Who can make a rose, or a penguin?

Pamela Gay posted an intriguing tweet whose meaning I don't yet know, but which got me thinking. She claims to be having great fun throwing galaxies together.

I wondered: what with? Then I suddenly remembered seeing a video on a website called Galaxy Dynamics from the dim and distant past. Arralen posted this video on the Galaxy Zoo Forum when it began - worth a watch. You can watch a larger version here on youtube; the rest of the website looks worth checking out too. I'm not convinced it's 100% accurate, because the galaxies don't seem to affect each other until after they've already collided, while our Galaxy Zoo mergers show signs of interaction long before the galaxies start to touch - it's the way to tell a merger from an overlap. They also seem to undergo a period of inflation, unless that's just me! The zookeepers would probably be keen to emphasise that this is models and conjecture, not observation - we can only keep studying mergers to see what seems to be happening. But in any case, I wondered if we could turn this into a game.

Last year I blogged about a gravitational waves game, where citizen science is being done by playing; and still without knowing what Pamela's talking about, I now have an idea. I know Chris has some nifty merger simulations getting ready for zoo classification by comparison - now, who's up for designing a game where we make mergers for ourselves?

Design two galaxies. Pick their type and features. Choose their mass, starforming rates, free gas, distribution of mass (i.e. is the bulk of it near the nucleus, or is it a pretty evenly-laid out spiral disk?), rotation speed (if a spiral; in an elliptical that might get too complex!), speed of movement and angle towards the other one. As you start going up levels, add more galaxies into the equation, or increase the density of the local environment. Perhaps we'll get a complex enough game for us to be able to make some of the following. Fifty points for the rose. 142 (after its ARP number) for my penguin. Get merging!



All images courtesy of the wonderful SDSS and Galaxy Zoo Forum - and I honestly did lay them out so they'd be small, and in rows (sigh) . . .