Unfotunately most of the most gifted and passionate teachers are stuck behind the paywall of college. In the US teachers dont make enough to choose teaching over another more lucrative career. Unless you want to be a college professor of course, but alot of that has to do with research funding anyway
absolutelysobeast not so. I’ve had some serious dunces in college. The most boring, to the most arrogant. But I’ve also had really awesome professors. It’s a mixed bag really. I majored in physics and geology and believe it or not, most of my favorite and the most passionate professors were straight outta Germany haha.
Scientists usually give the name “dark” to things we can’t observe, like dark energy. So in calling it dark matter, scientists are just specifying that it is the matter we can not observe.
+FriedrichHerschel How is that "special"? With the way dark matter works, it couldn't form structures other than clouds. We couldn't have been made from anything but visible matter.
Whenever I get to see Phil's episode, my love for astronomy is increasing. Such an inspiring series. You guys are doing awesome! Keep going! Waiting for more episodes!
Dark energy: Cool discovery guys, here's your Nobel. Dark matter: Cool discovery lady here's ummm.... a gift certificate. C'mon guys, blue LEDs were nice, but dark matter needs some recognition here.
They probably waiting for the detection of dark matter particle, so let's wait for the 2019 prize. Physics Nobel prizes usually alternates between experimental and theoretical, and blue LED has a huge impact in the modern world because it enables highly energy efficient white LED lighting. Physics Nobel prizes are not really very political.
"We still dont know what black matter is but we know its there"....here you go lady...your noble prize for finding out what others did already but for adding a bit more into it than finding new things.... all of you must be dreaming...
I just want to thank the crash course team for having this astronomy series. The video uploads corresponded almost perfectly with the topics in my college astronomy class, and I'm using it currently to study for my final. It was a huge help. Thank you!
yo crash course, i know this i kinda cheesy, but i really really want to thank all of you, for giving someone who was to frikn lazy to do anything at school easy acses (acces? well wathever) to the basic of knowledge i crave for so much, in a way i can understand it. lazyness + unfortunate events are the cause of the fact that i'm still a few years behind before i've payed all the debts i had made, or else i would sponsor the sh*t out of you haha! thank again!
+CrashCourse I'm pretty bad with physics, so a good "crash course" on lots of physics stuff would be amazing for me. I'm really eager to see Crash Course Physics!
When you end this series I will feel very sad and depressed. Until then though, I'm always super giddy whenever a new episode is released! Keep up the great work.
+Bob war 1) smaller is irrelevant because you are also unbelievably big compared to some structures. 2) Irrelevant how? Just because some Abrahamic-like god hasn't come down and spelled it out for us doesn't mean that we aren't a way for the Earth to express itself... We GROW out of this universe so the question of whether or not we are relevant is meaningless because we ARE the universe.
Thank you Phil Plait for being such an awesome instructor, and sharing your passion for space with us. I love this course, whether I am dancing to the theme song, taking hand-written notes, or sharing fun facts with family and friends.
So by measuring the rotations of stars in galaxies you can find out that there is a uniform cloud of dark matter that surrounds the galaxy that speeds up the rotation of the outer parts of the galaxy more than it does things near the center. That must mean there is much more dark matter on the outskirts of the galaxy then there is inside the center, correct? But if dark matter is affected by gravity but weakly interacts with matter, why doesn't it clump into the center of the Galaxy like normal matter does?
It does "clump" also in the centre. The thing is that this dark matter halo is much bigger than the visible (stars + gas) galaxy. usually around 10x bigger. The fact that the halo is much bigger, means it gets much more massive and that’s why its gravity stabilizes the stars and the gas rotation. On the other hand Dark matter cannot get nearly close to the density of the ordinary matter. That's because it cannot radiate-away internal energy (which translates to kinetic energy of motions). So visible mater can get much more denser, but since the volume grows as a radius cubed (R^3), at scales bigger than the visible galaxy radius R* the gravity of dark matter quickly becomes dominant factor.
Fun fact: Most people don't know this 1% of the observable universe is made of gases, solids and liquids, while the other 99% is plasma, the fourth state of matter, and we are apart of the 1%.
Dr. Plait, you've done some pretty great science outreach, but I really hope you agree with me that Crash Course Astronomy is some of your best work yet.
This is amazing! Thank you so much for taking the time to create something as educational as this, on a platform as readily and globally available as RUclips! Inspirations and role-models you all are! P.S. those are some beautiful references you're packin in that description
What if other dimensions or branes interact via gravity and we are observing the effects of all of the universes that contain mass. It could explain how there is so much of it, why none of the fundamental forces seem to affect it, and why it seems to interact with itself so weakly. I love all of Crash Course, and this course is possibly my favorite. Keep it up!
+Owen Hunt I had the same idea before, but it does not explain the cluster collision. The gas colliding should contain the mayor part of the mass of the cluster, but the gravity map clearly shows it doesn't. In the parallel universes the gas clouds should hit each other just like in ours, so overall gravity should be clamped around the gas.
KohuGaly Agreed, however, I wonder if our gravity maps would be high enough resolution to resolve the tiny interactions between the particles of each universe. We could be seeing the affects of a large or even infinite number of branes, so even if their laws and particle density were simar to ours, most of the dark matter wouldn't interact with itself. I suppose it would clump, but it's also possible that this dimension is the only one with the right properties to allow for that kind of interaction, or for familiar particles to even form at all.
