For most of its history until fairly recent times the general pattern for Earth was to be hot with no permanent ice anywhere. The current ice age – ice epoch really – started about forty million years ago, and has ranged from murderously bad to not bad at all.
The upward flow of ancient heat to the Earth’s surface is measured in tens of milliwatts per square metre; the flow from the Sun above is measured in hundreds of watts per square metre.
Among the tiny atomic structures the plankton take to the grave with them are two very stable isotopes – oxygen-16 and oxygen-18.
The amount of energy actually liberated in the burning of these fossil fuels is tiny by planetary scales – ten terawatts or so a year, not that much more than the nuga-tory contribution made by the tides. But the side effects are huge.
Comets develop their distinctive tails when their surface material begins to evaporate as they approach the Sun.
It is a natural human impulse to think of evolution as a long chain of improvements, of a never-ending advance towards largeness and complexity – in a word, towards us. We flatter ourselves. Most of the real diversity in evolution has been small-scale. We large things are just flukes – an interesting side branch.
Sheepskin is a marvelously durable medium, though it has to be treated with some care. Whereas ink soaks into the fibers on paper, on sheepskin it stays on the surface, rather like chalk on a blackboard, and so can be rubbed away comparatively easily. “Sixteenth-century paper was of good quality, too,” he went on. “It was made of rags and was virtually acid free, so it has lasted very well.
The process became known as sea-floor spreading. When the crust reached the end of its journey at the boundary with continents, it plunged back into the Earth in a process known as subduction.
Somehow, from this Gilbert concluded that the Moon’s craters were indeed formed by impacts – in itself quite a radical notion for the time – but.
Elizabethans were as free with their handwriting as they were with their spelling. Handbooks of handwriting suggested up to twenty different – often very different – ways of shaping particular letters.
History, Jared Diamond notes, is full of diseases that ‘once caused terrifying epidemics and then disappeared as mysteriously as they had come38’. He cites the robust but mercifully transient English sweating sickness, which raged from 1485 to 1552, killing tens of thousands as it went, before burning itself out. Too much efficiency is not a good thing for any infectious organism.
The bad news is that atoms are fickle and their time of devotion is fleeting – fleeting indeed. Even a long human life adds up to only about 650,000 hours. And when that modest milestone flashes past, or at some other point thereabouts, for reasons unknown your atoms will shut you down, silently disassemble, and go off to be other things. And that’s it for you.
The history of any one part of the Earth, like the life of a soldier, consists of long periods of boredom and short periods of terror.
Hutton noticed that if he used a pencil to connect points of equal height, it all became much more orderly. Indeed, one could instantly get a sense of the overall shape and slope of the mountain. He had invented contour lines.
Owen. He coined the term Dinosauria in 1841. It means ‘terrible lizard’ and was a curiously inapt name.
It is only the brevity of lifetimes that keeps us from appreciating the changes.
I remember once reading that the tenth Duke of Marlborough, on a visit to one of his daughter’s homes, announced in consternation from the top of the stairs that his toothbrush wasn’t foaming properly. It turned out that his valet had always put toothpaste on his brush for him, and as a consequence the duke was unaware that dental implements didn’t foam up spontaneously. I rest my case.
If we were randomly inserted into the universe,” Sagan wrote, “the chances that you would be on or near a planet would be less than one in a billion trillion trillion.
Perhaps it would be an idea to require developers to live on their own estates for five years, as a demonstration of their superb liveability. It’s just a thought. I.
Glance at the night sky and what you see is history and lots of it – not the stars as they are now but as they were when their light left them.