Today’s guest blogger is veteran forum member Geoff Roynon.

My interest in the night sky (and astronomy) goes back to the late 1950s when I was growing up in South Africa and we were blessed with dark skies. I soon learned to spot the Southern Cross and Orion and various other “star shapes” in the night sky. We also saw some of the early satellites going by overhead so this must have been 1958/59.

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What are these mysterious buttons? You shouldn’t have to wait too long to find out (we’re still testing…). 

Final testing underway… 

Hello to everyone that found Galaxy Zoo today through Gregg Easterbrook’s Tuesday Morning Quarterback column on espn.com. We welcome you to Galaxy Zoo, and we are glad to have you here as we journey together to understand more about our universe.

There is also a Galaxy Zoo forum with active discussions on all topics, including people sharing some of the beautiful galaxy pictures they have seen on the site. Take a look at the Threads to help you find your way around Galaxy Zoo for an introduction to the forum. There is also a thread with more information about Hanny’s Voorwerp.

We’re looking forward to seeing you around!

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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Yesterday Chris announced that Galaxy Zoo will be on The Sky At Night this weekend and that Patrick Moore interviewed me for that episode about the discovery of Hanny’s Voorwerp. As most of you probably know, we’ve been in the press a lot lately, and I’m keeping a list of relevant links on the forum.

Today I can announce that I’ll be a guest in the Dutch TV show ‘De Wereld Draait Door‘ (The World Keeps Turning) this Monday, (8th of September). It’s a well-known national and live daily talk show on channel ‘Nederland 3’ from 7.30 till 8.15pm (CEST). According to Wikipedia numbers show that it’s one of the most popular programmes on the channel.

So, tomorrow I’ll be travelling to the studios in Amsterdam and soon I’ll tell you all about part two of the ‘tour’.

Hanny.

I’m delighted to confirm that this month’s Sky at Night will cover Galaxy Zoo. Patrick talked to Hanny earlier in the summer, and Bob, Kate and I spent some of last weekend talking in front of the cameras. We talked for more than an hour, and the team led by producer Jane Fletcher have spent the last week editing us down so that we fit within the programme. I have no idea what they’ve come up with, and am looking forward to seeing it.

There are many, many ways to get to watch this gem of televisual entertainment :

If you’re in the UK :

BBC One : Midnight, Sunday night (ie early Monday morning), repeated on Saturday 13th at 2pm on BBC Two.

BBC Four : Special EXTENDED edition (30 minutes instead of BBC one’s 20) : Tuesday evening at 7.30pm, repeated at 1.35am on Wednesday morning.

The show will also be available on the iplayer for a week after broadcast.

If you’re not in the UK :

The show will turn up on our webpage at a week or two after broadcast.

edited by Edd to update BBC Four broadcast time

While you are busy clicking away at the mergers, it has been straight forward to record where in the world everybody is. (This comes from your IP address).

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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.