George's Secret Key to the Universe

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George's Secret Key to the Universe Page 9

by Stephen Hawking


  “Help! Help!” he yelled. The other members of his gang stopped and turned, but no one wanted to go back for him. “Quick!” said Zit, who was the smallest. “Go and save Ringo!”

  The other two just shuffled awkwardly and mumbled. The spooky man wasn’t wearing a gas mask anymore, and the boys could almost make out his features through the clearing smoke. Ringo was standing up now, and the man seemed to be speaking to him, although the other boys couldn’t hear what he said.

  After a few minutes Ringo turned and waved to his gang. “Hey!” he shouted. “All of you! Get over here!”

  Reluctantly the other three straggled toward him. Strangely, Ringo seemed very pleased with himself. Standing next to him, looking just a tiny bit sinister, was none other than Dr. Reeper.

  “Good afternoon, boys,” said the teacher. He looked at them, standing there in their Halloween costumes, clutching their masks. “How kind of you to think of including your poor old teacher in your fun Halloween games.”

  “But we didn’t know … ,” protested Zit. The other two looked too surprised to speak. “We wouldn’t have, not if we’d known this was a teacher’s house.”

  “Don’t you worry!” said Dr. Reeper with a forced chuckle. “I like to see young people enjoying themselves.” He waved a hand around to clear a bit of the lingering smelly smoke. “I’m afraid you interrupted me just as I was in the middle of something. That’s why it’s a little foggy around here.”

  “Ugh! Were you cooking?” said Whippet unhappily. “It stinks here.”

  “No, not cooking—well, not food, anyway,” said Dr. Reeper. “I was doing an experiment. I should get back to it. And I shouldn’t keep you here—I’m sure you have other people in the neighborhood to delight with your amusing tricks.”

  “What about … ?” said Ringo, trailing off deliberately.

  “Oh yes!” said Dr. Reeper. “Why don’t you boys come and wait on the doorstep while I go get something. I’ll only be a moment.”

  The boys followed him as far as the open front door, where they hovered while Dr. Reeper went in.

  “What’s going on?” Whippet hissed to Ringo as they waited.

  “Listen up, gang,” said Ringo importantly. “Gather round. Greeper wants us to do something for him. And he’s gonna pay us.”

  “Yeah, but what does he want us to do?” asked Tank.

  “Relax, chill,” replied Ringo. “It’s nothing. He just wants us to deliver a letter—to the house with the weirdo in the space suit.”

  “And he’ll pay us for that?” squeaked Zit. “Why?”

  “I dunno,” admitted Ringo. “And I don’t really care. It’s money, isn’t it? That’s what matters.” They waited for a little longer. The minutes ticked by, and there was still no sign of Greeper. Ringo peeked through the front door. “Let’s go in,” he said.

  “We can’t do that!” exclaimed the others.

  “Yeah, we can,” said Ringo, his eyes sparkling with mischief. “Just think—at school we can tell everyone we’ve been inside Greeper’s house! Let’s see if we can take something of his. Come on!” He tiptoed into the house, stopped, and beckoned furiously for the others to follow. One by one they sidled through the front door.

  Inside, they saw a hallway with several doors leading off it. Everything in the hallway was covered with dust, as though no one had touched it for a hundred years.

  “This way,” ordered Ringo, snickering with glee. He set off down the hallway, stopping in front of one of the doors. “I wonder what the old doc keeps in here.” He pushed it open. “Well, well, what’s all this?” he said, a sly smile spreading across his face as he peered in. “Seems like there’s more to the doc than meets the eye.” The other boys crowded around him to see what lay in the room beyond, their eyes widening as they took in the strange scene before them.

  “Wow!” said Zit. “What’s in there?”

  But before anyone could answer, Dr. Reeper had reappeared in the hallway behind them.

  “I asked you,” he said in the scariest voice imaginable, “to wait outside.”

  “Sorry sir, sorry sir,” said the boys quickly, whipping around to face him.

