Chapter 14
At the bottom of the crater, Eric stepped quickly through the portal and promptly fell flat on his face. He had prepared his telling-off speech to the kids while he was getting ready to walk through Cosmos’s doorway. But once he reached the distant planet, all he came out with was “Nrrgghh!”
“Dad!” cried Annie from the top of the crater, and burst into tears inside her space helmet. She no longer cared whether he was going to be mad at her. She just felt overjoyed to see him. She slithered over the crater’s lip and wriggled down toward him on her tummy. As Eric rolled over onto his back, Annie crashed into him and gave him a great big hug.
“Dad!” she sobbed. “It’s so nasty here! I don’t like this planet.”
Eric gave a huge sigh that Emmett and Mabel heard many millions of miles away on planet Earth, and he decided to save his speech about kids who traveled through space by themselves when they shouldn’t for another time. Instead, he hugged Annie.
George’s gran had no such reservations. “George!” she said sternly over the link from Earth. “I can’t believe you roped me into this dangerous scheme without telling me! I’m very angry that you didn’t see fit to properly inform me why you wanted to come to America….” She went on and on, and George wished he could turn down the volume, as Emmett had done with Cosmos. But then he looked into the crater and saw Eric beckoning George to come and join them.
“Sorry, Gran!” said George. “I have to go! We’ll talk later.” And he slid down the side of the enormous hole to join Eric and Annie, ending up in a group hug in space suits at the bottom of the crater on an unnamed planet orbiting Alpha B in the Alpha Centauri star system.
“I’ve got to close down the portal for a few minutes,” came Emmett’s voice. “I can’t hold the portal and do all the other things I need to with Cosmos. So don’t panic when the doorway vanishes. I’ll get it back to you right away.”
The portal doorway became translucent and started to fade away. George, Annie, and Eric lay back against the curved surface of the crater’s wall and gazed at Alpha A, moving across the clear, dark blue sky.
“So, George and Annie,” said Eric as they lay on either side of him. “Here we all are, together, once again. Lost in space, once again.” By now, the portal had completely disappeared.
“Can we go home now?” sniffed Annie. “I’ve had enough of this.”
“Soon, very soon,” said Eric calmly. “Just as soon as Emmett gets the reverse portal working again.”
“What!” exclaimed George, trying to sit up but finding he didn’t have the strength left to fight gravity. He lay back down again. “You mean we can’t go back to Earth?”
“I’m afraid not,” said Eric quietly. “Cosmos is having some problems, but Emmett will sort them out. I wouldn’t have left him in charge if I weren’t sure he was the best person for the job. He’s already done things with Cosmos I couldn’t even dream of.”
“You mean you came here to find us even though you knew we might not be able to get back?” said Annie. “That we might be stuck here forever?”
“Of course I did,” said Eric. “I couldn’t leave you out here by yourselves, could I?”
“Oh, Dad!” cried Annie. “I’m so sorry! Now we’re going to be burned to a crisp on this horrible planet, and it’s all my fault!”
“Don’t be silly, Annie. This isn’t your fault, and it’s going to be okay! We’re not going to stay long enough for that to happen,” said Eric firmly. “But we do need to leave here before Alpha B rises again. Even with our space suits, it’s too hot for us on this planet because it lies too close to its star—that’s why there is no water and no life here. But we’ll go somewhere else. Somewhere nicer.”
“So Cosmos can still send us farther out?” said George hopefully. He didn’t want to see the blinding light of Alpha B ever again in his whole life.
“Yes,” said Eric, more confidently than he felt. “Sometimes we have to go far, far away in order to be able to get back. So don’t worry if it feels like we are traveling in the wrong direction. Think of it as gaining perspective.”
“How soon will Alpha B rise again?” asked George.
“I don’t know for certain,” said Eric, “but we must be gone before its dawn.”
“Where are we going?” said Annie.
“Another planet,” Eric told her. “Cosmos is looking for another planet to send us to. Emmett tells me that you have been following clues across the Universe—in a sort of cosmic treasure hunt.”
“Um, yes,” George admitted. “We kept going because in each place we found another clue that sent us to a new location.”
“And you came here because the clue you found on Titan told you to go to a binary star system with a planet in orbit around one of the stars?”
“We thought we’d been really smart,” said Annie sadly.
