by Lucy Hawking
Q: Does it have an atmosphere?
A: No. This explains why the sky is always dark on the Moon, meaning that if you stay in the shade, the stars are visible all the time.
Q: What explanations did people have for the Moon before scientists discovered how it was formed?
A: A long time ago, people on Earth believed that the Moon was a mirror, or perhaps a bowl of fire in the night sky. For centuries, humans thought the Moon had magical powers to influence life on Earth. In one way, they were right—the Moon does affect the Earth, but not by magic. The Moon’s gravity exerts a pull on the oceans, which creates the tides.
Q: Could life exist on the Moon?
A: The Moon cannot support life—unless it’s wearing a space suit. But as a consolation prize, evidence is mounting that the Moon contains much more water—the prime ingredient for life as we know it—than scientists thought just a few years ago. It’s frozen, though, and any Earth emigrants to the Moon will need to put substantial effort into transforming it into its life-friendly liquid form.
Q: Has our Moon ever been visited by other civilizations?
A: The nearest celestial object to us has been visited twelve times by astronauts from Earth. Between 1969 and 1972, twelve NASA astronauts walked on the surface of the Moon. Could the Moon have been visited before human civilization even began on Earth by extraterrestrials who left deposits behind them? Could the aliens have come as close as “next door” to us? It’s a (very, very) long shot, but some scientists on Earth are looking again at Moon rock to see whether it holds any clues.
“Hello, Earthlings!” shouted George, taking a few bounds forward. He knew no one on Earth could hear him, but he just had to say something to mark his first steps on the Moon. Set against the darkness of the sky, his home planet looked like a blue-green jewel, flecked with white clouds. Although both Annie and George had been on exciting cosmic adventures before, this was the first time George had seen his home planet from so close.
From Mars, the Earth had been just a tiny bright fleck in the sky.
From Titan, George and Annie hadn’t been able to see the Earth at all through the thick, gaseous clouds on that strange frozen moon of Saturn.
And by the time they’d reached the Cancri 55 solar system, Earth had been hidden from their eyes altogether. Even using a telescope from that distance, they would have only known that the Earth was there from the very slight variable shift in the color of the light coming from our Sun, the star at the center of our Solar System.
On the Moon, however, he was near enough to see the detail of his home planet but far enough away to marvel at its beauty.
After admiring the view, he bounced off in Eric’s direction, covering the distance between them very quickly. By the time he reached the scientist, Eric had disappeared into the shallow crater and was looking at a dusty machine, stuck in the bottom of it.
“Eric!” shouted George into his voice transmitter. “Eric! It’s me, George!”
“Great gravitational waves!” exclaimed Eric in shock, looking up from the broken-down lunar vehicle. “You gave me quite a scare! I wasn’t expecting to meet anyone else up here.” He hadn’t heard the great shout of joy when George first stood on the Moon as George’s voice transmitter had been out of range.
“I came into the study and the door was open,” explained George. “What are you doing here?”
“I only meant to go to the Moon for a minute,” said Eric rather guiltily. “I wanted to get a little bit of Moon rock to take a closer look at it. I’ve got this theory about alien civilizations that I want to work on. I figure that if we were visited by aliens sometime in the past—say a hundred million years ago—they would have left traces somewhere. I don’t believe anyone has investigated Moon rock to see whether it shows traces of alien visitation. I want to look at Moon rock again with fresh eyes, to see whether there is any signature of life in it. No one has examined Moon rock this way before so I thought I’d get some and try myself. Look what I came across when I was collecting samples! It’s a lunar rover!”
“Does it still work?” asked George, quickly scrambling down to where Eric stood. It looked as though a dune buggy had crashed and been abandoned on the Moon. Eric climbed into the driver’s seat while George surveyed the rover thoughtfully. “Can you make it go?”
“I expect the batteries are dead by now,” said Eric, brushing some dust off the rover with the arm of his space suit.