Thanks! I love your series! So, see if I got this right: We can detect dark matter's gravity even within our own galaxy, right? But why can't we detect it within our own solar system? (or can we?) Does dark matter "pass through" ordinary matter, and/or stay segregated from it? Does dark matter clump together with itself, forming planets, etc? Fascinating stuff!
So we can't see the dark matter precisely, we can only estimate its presence via gravity... What if the "main" matter of the universe is dark matter, and there are galaxies, stars, planets and other lifeforms made of dark matter? What if those lifeforms are observing the universe and trying to figure out where the extra gravity is coming from (as they wouldn't be able to see "our" matter)?
+Darth Mongoose The problem there is we haven't detected any 'clumps' of dark matter, no planets or galaxies. We'd expect 'dark stars' to emit *something*, if you squash dark matter like that it should be transforming into all sorts of stuff.
+Darth Mongoose "... galaxies, stars, planets ... made of dark matter?" This can't happen. Planets cannot form from dark matter. Building planets from dust grains requires the grains to stick together; they don't have enough gravity to do that, so they stick by the electromagnetic force -- but dark matter doesn't "feel" the electromagnetic force. Stars cannot form from dark matter, either, because magnetism plays a role in protostar formation, and, as well, dark matter does not emit light. And galaxies are made of stars, so there are no dark matter galaxies, either.
The studying of clusters colliding is mind blowing. Yeah we have come a long way to study the cosmos but I never realized at this scope and scale! Einstein truly did provide us the tools to understand the universe by leaps and bounds.
NOTES: 1960-70´s Observing the spiral galaxies Rotation of bodies More distance from the sun, slower the orbiting Then you can get the sun's gravity Then you get it's mass Using the same method for the galaxies Movement and velocity is calculated through the Doppler shift Lead to unexpected results: Clouds were moving faster, the farther out from the center Velocities flattened out with distance instead of declining Implying a constant gravity, instead of a decreasing What gravity was keeping them from flinging off? What mass was causing the rapid rotation rates? We couldn't see them, so... "Dark" material is contributing to the gravity Galaxy must be embedded in a halo of it to fit the shape of the rotation There must be 5-6 times more of it than visible material 85% of the universe So what is it? Cold gas? Dust? Dead star? Rogue planets? Subatomic particles? They didn't emit light The signs contradicted everything made of normal matter (atoms) Except invisible subatomic particles from quantum mechanics These are just possibilities Like Axions: has mass, little light and and passes through matter Space is like a fabric with matter and energy embedded in it Gravity is a bending of this fabric Like a bowling ball on a mattress would warp its surface Light bends along the distortion of space caused by gravity Gravitational lensing: Effect of the matter between a light source and its observer, on the light So: more mass, more gravity, more light bending A cluster of galaxies have a lot of mass So by being far away their light bends towards us Bullet Cluster: Two colliding galaxies Their colliding gases get hot and emit x-rays Bullet Cluster distorted it's background Using that we could map it's mass And see the matter that wasn't the hot gas and didn't emit light
I'd really like to see a Crash Course on the different subatomic particals we have detected and theorized, explaining their properties and what their effect in the universe is.
I dunno, it still seems like dark matter was thought up when a bunch of astronomers found their equations weren't working, all got together, and one of them said, "Well, what if there was all this, I dunno, invisible ... intangible ... stuff out there?" And all the others were like, "Yeah, yeah, write that down!" tl;dr - the invisible and nonexistent look very much alike.
+Cullen Paradis yeah wouldn't that be something if all the scientist came out and said "Soooo everything based off, of Newtonian physics is wrong and were going to have to start science all over"
Newtonian physics is right, is a way. But you must know how to use it. Comparing galaxy with solar system is dumpest thing I heard of. You shouldn't expect that speeds would be like in solar system. You need doing some integration to trully understand how rather complex objects interact with each other. And, surprise, there are guys who did some integration, but rather popular than scintific scolars never heard of it and never tired to repeat this folly: It's weird that galaxy behaves different than solar system does... What of it? It shouldn't!
Verlinde has just (pre-)published a paper that does away with Dark Matter as a particle. You might find it intriguing. It's available on the interwebs here: arxiv.org/abs/1611.02269
The studies into the CMB supports the dark matter results as well as other indirect studies into dark matter. Claiming it is a figment of scientists imaginations shows how clueless you are about the matter.
this is one of the coolest videos yet, i get that people that haven't been introduced into this concepts get lost, but when you know a little bit about and you have an open mind it's really interesting, and this video gives the information in a simple way, i'm really exited to know how scientist will prove that there's black matter everywhere.
Thank scientists, I live in an age where real and true knowledge can be known through the scientific method and I don't have to adhere to stone age myths and superstition.
There's dark matter, which, when added to conventional visible matter, helps us accurately predict the trajectories of celestial objects, as explained in the video. Then there's dark energy, which accounts for the accelerated motion of galaxies away from one another. I wonder if there's also "dark space" and/or "dark space-time".
Thanks Phil. What a channel! Everything here is so great that doesn't feel right to be free. I've being learning a lot here. I'm just an artist but space fascinates me since childhood. It's a honor to have someone with this prestige to teach us so much more. my best regards from Brazil
+Sam Lund Definitely worth re-watching in preparation! But it's being covered from a different perspective. The Big Bang as it relates to Big History is a little different than a primarily ASTRONOMY vantage point. Plus, we certainly couldn't do a course on Astronomy without covering it. :) -Nicole
+CrashCourse Ooh, I am so excited already! Please give everyone involved in making these videos a hug from me, I appreciate your work with this soo much!
