The greatest threat?

Recently I was contemplating the significance of Earth Day (today, 22 April) and asked people on one of my websites what they thought of as the main candidates as the “greatest threat to Earth”. The answers included global warming (and related factors such as the ice caps melting and major coral reefs and forests dying), over-population, the lack of (or limited use of) renewable energy resources, a strike by a major asteroid or comet, some other major event in the Solar System, a nearby supernova and of course also the Sun.

My original question had been a bit misleading, because I wanted to see to what extent people equate the future of the planet with the future of life on Earth, and specifically the future of the human race. It is natural that we see the universe from the one point of view with which we can identify – the human perspective.

Although natural disasters may play a role, modern man is the probably the greatest threat to life on Earth - or to sustain life for beings such as the human race. There is no agreement on the time scales involved, but the majority view seems to be that, unless we act fast, we are heading towards destroying the environment to such an extent that in time to come, only very resilient life forms (and man might not be one of those!) will survive.

Fleeting moments - astronomically speaking

The fireball seen in the Northern parts of South Africa the country late last year prompted me to ponder about our fragile planet being hit by objects from space. However, it also made me think about the thrill and lasting impressions of some fleeting moments relating to astronomy.

There is the “everyday” beauty of moments of unexpected delight: a full moon that suddenly rises from behind buildings or a mountain like a butter-coloured yellow balloon against a navy-blue early evening sky. Or the pleasant surprise of looking up from the centre of a light-polluted city on a very clear evening - and realising that I could easily count six of the Seven Sisters in the Pleiades. Or watching the stars pop out one by one as you sit at the beachfront and having a stranger come up to you to ask if they may borrow your binoculars for a moment to look at Jupiter or Saturn.