Last month, local media made a huge fuss about the discovery of a black whole at the centre of the Milky Way – something postulated for decades.

Yesterday at a meeting of the American Astronomical Society, a team of international scientists announced a much bigger discovery, and there has been nary a mention in New Zealand.

Given the fact of singularities at the centre of galaxies, there has been much speculation as to whether the black holes formed first and attracted the surrounding galaxy, much as the cooling interstellar dust around a forming star coalesces into the planets and other flotsam that make up a solar system, or whether the galaxies already existed and the super dense cluster of stars at the centre collapsed in on themselves to form the singularity.

Christopher Carilli, of the National Radio Astronomy Observatory, and his colleagues used radio telescopes to study four host galaxies bearing black holes around 12 billion light years away (and hence being in effect 12 billion years in the past, or about 1 billion years into the life of the universe). By measuring the relative weights, they made a surprising discovery. All local galaxies have a black hole weighing roughly one thousandth of the mass of the central spherical portion of the galaxy. These ancient black holes proved to be much heavier, up to three times the proportional weight than those in the present-day universe. Because black holes can not shrink, the galaxy must have gained mass in order to account for the present average mass ratio of 0.1 percent. Carilli:

Black holes came first and somehow—we don’t know how—grew the galaxy around them

While there are claims that four galaxies is far too small a sample, and the present day 0.1% is only an average with some much higher, if it is not a statistical anomaly then this could have far reaching effects on our understanding of the formation of our post big-bang universe. The egg did indeed come before the chicken¹.

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¹I hope that doesn’t offend anyone – I still remember the last time someone made a casual reference to not knowing whether the chicken or the egg came first. I said “it’s quite obviously the egg – birds evolved from reptiles, which had been laying eggs eons before their scales mutated to feathers”. What I didn’t realise was that the group included a very Christian member, who took great umbrage as “it was obviously the chicken first, as god created them fully formed”. And no, they weren’t joking, unfortunately! It was several days before they’d speak to me again.