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Q & A: Does the universe have net spin or rotation?

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Q:
Does our Universe spin/rotate?
- Matthew (age 17)
Rockville MD USA
A:

Nice question Matthew,

As far as we know the answer is no.  Astronomers have looked at the spin and rotation directions of a large number of galaxies but the net angular momentum is zero, within statistical uncertainties.   You can always find a few local anomalies but, again, consistent with statistical fluctuations.

LeeH 


(published on 10/30/13)

Follow-Up #1: Is there a galactic rotational asymmetry?

Q:
Has it been determined as to the direction of rotation of all galaxies? Are there more rotating clockwise or counterclockwise? I would think that if one spin were to be the norm, something could be inferred about the formation of the universe.
- Jim Wells (age 65)
Valparaiso,IN 46383
A:
People have looked at more than ten thousand galaxies in search of this effect. There seems to be a slight preference of clockwise rotation in parts of the sky and counter-clockwise in other parts. The amount of asymmetry is very small but appears to be statistically significant. See http://astrodatamining.net/category/galaxies/ or http://algomagic.com/0904.2529v1.pdf for some technical details. Some people have suggested that an inter-galactic magnetic field might be responsible.

LeeH

Just a reminder- whether the spin is CW or CCW depends on which side you're viewing the galaxy from. The website Lee links to of course explains this properly, but it seemed important to mention it here in case anyone might be perplexed. Mike W.

(published on 10/30/13)

Follow-Up #2: Does the universe rotate?

Q:
Hi every body! Basically i have done my masters in linguistics but i am very much interested in science subjects. i have studied various theories of physics. i didn't understand BIG BANG THEORY and it is not justify able.Because we know that every object in this universe revolves or rotates only anti clock wise??? if universe is to be supposed as a result of B.Bang then that was a sudden explosion in all directions. According to this theory things must rotate or revolve randomly i.e some objects clock wise and some anti clock wise.....??????
- Azam (age 28)
Gilgit,Pakistan
A:

I guess that you're referring to the effect described in  this article: 
 http://physicsworld.com/cws/article/news/2011/jul/25/was-the-universe-born-spinning . The paper it describes said that, looking northward from Earth, a slight but statistically significant majority of the galaxies are seen to rotate counter-clockwise. However, another survey of a large number of galaxies found no effect: http://adsabs.harvard.edu/abs/2008MNRAS.388.1686L. I can't find any paper confirming the surprising results of that first one. So it's hard for outsiders (or even an astrophysicist who helped out here) to be sure of whether the effect is real. 

The standard Big Bang pictures don't include any overall rotation, although obviously local accidents make galaxies, stars, etc. revolve. If the non-random looking rotation effect turns out to be real it might involve just some corrections to a messy picture of how large-scale swirls and counter-swirls got going as the early universe evolved. There's some discussion of this issue in a paper posted on the Arxiv (not refereed):  http://arxiv.org/pdf/1201.5180v3.pdf, but I'm not familiar enough with the area to evaluate it. That paper describes some rotation effects that extend  farther than expected but not throughout the universe. 

There's always a slight chance that some surprising result might overturn central parts of our understanding, but usually strange results turn out to be somehow off. 

Mike W.


(published on 10/30/13)

Follow-up on this answer.