There is no dark matter. It is just a unscientific concept that protects "scientists" from the all so horrible cognitive dissonance. The gravity model is disproved. Showing lensing effects in space and claiming it to be gravity lensing does not make it gravity lensing. If we hypothesize that the lensing effect is due to gravity then we have to find the source of that gravity. Otherwise we can't assume that it is gravity lensing. That is how science works.
The thing about believing humanity should be humbled by the splendor of the cosmos is, splendor is only splendid when it comes to the attention of an intelligence sufficient to perceive it as such. As the only known intelligence that qualifies, it's not at all unfair for us to continue to perceive ourselves as the crown jewel of the universe.
I like the way Gargravarr described our place in the universe to Zaphod; "An invisible dot on an invisible dot. Infinitely small. (*...small small small...*)"
Years from now, we're gonna look back on this video and laugh after we've found out that dark matter doesn't even exist and it wasn't "the only explanation" for what we observe.
Black Matter is where our unwanted conciseness goes when they die. So no hell, just unwanted black matter. Can’t be measured because it is our unwanted. Tyvm
It that really the only possible conclusion from what we're seeing? That there must be some invisible, undetectable, and utterly unknown type of matter responsible? I'm going to invite downvotes by suggesting that there is no such thing as dark matter; it is an erroneous assumption based on evidence we cannot (yet) otherwise explain.
+TheSwamper You'll get no downvote from me; it's a reasonable question to raise. Consider, however, that there are (at least) 4 different independent physical situations in which observations indicate that there is far more gravity than can be accounted for by the visible matter. In each of those 4 cases, essentially the same percentage of dark matter explains those observations. So if there really is "no such thing as dark matter", the correct explanation is doing a remarkable job of disguising itself as dark matter. Note, further, that there are a number of experiments under way to detect the dark matter particle, so the issue may be settled in the foreseeable future.
Nice comment. Dark Matter was 'invented' when visual observations of massive structures (like galaxies) did not move the way current physics predicts they will. I suspect that this may come down to a greater understanding of observing/interpreting gravity over tremendous distances, negating the need for inventing an invisible, undetectable matter.
TheSwamper "... gravity over tremendous distances ..." The problem is that maps of the distribution of gravity in clusters of galaxies, as demonstrated by gravitational lensing, show large concentrations of gravity in the space *between* the galaxies. The distribution of gravity does not completely follow the distribution of the galaxies, so it's not just a matter of fixing up the strength of gravity over distance. There would need to be a way of sourcing gravity in essentially empty space. Dark matter does that nicely. Several alternative theories of gravity invented so far have all run afoul of observational tests.
I don't refute that dark matter explains a lot of the observations, it just seems like one hell of a leap of logic to me "Oh, must be some heretofore utterly unknown matter, that is utterly undetectable by direct means." I think it's less of a leap to suggest that maybe our current understanding of gravity is incomplete (which it is), and we are interpreting at least some data that is false (like a duplicate galaxy that appears, warped by gravitational lensing). You may be absolutely right, and I admit I'm only a hobbyist, not a physicist. Either way, I'm enjoying the discussion.
TheSwamper From my perspective, I don't feel that you're giving sufficient weight to the fact that the same amount of dark matter solves the observational problems in at least 4 completely independent astrophysical situations, including ones that are very difficult to interpret as mere changes in the strength of gravity. It didn't *have* to be that way; it could have turned out that each situation required differing amounts of dark matter -- but they don't. And you're also not appreciating that we see dark matter evidence from lensing in not just *one* galaxy cluster, but *many* (I've not done a count, but there are at least dozens). You'd have to suggest that we're fooled by false duplicates in *every single case*, despite the careful observations made to cross-identify the multiple images. (And it's more than that, BTW; it's also the specific distortions of the individual images, and the exact locations of the multiple images, that help map the dark matter.) False positive identifications wouldn't necessarily yield consistent solutions. I'll grant, however, that backwards-engineering the gravitational field by starting with the lensing effects is not easy. Having said all of that, the search for the dark matter particle continues. Few folks are going to be satisfied until it is discovered and identified.
Riddle me this, if dark matter is some form of matter that only interacts with normal matter via gravity, then why does it not have the same distribution as normal matter? Why would it collect more on the outskirts of the galaxy, and less toward the center? The only reason I can think of is, dark matter is a gap theory/hypothesis.
+Velexia Ombra Since the galaxy spins, wouldn't things get pushed out via centripetal force? Unless I'm mistaken, dark matter doesn't have a lot of mass, just there's a lot of it? So the galaxy spins it right out to the edges since planets and stuff don't get in the way. I see a hole in my thinking but i think i'm on the right track.
+Velexia Ombra The most likely cause is that it consists of very light particles. These would then move much faster than normal matter particles, and something that moves faster will be less precisely kept in a gravity well. Another possibility is that the distribution we see is also not the distribution of normal matter. What we see as galaxies and such would just be the areas where matter exceeds a certain density so that it can clump together to form clouds, stars and such. Elsewhere the matter density is lower, but not as much lower as it seems to be.
