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From: sixtysymbols
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  • Do spiral disks behave like accretion disks?

  • Here's my theory:

    the arms are orbiting around the center of the galaxy

    at the center of the galaxy is a black hole

    things orbiting the galaxy are slowly being sucked in to the black hole

  • @aljirvine That is not a theory, that is just repeating what you've been told since childhood

  • I have never heard of the density wave before.

    Does George Bush know about this?

  • @UncleKennybobs No but Palin can see one from her house.

  • Alright here is a question i always wondered about, why are galaxies are mostly shaped in a 2 dimensional circular shape?? why can't a galaxy be shaped like a sphere??

  • @klesstwo Matter has angular momentum and it has to do with the conservation of angular momentum (such conservation plays a role in protoplanetary disks, accretion disks, planetary rings, etc.). The matter rotates in a particular direction and gravity pulls any matter above or below the plane of rotation into the plane. Unless it can overcome the gravity (if it has enough energy), it will remain within it forming the disk shapes you observe.

  • @klesstwo Elliptical galaxy's are shaped like spheres, it all depends on gravity and rotation, the size of black holes in elliptical galaxy's is terrifying.

  • @klesstwo Sixtysymbols has done this before

    /watch?v=V6ZPpC_lyYw 6:01

  • @klesstwo Imagine an Italian pizza chef tossing a ball of dough up in the air while spinning it... the dough flattens out into a flat circular shape. Same thing with galaxies, the centrifugal force would spread the sphere of stars out into a flat pancake shape.

  • @klesstwo conservation of angular momentum.

    Sixty symbols explains this in another video watch?v=V6ZPpC_lyYw.

  • Wait, so we actually don't really see most of the stars in a galaxy, but only those that are "lit up"?

  • What if the time was slowing down the closer you get to the center of the galaxy? The supermassive black hole in the middle of the galaxy could be causing this... just an idea

  • @Typho0n86 If what I've been reading up on on various websites is (or is it are?) to be believed, then it is possible if not likely that a black hole can and does distort time itself.

  • @Treefyleaf It's called time dilation. It's not "likely", it special relativity.

  • Press 6 for a chode wank

  • Press 3 and repeat for a wank affect:P

  • Could the spiral arms be caused by the framedrag of the supermassive blackhole in the center of the galaxy? It would be a sort of gravity vortex wave. Like Lagrange points but elongated and distorted, causing matter to fall into the arms, and be dragged around at the same angular speed. Does that make sense at all?

  • how do you know that the spiral is onedimensional? It's more like into looking into cylinder - the converging point is just an illusion - at this point the diameter is equal to the diameter which seems larger in this picture. And now flatlander ... do your work.

  • This may be a silly question but you say that all of the stars are traveling around at the same speed. As a galaxy is thought to have a black hole at the centre doesn't that mean that the stars are orbiting? And if they are orbiting doesn't that mean that their distance from the gravitational centre and their velocity are linked according to Newton's laws? I thought that the stars further out had to be moving faster, otherwise they would be compelled to fall in towards a lower orbit.

  • @ianbcnp at those speeds and gravitation levels, general relativity takes place. and it's not a "simple" system. a man can calculate a binary system, computers can calculate (lets say) 10 stars. here you have billions. and i doubt that you can reduce the system to the "superposition" of gravity (like you refer to a star as a singular point in it's center that holds all the mass).

  • dudes like you cannot even explain why factorials are being used - saves writing. all the "higher mathematics" just saves some writing so that more and more complex things can be described

    by using the same or even less space than before. it's simple compression - just like to compress the .wav pattern into the .mp3 pattern.

  • When we say that all of the stars are moving at the same speed, are we saying they have the same orbital speed, or are we saying they have the same angular speed? The runner analogy alludes to the same orbital speed, but later in the video he refers to the rotation of the galaxy and its angular speed, as though the galaxy rotates like a rigid disk.

    So which is it?

  • /watch?v=mA37cb10WMU

    The reason for vendettas or even bigger ones called "wars" is by the same. Each of the ants does what the other does - the enemy does what his enemy does. They sniff on each others arse - if sniffing with their "olfactorial", the "visual" or any other sense is negligible.

    By the way: why not measuring time on any degree of the scale dimension by using 10, 100 or 1000. We say 1/10 of a second, in industry they use 100 minutes rather than 60 minutes.

