Just a quick notice that our spin correlations paper was accepted by the Monthly Notices of Royal Astronomical Society (where all Galaxy Zoo papers go)

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Zooites of the U.S. West Coast organized a meeting.

Michelle described it as follows:

“It quickly became clear to me as a newbie that most of our members are in Europe…but we still have a hefty-and lively-bunch here in America! I (code name diver4skynsea!) was perusing threads one day and stumbled across the information on Galaxy Zoo’s first member meet up held in February at Astrofest and, too, of the subsequent gatherings since then. Garrett spearheaded the project of trying to get a similar meet up of members started here in the States. I noticed in the thread that a lot of Americans were concerned about how much harder it is logistically for our members here to “gather” as one big group.

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This blog post is a continuation from the previous blog post on Spin Correlations. See that post for the introduction to what comes here.

Imagine throwing a handful of spinning ballerinas into an empty space (since they are in empty space now, there is no need to for them to be ice-skaters). We can associate a thumb with each one in a similar manner as we did with galaxies in the last post. This thumb points towards her head if the ballerina herself thinks that she is rotating anti-clockwise, and towards her feet if she things she is rotating clockwise. Alternatively, we can also wind our right-hand fingers around her body in the sense in which she is spinning and look at where the thumb is pointing - this will give consistent results.

If ballerinas are thrown in at random, there are no correlations in their spinning directions. We discussed the concept of correlation in the previous post: if there are no correlations, the two neighbouring galaxies are equally likely to have parallel, anti-parallel or perpendicular spin directions - in other words, by knowing a spin direction of one galaxy, you can’t deduce anything about the spin direction of its galactic neighbour. This is illustrated here by these five animated photos of a spinning girl:

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This is the first of the two blogs that are dedicated to our latest paper, that we already advertised here. The topic is fascinating, but quite tough to understand for the first time. Have patience and enjoy.

Every single high-school textbook that I come across has the spinning ice-skater story hidden somewhere in the section on the angular momentum. The main question is, how do ice-skaters manage to spin-up to these dazzling spinning velocities? The answer lies in carefully observing what they do: they spin up a little bit, by pushing with their legs and with their arms outstretched and then they spin-up by bringing their arms towards their bodies. The physics behind it is the conservation of angular momentum. You can watch an edifying Youtube video that incidentally include an ice-skater here.

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I’ll let Anze tell you the story in more detail, but I wanted to point out that the 6th Galaxy Zoo paper is now available online.

We’ve decided to make this one public just before submitting it to the journal - you can find it here. Thanks, as always, for making this possible.

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