The oort cloud exists because the planets and sun cleared out the interior area of the solar system of similar objects... I don't see how that applies to dark matter.
So why does dark matter seemingly only affect galaxies and not stars/planets? In other words, why does it only seem necessary to include dark matter for galactic observations? Wouldn’t there be dark matter in our solar system, affecting the movement and orbits of the sun snd planets? Is it too spread out to have a meaningful impact on something as small as our solar system? Is it only concentrated at the edges of galaxies?
Nice. I already heard about the bullet cluster, but that wasn't clear to me why it was important, and what we did with its gravitational lensing. Now I understand its awesomeness. I know I say that on almost every episode but : THANKS TO ALL THE PEOPLE WHO MAKE THIS SHOW AVAILABLE ! Love it !
If I had teachers like the Crash Course folks, and specifically Phil, life would have turned out very different for me.
Unfotunately most of the most gifted and passionate teachers are stuck behind the paywall of college. In the US teachers dont make enough to choose teaching over another more lucrative career. Unless you want to be a college professor of course, but alot of that has to do with research funding anyway
not a good name smh
absolutelysobeast not so. I’ve had some serious dunces in college. The most boring, to the most arrogant. But I’ve also had really awesome professors. It’s a mixed bag really.
I majored in physics and geology and believe it or not, most of my favorite and the most passionate professors were straight outta Germany haha.
I love Phil Plaits ability to explain so well. The graphics and illustrations really make this great.
John Morris ikr 😁
If there is more dark matter in the universe than normal matter, isn't dark matter the "normal" matter now?
Leonard Marc Ramos true
If more minorities live in a city aren't you the minority
Scientists usually give the name “dark” to things we can’t observe, like dark energy. So in calling it dark matter, scientists are just specifying that it is the matter we can not observe.
@S. O. i suppose they mean legal (like women), historical (white people) or local (asians) minorities
'Normal' is relative. If you consider it normal, then it is, to you.
If 85% of the mass of the universe is Dark Matter, I'd say we are "special" for being made of the unusual stuff that makes up the last 15%.
+FriedrichHerschel If it's that important for you to be "special".
+FriedrichHerschel How is that "special"? With the way dark matter works, it couldn't form structures other than clouds. We couldn't have been made from anything but visible matter.
In theory there is 70% dark matter 25% dark energy and 5% matter.
+An Atheist. What theory makes that prediction?
Zuzu Superfly I think I heard that in another vídeo, but maybe im wrong.
Today I learned that dark matter is the force.
I was thinking more along the lines of magic
+notnormalyet Same thing, different names
+DvS and its the dark side :)
+ImmortalTimothyM But does it have a light side? (Or an upside\downside?)
+Gareth Dean There is no Dark Side, nor a light side, there is only the Force. -Gray Jedi Code
I hope this series never ends
you're not the only one.
It won't survive the death of the universe.
+Krombopulos Michael hmmmmm I thought you dead
Lirst Fast That was only one of the realities I exist in.
Whenever I get to see Phil's episode, my love for astronomy is increasing. Such an inspiring series. You guys are doing awesome! Keep going! Waiting for more episodes!
Please don't end this series ;___;
I heard that there will be only 46 episodes.
+Ayush A. (KillerSoda) I'm sorry but it's true DX
+Hans Yu 😢😢
+Ayush A. (KillerSoda) Where did you hear it?
+teubert2 he replied to a random guy in an old video.
Ayush A. I see. I hope they end up making more than 46 episodes though xD.
The BEST series in the observable cosmos!
not so good on the dark side
This series is full of puns I am *delighted*
Kagamine Himeka oh my god c:
Dark energy: Cool discovery guys, here's your Nobel.
Dark matter: Cool discovery lady here's ummm.... a gift certificate.
C'mon guys, blue LEDs were nice, but dark matter needs some recognition here.
+Gareth Dean yes yes and yes. Cannot like this enough.
And this is why I dont respect the nobel prize
They probably waiting for the detection of dark matter particle, so let's wait for the 2019 prize. Physics Nobel prizes usually alternates between experimental and theoretical, and blue LED has a huge impact in the modern world because it enables highly energy efficient white LED lighting. Physics Nobel prizes are not really very political.
You're right
"We still dont know what black matter is but we know its there"....here you go lady...your noble prize for finding out what others did already but for adding a bit more into it than finding new things....
all of you must be dreaming...
I just want to thank the crash course team for having this astronomy series. The video uploads corresponded almost perfectly with the topics in my college astronomy class, and I'm using it currently to study for my final. It was a huge help. Thank you!
"It surrounds us and penetrates us..."
I need an adult.
Show me on this doll where the dark matter penetrated you.
Jayken DARK MATTER says "I am ADULT!"
@@KutWrite lol crazy
@@KutWrite hahahaha!
KutWrite haha 😂
yo crash course, i know this i kinda cheesy, but i really really want to thank all of you, for giving someone who was to frikn lazy to do anything at school easy acses (acces? well wathever) to the basic of knowledge i crave for so much, in a way i can understand it. lazyness + unfortunate events are the cause of the fact that i'm still a few years behind before i've payed all the debts i had made, or else i would sponsor the sh*t out of you haha! thank again!
+Lennart Maes damn my english i bad toningt lol
"Access" is the spelling you were questioning. Are you drunk, high, or excessively medicated?
