I still jaw drop every time I hear "Newton invented calculus." I could barely pass 3 semesters of it with a marginal understanding of what the heck I was looking at, and this dude, more or less on his own, INVENTED MATH! It's absolutely incredible.
I just loved how he dealt with Pluto with such affection. You can feel the fascination in his eyes, which is something that was transmited to me. Pluto, Ceres, Sedna, you name it: they're all mind-bogling and fascinating!
this is absolutely beautiful. im so enlightened and intrigued about the creation of our solar system and puting it into the perspective of how every single thing on earth is created from the matter of stars.. my mind is exploding and why the middle planets are so big while the closer planets are so small.. AMAZING!
He kinda simplified it a bit, but between Mars and Jupiter is the frost line. Water could not turn solid in the inner solar system early on and it was far more abundant than rocks and metals. So Jupiter was a mixed ice/rock/metal planet ten times larger than earth that grew to the point where it could capture the extremely abundant hydrogen and helium and then become super massive. There also this interesting idea that originally Saturn, Uranus and Neptune started closer to the sun and migrated outward and that Neptune was originally closer than Uranus but passed beyond it and along the way, gave the Kuiper belt objects their more eccentric orbits as they moved outward and tossing some of those icy objects to the inner solar system, causing the late heavy bombardment and bringing them water after formation when it was cool enough for the inner planets to hang on to it. Most of those models involving Saturn, Neptune, and Uranus migrating work better in the scenario where there was a 5th gas planet that got toss out of the solar system. Anyhow, keep following this series, astronomy is fascinating. I've known this stuff for years and I always enjoy new discoveries. We'll get to see Pluto up close in a few months, I expect surprises.
This is awesome. This is how we should be teaching ALL subjects at schools; fundamental knowledge conveyed by a captivating personality. Phil is a prime example of the best mentor anyone can get - a passionate one. Thank you, Phil.
Seriously great point re: defining "planet", Phil. I'd love to read an astronomy article by you: "We've observed things doing some stuff. Who cares how I describe it? The universe is the universe, no matter what I say."
Earth: Hey Sun! Today is Earth Day. The one day they celebrate me! Sun: Wow, good for you (rolls eyes) Earth: You must be jealous, huh? Sun: Nope. Earth: You are! You don’t have a day for yourself, ha! Sun: Hm, I wonder what day it is? Earth: Silly, you forget everything! Today is Sunda- Sun: 🌞
Best crash course series ever! I've always wonderd why the planets are spinning in the same direction. And I got the answer to it now thanks to the angular momentum the cloud it was formed from.
I've always considered Pluto a planet, obviously since that's what I was taught when I was in elementary school, but especially because I played Pluto in a play we did about the solar system! :)
This is a great episode that was well written, at least to my taste. Awesome work Phil! I understand more of the underlying factor of why its a pre-planetary disk. But also had a moment of "holy crap this makes so much sense" when you explained how the outer planets are more gaseous. You sir, have my sub. I love all astronomy, keep this series going please!
Be humble, for you are made of earth. Be noble, for you are made of stars. -Serbian(?) proverb EDIT: Apparently the source I found attributing this to Serbia may be incorrect?
i've been following this series , my interest in astronomy was recently awaken by the book "a brief history of time".A lot that has been said in the book is present in this video. This greatly helped my understanding. Thanks
Anthony H. I studied this in my 11th grade astronomy class and it was one of the more interesting things that I learned this year, especially how that man Copernicos found out that the planets go around the sun in ellipses not circles.
Thank you very much for making this video, Phil Plait and the rest of the team at _Crash Course_ Astronomy. It was interesting to hear about the formation of our solar system, its content and how we thought about the universe in the past. By the way, didn’t the ancient people of Babylon know of 5 planets and that these are round? Anyway, I have a question about that illustration at 7:25: Is that illustration to scale? Are the planets to scale? If so, the distance between the planets are not to scale, right? I don’t think the planets are equally far from each other, as that image may suggest.
yep lol here is something to cheer us up! Earth: Hey Sun! Today is Earth Day. The one day they celebrate me! Sun: Wow, good for you (rolls eyes) Earth: You must be jealous, huh? Sun: Nope. Earth: You are! You don’t have a day for yourself, ha! Sun: Hm, I wonder what day it is? Earth: Silly, you forget everything! Today is Sunda- Sun: 🌞
Frankly, I think there is a larger category than "planet" -- there are four "compositional zones", each with four representative objects for convenient reference. Rocky objects (Mercury, Venus, Earth, Mars); icy rock objects (Ceres, Vesta, Pallas, Hygiea); gaseous objects (Jupiter, Saturn, Uranus, Neptune); and rocky ice objects (Pluto, Eris, Makemake, Haumea). My preferred way of defining a planet: 1) For objects orbiting a star, a non-fusing object that possesses more than 50% of the mass when grouped with all objects smaller than itself shall be designated a planet. 2) All objects larger than the smallest object to meet the first requirement shall be designated as planets, even if they don't meet the first requirement themselves (a precaution in the event of near-twin objects). 3) When it is clear that the examination has entered the "long tail" of smaller objects, we stop testing and define everything else as "subplanets." This process, when applied to our solar system, produces eight planets out of the couple dozen largest objects independently orbiting the sun, all eight of which meet the first requirement (although Neptune/Uranus and Earth/Venus demonstrate the value of having the second rule for ambiguous relationships in other star systems).
