
                         Roanoke Times
                 Copyright (c) 1995, Landmark Communications, Inc.

DATE: THURSDAY, October 28, 1993                   TAG: 9310270028
SECTION: EXTRA                    PAGE: 1   EDITION: METRO 
SOURCE: JOEL ACHENBACH
DATELINE:                                 LENGTH: Long

MYSTERY OF THE DINOSAURS STILL A BONE OF CONTENTION

Q. Why haven't scientists found fossils of dinosaurs that were injured, smashed or pulverized by that meteorite that hit the Earth 65 million years ago?

A. As you know, the Age of Dinosaurs ended when an asteroid 5 to 10 miles wide slammed into the Earth with the force of 300 million hydrogen bombs, leaving a crater now estimated at 185 miles wide. What really drives us crazy is that the scientists always blame the dinosaur extinction on climatic changes from the dust thrown into the atmosphere. Exsqueeze us, but what about broken bones?

Shouldn't there be signs of blunt trauma? Can't they go rooting around down near the Yucatan Peninsula, where this thing hit, and find some dinosaur bones with telltale scars from season-ending knee surgery?

The answer is, dinosaur bones are scarcer than we think. There are vast gaps in the fossil record of the dinosaur era. We know a lot about the period roughly 150 million years ago, when the brontosaurus and allosaurus and stegosaurus were thudding around, and we know a lot about the period just prior to extinction, when you had your tyrannosaurus and triceratops, but there are big pockets of mystery in between.

To find the bones of any dinosaur that was alive on the very day of the doomsday rock, much less one close to the impact, would be a doozy of a discovery.

Not only that, but most dinosaur bones that we find are already damaged and in pieces.

"Most of the stuff we collect has had the bejesus beaten out of it before we get to it," says Nick Hotton, paleontologist at the Smithsonian Institution.

Still, we're not going to believe the doomsday rock theory until we find some really hard evidence, like maybe a dinosaur femur driven through a tree trunk.

\ Q. Why is the universe expanding?

A. Because it's administered by someone with a Master of Business Administration degree?

Actually there's a rather wonderful answer: The universe is expanding because the universe has to do something.

The laws of physics say that the universe can't stand still. It can expand, it can contract, it can do the hokeypokey and turn itself around, but it can't just lie there in a cosmic torpor.

Gravity's to blame. Gravity ensures that everything we see, whether it is a spinning moon or an expanding universe, is going somewhere.

Let's say you pick up a rock. The first thing you notice is, they don't make rocks like they used to when you were a kid. Back then, a rock wasn't just a rock, it was a stone, something far more upscale and interesting. But never mind. You got this rock and you want to do something with it. What can you do? You can throw it toward the ground. You can toss it up into the air. You can continue to apply enough muscular pressure to the rock to keep it from falling to the ground. But what you can't do is place it into the air in front of you and make it stay there.

The rock must move. So too must the universe.

As for why the universe began expanding a long time ago, no one knows. It wasn't because of the Big Bang. The expansion is the Big Bang. There's no causality there. (In fact there wasn't even a bang!) We have no way of seeing back to the beginning of time itself; what we do see is evidence that the early universe was very hot and very dense, and becoming less so as it expanded, in the same way that steam shoots out of a tea kettle in an expanding cloud and cools into visible liquid water.

Science can't tell us who lit the fire.

\ The Mailbag:

Daniel M. of Boynton Beach, Fla. writes, "Are fat people really jolly? And why is it that it's fat people who are always geniuses or criminologists?"

Dear Daniel: Santa Claus is jolly. Orson Welles pretended to be jolly. Bill Clinton seemed jollier before he got on the intense jogging program. But despite this massive onslaught of hard evidence, we have to report that morphology and personality have no scientifically verified connection. Not since the 1940s has any reputable scientist tried to connect the twain. One problem is that, although you can precisely measure someone's weight and body dimensions, you can't really measure whether he or she is "jolly."

On TV, we might note, the occupation of genius or criminologist is perfect for a heavyset actor or actress (William Conrad, Raymond Burr, Angela Lansbury) who is not ideally suited to play the typical romantic lead.

Sid B. of Yorba Linda, Calif., says he read something in the paper about how sunlight has weight that exerts a pressure on the Earth's surface of 2 pounds per square mile. He writes, "Since light has no mass, it cannot have weight. But this raises the question: How can light exert a pressure?"

Dear Sid: The simple answer is that light does, indeed, have mass. Light is a form of electromagnetic energy, and anything with energy has mass. (Mass is not the same thing as matter.) So when light strikes something, it creates pressure as its momentum is absorbed. If the light is reflected, the amount of pressure is doubled, since the object has to absorb the light's momentum and then recoil even further as it launches the light back where it came from.

Your confusion probably stems from the often-asserted fact that a photon, the "particle" of light, has no "rest mass," which means that there wouldn't be anything there at all if you could slow it down and stop it. (Which is what we sometimes think about the Clinton administration.)

by CNB