+nrylee why not all three, a combo, or none of the above? :)
Kevin Barber I didn't use XOR just an OR
This probably the closest thing we get to a Crash Course Physics.
+Lawrence Tider Until March, that is...
-Nicole
+CrashCourse :O
+CrashCourse yeeesssss!
+CrashCourse Thank you! I really look forward to that! =D
+CrashCourse I'm pretty bad with physics, so a good "crash course" on lots of physics stuff would be amazing for me. I'm really eager to see Crash Course Physics!
When you end this series I will feel very sad and depressed. Until then though, I'm always super giddy whenever a new episode is released! Keep up the great work.
May the dark matter be with you
+pencilpen786 give in to the dark side
Haha, exactly
@@cpob2013 It's treason then
@a ramdom star try spinning that's a good trick
😂😂😅
After watching this I propose we rename Dark Matter, The Force.
What A Marvel obewan is our only hope!
Midicholrians are actually dark matter changing bacteria :P
That would be Dark Energy
Yeah nah
Will you do an episode on Dark Energy?
+Makcraft In two weeks! Episode 43 :)
-Nicole
Yaaa!! Know I know that I even more smaller and irrelevant to the universe then previously thought
+Bob war So why anything?
+Bob war That fact that you know that you are so irrelevant makes you relevant.
+Fipse far more relevant than the kind of religious zealot that claims the earth started some 2000ish years ago
+Bob war
1) smaller is irrelevant because you are also unbelievably big compared to some structures.
2) Irrelevant how? Just because some Abrahamic-like god hasn't come down and spelled it out for us doesn't mean that we aren't a way for the Earth to express itself...
We GROW out of this universe so the question of whether or not we are relevant is meaningless because we ARE the universe.
You're only as insignificant as you think you are.
A shame I can't hit the like button more than once
Quester91 you can hit it as many times as you like. . . 😀
I'm terribly sick and seeing this in my subscriptions feed cheered me right up! Time to get some soup and explore dark matter! :D
So, Dark Energy's up next?
+Zenyl Matter is just congealed energy anyway.
Ghost7489 Um Nope
Montgomery Bermann
Yes.
+Ghost7856 It is a form of energy, but It is not pure energy
+Ghost7856 congealed energy= matter
It's just so good, so knowledgable. I wish rest 90% of youtube was the same :)
I was just thinking about CC astronomy when this was just uploaded. That was perfect timing
Thank you Phil Plait for being such an awesome instructor, and sharing your passion for space with us. I love this course, whether I am dancing to the theme song, taking hand-written notes, or sharing fun facts with family and friends.
These episodes always feel like
I can’t get enough of this channel. Even though my knowledge of physics is basics. It’s growing.
So by measuring the rotations of stars in galaxies you can find out that there is a uniform cloud of dark matter that surrounds the galaxy that speeds up the rotation of the outer parts of the galaxy more than it does things near the center. That must mean there is much more dark matter on the outskirts of the galaxy then there is inside the center, correct?
But if dark matter is affected by gravity but weakly interacts with matter, why doesn't it clump into the center of the Galaxy like normal matter does?
It does "clump" also in the centre. The thing is that this dark matter halo is much bigger than the visible (stars + gas) galaxy. usually around 10x bigger. The fact that the halo is much bigger, means it gets much more massive and that’s why its gravity stabilizes the stars and the gas rotation. On the other hand Dark matter cannot get nearly close to the density of the ordinary matter. That's because it cannot radiate-away internal energy (which translates to kinetic energy of motions). So visible mater can get much more denser, but since the volume grows as a radius cubed (R^3), at scales bigger than the visible galaxy radius R* the gravity of dark matter quickly becomes dominant factor.
this is hands down my favorite series on RUclips. please don't ever stop making these. Phil, your are awesome mate!!
Fun fact: Most people don't know this 1% of the observable universe is made of gases, solids and liquids, while the other 99% is plasma, the fourth state of matter, and we are apart of the 1%.
I knew that. :)
Project Dante I'm pretty sure that most people that would watch this video knew that.
winston byman Not a safe thing to assume considering everyone's here to learn something.
Moses Tall wow very dangerous
Moses Tall plus I was here to learn something but knew that.
I understand some of these words
This is the best explantion of Dark Matter I've heard by far, and I've heard many. Can't wait for the dark energy episode.
Dr. Plait, you've done some pretty great science outreach, but I really hope you agree with me that Crash Course Astronomy is some of your best work yet.
where can i ask questions about astronomy??? I frequently get many, many questions about it...
Is there any good books on the basics of this kind of science?
"It surround us and it penetrate us"well,that escalated quickly😎
This is amazing! Thank you so much for taking the time to create something as educational as this, on a platform as readily and globally available as RUclips! Inspirations and role-models you all are!
P.S. those are some beautiful references you're packin in that description
I have been waiting for this for quite long
Yeahh!! A video about dark matter!
Omg omg omg i was so excited when i saw the title, i like dropped my phone lol
What if other dimensions or branes interact via gravity and we are observing the effects of all of the universes that contain mass. It could explain how there is so much of it, why none of the fundamental forces seem to affect it, and why it seems to interact with itself so weakly.
I love all of Crash Course, and this course is possibly my favorite. Keep it up!
+Owen Hunt I had the same idea before, but it does not explain the cluster collision. The gas colliding should contain the mayor part of the mass of the cluster, but the gravity map clearly shows it doesn't. In the parallel universes the gas clouds should hit each other just like in ours, so overall gravity should be clamped around the gas.
