It started with a bang, and has been expanding ever since. For nearly a century, this has been the standard view of the Universe. Now one cosmologist is proposing a radically different interpretation of events — in which the Universe is not expanding at all.
However now, Christof Wetterich, a theoretical physicist at the university of Heidelberg, has produced a paper theorising that the universe is not expanding, but the mass of all of its particles are instead increasing.
Astronomers measure whether objects are moving away from or towards Earth by analysing the light that their atoms emit or absorb, which comes in characteristic colours, or frequencies.
When matter is moving away from us, these frequencies appear shifted towards the red, or lower-frequency, part of the spectrum, in the same way that we hear the pitch of an ambulance siren drop as it speeds past, reports the Nature.
His theory could potentially help examine the more problematic aspects of the big bang theory, such as the ‘singularity’ present during the big bang.
He points out that the tell-tale light emitted by atoms is also governed by the masses of their constituent particles, notably their electrons. The way these absorb and emit light would shift towards the blue part of the spectrum if atoms were to grow in mass, and to the red if they lost it.
Because the frequency or “pitch” of light increases with mass, Prof Wetterich argues that masses could have been lower long ago.
If they had been constantly increasing, the colours of old galaxies would look red-shifted – and the degree of red shift would depend on how far away they were from Earth. “None of my colleagues has so far found any fault [with this],” he says.
His paper was published on the arXiv preprint server. In his abstract, he writes: “Only dimensionless ratios as the distance between galaxies divided by the atom radius are observable. The cosmological increase of this ratio can also be attributed to shrinking atoms.”
Although the paper has yet to be peer-reviewed, none of the experts contacted by Nature dismissed it as obviously wrong, and some of them found the idea worth pursuing.
“I think it’s fascinating to explore this alternative representation,” says Hongsheng Zhao, a cosmologist at the University of St Andrews, UK. “His treatment seems rigorous enough to be entertained.”
Actually, the idea that the universe is unchanging – a constant backdrop that alters only with our parochial view of the heavens – was long ago consigned to the dustbin, thanks to the work of astronomers such as Edwin Hubble in the 1920s.
In the 1920s, astronomers such as Georges Lemaitre and Edwin Hubble analysed the light emitted or absorbed by atoms, which appeared in a spectrum of characteristic colours, or frequencies.
When matter moved away, they discovered that galaxies exhibited a shift to the red, lower frequency part of the spectrum.
After observing that most galaxies exhibit a red shift that became greater for more distant galaxies, they theorised that the universe was expanding.