They are *former* planets, defined by their presumed past, not their present. Whether they were major or minor planets would depend on the particular history of the system they formed in ... but given that our technology can currently only detect rogue planets in the "gas giant" category, it's a fair assumption that they are former major planets of their parent system.
People say there is no CREATOR because they don't want to understand HIM. When mere men do things the world can't explain it's most often excused. It's considered understandable; it's made allowable... ...But GOD, OUR CREATOR is not allowed to do things too elusive to understand?? . People think there is no CREATOR because they can't understand HIM. Narcissism disables wisdom.
Isn't a planet defined as - a celestal object large enough to be round - that isn't a star - (that orbits a star) - that cleared its orbit (not counting objects in Lagrange points or in orbit around the planet) of other objects ? Because I can't think of any celestial object called a planet that doesn't meet this criteria, nor any that do meet this criteria and aren't called planets. Mercury may be smaller than Ganymede, but it orbits the sun rather than a planet, like Ganymede does. And Pluto, Pallas and Ceres all fail at being planets because they haven't cleared their orbits.
That would include half of the asteroids in both belts, but as some people already pointed out, the standar definition often includes " has cleared the neighbourhood around its orbit",if there is other matter baside it in the orbit, i has to be orbiting the planet, snot orbiting the star alongside it. so, not esteroid belts basically. its still a fuzzy definition, but its something
Tobias Azpiazu I do believe I included "has cleared its orbit" and "large enough to be round", both of which would exclude asteroids... Unless, of course, you don't know what clicking on "Read more (X lines)" does.
A planet is any celestial body that has cleared it's orbital field. Pluto has other asteroids relatively close to it so it hasn't cleared it's orbital field and as such, is not a planet. There are 8 celestial bodies in our solar system that HAVE cleared they're orbital fields. Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.
The definition can be vague but it makes sense: a celestial body earns the title of "planet" if it has "attracted" at least 51% of the mass revolving the Sun in it´s orbit. Thats why Pluto is not a planet, it shares orbit with many other bodies and it even crosses Neptune´s orbit, hence not a planet btw, isn't the continent called Oceania, not Australia?
I was hoping this video would contain some explanation of star system formation in light of the "hot Jupiters" being discovered by Kepler. It seems the idea that only small rocky worlds can form close to the star because the heat and solar wind pushes away light gases needs adjustment. Are there simply no hypothesis besides the idea that those large gas giants somehow migrating into the inner star system in which they formed?
I came to these videos via a search about how heavy elements are made. Watched a few of the later ones, and then started over from the beginning. These are absolutely wonderful.
Actually, we are *the* solar system. If planets are orbiting around Alpha Centauri, that is the Alpha Centauri system. We have the only star named Sol.
I love this series, and hope one episode comprises of Phil debunking some of the controversies about the Moon Landing. Not all my friends have read about the scientific responses to common beliefs.
***** last i herd it was black holes. the idea that there are massive black holes in ow universes so big that thay could have universe's inside of them and that this universes is inside of a massive black hole in side another universes in side another universes in side another universes in side another universes in side another universes.........
***** Thing is, universe at the very beginning only had one kind of matter in it - Hydrogen. This hydrogen somehow had to be transformed into all the other elements.
Anyone know of a good video that shows things as seen by the naked eye and then zooms into it really close? I would love to see that but cant find anything like it
omg man i'm loving this series! i know a lot of things about all of this, but the way you explain it is really cool, i would like it if they were translated to spanish so my little brother could understand them, i'll try translating it myself !
Space has no fixed direction; just turn it upside down, and you get it right again. Oh wait! There is no up or down in space, it is all about your reference system...
Well, I believe you meant to say revolve, but it is because when there is a trend in a set of objects any trend that gains a sort of advantage will eliminate those objects going against the trend by random collisions and either knock them out of orbit or absorb them into their own mass. This is why all major bodies in the solar system revolve around the sun in the same direction.
