Life on Earth
This morning’s BBC news contained an update on the search for exoplanets. Over 800 are listed since the first one was discovered in 1988, and on the average every star contains 1.6 Earth-sized planets, resulting in a low estimate of 17 billion Earth-sized planets in our galaxy alone. There is an estimated 170 billion galaxies in the observable universe, so the number of Earth-sized planets can be roughly estimated at 3 000 000 000 000 000 000 000.
Of course, to be Earth-like, the Earth-sized planet’s orbit has to be within a distance from the star allowing for liquid water. Even if a perfect orbit was a one in a billion chance, that would still allow a presence of 3 trillion Earth-like planets. A probe to a nearby Earth-like planet, maybe as close as 13 light years (BBC’s main news), may however just yield dead matter, since there was no life on Earth during the first 1 billion years. If we manage to find a planet where life exists, it is likely there will just by bacteria-like organisms. Multicellular organisms have only occurred here during the past 1 billion to 660 million years, or during 15-20% of Earth’s age. Colonization of land was even more recent, some 450 million years ago, hinting that life on land has only existed during 10% of Earth’s age. Civilizations, if there were stone age dinosaur communities there would be no traces left, so we assume our species Homo sapiens is the only animal so far which can make tools with at least two components. Our modern form is about 200 000 years old, and so has been around during 0.005% of Earth’s history. Metal based civilizations occurred 7500 years ago, so metallurgy has been known to Earthlings during 0.00017% of the planet’s age. Our electrical civilization began in 1884 at the International Electrical Exhibition in Philadelphia, a time when electrical devices left the experimental stage. This was 130 years ago. To increase our chances in finding another civilization we should look for planets older than ours.
Dreaming about other worlds is appealing, but yet, in reality they are still just mathematical numbers and the actual flowers we can sense grow here on Earth. BGCI estimates that one third of this planet’s plant life is facing extinction. Before that happens, we need to document their existence and interactions with other organisms. Ability to document paradise is important the day a probe is sent to a virgin planet vibrating of innocent life, later to be transformed into casinos, concrete deserts and football fields.
One observation of a space inhabitant of planet Tellus is that of a tentative pollinator of the Baronet orchid. It is another Bactrocera fruit fly, which I have seen on the flowers four times now, pictured twice by visiting guests around noon. I am blocked to the orchid’s fragrance, but visitors have described it as honey-like.
This fantastic picture was taken at Dokmai Garden on January 30th, by visiting Briton Geoffrey Pimlott, now a resident of Calais. The flower is the native Thai Baronet orchid (Hygrochilus parishii var. marriottianus, Orchidaceae) and the fly is a fruitfly (Bactrocera sp.). It is a larger fly species than seen on the Bulbophyllum hybrid I mentioned before. It still does not fit the size of the flower, but maybe the trampling around is enough? We keep observing the flowers to see if they transform into fruits. Observations from our many readers in Thailand, Malaysia and India are most welcome!
Text: Eric Danell