Do all galaxies spin in the same direction?

aetherius · Apr 28, 2005

Just curious after looking at the Hubble Deep Field which is always an awe inspiring sight no matter how many times you have seen it. Sorry I can't get the link to post correctly. http://img&%$#@!.hubblesite.org/hu/db/2004/07/images/a/formats/print.jpg

Saiph · Apr 28, 2005

actually, considering all the different orientations of the galaxies in the Hubble deep field...it'd be pretty hard to do so <img src="/images/icons/smile.gif" />! But no, it appears to be randomly and evenly distributed. <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

vogon13 · Apr 28, 2005

IIRC, at one time it was not known if the tips of the spiral arms led or trailed. <div class="Discussion_UserSignature"> TPTB went to Dallas and all I got was Plucked !!So many people, so few recipes !!Let's clean up this stinkhole !! </div>

aetherius · Apr 28, 2005

Sorry I can't get the link to post correctly. The jpg is at hubble.org. Look for "ultra deep field" if you haven't seen it in a while.

nissasa · Apr 29, 2005

If you think about it, all spinning galaxies spin the same way. I haven't noticed any spinning end over end. <img src="/images/icons/wink.gif" />

spacehead · Apr 29, 2005

What i wanna know is what causes themn to spin? Is it the gravitational forces from all the stars etc... in that galaxy(s) ?

Saiph · Apr 29, 2005

just conservation of angular momentum. The cloud the galaxy condensed out of had some net rotation left over from random motions of the big bang. As the cloud condensed, the rotation sped up, and everything in it has it too. Now, if you take a big enough sample of galaxies, it should all average out to zero net rotation (which is what you'd expect with a random beginniing). If it doesn't, the universe has a net rotation..which would be interesting. <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

Leovinus · Apr 29, 2005

And which direction is our galaxy spinning? If viewed from "above", perhaps it is clockwise. If viewed from "below", perhaps it is counter-clockwise. So yes, all galaxies spin the same way: around their center. <div class="Discussion_UserSignature"> </div>

Saiph · Apr 29, 2005

that is, of course, the nature of anything spinning, that it must rotate about an axis of rotation... <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

star_sirius · Apr 30, 2005

NGC 4622 in constellation Centaurus, a colliding galaxy spins in the wrong direction, a clockwise instead of anti-clockwise. http://unisci.com/stories/20021/0207023.htm <div class="Discussion_UserSignature"> A dazzling bluish luminosity from A distant south pacific. <img id="cb51e87e-8221-424c-8ff2-78c95122196c" src="http://sitelife.livescience.com/ver1.0/Content/images/store/11/15/cb51e87e-8221-424c-8ff2-78c95122196c.Large.jpg" alt="blog post photo" /> </div>

yevaud · Apr 30, 2005

<blockquote>In reply to:<hr />If it doesn't, the universe has a net rotation..which would be interesting.<hr /></blockquote> Not the least of which, it would mean Kurt Godel was right, and time travel may be possible (rotating, but otherwise static universe, with a non-zero cosmological constant). <div class="Discussion_UserSignature"> Differential Diagnosis: "I am both amused and annoyed that you think I should be less stubborn than you are." </div>

Leovinus · Apr 30, 2005

That depends on which side you're looking at. Imagine a see through clock that has its face against the wall. When you watch the hands, they move counter-clockwise. <div class="Discussion_UserSignature"> </div>

centsworth_II · Apr 30, 2005

Better yet, take the clock off the wall. Holding it in your hands, you can maneuver it into any position required for the movement of the hands to represent the rotation of any galaxy in the universe. No need to reverse the "clockwise" motion of the hands. If you need to reverse the spin of the hands, just flip the clock over. So its true to say that there is only one possible way for a galaxy to spin and all galaxies spin in the same direction. UNLESS...unless you are measuring the directtion of spin in relation to something -- like a magnetic or gravitational field. <div class="Discussion_UserSignature"> </div>

star_sirius · May 1, 2005

I'm aware of that, you're generally right, but i stumbled few cases especially colliding galaxies, in which the proximities of two colliding galaxies reverse and cause the directions to change. <div class="Discussion_UserSignature"> A dazzling bluish luminosity from A distant south pacific. <img id="cb51e87e-8221-424c-8ff2-78c95122196c" src="http://sitelife.livescience.com/ver1.0/Content/images/store/11/15/cb51e87e-8221-424c-8ff2-78c95122196c.Large.jpg" alt="blog post photo" /> </div>

