Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: THURSDAY, September 15, 1994 TAG: 9409190017
SECTION: EXTRA PAGE: 1 EDITION: METRO
SOURCE: Joel Achenbach
DATELINE: LENGTH: Long
A: We do a lot of cow items in this column. We're also working on a piece about why backyard burgers taste so good. Maybe we should just turn this into a weekly column about meat. We could call it the Meat Beat.
We began thinking about cows again after noticing, during a recent trip to the zoo, that there is no cow exhibit. You'd think there'd be at least some kind of obscure, little-known Wild Cow of Borneo. Instead, cows are completely snubbed, just like cats and dogs.
The obvious reason for this is that zoos are for wild and exotic animals and cows are neither. There are no wild cows anymore. This is actually a fairly recent development.
All the domestic cows on Earth are descended from a single species of wild cow, called Bos primigenius. This wild cow is now referred to as the aurochs, or sometimes the urus. (Aurochs is a singular word; depending on who you are talking to and on what continent, the plural is either aurochs, or aurochsen.)
The Asian and African aurochs disappeared thousands of years ago, but the European aurochs continued to linger in the forests of Europe. The last wild cow on Earth is believed to have died in Poland in 1627. (We don't know the details of the death. But we are guessing that the meat was tough.)
Since then, a few zoos have tried to ``re-create'' the aurochs. The silly things people think of! ``Back-breeding'' techniques can produce a cow with scary horns and a shy temperament, but that doesn't make it a real aurochs, much less a genuinely wild animal. (It's hard to be a wild cow when you're stuck in a zoo.)
When was the first aurochs domesticated and turned into a ``cow''? Who knows? But the archeological record shows traces of domesticated cattle as long ago as 6400 B.C.
``It is impossible to say that at such and such a place at such and such a time the first domesticated aurochs calf was born ... It is more than likely to have been domesticated quite independently by different peoples in different places at different times,'' says the book ``Cattle: A Handbook to the Breeds of the World'' (soon to be a television movie starring Roseanne).
The descendants of the aurochs come in two subspecies: Humped and humpless. All told there are about 250 breeds within those subspecies. An argument can be made that there are other wild cows still in existence, in the form of yaks, bison, buffaloes and oxen. All these creatures are even-toed ungulates, members of the Artiodactyla order of mammals, and of the family within that order called Bovidae. (Yes, there will be a test.)
But we would argue that it's a terrible mistake to lump all even-toed ungulates together and call them cows. A yak is just not a cow. For one thing, there are domesticated yaks, and they aren't called cows, they're called ``domesticated yaks.''
You would say, ``This here is our family yak, Bessie.''
Q: Why is Jupiter so big? And why doesn't it have a surface?
A. Jupiter could eat Earth for lunch, with room for a Pluto dessert. You could fit a thousand Earths inside Jupiter. Jupiter is one big hunk-o-planet.
How did this thing get there? Partly it's just a random event. During the formation of the solar system a lot of matter accreted in that area. Big things get bigger: All that matter has lots of gravity, pulling in yet more matter.
Here's a critical fact, should you decide to recall any of this column: Jupiter has enough gravity to keep its hydrogen gas from floating away. You, by contrast, cannot hold onto your gas. Neither can Earth. Any hydrogen gas on this planet just leaks off into space.
Why does hydrogen float away on Earth? Because hydrogen is so puny. It heats up easily. If a hydrogen molecule bumps into a big ugly nitrogen molecule, the hydrogen goes flying and sometimes careens into space.
``When the light guy hits the fat guy, the light guy bounces off at a higher speed,'' says NASA spokesman Steve Maran.
A gas giant like Jupiter probably couldn't form close to the sun, because it would get too hot. That solar radiation would heat up the Jovian hydrogen. Hot means fast. Fast means you reach escape velocity.
Because it has all this gas, Jupiter doesn't have a surface, exactly. If you could descend into the atmosphere you would find yourself in an increasingly dense, muggy, soupy, pressurized environment. You would be crushed.
If you could somehow keep going, you might reach a surface of sorts: A core of liquid metallic hydrogen. This stuff would behave a little like mercury (the metal, not the planet). We can't make liquid metallic hydrogen on Earth because it requires so much pressure.
Finally, deeper still, you'd hit a rock core. Or so scientists think. Actually they're not really sure. In December 1995 the Galileo spacecraft will reach Jupiter and drop a small probe into the Jovian atmosphere. That'll give us a better idea what's under those clouds.
We've assumed there was some water vapor down there. When the comet Shoemaker-Levy 9 slammed into Jupiter, everyone expected to see signs of water vapor rising toward the top of the atmosphere. It didn't happen. No one is sure why. For now, astronomers are assuming that the comet just didn't penetrate far enough to reach the water vapor.
In other words, scientists presume they had the right theory--it was the comet that messed up.
- Washington Post Writers Group
by CNB