Hey guys so it's pretty hard to get noticed on youtube but I was really hoping that you guys would give my channel a shot. I make educational videos in hopes that it will help students. You don't even have to subscribe if you don't want to but it would mean a lot to me if you took a look! Thanks so much in advance for your time!
It's incredible that our entire solar system was a beautiful and gargantuan cloud of matter, which eventually was able to ball itself due to the forces of gravity. That would mean that the contents of a solar system are determined in part by the original chemical make up of the aforementioned cloud. Pretty cool!!
6:17 Wouldn't a good angular momentum analogy also be a gymnast doing a double/triple tuck? The athlete pulls their legs in to make themselves flip faster. Not flipping fast enough could make one fall on their butt or flipping too fast could cause a transfer of kinetic energy on landing and cause one to go off the matt, etc.
I knew I couldn't be the only person to look for the formal definition of a planet when first asked about classifying Pluto. Upon learning that there was, at that time, no formal definition of a planet, I held no opinion on the status of Pluto. Until such a definition was created, no meaningful conclusion can be reached.
There's a lot of advanced vocab in this so I don't know how good an intro it would be. Who's the target audience? Also, that's not what the star-stuff phrase refers to. We are star stuff because we contain elements that could only be formed during supernovae. You didn't mention that in this video. Otherwise, nice, succinct overview of our solar system. I'd never really stopped to think about the definition of a planet that carefully. It got me thinking.
I don't think anybody is having any trouble understanding the vocabulary, especially if they watched the other episodes. But I do agree on the point about not mentioning why we are star stuff. That would have been better saved for the episode about stellar evolution.
Scott89878 I haven't watched the prior videos in this series so I don't know how much some of these have already been explained. In the UK, children can expect an introduction to the solar system in year 5. By this point they should know what mass means, diameter would most likely be a new word, they may have been taught about percentages, philosopher would probably be new to most of the kids in year 5 at the school where I work. They should know sphere, would probably have to guess what unweildy means from context. They should be able to infer what geocentric and geocentrism means but I wouldn't expect it. I'm just trying to figure out where most 9-10 year old kids would turn off and stop listening. 2:10 in and I've found so many references that they'd probably need to stop and think about.
Here's a possible method for defining things: The things that orbit the sun (excluding asteroids and the like) are planets. The things that orbit the planets are satellites. Things like asteroids, comets, meteors, etc. are rogues, they do what they want whenever they want. These definitions would make things like Ceres and Makemake be considered planets, which makes sense seeing as they are big enough to be classified as dwarf planets anyway. It has some problems (mainly the comets and asteroids) but it seems like a good start.
Could you please do a video which explains how our solar system fits into the rotation of the milky way galaxy. I find that difficult to visualize how things don't collide. Thanks.
The most important reason is that space is mind-numbingly empty. In about 2 billion years, the Milky Way is predicted to impact the Andomeda galaxy. Over a trillion stars will be involved in the collision. It's estimated that a total of a few dozen stars will actually hit each other in the process. Add to that the entire galaxy is rotating in roughly the same direction and there's not much opportunity for things to hit each other.
isiart.net beauty and lifestyle time is the answer to everything......the reason things dont collide more like you would expect because they do but its just happen a billion years ago which is like 10 years in space time... also....we are so small in relation to the universe//// we are just crumbs of the sun we in total control of the sun as well as the rest of the bodies around us....collision for us small crumbs are rare ...the bigger your are the more likely you will collide with something....
In a very loose sense, if you look 'down' at the spinning solar system, the sun and everything orbiting it is moving directly toward you; The 'lines' drawn by the orbiting planets would make a huge helical spiral.
Lots of space between things. Also, everything is orbiting in the same direction mostly. Take a handful of marbles and throw them at someone who is also throwing a handful of marbles at you. Fat chance of any marbles hitting in mid air. Now contemplate that if the sun were the size of a marble, the closest star system would be three other marbles in the Alpha Centauri system 210 miles away. Probability just doesn't allow collisions to happen often. Even when the Andromeda collides with us and merges, you can see how there will be very few collisions, outside the cores merging.
Great video! So, if the growing proto sun took all the hydrogen/helium from Earth and the closer planets, does that mean the sun will pull the outer planet's gases when the sun gets really big on its way to being a red giant? Could that break the orbits of the outer planets?
"How'd the moon get there? How'd it get there? How'd the sun get there? How'd it get there? You can't explain that." -Bill O'Reilly Well, Bill... It seems you're wrong... Again. #science
You are living in the 21st century, with thousands of years worth of knowledge heaped on you. Aristotle was brilliant, he made a logical guess, which I am sure you made also when you were in kindergarten. His model, which you can see if you Google it, was very accurate at predicting the positions of stars and planets. Back then, astronomers didn't have telescopes and they didn't have the scientific method. Careful observation and blind studies were completely foreign to them. What would you have thought, being one of the first astronomers, looking up at the sky?
