I hvert fall om vi skal basere oss på en artikkel om lederen i seneste New Scientist (med tittelen The Genesis Problem, krever abonnement for å lese) som oppsummerer en konferanse holdt i anledning Stephen Hawkings 70-årsdag.
Why physicists can't avoid a creation event.
Og det var vel ikke den beste bursdagsgaven han kunne få. For i motsetning til hva Hawking og en del andre fysikere har antatt var konklusjonen at det fysiske universet ikke er evig, men har en begynnelse.
Som vi har vært innom en gang eller syv tidligere skapte Hawking
headlines about a year ago when he claimed that the fundamental forces of the universe (like gravity) were eternal and were sufficient to explain the sudden emergence of all matter and energy spontaneously in the Big Bang. Hawkings has admitted he wants the universe to be eternal, in order to avoid having to acknowledge the existence of a creator.Hvilke hovedmodeller er det så vi snakker om? Kort sagt, enkelt og tabloid oppsummert, de følgende.
- Eternal inflation: Built on Alan Guth’s 1981 inflation proposal, this model imagines bubble universes forming and inflating spontaneously forever. Vilenkin and Guth had debunked this idea as recently as 2003. The equations still require a boundary in the past.
- Eternal cycles: A universe that bounces endlessly from expansion to contraction has a certain appeal to some, but it won’t work either. “Disorder increases with time,” Grossman explained. “So following each cycle, the universe must get more and more disordered.” Logically, then, if there had already been an infinite number of cycles, the universe would already been in a state of maximum disorder, even if the universe gets bigger with each bounce. Scratch that model.
- Eternal egg: One last holdout was the “cosmic egg” model that has the universe hatching out of some eternally-existing static state. “Late last year Vilenkin and graduate student Audrey Mithani showed that the egg could not have existed forever after all, as quantum instabilities would force it to collapse after a finite amount of time (arxiv.org/abs/1110.4096).” No way could the egg be eternal.
Cosmologists thought they had a workaround. Over the years, they have tried on several different models of the universe that dodge the need for a beginning while still requiring a big bang. But recent research has shot them full of holes (see "Why physicists can't avoid a creation event"). It now seems certain that the universe did have a beginning.Noe som altså ikke er enkelt selv om Lawrence Krauss slik New Scientists anmeldelse lenket til i forrige setning prøver desperat. Det hører med å nevne at Dawkins ikke overraskende ikke akkurat ... imponerer i etterordet.
Without an escape clause, physicists and philosophers must finally answer a problem that has been nagging at them for the best part of 50 years: how do you get a universe, complete with the laws of physics, out of nothing (see "Trying to make the cosmos out of nothing")?
The same can't be said about the Dawkins afterword, which is both superfluous and silly. A Universe From Nothing is a great book: readable, informative and topical. Inexplicably, though, Dawkins compares it to On the Origin of Species, and suggests it might be cosmology's "deadliest blow to supernaturalism". That leaves the reader with the entirely wrong sense of having just ingested a polemic, rather than an excellent guide to the cutting edge of physics. Krauss doesn't need Dawkins; a writer this good can speak for himself.La nå det være som det vil, lederartikkelen konstaterer i hvert fall tørt at "If there was a start to the universe, that means we have to explain how something just appeared from nothing".
Da mangler bare den lille detaljen å vise resten av Første Mosebok 1,1. Selv om det ligger noen Planck-lengder unna New Scientists ansvarsområde.