Planck Density. Something to get your head around.

So last week’s New Scientist attempted to familiarise me with the concept of  ‘loop quantum cosmology’. If I get this right (and please, somebody correct me if I am wrong) this theory states that before the big bang our universe already existed: after expanding to its fullest diameter it then shrank back until it reached microscopic volume in which things were pretty dense: 5.1 × 1096 kilograms per cubic metre dense (also called Planck Density) . Now that is even denser than population density in the East End. So when the universe reached that state of density, every thing started anew with a ‘big bounce’.

That of course means that we are all recycled, like a park bench made ouf recycled plastic.  A comforting thought, but the creationists will probably have another hissy fit when they find out (again) that the universe is older that 6000 years.

The Tunguska Event, 100 years on.

This week’s New Scientist has a superb feature on the current state of research on the Tunguska event. Just to refresh your memory, on 30 June 2008 an explosion 1000 times more powerful than the nuclear detonation over Hiroshima incinerated the sky over the northern half of our planet. Originating somewhere above the Tunguska river in Siberia, it knocked down trees over an area of 2000 square kilometers.

image courtesy of wikimedia

This week, a bunch of scientists will be meeting in Moscow to discuss the current state of knowledge about this immense event. The theories are mindboggling. There’s the usual UFO theories, the more plausible explosion of an asteroid, and the intriguing idea of the ‘Verneshot‘: with other words an ‘Earth Burb’, in which  a large bubble of C02, accumlated via vulcanic activity, suddenly gets released, spewing toxic gases and large chunks of matter into the atmosphere.

And why am I interested in all this?

Ghostbusters, of course.