Saiph · May 1, 2005

rotation is actually relatively easy thing to determine for a galaxy, if you care to do spectroscopy: You merely look for a doppler shift in the lines on the edges of the galaxy. That'll tell you the net component of the motion, and which way it's rotating. You may be a bit off about how fast it's rotating (due to orientation issues, face on galaxies will appear to rotate slower than edge on), but you'll have the relative proportions, and hte directions correct. There are only 3 axis an object can rotate around, and it can rotate two ways, for a net possibility of 6 rotation orientations. However, there is no real difference between the two ways (counter clockwise and clockwise) as you can merely imagine looking form the other direction. That means we're back down to three. Good news is, conservation of angular momentum, and the fashion in which galaxies form, most rotation is around a single axis. So when you ask if they all rotate the same way, there really are two answers. Yes, they all rotate, for the most part, about a single axis. No, not all those axis are pointed the same way. So some rotate with the axis pointed at us, some away (thus the clockwise and counterclockwise) some with it up, or down, or any angle in between (left and right too!!). And those really are different if you consider the angular momentum invovled. <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

Saiph · May 2, 2005

what can I say...I just took a senior level course on galaxies... <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

nexium · May 3, 2005

The summary is, I think, about half are clockwise and half counter clockwise. The axis of rotation points in a different direction for each galaxy, without preference to axis pointing direction, except locally, some prefence is observed. Results are about the same with any reference, but you are doing bad science, if you keep changing reference without good reason. In our solar system, no two axis of rotation point exactly the same direction, but about half are plus or minus 10 degrees of the direction that Earth's axis points, so we see some prefernce in our solar system, if we don't consider comets which are quite random. Neil

newtonian · May 5, 2005

Neal - Are you sure? Clockwise vs. counterclockwise, i.e. Remember, it depends on whether you are looking at the galaxy from the north or south. Remember, north is up!

newtonian · May 5, 2005

Saiph - Hi! Anything especially interesting you learned in that course that you would like to share with us? You posted: "Now, if you take a big enough sample of galaxies, it should all average out to zero net rotation (which is what you'd expect with a random beginniing). If it doesn't, the universe has a net rotation..which would be interesting." Interesting is an understatement! So, is there a net rotation, considering North as up? It would be difficult, in view of the current state of expansion, to detect this in our portion of universe. But it may indeed have caused a bias in rotation of galaxies. How fast could the singularity have been spinning before the big bang - was it so fast as to cause the big bang? FTL? Or modeling the other way through time: If the singularity was spinning just under the speed of light, say 99.99999990 % the speed of light, then how fast would the universe be spinning now? I assume you would have to assume a certain shape for the universe to do the calculation - but conservation of angular momentum should give a definite answer!

newtonian · May 6, 2005

steve- Yes, I knew that. Rather funny, btw. Seriously, the Bible uses north as up: (Job 26:7) ". . .He is stretching out the north over the empty place, Hanging the earth upon nothing;" I'm not sure why, btw. But please consider: looking at our universe from beyond, as God would do, what if North is indeed up? Even if not, consider the reference to North, which astronomers also use (coincidence???), to distinguish spin direction. Now, do galaxies have a net rotation perhaps as a relic of spin of the singularity at the big bang? I.e.- is there a bias looking from North down for either clockwise or counterclockwise? Or any other bias? Or do we have any evidence of early spin in our universe before expansion slowed said spin down????

paintwoik · May 7, 2005

There is probably a north and south to galaxies. Should this ever be figured out ...... there should be a preference to the spin direction. I.E. They will all spin in the same direction. I'll go out on a limb and say that an antimatter galaxy will spin opposite to that of a matter galaxy. I'll also say there are no antimatter galaxies because there is a preference to the spin direction of what makes up matter since the beginning of the universe, and that preference leads to the preferred spin direction of galaxies.

newtonian · May 7, 2005

paintwoik- From earth as a reference point, astronomers already use north and south - that is the standard reference frame. Galaxies are observed from our reference point at all angles and at different spins. I am hoping someone will post a link or quote clarifying whether there is any tendency towards one spin over another..... BTW - our upcoming merger with Andromeda galaxy will involve spin. Does anyone know whether the spin of Andromeda will be against the spin of Milky Way at initial contact, or if the spins will compliment each other? At what angle will our galactic disk be to Andromeda's galactic disk? BTW- both galaxies are spiral.

paintwoik · May 7, 2005

<blockquote>In reply to:<hr />paintwoik- From earth as a reference point, astronomers already use north and south - that is the standard reference frame. <hr /></blockquote> You misunderstood. my meaning

Do all galaxies spin in the same direction?

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