As usual my tendency is to look at things with a long perspective and scientific bent. However, it’s evident I’m not alone in wondering about the chances we’ll ever reach any form of life out there in the Universe. As is common knowledge, a radio call is being sent out through SETI – the global Institute whose purpose is to explore the ‘nature and prevalence of life in the universe’.
To answer that message, the life form on another planet would have to be advanced enough to understand it. Certainly we are unique on Earth in that we are intelligent enough to be logical and to communicate but it has taken most of the time since our planet was formed for us to have reached this level of complexity.
The fossil records are our main source of information on just what has happened during the evolutionary process. These scientific records tell us that:
- 4.6 billion years ago our planet was formed
- 3.8 billion years ago, life evolved in the form of single celled bacteria or microbes
- 0.53 billion [or 530 million] years ago bacteria got together to form multi-celled life forms and in a remarkably short period, many different species came into being in the so-called Cambrian Explosion
- 0.050 billion [or 50 thousand years ago] homo sapiens reached the modern form that could be recognized as us.
- 0.000,000,050 [or about 50 years] since radio became advanced enough to send messages out to the Universe. That has happened in the last very small fraction of time since the planet has existed.
If you consider that from our point of view on Earth, the sun has risen and set and the seasons have existed all those billions of years – in comparison to other planets, that makes ours a very rare and remarkably stable one. For this stability to occur we have had to:
- Be orbiting around a medium-sized, single sun in the outer reaches of our galaxy so as not to have been disturbed by other nearby suns.
- Be a planet that makes a circular orbit around the sun at just the right distance away to be in a good temperature range where most water was liquid.
- Be a planet spinning on its axis frequently enough (24 hours for us) so all parts were warmed in the day and cooled off at night. The axis had to be tilted so over a period of a year it wobbled and gave both hemispheres summer and winter seasons.
- Be fortunate enough to have a large moon that caught much of the debris during our planet’s early formative years.- There is much more about how rare our stable Earth has been if you click on the highlighted text.
Let’s try to always be aware how special and precious our planet is and do everything possible to prevent environmental deterioration so future generations can enjoy its beauty and bounty. Rie