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More Reading
2.
Earth's Big Breakup
Under Alien Control
From
Science World
by Miles Oxlade
A small spacecraft, the size of
a clamshell, hovered over the dark, snow-covered fields of Nebraska. Kooli,
a pixie-looking character no bigger than a flea, made notes. He spoke to his
pilot, "One more specimen and we'll head home."
"All right" exclaimed Odem. He maneuvered the spacecraft between
snowflakes and headed for a farmhouse where a porch light glowed. He steered
through a partially open dormer and parked five inches above a sleeping boy's
chest.
"Fourteen Earth years old...male..."chanted the computer.
"Pulse: 64...brain waves: 2 nanowatts and erratic." Kooli was puzzled by
the readings.
"Life-form is dreaming...,"the computer added.
The boy's eyes opened, but the visitors didn't see them. His hand headed for
their craft. "Life-form is awake..."warned the computer.
"Full power, reverse！" Kooli yelled.
Odem reached for the throttle. Too late. The spacecraft shook as a hand closed
over them. Kooli picked himself up and rubbed a few bruises.
"Should've fastened your seat belt," said Odem.
"Odem, get us out of here！"
"Can't. System's weak and the boy's holding
on."
"Use emergency drives," commanded Kooli.
"We can only use them once."
"Then use them." The spaceship vibrated and then popped from the
boy's hands.
"Head for the window."
"Controls are erratic," cried Odem. "Left thruster
damaged..."
declared the computer.
The craft shattered a windowpane, lost power and spiraled to the edge of the
roof. Odem cleared his head and surveyed the instruments. "Lots of repairs
before we're going home."
Kooli wasn't listening. He was watching the boy climb out of the window and
work his way along the roof. "Go back," he cried. " You're putting
yourself in danger."
The pair cringed as the boy reached for their spacecraft, lost his footing and
grabbed for nearby power lines. Sparks flew. The boy was hurled from the roof
but cushioned by a snow bank below.
"We were not supposed to interfere," muttered Kooli. He watched the
boy's face turn pale as snowflakes formed a thin blanket. He hadn't wanted to
hurt anyone. "Any power at all, Odem?"
"Just a little."
"Use it. We can't leave tonight anyway."
The spacecraft lifted weakly and fluttered down to the boy.
Kooli pushed some buttons. "Computer?"
"Central processor damaged...Heart rate: zero...Brain waves:
zero."
The computer sounded melancholy.
"Can he be repaired?"
"Must be repaired within four minutes...."
"We've never lost a specimen before," said Odem.
Kooli had data on how these creatures worked. "Want to try to save him,
Odem?"
"If he were mine, I'd want it," Odem replied.
The two put on life-support systems, and then loaded up tools, batteries, and
computer. Odem pushed a red button and a door opened. The pair jumped and landed
on the boy's wrist. Odem parted the skin with an electronic knife and they climbed
in. The opening closed.
"This way," said Kooli. He headed up one tunnel, and then another,
always talking to the computer.
The tunnels were big. Sugars drifted about like snowflakes.
"Just like home," remarked Odem. After three minutes, the two emerged into a large
control room.
Odem whistled. "The whole center's burned out. Are you sure we can fix
it?"
Kooli shrugged. He gave directions while Odem stripped out old circuits and
linked in their electronics. Kooli pressed a button, hoping for automatic response.
Nothing.
"We only have a few seconds left," Odem urged.
Kooli was worried. The boy was taking everything they needed to repair their
spacecraft.
Odem read Kooli's thoughts. "He'd die someday,
anyway."
"Yes, but we had no right to shorten his life," Kooli replied.
"If we repair him, we may never get
home. Can you live with that?"
Odem thought for a moment and then nodded.
"Aye, aye, sir！" Odem connected it in a flash.
Kooli pounded some buttons and an ominous drumming shook the room.
They smiled. It was a heartbeat.
Kooli hooked up a video monitor. "See if you can open his
eyes."
A bare tree and snowflakes came on the screen.
"We did it！" Odem clapped his hands.
"Now let's get him to bed."
Kooli gave the commands. Odem worked the controls. Nerves activated, muscles
moved. The boy first staggered, then headed smoothly upstairs.
"Maybe we'll like it here," said Odem.
"We'd better. We can't survive otherwise."
"All systems like new," said the computer.
"This kid's gonna be smart," said Kooli.
"Perhaps he can signal our rescue fleet."
"Perhaps."
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Earth's Big Breakup
From Science World
Once upon a time, a kid in western Montana could have easily
ridden his bike to his girlfriend's house in east Antarctica. No boat? No problem!
And she could have talked to him on the phone for hours without her parents
howling about the long-distance rates. At least, she could have if telephones
- or humans - were around hundreds of millions of years ago.
That's because Montana and Antarctica were next-door neighbors back then, or
so says the latest group of scientists to examine the matter. The American West
and Antarctica, they say, lay side by side on one giant landmass that later
split to form the seven continents we know today.
Global Jigsaw
Looking at a globe, you can see how scientists got the idea for one giant landmass.
Some of the world's continents look like pieces of a puzzle that, with just
a push, would fit snugly together.
Try it (see "Continental cutup," below). You may end up with an arrangement
like the one proposed by geologist Alfred Wegener in 1912 (see sequence, right).
His super-continent, called Pangaea ("all lands"), is thought to have
existed some 300 million years ago.
Then again, your arrangement might look like Chicago high school student Daryl
Johnson's. He strung the continents edge-to-edge along the equator. "That
way, everybody gets lots of sunshine and beaches - especially Chicago,"
he said with a grin, pointing toward the window that separated him from single-digit
wind-chill.
The Evidence, Please
No matter what arrangement you come up with, you'll need some
proof - more than
just well-fitting pieces of a global puzzle.
Think for a moment: What do you look for when you're trying to fill a hole in
a puzzle, besides the right shape? Well, if the missing piece will complete
the picture of a castle, you look for pieces that show stonework and turrets.
In much the same way, geologists look for similar features on the pieces of
land they think may have once been connected.
Take Eldridge M. Moores and Ian W. D. Dalziel, the geologists whose continental
arrangement links North America with Antarctica. They look at rocks.
"What we're trying to do is learn how to read the rocks like a history
book," says Moores. He has found rocks of similar types and ages in Antarctica,
eastern North America and western South America. He believes these rocks were
once part of a huge belt of stone that ran thousands of miles through the three,
then-connected continents.
Moores and Dalziel plan also to look for similarities in
fossils - preserved
remains of once-living things - from the areas they think were once joined. It's
unlikely that plants and animals could have migrated across the vast oceans.
So if a species is found to have lived on two "pieces" of today's
global jigsaw, it suggests that these pieces once fit together.
Other scientists are actually tracking the movement of continents. They use
satellites, lasers and quasars to measure distances between Earth's landmasses
at different times (see "How do we know?" above).
With this data they can backtrack and guess where the continents began their
journeys, and try to predict where they'll end up in the future. Where do you
think the continents will go?
Catch the Drift
And by the way, how will they get there? After all, if you want anyone to believe
your theory, you'll have to describe how these huge landmasses move. In other
words, what's the mechanism behind this continental drift?
Do the continents float like tennis balls on water? What role, if any, does
gravity play? Come up with your own theory. They check out the illustration
on the bottom of page 12 to see how your theory compares with what scientists
currently believe. Who knows? Maybe you'll give them something to think about!
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