  • Very interesting, thx.

    so let me get this straight - the arms are soundwaves (waves in the density distribution of the particles) in the galactic gas/ dust? That's a very cool idea, because of how simple it is. But what makes the waves move in circles? or is it just superposition of a rotating wave source? i mean - do the waves travel in a straight line even though it looks spiral. or do the waves actually move in a circular motion?

  • @kidi1232 God swirls it with his finger like you or I do with our Kool Aid in a cup of water

  • @itsMinuteMaid Of course! it all makes sense now! NASA should hire you. no, you should hire NASA.

  • @kidi1232 soundwaves? What? Are you serious?

  • @culwin well, there's a lot of gas and dust, and soundwaves are waves of density in gases / small particles, so why not?

  • Do the Universe have a coriolis effect ? - That is does the relative rotational directions of galaxies tell us anything about the structure / topology of the universe ? Is there a tendancy to rotate one way 'over here' and the opposite 'over there' ? Is it random / 50-50 chance ? What is the reason that a particular galaxy formed rotating the way it did i guess is the deeper question ?

  • @Hythloday71 This is a good question, I hope someone who knows there stuff can give an answer. Indeed, has there been a study into the distribution of the rotations of these galaxies? I'm guessing it's likely that they seem rather randomly distributed in that sense.

  • Holy shit. A "wave of density."

  • Considering the fact that the Earth is orbiting the Sun at an incredible speed in addition to the fact that our galaxy is moving around at an incredible speed, would life on Earth be a lot shorter if this were not the case since time is relative to speed? 

  • I'm so happy vsauce showed me this channel :D i love astronomy!

  • is it just me or does he talk unusually fast?

  • @safenders Solution is to listen faster. He talks at a good pace, but definitely not anywhere near how fast some people talk.

  • @regemo well I can understand him just fine but I seem to lose interest in what he's saying and start to focus on the rhythm of the words lol

  • What is the cause of the density wave ? The black hole at the center ?

  • @1isaacmusic I believe it is,  I doubt the density wave is causing the black hole, although black holes without any matter, fade!

  • @javonoUTube They look so much like the 2d simulation of gravitational waves on Wiki, for two Neutron stars tho'.

  • I can't help but wonder why every one of these videos has a single down-vote?

  • @codykonior

    I suspect Professor Moriarty...

  • The video shows an image of the supernova "of summer 2011" in the "Whirlpool Galaxy" M51. It was brightest around June 20, and could already be discerned in a telescope with a mirror/lens of 5-inches in diameter back then. It's brightness has dropped since then, but it can still be easily seen in a 10-inch telescope - provided you observe in dark skies.

  • you guys should do a video on lenz's law and eddy currents :P

  • From my knowledge the arms are created due to the rate at which material is ejected from the nucleus of the galaxy. The system rotates at a fixed velocity but the rate at which matter is projected(your waves I guess) is erratic.

  • 6:15 Doesn't relativity say that it doesn't really matter, that true you could argue we were standing still and the arms are sweeping through us, or the arms are standing still and we're sweeping through them? So it doesn't really matter and the answer to the question is both? Correct me if i'm wrong..

  • I love the videos :) 

  • What are the proffessor's opinion's on Prof. Brian Cox??

  • Science can be really fun sometimes, when they say things like, "We don't really know why it works this way, so we're going to make an educated guess and assume it works some other way, then all nod our heads as if we believe it."

    The most fun bit is that theories and ideas are often presented as fact, instead of being presented as just theories and ideas.

  • @theverbalrelease No, a theory explains a fact, it can not be a fact or an idea. That's how it works. A theory can make predictions about the fact. If the prediction fails then the theory is thrown out or revised. Look it up because a Scientific Theory and a "theory" are two very different things. Here is a good example of a theory: The fact of biological evolution is best explained by the Theory of Evolution.

  • @Grymyrk

    Well put. It's actually very simple, but many people seem to have great difficulty understanding it.

    Most of the time I believe it's because they choose to not understand, but I don't think that's always the case.

  • @Grymyrk You are just plain old autocratic!

  • @theverbalrelease By calling them "theories", you are trying to imply that they do not have evidence - proof - to back them up. That is false and intentionally misleading.