Planet has a definition: it's an object orbiting a star or stellar remnant that is massive enough to be round under its own gravity, not massive enough to start fusion at its core, and has cleared the neighbourhood around its orbit. That you might not like that definition or think its more poetic without it is irrelevant. Your explanation of solar formation postulated that the increased solar wind closer to a star prevented the formation of close gas giants, but many (most?) of the exoplanets we have found are gas giants close to stars (because they're easier to see).
I was about to say something similar too. I am pretty sure planet has more or less a good definition, and the reason Pluto was unclassified as a planet was because its moon was found to affect its rotation too much or something like that.
Pluto was demoted because it hasn't cleared its orbit so it doesn't have the 3 criteria for a planet set by the IAU (1: massive enough to be round, 2: orbit the Sun, 3: massive enough to clear its orbit) The hot Jupiters (that's what the gas giants close to their stars are called) did not form that close to their stars. At least we don't think they did. Current models suggest they formed further out and then spiraled inward to their current orbits.
Jacob The Earth is slightly bulged because of its spin and the Moon's/Sun's gravitational pull. If those effects were not there, it would be spherical. That's what that criteria is saying. That an object is massive enough to pull itself into a sphere, if there were no other effects (spin, gravitational pulls, etc.) acting on it.
Gravitational interactions would make them "chaotic" as the objects (planets) pulled on one another by varying degrees as they got closer or farther away from each other in their orbits, so essentially their orbit would change every time they interacted. Over time these forces would either tend to throw things out of the solar system, cause them to drop into the sun or crash into each other, or flatten out their orbits into a flat ring-shape, with the forces diminishing the closer to a ring shape they got. Later! OL J R :)
The plug for Squarespace is so amazing - "Go visit that site that you never heard of before, because it just got off it's lazy ass and made itself user friendly" - not the message you were looking to send, I bet. Phrasing.
Big enough that gravity collapses it into a sphere, orbits a star without orbiting another planet. Takes up the majority of the mass of its orbital path. If it has a partner, it must be the more massive of the two. So the planet is the one with the smaller orbit of the 2 interlocked objects (we orbit the moon, the sun orbits us, but the sun's orbit is much smaller than ours. The moon's orbit around us is much larger than ours around it). This eliminates out all asteroids because no single asteroid makes up a majority of the asteroid belt, I'm still conflicted about Pluto... I guess it's a Kuiper belt object, and there are other KBOs around its size, and much more material including comments, frozen asteroids, etc. I personally still call pluto a planet because I'm stubborn, but I can recognize it doesn't actually qualify. (FYI I didn't copy/paste that whole thing, that's my personal definition, but then we get into rouge planets, but I guess they deserve their own definition. :/)
Last time I checked India is considered a sub-continent. And there are obviously a lot more than just plates that go into how we define the continents, such as history, but I am just saying, Australia is on its own continental plate, while Greenland is not.
I wish people in videos like this would make it a point to say that this is in fact the only Solar System. He says "we aren't the solar system, we are A solar system". Which is incorrect, for the reason he says only a minute before, it's called the Solar System because we call our sun "Sol" (Except in english), thus Solar is the adjective We are the only Solar System. There are other STAR Systems, who's names depend on what the star in the center is called. We will never travel to other Solar Systems... that's like saying we're going to travel to another United States of America. We will travel to other star systems, which is like saying we'll travel to other countries.
desertraven There is no difference between a solar system and others. Ours is controlled by a sun (star) and all the others are controlled by a sun (star) as well. We are A solar system in A galaxy containing millions of solar systems not in a galaxy of one solar system and millions of star systems.
Your last sentence is where you're incorrect. We are a star system, which we've called the Solar System, because our sun is named Sol (we just don't call it that in every day speech). There are other star systems. They are not solar systems. Unless we go around naming every other star Sol.
Just in case you were wondering, the sun is named Sol after yet another Roman god - just like most of the planets. In English, we call it the Sun... we're the only language that does that. Look it up in any other latin/romantic language, it's Sol. Just like we call it Earth, when everyone else calls it Terra (yet we still use worlds like extraTERREstrial, subTERRAnean, etc.). Other star systems woud be named after the star/sun in the middle... Ours is Sol. Theirs is something else.
Nick A. You are not understanding this guy at all. He is saying that solar system implies sun and other stars like alpha centauri could be the centauri system. Granted, I am sure the word solar system will evolve to be the word for all planetary systems. Just like how planet (which means wanderer) came to be what Earth is and the word moon came to mean objects which orbit planets. Also, your point about every planetary system having a civilization that worships a sun god, is just trollish as fuck, his point was not that hard to understand.