“There’s no steering wheel,” noticed George. “How do we drive it?”
“Good question!” Eric wiped his sleeves on his legs, leaving long gray trails of moondust on his white space suit. “There must be some way to switch it on …” He fiddled around with a T-shaped joystick between the front seats. But nothing happened. The joystick seemed to be part of a console. Wiping away the lunar dust around it with the thumb of his space glove, Eric uncovered a series of switches with the labels power, DRIVE POWER, and DRIVE ENABLE. “Aha!” said Eric happily. “Houston, we have the answer!”
George leaped into the rover alongside Eric. “What happens if you flip those switches?” he asked excitedly. “Can we find out?” He hoped Eric wouldn’t turn all grown-up on him and say they shouldn’t mess around with someone else’s moon buggy. But Eric didn’t let him down.
“Yes, we certainly can!” replied Eric. He flipped the switches one at a time and then pushed the joystick, making the rover shoot forward very suddenly. The unexpected movement catapulted them both up into the air and out of the vehicle.
“It works!” Eric cried, climbing back in. “George, could you give the rover a push from behind while I drive it out of the crater. With the Moon’s lack of gravity, it’ll be easy.”
“Why do I have to push?” grumbled George. “Why don’t I get to drive it?” But he took up a position behind the moon buggy and braced himself. Eric pushed the joystick forward once more. As he did so, the rover churned its wheels into the ground, showering George with fountains of dust and Moon rock.
“Push harder!” shouted Eric. At that moment George gave an almighty heave, and the lunar rover struggled out of the crater and onto the flat plain above.
“There!” said Eric, brushing his gloved hands together happily and hopping out of the driver’s seat. “That’s better!” He patted the lunar rover in admiration. “What a piece of machinery! It can’t have been used for forty years and it still works! Now that’s what I call a car.”
“Who does it belong to?” asked George, who was now almost entirely covered in moon rock and dust.
“Left by the Apollo Moon landers, I would think,” said Eric. “Look, over there! That must be the descent stage of the Lunar Module.” Eric pointed to a four-legged object, squatting in the distance. “This is a piece of space history.”
There was a brief silence as they both paused in wonder at what they had found. Then, suddenly, Eric seemed to realize that he was in fact standing on the Moon in the company of his next-door neighbor, a schoolboy called George.
“George, what are you doing following me out to the Moon?” he asked.
“I came to ask you about Freddy,” explained George. “You didn’t tell me where his new home is—I don’t even know which planet he’s on!”
“Oh, quivering quasars!” exclaimed Eric, hitting himself on the space helmet with his space glove. “Neither do I! We’ll have to ask Cosmos. Don’t worry—we know that Freddy is perfectly safe and well—we just need to find out where! Was there anything else I forgot?”
Eric was famous for forgetting things, as he freely admitted. He never forgot important matters like his theories about the Universe, but he often forgot day-to-day tasks like putting on his socks or eating his lunch.
“Well, it’s not so much that you forgot,” explained George. “More that I didn’t get to ask you.”
“Ask what?” said Eric.
“Your work … Looking into the origins of the Universe—is that a dangerous thing to do?”
“No,
George,” said Eric firmly. “It is not dangerous. In fact, I think it would be dangerous if we didn’t think about the origins of the Universe—if we dealt in speculation rather than in facts about where we come from and what we’re doing here. That’s dangerous.
“What we’re trying to do is understand how this magnificent Universe”—Eric swept his arm around to point at the craggy mountain ranges, the huge dark expanse of black sky, with the distant bauble of planet Earth hanging above the moonscape—“came into being. We want to know how and why these billions of stars, the infinite and beautiful galaxies, planets, black holes, and the incredible diversity of life on planet Earth came about—how did it all begin? We’re trying to go back to the Big Bang to find out. That is what the science of cosmology, studying the origins of the universe, is all about. The Large Hadron Collider will let us re-create the first few moments of time so we can understand better the way the Universe formed.