  • @culwin If something has evidence, but not enough evidence to prove the theory, it is still a theory, especially considering sometimes even though there may be some evidence, it might exists for reasons outside of the theory. Only when something is proved does it stop being a theory.

  • @theverbalrelease That is not the only meaning of the word "theory", and I think you know it. Troll harder.

    1.

    a coherent group of general propositions used as principles of explanation for a class of phenomena: Einstein's theory of relativity.

    2.

    a proposed explanation whose status is still conjectural, in contrast to well-established propositions that are regarded as reporting matters of actual fact.

  • @culwin At its base, there is theory and fact. Before an idea is proven, it is theory. Once it is proven, it is fact.  It's really quite simple. Have a nice day :).

  • @theverbalrelease In Science a theory is there to explain the facts and provide us a model. So a theory in science is just as important if not more so than fact.

  • supernovae

  • @mykmmc Space is not a vacuum so there is sound in space. The waves you see in this video ARE sound. However the wavelength of sound in space is very big, so you cant hear it unless it is being compressed by a computer. :)

  • @GammahooX space is a vacuum retard so there is no sound retard

  • @GammahooX no. space is a vacuum.

  • @volound

    Well, it's an imperfect vacuum. There is quite a lot of material to be found in any given region of space, but no, it shouldn't be enough to carry things like sound waves, regardless of wavelength. The particles of matter are separated by far to much empty space to carry a coherent wave.

  • @InB4Desu which is exactly what i was alluding to.

    space is (effectively) a vacuum, although it isnt a perfect vacuum.

  • @InB4Desu Yes, space does carry sound. Watch the video your commenting on again.

    It explains how sound waves of very large wavelengths move around the galaxy in certain patterns and create those spiral arms and even tho the galaxy looks pretty dense from far away, think about all that "empty" space between the stars and planets - it does carry the wave.

  • @GammahooX This video has nothing to do with sound. Are you a troll? If so, good one, you got me.

  • @culwin He says the wave moving around the galaxy is a wave of density. And what are waves of density usually called? Sound. In this particular example: Infrasound. Why do you try to correct other people if you have no idea what you're even talking about? You should've learned that in school.

  • @volound Space cant be a vacuum (meaning that there is ABSOLUTELY nothing in it), because WE are in it, even if you only mean that "black stuff" all around us, there are still a couple of hydrogen or helium atoms in it.

  • @GammahooX i already know this. why did you post that comment?

  • Yeah, 620 likes out of 300 viewers. Everybody knows that the guys from Sixty Symbols are brilliant; everybody votes twice!

  • Interesting as always. My most loved YouTube Channel by far.

  • Charlieissocoollike in a couple of years :D

  • interesting, i wonder if dark energy is helping to form the wave, but i suppose thats overly simplistic.

  • I notice you've got the "Atlas of Creation" in your bookshelf. Is that there for whenever you want a good laugh?

  • @kentrel2 Yes, he answered that in a different video.

  • @kentrel2 well spotted.

  • @kentrel2 there is a video on the channel explaining that book

  • @kentrel2 do your researches this book gives arguments against creationism

  • I'm wondering what makes the spiral arms light up if there are also stars in between them...

  • "There's nothing like a bit of galactic spiral arm star formation in the morning."

  • what the fuck? i feel really stupid now

  • Nice! But how do we have pictures of the milky way or are they just computer generated?

  • @V3N0MousProductions the pictures of the "milky way" we have are from the inside out, only a part of the milky way galaxy. We can't take pictures of it in it's entirety from here

  • @Riou2294 That's what I was thinking, but I thought I saw some pictures of it...turns out they were just computer generated

  • my mind was just blown

  • Aparently the universe it flat.

  • I was wondering about how dark matter keeps the galaxy together.

  • Does moving in/out of a spiral arm have any effects? My intuition says no, but am I incorrect?

  • @1RadicalOne listen to the last part about stars.

  • No, not on star formation, but effects on preexisting stars and their planets, if any.

  • @1RadicalOne I think he said something about supernovas only happening in the gas dense area? Im not sure about planets though.

  • He made that comment because it implies that star formation takes place almost exclusively in the spiral arms. But again, that is not what I am looking for.

