell you to aim for a higher degree of animation and expressivness than you would in everyday conversation, to keep people engaged. It's possible to go overboard to the point of making the presentation distracting rather than entertaining or educational. Specifically, scrunching your face into a parody of joy, waggling your fists and proclaiming "YAAYYY!!" rings the bell on the Dork-O-Meter, and the distraction overwhelms the content. I guess a good rule of thumb is "Anything that would get you a wedgie in middle school should probably be edited out." Your content and ability to explain will stand on their own. Otherwise, really excellent. Please keep it up.
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
Awesome episode Dr. Plait