KohuGaly Agreed, however, I wonder if our gravity maps would be high enough resolution to resolve the tiny interactions between the particles of each universe. We could be seeing the affects of a large or even infinite number of branes, so even if their laws and particle density were simar to ours, most of the dark matter wouldn't interact with itself. I suppose it would clump, but it's also possible that this dimension is the only one with the right properties to allow for that kind of interaction, or for familiar particles to even form at all.
"SPACE IS SO COOL!"
-Markiplier2015
+Arctic Lancer HAHAha YEa :p
no one cares
+Jaximus Space.. space... SPAAAAAACEEE!
+Alejo Tassile Aww, I was about to make that joke, but then I saw your comment. Oh well. :D
he he.. :v
Thanks! I love your series! So, see if I got this right: We can detect dark matter's gravity even within our own galaxy, right? But why can't we detect it within our own solar system? (or can we?) Does dark matter "pass through" ordinary matter, and/or stay segregated from it? Does dark matter clump together with itself, forming planets, etc? Fascinating stuff!
0:13 why is Jupiter larger than the Sun...?
Watching this with closed captioning helps so much.
So we can't see the dark matter precisely, we can only estimate its presence via gravity... What if the "main" matter of the universe is dark matter, and there are galaxies, stars, planets and other lifeforms made of dark matter? What if those lifeforms are observing the universe and trying to figure out where the extra gravity is coming from (as they wouldn't be able to see "our" matter)?
+Darth Mongoose Like an alternate dimension or something along those lines?
+Darth Mongoose The problem there is we haven't detected any 'clumps' of dark matter, no planets or galaxies. We'd expect 'dark stars' to emit *something*, if you squash dark matter like that it should be transforming into all sorts of stuff.
+Darth Mongoose "... galaxies, stars, planets ... made of dark matter?" This can't happen. Planets cannot form from dark matter. Building planets from dust grains requires the grains to stick together; they don't have enough gravity to do that, so they stick by the electromagnetic force -- but dark matter doesn't "feel" the electromagnetic force. Stars cannot form from dark matter, either, because magnetism plays a role in protostar formation, and, as well, dark matter does not emit light. And galaxies are made of stars, so there are no dark matter galaxies, either.
That screwed me up a little bit
The studying of clusters colliding is mind blowing. Yeah we have come a long way to study the cosmos but I never realized at this scope and scale! Einstein truly did provide us the tools to understand the universe by leaps and bounds.
is this a red glowing degree knife in the thumbnail?
Vincent Weise lol
I like it how he describes, he makes it easier for us to understand.
We are as atoms in a human body trying to figure out how a human works.
BlackJackel12 or how the earth works
Now I just imagine entire civilizations of atoms researching and observing us
I get so excited when I see that a new Crash Course episode is released. Thank you guys for making these.
"1 view, 6 seconds ago"
+natnew32 lol
great channel,big thanks for subtitles!
I feel like I say this every new episode but, this is getting WEIRD.
NOTES:
1960-70´s
Observing the spiral galaxies
Rotation of bodies
More distance from the sun, slower the orbiting
Then you can get the sun's gravity
Then you get it's mass
Using the same method for the galaxies
Movement and velocity is calculated through the Doppler shift
Lead to unexpected results:
Clouds were moving faster, the farther out from the center
Velocities flattened out with distance instead of declining
Implying a constant gravity, instead of a decreasing
What gravity was keeping them from flinging off?
What mass was causing the rapid rotation rates?
We couldn't see them, so...
"Dark" material is contributing to the gravity
Galaxy must be embedded in a halo of it to fit the shape of the rotation
There must be 5-6 times more of it than visible material
85% of the universe
So what is it?
Cold gas? Dust? Dead star? Rogue planets? Subatomic particles?
They didn't emit light
The signs contradicted everything made of normal matter (atoms)
Except invisible subatomic particles from quantum mechanics
These are just possibilities
Like Axions: has mass, little light and and passes through matter
Space is like a fabric with matter and energy embedded in it
Gravity is a bending of this fabric
Like a bowling ball on a mattress would warp its surface
Light bends along the distortion of space caused by gravity
Gravitational lensing:
Effect of the matter between a light source and its observer, on the light
So: more mass, more gravity, more light bending
A cluster of galaxies have a lot of mass
So by being far away their light bends towards us
Bullet Cluster:
Two colliding galaxies
Their colliding gases get hot and emit x-rays
Bullet Cluster distorted it's background
Using that we could map it's mass
And see the matter that wasn't the hot gas and didn't emit light
The Dark force...
>far left
plz go
Not far enough left but adequate. Please stay :3
I'd really like to see a Crash Course on the different subatomic particals we have detected and theorized, explaining their properties and what their effect in the universe is.
Anti matter vs dark matter vs matter
Ohhhh boy i was waiting for this soo long
I dunno, it still seems like dark matter was thought up when a bunch of astronomers found their equations weren't working, all got together, and one of them said, "Well, what if there was all this, I dunno, invisible ... intangible ... stuff out there?"
And all the others were like, "Yeah, yeah, write that down!"
tl;dr - the invisible and nonexistent look very much alike.
+Cullen Paradis yeah wouldn't that be something if all the scientist came out and said
"Soooo everything based off, of Newtonian physics is wrong and were going to have to start science all over"
+uncreativename XD
Newtonian physics is right, is a way. But you must know how to use it.
