atmosphere.When the eclipse began over Manhattan, the shadow of the Earth seemed to eat away the moon, leaving nothing behind, not even the usual red glow. At totality, only a very faint, lighter smudge remained to show where the moon was located in the night. With the pollution of the city lights, it was almost impossible to find the moon without using binoculars to look for the faint smudge ...
can be found very high up. Dust storms stir up Mars as well as Earth. Humans have left their footprints behind on the dusty surface of the moon. But perhaps most important is the dust high in Earth's atmosphere.Of the several layers of our atmosphere, the most stable is the stratosphere, extending from about 10 to 50 kilometers above Earth. The dangerous hole in the stratosphere's ozone layer ...
gatherers were better off, since there weren't so many of them and they left their largely biodegradable garbage behind, to be recycled into the planet's ecology. The key word is "biodegradable." The garbage produced by industrial societies is generally not at all biodegradable. Work is being done on this problem, but if you engineer a microbe to eat up the plastic and metal in garbage dumps, ...
We could not live without our own mitochondria.It seems that self-interest, once thought to be the driving force behind evolution, is not necessarily the norm. Being altruistic and cooperative has enormous advantages, ensuring that the species will survive even if the individual does not. This is most dramatically seen in the social insects-termites, bees, wasps and ants. Some members of ...
around 500 million years ago (and so tough it's suitable as the bedrock for skyscrapers) - contains grooves left behind by the ice age glacier.Some say that Central park is over-wooded, the trees not thinned out as they were meant to be. My wife and I like lots of trees, possibly because we came from ancestors who were primitive hunters in Northern forests while peoples further south were ...
then remain there.They don't necessarily remain there forever for shallow parts of the ocean sometimes dry up, leaving behind what we now call "salt mines, " which contain traces of all the various dissolved materials in ocean water in addition to salt, the major component. Even allowing for this occasional drying and removal, a little bit of every known element is found in ocean water ...
dodo exists only in the common phrase "dead as a dodo." The word is also used to signify any person who is hopelessly behind the times, and who finds refuge in blind conservatism. (Poor dodo! To be remembered for that.)We know of the dodo's appearance from the diagrams that were made of it, from a few skeletons that exist, from one surviving head and a couple of surviving feet.Its looks are ...
in a desert? Well, it wasn't a desert 40 million years ago -it was an arm of the ocean that has shrunk since and left behind the Mediterranean Sea as its present-day remnant.What was really unusual about the fossil whale, however, was that it had two small hind legs that had the same kind of bones we have in our own legs, including bones that indicated the presence of three toes on each foot ...
we know that such a star was ever in the sky?For one thing, the colossal explosion of that star left a cloud of debris behind that astronomers call the "Crab Nebula." It is still expanding, and from the rate of its expansion, astronomers can calculate backward and determine that the explosion began around 1054.One of the reasons that there were no European reports on the star may have been ...
billions or even trillions. Furthermore, one would have to check the programming and make sure that the assumptions behind the instructions were valid.Other astronomers are laboring to make larger, and perhaps more valid simulations, and it may be that, as a result, "universes" can be constructed in greater and greater detail and the results compared with reality.This has become possible only ...