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| A Pierson's Puppeteer |
When I was younger, much younger, I particularly enjoyed the novels of Larry Niven. They fizzed and sparkled with strange and novel ideas: Klemperer rosettes, aliens like the Kzin, Pierson's Puppeteers (see above) and Bandersnatchi, humans bred for luck and, of course, the Ring World:-
One of the reasons I'm so fascinated by astronomy is that, in the last few years, we have discovered many strange and exciting new things that far out-do Larry Niven's vivid imagination. Ringworld was a construct the size of a Solar System. Below is a picture of a ring the size of a galaxy:-
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| NGC 660 - A Polar Ring Galaxy |
NGC 660 is a rare polar ring galaxy - only a handful have been discovered. In the above picture the galaxy is aligned roughly NW to SW and the ring is approximately horizontal. Dark dust lanes can be seen in the host galaxy.
The host galaxy is a lenticular galaxy. A lenticular galaxy is one that's in transition between a spiral galaxy and an elliptical galaxy. The difference between spiral galaxies and elliptical galaxies is that spiral galaxies contain the gas and dust necessary for star formation to take place, and so contain many young blue stars.
Elliptical galaxies have either lost, or used up, all their gas and dust, so the formation of new stars has stopped and the galaxy contains mainly contains old red stars,
Polar ring galaxies are believed to be formed either by a piercing merger between two galaxies aligned roughly at right angles, or when one galaxy tidally strips material from a passing gas-rich spiral and strews it into a ring. Numerous star formation areas can be seen in the ring which also contains numerous blue and red supergiant stars.
Studies of the rotational speed of the ring indicate that NGC 660 is embedded in a huge cloud of dark matter.