Comparing galaxy with solar system is dumpest thing I heard of. You shouldn't expect that speeds would be like in solar system. You need doing some integration to trully understand how rather complex objects interact with each other.
And, surprise, there are guys who did some integration, but rather popular than scintific scolars never heard of it and never tired to repeat this folly:
It's weird that galaxy behaves different than solar system does...
What of it? It shouldn't!
Verlinde has just (pre-)published a paper that does away with Dark Matter as a particle. You might find it intriguing. It's available on the interwebs here: arxiv.org/abs/1611.02269
The studies into the CMB supports the dark matter results as well as other indirect studies into dark matter. Claiming it is a figment of scientists imaginations shows how clueless you are about the matter.
this is one of the coolest videos yet, i get that people that haven't been introduced into this concepts get lost, but when you know a little bit about and you have an open mind it's really interesting, and this video gives the information in a simple way, i'm really exited to know how scientist will prove that there's black matter everywhere.
You forgot to cover the part where if you get diamond for everything, you unlock dark matter.
LMAO
out of all crashcourse videos yours is the one i look forword to
I got here from The Problem of Evil: Crash Course Philosophy
Oh shit, DarkMatter2525
Please never stop making these. They are awesome
Thank scientists, I live in an age where real and true knowledge can be known through the scientific method and I don't have to adhere to stone age myths and superstition.
Jackboy019 as a rationalist I love your comment.
There's dark matter, which, when added to conventional visible matter, helps us accurately predict the trajectories of celestial objects, as explained in the video. Then there's dark energy, which accounts for the accelerated motion of galaxies away from one another. I wonder if there's also "dark space" and/or "dark space-time".
Woah...this is some night vale shit
Thanks Phil. What a channel! Everything here is so great that doesn't feel right to be free. I've being learning a lot here. I'm just an artist but space fascinates me since childhood. It's a honor to have someone with this prestige to teach us so much more.
my best regards from Brazil
I started studying for a Physics test and now I'm here and its 130 in the morning, help please.
Pickman its been a year, how did you do on it?
It gets worse!!! Lol
It's been two years. Did you pass? Let us know, we care.
Great video! This is one of the best series on all of youtube.
Wait, didn't crash course do an episode on the big bang in big history? Just go watch that instead!
+Sam Lund Definitely worth re-watching in preparation! But it's being covered from a different perspective. The Big Bang as it relates to Big History is a little different than a primarily ASTRONOMY vantage point. Plus, we certainly couldn't do a course on Astronomy without covering it. :)
-Nicole
This video doesn't discuss the big bang and that one doesn't discuss dark matter. Why are you even comparing them?
+CrashCourse Ooh, I am so excited already! Please give everyone involved in making these videos a hug from me, I appreciate your work with this soo much!
+Krombopulos Michael The comment refers to the next episode of CC Astronomy which will be about the Big Bang (see end screen). :o)
+Krombopulos Michael They are referring to the next episode which is on The Big Bang.
Yet another mind boggling episode. I truly appreciate all the hard work you all are doing.
If mankind finds out the secrets to dark matter in my lifetime, I'll be a happy lil' nerd
There is no dark matter. It is just a unscientific concept that protects "scientists" from the all so horrible cognitive dissonance. The gravity model is disproved. Showing lensing effects in space and claiming it to be gravity lensing does not make it gravity lensing. If we hypothesize that the lensing effect is due to gravity then we have to find the source of that gravity. Otherwise we can't assume that it is gravity lensing. That is how science works.
@@MegaBanne Didn't read lol
The thing about believing humanity should be humbled by the splendor of the cosmos is, splendor is only splendid when it comes to the attention of an intelligence sufficient to perceive it as such. As the only known intelligence that qualifies, it's not at all unfair for us to continue to perceive ourselves as the crown jewel of the universe.
Is it just me or does he look just like the quirkology guy
I like the way Gargravarr described our place in the universe to Zaphod; "An invisible dot on an invisible dot. Infinitely small. (*...small small small...*)"
Years from now, we're gonna look back on this video and laugh after we've found out that dark matter doesn't even exist and it wasn't "the only explanation" for what we observe.
+KidEatingClown I dunno, nobody really laughs at Newton.
+Gareth Dean ;-)
Still nothing...
maybe we will be laughing at you, actually no one will because what you say doesn't matter
Star wars reference in a physics video. Made my night. Best track in all of crash course.
WTF my brain is broken
Crash Course Astronomy is the only series where I click the like button before seeing the video.
Am I the only one who thinks we just need a better theory of gravity?
+Brandon Stoppel
No. See "modified models of gravity" MOND and MOG et al. They don't seem to explain the whole bullet cluster thing though.
Thank you
Best example of Gravitational Lensing! Keep the hits coming CC :-)
And people still think all this was made for us. Ha ha ha ha ha ha ha ha. Science always wins.
Black Matter is where our unwanted conciseness goes when they die. So no hell, just unwanted black matter.
Can’t be measured because it is our unwanted. Tyvm
nice
It that really the only possible conclusion from what we're seeing? That there must be some invisible, undetectable, and utterly unknown type of matter responsible?
I'm going to invite downvotes by suggesting that there is no such thing as dark matter; it is an erroneous assumption based on evidence we cannot (yet) otherwise explain.