  “Did I invite you into my house? I don’t think so. Perhaps you could explain why you have behaved so very badly? Or I will be forced to give you extra detention at school for disobedience.”

  “Sir, sir,” said Ringo very fast, “we were waiting outside, but we were so interested to know … the experiment you talked about earlier … we wanted to come in and see.”

  “You were?” said Dr. Reeper suspiciously.

  “Oh yes, sir!” chorused the boys enthusiastically.

  “I wasn’t aware that any of you were interested in science,” said Dr. Reeper, sounding a little happier.

  “Oh, sir, we love science!” Ringo assured him feverently. “Tank here wants to be a scientist. When he grows up.” Tank looked rather startled but then tried to compose his face into what he hoped was an intelligent expression.

  “Really?” said Dr. Reeper, perking up considerably. “This is wonderful news! You must all come into my laboratory—I’ve been longing to show someone what I’ve been working on, and you seem like the perfect boys. Come in, please. I can tell you all about it.”

  “What’ve you gotten us into now?” muttered Whippet to Ringo as they followed Dr. Reeper into the room.

  “Shut up,” Ringo replied out of the corner of his mouth. “It was this or detention. So look sharp, all right? I’ll get us out as soon as I can.”

  Dr. Reeper’s laboratory was clearly divided into two parts. On one side, a strange-looking chemistry experiment was in progress. Lots of glass balls were linked to others via glass tubes. One of the balls was connected to what looked like a miniature volcano. Most of the volcano fumes funneled upward into the glass ball, but from time to time little wisps of them leaked out. Gases poured from one glass ball to the next, eventually ending up in one large ball in the center. There was a cloud inside this last ball, and now and then they saw sparks flying around.

  “So, who wants to go first with the questions?” asked Dr. Reeper, excited to have an audience.

  Ringo sighed. “Sir, what’s that?” he said, pointing to the large chemistry experiment.

  “Aha!” said Dr. Reeper, grinning and rubbing his hands. “I’m sure you remember the wonderful rotten-egg stink you smelled when you entered the house. Well, do you know what it is?”

  “Rotten eggs?” piped up Tank, feeling happy he knew the answer.

  “Stupid child,” grumbled Dr. Reeper. “You’ll have to try harder than that if you want to become a scientist. Think! What could it be? Such an easy answer.”

  The boys looked at each other and shrugged. “Don’t know,” they all murmured.

  “Dear, oh dear,” sighed Dr. Reeper. “Children today, they really do know nothing. It is the smell of the Earth—billions of years ago, when there was no life on it.”

  “Well, how were we supposed to know that?” moaned Whippet.

  But Dr. Reeper ignored him. “This isn’t a real volcano, obviously,” he continued, pointing at the small homemade volcano, which had smoke erupting from the crater at its top.

  THE EARLY ATMOSPHERE

  The Earth’s atmosphere hasn’t always been as it is today. Were we to travel back 3.5 billion years (to when the Earth was about 1 billion years old), we would not be able to breathe.

  Today, our atmosphere is made of approximately 78% nitrogen, 21% oxygen, and 0.93% argon. The remaining 0.07% is mostly carbon dioxide (0.04%) and a mixture of neon, helium, methane, krypton, and hydrogen.

  The atmosphere 3.5 billion years ago contained no oxygen. It was mostly made of nitrogen, hydrogen, carbon dioxide, and methane, but the exact composition is not known. What is known, however, is that huge volcanic eruptions occurred around that period, releasing steam, carbon dioxide, ammonia, and hydrogen sulphide in the atmosphere. Hydrogen sulphide smells like rotten eggs and is poisonous when used in larg
e amounts.

  “Yeah, like, obviously,” murmured Ringo. “I mean, like we hadn’t noticed that.”

  “It’s just a little chemical reaction that emits the same kind of fumes,” Dr. Reeper enthused, seemingly unaware of Ringo’s rudeness. “So, I made it look like a little volcano with mud from the garden. I very much like it.”