“What we’re doing isn’t dangerous and neither is the LHC. The only real danger comes from people who want to stop us: Why don’t they want the secrets of the early Universe to be revealed? Why do they want people to be scared and afraid of science and what it could do for us? That, George, is the great mystery to me.” Eric sounded mildly frustrated.
“But do you think those people will try to harm you and the other scientists?” asked George.
“No, I don’t think so,” said Eric. “They’ll just sneak around being a nuisance—they’re not even brave enough to show their faces, so I don’t think we have much to fear from them. Forget them, George. They are just a bunch of losers.”
George felt much better now—both about Freddy and the origins of the Universe. Suddenly nothing seemed so bad after all. He and Eric turned and bounced back toward the portal, which was still glimmering in the distance. Usually they closed the portal down when they were on a space adventure, but because Eric had only meant to be gone for a couple of minutes, he’d left it propped open with an old shoe.
Before they reached the doorway Eric got his space camera out of his pocket. “We should take our photo! Say, ‘Cheese! The Moon is made of!’” he said, holding the camera out and snapping a picture of them as George made the thumbs-up sign with both hands.
“Will anyone notice that we moved the rover?” asked George as Eric put the camera away.
“Only if they look very carefully,” said Eric. “This part of the Moon isn’t under constant surveillance. That’s why I chose it as a safe place to land.”
“Anyway, they should be pleased,” George pointed out. “We got their rover out of a hole in the ground and made it work again.”
“Hold on a minute,” said Eric as he looked up into the sky. “That light over there—that’s not a comet.” A pinprick of light was moving through the dark sky toward them.
“What is it?”
“I don’t know … But whatever it is, it’s man-made—so it’s time to go. I’ve got the rock I need—let’s go!”
Together, Eric and George leaped through Cosmos’s space portal, back to the place where all their space adventures had begun.
THE LATEST SCIENTIFIC THEORIES
THE CREATION OF THE UNIVERSE
There are many different stories about how the world started off. For example, according to the Boshongo people of central Africa, in the beginning there was only darkness, water, and the great god Bumba. One day Bumba, in pain from a stomachache, vomited up the Sun. The Sun dried up some of the water, leaving land. Still in pain, Bumba vomited up the Moon, the stars, and then some animals—the leopard, the crocodile, the turtle, and, finally, man.
Other peoples have other stories. They were early attempts to answer the Big Questions:
• Why are we here?
• Where did we come from?
The first scientific evidence to answer these questions was discovered about eighty years ago. It was found that other galaxies are moving away from us. The Universe is expanding; galaxies are getting farther apart. This means that galaxies were closer together in the past. Nearly fourteen billion years ago, the Universe would have been in a very hot and dense state called the Big Bang.
The Universe started off in the Big Bang, expanding faster and faster. This is called inflation because it is like the way in which prices in the stores can go up and up. Inflation in the early Universe was much more rapid than inflation in prices: We think inflation is high if prices double in a year, but the Universe doubled in size many times in a tiny fraction of a second.
Inflation made the Universe very large and very smooth and flat. But it wasn’t completely smooth: There were tiny variations in the Universe from place to place. These variations caused tiny differences in the temperature of the early Universe, which we can see in the cosmic microwave background. The variations mean that some regions will be expanding slightly less fast. The slower regions will eventually stop expanding and collapse again to form galaxies and stars. We owe our existence to these variations. If the early Universe had been completely smooth, there would be no galaxies or stars and so life couldn’t have developed.
Stephen
Chapter Five
They tumbled back into the scientist’s messy study. In their hurry to avoid being spotted by the mystery satellite, they fell over in a dirty jumble of space suits that were once—but no longer—white.
“The portal is closed,” Cosmos informed them. “You have been brought back to your terrestrial home, the beautiful planet Earth.”
