Original URL: http://www.theregister.co.uk/2004/05/27/universe_picard_topology/

Boffins trumpet horn shaped universe

Called Picard. No, really.

By Lucy Sherriff

Posted in Science, 27th May 2004 11:31 GMT

Researchers in Germany have been looking carefully at the after glow of the big bang and have decided that the universe is shaped like a trumpet bell, or as some would have it, the Eiffel Tower. And in a twist of fate that will have Star Trek fans in a state of near apoplectic glee, the particular topology that best fits the observations is called Picard.

British scientists are understood to be devastated, having assumed that the universe was shaped like a football, or an infinitely extended Nelson's Column or, at the very least a passable likeness of the late Queen mum.

More seriously, this model has the advantage of explaining some rather puzzling observations, New Scientist reports.

In the afterglow of the big bang, there is a pattern of hot and cold spots. However, recent maps of that region of space made with data from Nasa's Wilkinson Microwave Anisotropy Probe, show that none is larger than about 60 degrees across. Frank Steiner, the lead researcher, says that a finite, horn shaped universe fits this observation: there just isn't room back there for the blobs to be any bigger.

The curve of the Picard horn, described as pringle-like, would also explain why these background blobs are elliptical, rather than circular. Observations of circles on the sky would be stretched into ellipses by the curve of the universe.

The soccer ball shaped universe was actually a serious suggestion, put forward last year as part if a finite universe theory. However, there should be a particular pattern on the background radiation, if the universe is shaped like a football, but researchers have not been able to identify it.

A Picard shaped universe would also leave a pattern on the background microwaves, but the exact pattern we see would depend on which bit of the bell we are in. So the fact that we can't see them doesn't actually rule out the Picard topology.

If this is the true shape of the universe, it means space is finite. The narrow tube section is infinitely long, but so narrow its volume is finite. [Yes, we have a headache too]. However, the bell section flares outward only so far. Theoretically, you could fly out of the universe on one side of the bell and arrive back on the other.

It also means that scientists need to chuck out a couple of assumptions, like the "cosmological principle". This is the idea the universe is roughly the same everywhere. In the narrow end of a Picard shaped universe, things would start to look very odd indeed, with only two, very small, dimensions.

If this is all a bit too much, console yourself with the thought that this research has come from the University of Ulm, Einstein's home town. There must be something in the water. ®

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