+TheSwamper You'll get no downvote from me; it's a reasonable question to raise. Consider, however, that there are (at least) 4 different independent physical situations in which observations indicate that there is far more gravity than can be accounted for by the visible matter. In each of those 4 cases, essentially the same percentage of dark matter explains those observations.
So if there really is "no such thing as dark matter", the correct explanation is doing a remarkable job of disguising itself as dark matter.
Note, further, that there are a number of experiments under way to detect the dark matter particle, so the issue may be settled in the foreseeable future.
Nice comment. Dark Matter was 'invented' when visual observations of massive structures (like galaxies) did not move the way current physics predicts they will.
I suspect that this may come down to a greater understanding of observing/interpreting gravity over tremendous distances, negating the need for inventing an invisible, undetectable matter.
TheSwamper
"... gravity over tremendous distances ..."
The problem is that maps of the distribution of gravity in clusters of galaxies, as demonstrated by gravitational lensing, show large concentrations of gravity in the space *between* the galaxies. The distribution of gravity does not completely follow the distribution of the galaxies, so it's not just a matter of fixing up the strength of gravity over distance. There would need to be a way of sourcing gravity in essentially empty space.
Dark matter does that nicely. Several alternative theories of gravity invented so far have all run afoul of observational tests.
I don't refute that dark matter explains a lot of the observations, it just seems like one hell of a leap of logic to me "Oh, must be some heretofore utterly unknown matter, that is utterly undetectable by direct means."
I think it's less of a leap to suggest that maybe our current understanding of gravity is incomplete (which it is), and we are interpreting at least some data that is false (like a duplicate galaxy that appears, warped by gravitational lensing).
You may be absolutely right, and I admit I'm only a hobbyist, not a physicist. Either way, I'm enjoying the discussion.
TheSwamper
From my perspective, I don't feel that you're giving sufficient weight to the fact that the same amount of dark matter solves the observational problems in at least 4 completely independent astrophysical situations, including ones that are very difficult to interpret as mere changes in the strength of gravity. It didn't *have* to be that way; it could have turned out that each situation required differing amounts of dark matter -- but they don't.
And you're also not appreciating that we see dark matter evidence from lensing in not just *one* galaxy cluster, but *many* (I've not done a count, but there are at least dozens). You'd have to suggest that we're fooled by false duplicates in *every single case*, despite the careful observations made to cross-identify the multiple images. (And it's more than that, BTW; it's also the specific distortions of the individual images, and the exact locations of the multiple images, that help map the dark matter.) False positive identifications wouldn't necessarily yield consistent solutions.
I'll grant, however, that backwards-engineering the gravitational field by starting with the lensing effects is not easy.
Having said all of that, the search for the dark matter particle continues. Few folks are going to be satisfied until it is discovered and identified.
Vera Rubin is an amazing person. The fact that she was able to discover it is incredible.
Riddle me this, if dark matter is some form of matter that only interacts with normal matter via gravity, then why does it not have the same distribution as normal matter? Why would it collect more on the outskirts of the galaxy, and less toward the center?
The only reason I can think of is, dark matter is a gap theory/hypothesis.
+Velexia Ombra Since the galaxy spins, wouldn't things get pushed out via centripetal force? Unless I'm mistaken, dark matter doesn't have a lot of mass, just there's a lot of it? So the galaxy spins it right out to the edges since planets and stuff don't get in the way. I see a hole in my thinking but i think i'm on the right track.
+Velexia Ombra The most likely cause is that it consists of very light particles. These would then move much faster than normal matter particles, and something that moves faster will be less precisely kept in a gravity well. Another possibility is that the distribution we see is also not the distribution of normal matter. What we see as galaxies and such would just be the areas where matter exceeds a certain density so that it can clump together to form clouds, stars and such. Elsewhere the matter density is lower, but not as much lower as it seems to be.
+Velexia Ombra Maybe the same reason that the Oort cloud exists. Just a hunch, but seems reasonable.
The oort cloud exists because the planets and sun cleared out the interior area of the solar system of similar objects... I don't see how that applies to dark matter.
Velexia Ombra Maybe something similar is happening with Dark Matter.
That font at 3:54 looks terrific!
So why does dark matter seemingly only affect galaxies and not stars/planets? In other words, why does it only seem necessary to include dark matter for galactic observations? Wouldn’t there be dark matter in our solar system, affecting the movement and orbits of the sun snd planets?
Is it too spread out to have a meaningful impact on something as small as our solar system? Is it only concentrated at the edges of galaxies?
I'm just going to say astronomy is the most bad ass science, stretching math and the unknown to its limits. It's pretty damn cool.
I requested this episode at the beginning of the semester and it came out the day before my astronomy final! YAS PHIL THANK YOU
Nice. I already heard about the bullet cluster, but that wasn't clear to me why it was important, and what we did with its gravitational lensing. Now I understand its awesomeness.
I know I say that on almost every episode but : THANKS TO ALL THE PEOPLE WHO MAKE THIS SHOW AVAILABLE ! Love it !
Can't wait for the big bang video! I love this series so much.
Finally an episode on this!Well Anti-Matter, you got some competition.
I hope Dark Energy is next up. Can't wait to see Phil explain that one like Dark Matter :)
i just love the way he presents it
Awesome video. Much better than others about this issue.
YAY for Phil Plait! I love that guy, he was on P&T's show too.