  • @1RadicalOne OK then I do not understand what he meant because it seems like a contradiction saying that stars move in and out of the arms over time.

  • No, he was talking about massive stars when talking about the supernovae; those stars live only a few tens of millions of years, and that was his point: those stars essentially die where they form and thus where there are supernovae, there is star formation.

  • @1RadicalOne Thank you, now I understand.

  • @G3org3Master The stars in an arm are not all moving the same direction or speed.

  • Welcome back viewer 303!

  • Question: Could the density wave be gravity waves from the super massive black hole in the center of the galaxy?

  • A great birthday present! Thank you!

  • Every part spinning in unison looks like a spinning gear or wheel, not rotating freely like the runners around the track.

  • Are we currently on the leading or trailing edge of a wave?

  • @fegolem I asked this also, with no replies. According to NASA and contemporary belief we are in a Local Interstellar Cloud, also according to NASA & some Russian astronomer we are now entering a denser area of the Interstellar cloud that is affecting the Sun's magnetosphere. I would like to know if the denser area is the centre of the Wave/Arm?

  • I wonder if the spirals are from gravitational waves.

  • How about sombrero galaxy? :D

  • more likes than views?

  • @PizzaManTech YouTube is slow at first updating their views.

  • you guys need your own show

  • @sixtysymbols I had made a video repost (i personally made the video) and the research i put inside of the video and information section of the video is specifically a question i have for this professor, please accept my video response and don't be fooled by its title, I'm not talking about a man in the sky but Thales-Einsteins Spinoza's God and Golden-Ratio Spiral Phi Vortex Structures etc

  • You spin me right round baby right round

    Like the Milky Way

    Right round round round.

  • Anyone else see the 'Atlas of Creation' book on the shelf. I laughed. It would be more appropriate to use it as a door stop than to display that trash on a shelf.

  • @YZBot They discuss this in another video... basically the Prof says he likes the pictures in it

  • Hm-mm, ... That never occurred to me before ...

    UNLIKE EVERY OTHER EVERY OTHER THING I WAS TO GODDAM DENSE TO PICK UP ON!!!!

    Thanks for the enlightenment. : )

  • @THEkidYOUallKNOW24 we can't see the full structure of the milky way

  • How does NASA get pictures of the Milky Way? How is it that we could see its full structure even though our most powerful telescopes are circling earth? Can anyone explain

  • Is there any evidence to suggest that these density waves are caused by gravity waves?

  • I watched a vid that had the "sound" of a pulsar? if space is a vacume how dose one hear sound?

  • This is some great insight into the overall complexity of galactic processes!

  • I'm sorry, I thought that dark matter was the force that caused the outer arms to keep speed. Doesn't this theory contradict that?

  • Great vid

  • Great video!

  • The galaxy is a plasmoid, there, your questions are answered. But hey ignorance is a sad thing.

  • some galaxies are spiral and some not, if the rotation of a galxy takes hounderts tousends years then u can not tell that the galaxy always was spiral, yo are watching one galaxy not more then about houndert years, like you gave the example whit the runers around the football field, maybe the galaxy is gona lose the spirals after some time just in larger skale? or why the other galaxies do not have spirals?

  • hey proff, what do u think of white holes? recently ive been looking at the theory of it, Einstein's theory says its possible but not stable for long periods of time...we used to see black holes the same way we see the white hole (a mythological creature pretty much), but what do u think of it?

  • @XxhilfmirxX For goodness sake, tell me where in Einstein's theory does it say that black holes (or even a white hole) are possible??! I'd pay you good money if you showed me. Please stop lying or tell that to whoever lied to you, thank you.

  • pythagoras / keplars Music-harmony of the spheres explains alot of this, Walter Russell has explained ALL of this (If only academia would take notice of him)

  • Degrees per second! Hahah! Are pattern rates based on comparisons with the earliest photographs of galaxies? How far back does the evidence you are using go?

  • M51 rocks !! Great spiral galaxy, I'll aim my scope to that by the next week when the Full moon while start to fade

  • This is one of the most worthwhile/fun channels I've found! Thanks so much for taking the time to make these videos.

  • cool

  • 1:30

    No you.

  • Wow, that's really quite clever, using supernovae to figure out where stars are forming in galaxies!

