Heelal als ‘Russische pop’
This, they say, is exactly what you’d expect if the universewere eternally cyclical. By that, they mean that each cycle endswith a big bang that starts the next cycle. In this model, theuniverse is a kind of cosmic Russian Doll, with all previousuniverses contained within the current one. That’s an extraordinarydiscovery: evidence of something that occurred before the(conventional) Big Bang.
Today, another group says they’ve found something else in theecho of the Big Bang. These guys start with a different model ofthe universe called eternal inflation. In this way of thinking, theuniverse we see is merely a bubble in a much larger cosmos. Thiscosmos is filled with other bubbles, all of which are otheruniverses where the laws of physics may be dramatically differentto ours.
These bubbles probably had a violent past, jostling together andleaving “cosmic bruises” where they touched. If so, these bruisesought to be visible today in the cosmic microwave background. NowStephen Feeney at University College London and a few pals saythey’ve found tentative evidence of this bruising in the form ofcircular patterns in cosmic microwave background. In fact, they’vefound four bruises, implying that our universe must have smashedinto other bubbles at least four times in the past.
Planck-sonde gaat nog meer laten zien ofhoren
Again, this is an extraordinary result: the first evidence ofuniverses beyond our own. So, what to make of these discoveries.First, these effects could easily be a trick of the eye. As Feeneyand co acknowledge: “it is rather easy to find all sorts ofstatistically unlikely properties in a large dataset like the CMB.”That’s for sure!
There are precautions statisticians can take to guard againstthis, which both Feeney and Penrose bring to bear in various ways.But these are unlikely to settle the argument. In the last fewweeks, several groups have confirmed Pernose’s finding while othershave found no evidence for it. Expect a similar pattern forFeeney’s result.
The only way to settle this will be to confirm or refute thefindings with better data. As luck would have it, new data isforthcoming thanks to the Planck spacecraft that is currentlypeering into the cosmic microwave background with more resolutionand greater sensitivity than ever.