“Cosmos, you are the most amazing and intelligent computer ever created,” said George, who knew how much the supercomputer enjoyed a compliment.
“While I suspect you are flattering me,” replied Cosmos, his screen turning rose-pink, as it always did when he blushed, “nevertheless I find your statements to be consistent with reality.”
As soon as he had gotten to his feet, George started to wriggle out of his space suit. It now lay on the floor, looking like an empty caterpillar cocoon after the butterfly has broken free. Eric was carefully wrapping up his pieces of precious Moon rock, still wearing his space suit, when they heard footsteps outside the door.
“Quick!” hissed Eric. “Hide your space suit.”
George bundled it into the big cupboard in the corner of the study. The air was full of floating fragments of dust, brought back from the Moon.
“Hello!” called Eric in a rather high voice. “Susan, is that you?” After the last adventure, when they had very nearly not made it back from a distant solar system forty-one light-years across the Galaxy, Susan, Annie’s mom, had banned the kids from accompanying Eric into space.
“Hello, yes, it’s us,” said Susan. She didn’t come into the study but walked past into the kitchen instead. The sound of thumping feet announced that Annie was back too.
“It was very cool!” she cried, flinging back the study door. “Dad, can I have a skateboard for my birth—?” She stopped in surprise. “Why have you got a space suit on?” she asked. “Why is George here?”
“Shush!” said her dad quickly.
“No! You haven’t … You have! Have you been into space without me?” She glared at George.
“You went to the skate park,” he said sweetly. “It was … very cool. Much cooler than the Moon, I should think.”
Annie looked like she might erupt. Eric just looked baffled, as though the kids were speaking Vulcan and he had forgotten to plug in his translator.
“I’ve got to go,” said George. “Dinnertime! Bye, Annie. Bye, Eric. Bye, Susan!”
As he dashed out of the back door, Susan called after him, “Don’t forget, George! You’re coming to the lecture with us tomorrow evening! We’ve got your ticket …”
*
The next day, as arranged, George went over to Annie’s house before Eric’s lecture at the university. Annie was not pleased to see him.
“How was the Moon?” she asked angrily as they strapped on their bike helmets. “Actually, no, don’t tell me—I bet that it was tota
lly stupid.”
“But you went to the skate park,” protested George. “With Vincent. You didn’t ask me to come!”
“You never said!” Annie muttered, hopping onto her bicycle. “You never said you liked skateboarding! But you knew I wanted to go to the Moon. More than anything! It’s the place I most want to go to in the whole Universe. And you went without me. You’re not my friend.”
Even though George knew there was something very unfair about the way Annie was behaving, he was stumped for a reply. Why was she angry with him for doing something with Eric when she was busy anyway, doing something fun with Vincent son-of-the-film-director? But George couldn’t ask her that. Instead he just circled mutinously on his bike in front of their houses until Susan came out, carrying a large cardboard box that she balanced awkwardly on her handlebars.
“C’mon, you two,” she said cheerfully, deciding to ignore the fact that Annie and George looked really fed up with each other.
Together, the three of them rode toward the center of town. For several centuries the Math Department had been located in a grand building on a narrow street in the heart of old Foxbridge. But as they turned off the bike path to ride down the street, they found it was so full of people that they had no choice but to get off their bikes and push.
“Who are all these people?” asked Annie as they tried to shove their way through the crowd.
“Let’s leave our bikes here,” said Susan, pointing to a bike rack. “I don’t think we can get any closer to the department with them.” They locked up their bikes, then sidled through the crowd of people toward the entrance: A flight of steps led up to a pair of glass double doors with columns on either side. In front of the doors stood a university official, looking anxiously out over the heaving throng below.
“They’re all here for your dad’s talk!” said George to Annie as he squeezed his way toward the steps after Susan. “Look! They’re trying to get into the building!” The crowd surged around them, all pushing forward toward the old stone building with the inscription AD EUNDEM AUDACTER above the portico.
