The first, ‘Why we face grave danger from space’, by Michael Hanlon, lists the various perils that we live with. These range from communication and power disruption from solar flares, the effects of ‘flying mountains’ hitting the planet – like the one 65 million years ago that was supposed to have wiped out the dinosaurs - all the way up to global annihilation as the result of the earth being showered with radiation from a nearby supernova.
Hanlon takes some comfort from the fact that there is an unbroken record of life on earth stretching back 3.5 billion years; in that time the planet has not been close enough to any supernova to have been cauterised. Nevertheless, he cites several worrying instances in recent history. There was the Tunguska event in 1908, when a meteorite of between 200 and 620 ft in diameter exploded over Siberia with an energy estimated to have been equivalent to between 3 and 30 megatons of TNT. Then there was the similar incident this year at Chelyabinsk; that blast was equivalent, fortunately, to only a ‘small nuclear weapon’, and up to a thousand people were injured.
Clearly such risks are real, although there is little point in worrying about them since there is very little that can be done. Arthur C Clarke’s Rendezvous with Rama was predicated on the installation of a super space-probing radar system, following the deaths of millions of people on earth after a large meteorite strike.
I’m reminded of an incident when my daughter was about eight years old. She had been reading one of my astronomy books. “Daddy”, she said, “it says here that in about 5 billion years the sun will start to expand, turn into a red giant, and engulf the planets including the earth. Daddy, when was this book written?”
The second story, by Roger Highfield, concerns the expansion of the universe. I have been reading a lot about this recently, including a biography of Edwin Hubble. He was the first scientist to make a good estimation of the distance of the galaxies as well as measuring their spectra, and confirm from the red shift of those spectra, that the galaxies were moving away from us. He also found that the further away the galaxies were, the faster they were receding. Recent work suggests that the rate of expansion is accelerating, indicating that some sort of repulsive gravitational force is also at work.
Now, however, Professor Christof Metterich at Heidelberg, is suggesting that the cosmic red shift – long thought to be simply due to the Doppler effect – may, instead, be due to a long-term variation in the masses of the emitting atoms. This is fascinating stuff. Prof Metterich’s website contains downloads of PowerPoint presentations he has given on his ideas. Sadly, without a spoken commentary, I find these impossible to follow. Highfield comments that Metterich’s ideas might be as revolutionary as those of Hubble.
My interest is simply that I am fascinated by cosmology – how the universe came to be as we now see it, where it came from, and how God fits into it all. I shall follow Professor Metterich and his ideas with great interest.