  • I always wondered what is in the center of a galaxy it looks like a giant sun but it could be a bunch of stars in a short distance. I want to know what it is someone please tell me.

  • @ravenheart93 I think the theory is that at the center of a galaxy is a ridiculously massive black hole with millions of stars orbiting around it at relative close range. But there's probably a lot more to it.

  • @ravenheart93 A supermassive black hole sucking young stars. It's yellow because there are millions of stars compacted there

  • Perhaps in the grand scheme of things spiral galaxies aren't that old and so they still have their spiral patterns, but will deform in a few billion more years. Just a thought.

  • I can't quite visualize the wave. Are you saying the arms themselves are the waves?

    

  • It's things like this that make me feel helpless sometimes.

  • I thoroughly enjoy watching these videos, always gives me something fresh to bring to my physics class, very well edited and presented too.

  • Is all astronomy this exciting!

  • @Mojosbigstick As with anything, it is completly based on your attitude toward it

  • @Mojosbigstick my friend did astrophysics, thought it was like this and then realised he was just studying various branches of how light works and what you can glean from it. personally it sounds quite interesting to me though.

  • What if the Supernova was caused by a giant stable star entering the Wave, where critical mass was induced by the energy in the wave and caused the Supernova?

  • new youtube player is slick

  • Is the Interstellar Energy Cloud(Alexei Dmitriev) we are now entering, with more density than the local interstellar cloud one of these arms/wave? What effect would travelling into the wave have on our Solar System? Obviously the arms are created by the Black Holes gravity as water going down a plug hole!

  • Maybe because of the mass at the center of the galaxy, the spiral arms become part of some huge lagrangian point like area.

  • thanks for uploading. 

  • this is scary, in a few years human race will know so much about the world that they may get to meet the aliens in control of the milky way, if we know too much about the universe, then we will have to consult with the head of the milky way before we do anything, its probably the grey aliens. we're growing up as earthly creachures

  • @Zee96969696 Aliens have not been proven to exist. Stop reading fairytales.

  • I was going to post the angular speed of our galaxy in radians/second, but there's the 500 character limit :(

  • heh, I just found the wiki and the density wave theory seems to be like 50 years old! Good animations in that wiki to understand how the stars move between the arms.

    Density_wave_theory @ wiki

  • Could these waves be electromagnetic waves?

  • @nickharvey7

    They are density waves which compress the gas causing star formation.

  • @nickharvey7 electromagnetic waves will be in effect here, but the waves on this colossal scale are due to the huge amounts of mass. confusing!

  • 0 dislikes. Love it

  • Seems that "waves" are the new black in science. Waves for electrons, waves for galaxies, waves for everyone! :)

    I'm glad to see scientist are attacking the mysteries with all they have.

    Oh, and Nice video!

  • is the footage at @4:55 playing in reverse? i always imagined spiral galaxies to rotate with the arms trailing and not leading.

  • @mazzepa1 the galaxy's not rotating, just the camera or spaceship from which we're viewing it! ;)

  • @sixtysymbols I thought given two objects you couldn't  determine which of the two is 'stationary' and which is moving, only define which is stationary

  • @sixtysymbols

    I knew you had the technology to build a spaceship, now share with the rest of humanity!

  • @mazzepa1 its just a bloody picture and a certain graphic effect that makes it look like moving

  • Thanks Brady and Prof Merrifield! I had to watch that twice as I found the wave concept, as applied here, difficult, but think I understand now, thanks to the last bit about the wave often travelling independently to the stars. For me it just raises more questions, but thats par for science. off to extra footage time :)

  • Nice - thanks for posting!!

  • Is it true that they have find an almost perfect replika of our milkyway galaxy . Just couple times bigger

  • @FinTheDew Many....

  • @2plus2make4 ofc they have found many other galaxies but just lately exact replica of your galaxy

  • @FinTheDew There are many spiral galaxies that resemble our own, of course none are an exact replica but agree it is cool to see others from a different angle. We can more easily imagine what our own looks like from a distance. I enjoy looking at the various images of spiral galaxy collisions at different stages - it is kind of cool to be able to "see" the whole process at different stages and imagine our position when Andomeda passes through the Milky Way in a few billion years.

  • @2plus2make4 I didnt mean that if another galaxy is spiral its milkyways replica but whatever you dont seem to understand my point