Nature Notes: Anybody Out There?
Are there more stars in the universe than grains of sand on Earth? There could be. Carl Sagan once wrote that there are 100 billion galaxies, each with more than 100 billion stars! With each passing moment in time, stars are dying and new ones are popping up to take their place. But then, thousands of grains of sand are created every millisecond by erosion of rock.
The fact that the very large majority of stars are thousands and thousands of light-years away — one light-year is the distance light travels in one year at 186,000 miles per second — so humbles our ability to grasp the enormity of the universe. No wonder we spend hours watching television, eating fast food, and sleeping the night away. A star that is, say, only a mere 10 light- years away — close in astronomical terms — takes 10 light-years to be seen by someone on Earth. The star that you may be wishing on tonight could have died and become a dark star nine light-years ago. You are only witnessing light from its dying embers.
Our planets Mercury, Venus, Mars, Jupiter, and Saturn were all observed and studied by the ancient Greeks and Romans, thus the deified names. Uranus and Neptune were not observed by humans until they were discovered by 17th-century astronomers. Lately, we have come to know, photograph, and name their 41 moons: Uranus has 27 and Neptune 14. Pluto, now known as a dwarf planet, less than two-tenths the size of the Earth, wasn’t observed until 1930, and recent evidence points to a planet beyond Pluto, but it has yet to be observed.
Pluto is 4.67 billion miles away. If we were fortunate to see reflected light from it, the light would reach our eyes 17.1 hours after it had left the dwarf planet. Our closest planets, Venus and Mars, get as close to us as 34 and 54 million miles away. On those nights it takes only 3.1 and 4.8 minutes for their light to reach our eyes.
Is there life on any of these planets other than on ours? That is the question of the day. Mars is the planet with the best chance in terms of temperature range and the fact that it has some water. But most of our world’s biologists think in terms of what’s living on Earth. Attempts to create life in our laboratories by combining this and that element with this and that stimulus are still in the cold fusion category of possibilities.
The resurgence of blue-green algae, a.k.a. cyanobacteria — supposedly the first organisms on this planet and the ones that created the oxygen that allows us air breathers to survive and prosper — raises that question.
It’s kind of like that old saw, given enough monkeys and enough typewriters and an infinite amount of time, the Holy Bible and the Oxford English Dictionary would be rewritten, but many, many more times more probable. If it hasn’t happened on Mars or one of our other planets, or within our own galaxy, it has surely happened on some of Sagan’s billions upon billions of stars coming and going in all of the other universes’ galaxies.
Will such life be based on photosynthesis and oxygen, as it was more than three billion years ago on Earth? No, but it will probably be based somehow on water.
And who knows, by the time we begin to find out, our planet, now in very serious trouble, might not be around to witness such a discovery.
Larry Penny can be reached via email at [email protected].