  The fumes from the volcano puffed upward into a glass ball, where they mixed with water vapor. This came from another glass ball, in which water was being heated over a gas burner. When they mixed together, the fumes and vapor formed a little cloud inside the large ball. Dr. Reeper had built a device inside that cloud that produced electrical sparks.

  As the mini-volcano puffed dark smoke upward, a little crackle of lightning shot across the cloud inside the ball. Dr. Reeper tapped the glass gently.

  “You see, when lightning strikes clouds of gas, strange reactions occur, and scientists have discovered that these reactions can sometimes lead to the formation of the most basic chemicals that life on Earth needs. These chemicals are called amino acids.”

  MILLER & UREY’S EXPERIMENT

  In 1953 two scientists named Stanley Miller and Harold Urey were working on the origin of life on Earth. They believed the ingredients for life could appear out of completely natural phenomena in the Earth’s early atmosphere.

  At that time (the 1950s) scientists had an idea about the kinds of chemical compounds the early atmosphere probably contained. They also knew that lightning was frequent. So Miller and Urey conducted an experiment in which they stroked these chemical compounds with electric sparks (to mimic lightning). Astonishingly, they discovered that they had created special organic compounds.

  Organic compounds are molecules that contain carbon and hydrogen. Some of these molecules, like the ones called amino acids, are necessary for life. Miller and Urey’s experiment produced amino acids and gave hope to the scientific community that it may be possible to create life in a laboratory.

  Today, however, more than fifty years after Miller and Urey, such a creation has yet to be achieved, and we still do not know how life appeared on Earth. But we have been able to create, under special circumstances that mimic conditions on Earth a long time ago, more and more of the basic chemical building blocks of life.

  “But why?” said Whippet. “What do you want them for?”

  “Because,” said Dr. Reeper, a sinister look crossing his face, “I am trying to create life itself.”

  “What a load of garbage,” said Ringo under his breath.

  But Zit sounded more intrigued than his leader did. “Sir,” he said thoughtfully, “there’s lots of life around us. Why would you need to make some more?”

  “There is on this planet,” replied Dr. Reeper, giving him an approving look. “But what about on another planet? What about another planet where life has not yet emerged? What would happen if we went there and took life with us?”

  “Sounds a bit stupid to me,” said Ringo. “If we go to a new planet, there won’t be anything there, so there’ll be nothing to do.”

  “Oh, unimaginative boy!” cried Dr. Reeper. “We would be masters of the planet! It would be all ours.”

  “But hang on a minute,” said Whippet, somewhat suspiciously. “Where is this planet? And how are we gonna get there?”

  “All good questions,” said Dr. Reeper. “Come and have a look over here.”

  He walked over to the other side of the room, which was covered with a huge picture of space and stars. In one corner there was a red circle around a couple of little white dots with lots of arrows pointing at it. Near the red circle was another circle drawn in green—except that the green circle seemed to be empty. Next to the map were white boards covered with diagrams and crazy-looking scribbles. There seemed to be some kind of link between the scribbles and the star poster.

  Dr. Reeper cleared his throat as the boys gathered around him. “This, children, is the future!” he said, waving his hands toward the crazy scribbles. “Our future! I expect,” he continued, “you have never given a moment’s thought to what I do when I’m not teaching you at school.”

  The group nodded, agreeing that no, they hadn’t.

  “So let me save you the trouble. I”—Dr. Reeper drew himself up to his full height so he towered over the boys—“am an expert on planets. I have worked all my life on planets, trying to find new ones.”

  “Did you find any?” asked Whippet.

  “I found many,” replied Dr. Reeper proudly.

  “But don’t we know them all, like Mars or Saturn or Jupiter?” asked Whippet again.

  The other boys nudged each other. “Oooh,” whispered Tank. “Who’d have thought it? Whippet’s trying to be teacher’s pet.”

  “No, I’m not,” huffed Whippet. “It’s just interesting, that’s all.”

