Saturday, March 23, 2013

Cosmic egg

I may be wrong (I hope so), but I have the impression that few people today are aware of the amazing scientific achievements of this humble Belgian priest, Monseigneur Georges Lemaître.

You can read all about him here. In a nutshell, he (rather than Edwin Hubble) was the inventor of the theory of an expanding universe, initiated by the Big Bang.

Several decades ago, when I first heard the wonderful story of the origins of our existence, I was enchanted by Lemaître's explanation of an incredibly small and dense so-called "primeval atom" containing all the ingredients of the future universe. A little-known US physicist of Russian origins named Ralph Alpher (assistant of the famous Russian-born cosmologist George Gamow) came upon a delightfully mysterious name for this mythical entity, which we can hardly hope to imagine by means of our primitive Earth-oriented brains. He called it the ylem. But I prefer the charming metaphor of a cosmic egg.

In the 1960s (at about the same time that Lemaître died in his native Belgium), another fabulous scientific-invention story was unfolding on the other side of the Atlantic, at Bell Labs in Holmdel, New Jersey.

The engineers Arno Penzias (right) and Robert Wilson (left) were attempting to fine-tune a so-called horn antenna, designed to capture radio signals bounced off a satellite.

No matter how hard they tried, however, they kept picking up background static. There's a famous anecdote about how they imagined, at one stage, that the disturbance might be due to the presence of pigeons that had nested inside the big metallic structure and left some mess. After clearing away the nests, feathers and piles of shit, the engineers went one nasty step forward and shot the pigeons. But the antenna persisted in picking up mysterious non-stop microwave radiation, which seemed to emanate from outside the Milky Way.

At that same moment, at nearby Princeton University (50 km as the pigeon flies), three astrophysicists—Robert Dicke, Jim Peebles and David Wilkinson—were reaching the conclusion that the Big Bang, if indeed it had taken place in the way they imagined, should have bequeathed to us an omnipresent radiation. And their calculation of the theoretical value of this so-called cosmic microwave background coincided with the annoying static picked up by the horn antenna at Bell Labs. Although Penzias and Wilson hadn't been looking for such an entity, they had in fact detected the glow of the archaic cinders of the Big Bang.

The innocent pigeons slaughtered at Bell Labs in the 1960s were to become the world's first Big Bang martyrs. In their sacrificial nest, scientists would come upon the Cosmic Egg. Today, the memory of Monseigneur Georges Lemaître might be symbolized and celebrated by the following simple but extraordinary image:

Planck map of the cosmic microwave background.

This lumpy egg-shaped image represents the state of the expanding universe when it was about 370,000 years old. At that moment, for the first time since the Big Bang, there was light in the Cosmos. This image—in which hotter regions are orange, and colder regions are blue—was released a few days ago by the European-led research team behind the Planck space probe.

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