  “Aha!” said Dr. Reeper. “You are right! We know all the planets that are around the star closest to the Earth, the star that we call the Sun. But I am looking for other ones! I am looking for planets that are around other stars, planets that are very far away. You see,” he continued, enjoying having his class—or a few of them, anyway—actually listen to what he said for a change, “a planet is not an easy thing to find. I have spent years collecting data from telescopes, and I have looked at hundreds of planets in space. Unfortunately, most of the planets we have found so far are too close to their sun, making them too hot to support life and be habitable.”

  “That’s not gonna help then, is it?” said Whippet, sounding disappointed.

  Dr. Reeper pointed at his star map. “But wait,” he said, “I haven’t told you everything yet. Out there in space are extraordinary, fantastic things, things that until now we have only been able to dream about. But the time is coming when all that will change, when man will go out across the cosmos and inhabit the whole Universe. Just imagine, boys, if we were the first to discover a whole new planet.”

  EXOPLANETS

  An exoplanet is a planet that revolves around a star other than the Sun.

  So far, more than 240 exoplanets have been detected in space, and new ones are discovered every month. This may not sound like a lot in comparison to the hundreds of billions of stars that are known to exist within the Milky Way alone, but this small number is mostly due to the difficulty of detecting them. A star is easy to detect because it is huge and emits light, whereas a planet is much smaller and only reflects the light of its star.

  Most of the techniques used to detect exoplanets are indirect, meaning that the exoplanet is not seen directly but the effects of its existence are. For instance, a big exoplanet will attract its star via gravity and will make the star move a bit. This star movement can be detected from Earth. One hundred sixty-nine exoplanets have been found this way, and these are really big, much bigger than Jupiter, the largest of the giant planets of our Solar System.

  The Corot satellite launched in December 2006 is able to detect tiny changes in the amount of light shining from a star. Such changes can occur when an exoplanet (even a small one) passes in front of a star. The quality of the detectors Corot is equipped with should allow for the discovery of exoplanets much smaller than before, down to about twice the size of the Earth. We have not yet seen any Earth-size exoplanets.

  Only four exoplanets have been detected by direct imaging

  (i.e., by taking pictures) so far. These also are huge.

  “That’s like that TV show,” said Zit cheerfully, “where everyone gets on a spaceship and goes to a new planet, where they get eaten by green aliens.”

  “No, it’s not like that at all!” snapped Dr. Reeper. “You must learn to distinguish between science fiction and science fact. This planet here that I have found”—his finger traced the red circle drawn in the corner of the map around the white dots—“could be the new Planet Earth.”

  “But it looks like this new planet is pretty far away,” said Whippet doubtfully.

  “Yes, it is,” agreed the teacher. “It is very, very, very far. S
o far away that if I had a phone conversation with someone there, I would need to wait several years between the time I ask a question and the time they reply, just because of the time it would take my question to travel there and their reply to travel back again.”

  “Did you talk with them on the phone?” the four kids said in unison.

  “No, no, no!” said Dr. Reeper in an annoyed voice. “I said if I had. Don’t you understand anything?”

  “But is there anyone out there?” Zit persisted, hopping from foot to foot in excitement.

  “That’s hard to tell,” said Dr. Reeper. “So I need to get out there and have a look.”

  “How are you going do that?” asked Ringo, who was feeling interested now in spite of himself.

  Dr. Reeper gazed into the distance over their heads. “I have been trying all my life to get into outer space,” he said. “Once, I nearly made it. But someone stopped me, and I have never been able to forgive him. It was the greatest disappointment of my life. Ever since then, I’ve been looking for a way. And now I’ve got another chance. That’s where you boys come in.” Dr. Reeper reached for the letter in his pocket. “Here is the letter that we spoke about in the driveway. Take it to George’s friend. His name is Eric. Drop it in his mailbox and make sure no one sees you,” said the teacher as he handed the letter over to Ringo.

  “What’s in it?” asked Ringo.

  “Some information,” replied Dr. Reeper. “Information is power, boys. Always remember that.” Facing his star map and pointing with his burned hands toward the red circle drawn around the bright dots, he said, “And the information contained in this letter is the space location of this amazing new planet Earth number two.”

  Whippet opened his mouth to speak, but Dr. Reeper interrupted him.

 

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