“Oh you have!” said Eric. “All three of you. Emmett believes that the clues are taking you on a hunt for signs of life in the Universe. If he’s right, then we need to find a planet in what we call the Goldilocks Zone of its star. That means a planet that is not too hot, not too cold, but just right.”
“Oh!” said George. “I see—this planet is too hot! So we know this isn’t the right planet.”
“And I can think of another reason to suspect this isn’t the right place. How many stars did the clue show?” asked Eric.
“Two,” said George.
“Here,” said Eric, “there are three. That fainter star, the one you can only just see over there—that’s Proxima Centauri, so called because it’s the closest star to Earth. So this is a triple system.”
“Oh no! Wrong planet, wrong star system,” said George. “What do we do now?”
“So, do you believe us now, about the clues and the messages?” interrupted Annie.
“I do, darling,” admitted Eric. “And I’m so sorry. I’m sure those messages were left for me, not for you. And if I could send you back to Earth right this second, I would. But I can’t do that and I can’t leave you here. So I think we’re going to have to finish the cosmic treasure hunt together. Are you with me?”
Annie moved closer to him. “I am,” she said, “very definitely.”
ALPHA CENTAURI
At just over four light-years away, Alpha Centauri is the closest star system to our Sun. In the night sky it looks like just one star, but is, in fact, a triplet. Two Sun-like stars, Alpha Centauri A and Alpha Centauri B—separated by around twenty-three times the distance between the Earth and the Sun—orbit a common center about once every eighty years. There is a third, fainter star in the system, Proxima Centauri, which orbits the other two but at a huge distance from them. Proxima is the nearest of the three to us.
Alpha A is a yellow star and very similar to our Sun but brighter and slightly more massive.
Alpha B is an orange star, slightly cooler and a bit less massive than our Sun. It is thought that the Alpha Centauri system formed around one thousand million years before our Solar System. Both Alpha A and Alpha B are stable stars, like our Sun, and like our Sun may have been born surrounded by dusty, planet-forming disks.
In 2008 scientists suggested that planets may have formed around one or both of these stars. From a telescope in Chile they are now monitoring Alpha Centauri very carefully to see whether small wobbles in starlight will show us planets in orbit in our nearest star system. Astronomers are looking at Alpha Centauri B to see whether this bright, calm star will reveal Earth-like worlds around it.
Alpha A and Alpha B are binary stars. This means that if you were standing on a planet orbiting one of them, at certain times you would see two suns in the sky!
Alpha Centauri can be seen from Earth’s southern hemisphere, where it is one of the stars of the Centaurus constellation. Its proper name, Rigel Kentaurus, means “centaur’s foot .” Alpha Centauri is its Bayer designation (a system of star-naming introduced by astronomer Johann Bayer in 1603).
“Me too,” said George. “Let’s finish this. And find out who is sending those messages.”
“I’m calling the portal,” said Eric. On one side of the crater, they could already see the light of dawn as Alpha B hovered below the horizon. “Emmett!” he called. “Any chance of a trip back to Earth?”
“Not just yet,” said Emmett. “But I do have some reasonably good news….”
“You’ve found us a planet that might be just right, a planet about the size of Earth in the Goldilocks Zone?”
“Affirmative,” said Emmett rather weakly. “Or at least, we’ve found something. It’s our best guess. It’s a moon, not a planet, though.”
“How is Cosmos holding up?” asked Eric.
“I just want you to know,” Mabel chipped in, “that I promised George’s parents I wouldn’t let him get into any trouble during his vacation! I’m going to have a very difficult time explaining this to Terence and Daisy….”
“Cosmos is functioning,” said Emmett nervously. “I’ve nearly finished updating the reverse portal. I’ll be able to bring you in as soon as I’ve finished. Can you wait and I’ll get you back to Earth?”
Bright rays of light were stealing across the crater, chasing the dark shadows away.
“No, we can’t stay here any longer,” said Eric. “Send us onward, Emmett. And don’t worry, Mabel. We’ll be back.”
THE USER’S GUIDE TO THE UNIVERSE
THE GOLDILOCKS ZONE
Our Milky Way Galaxy contains at least one hundred billion rocky planets. Our Sun has four: namely, Mercury, Venus, Earth, and Mars—but only Earth has life.
What makes Earth special?
The answer is water, especially in its liquid form. Water is the great mixer for chemicals—breaking them apart, spreading them out, and bringing them back together as new biological building blocks, such as proteins and DNA. Without water, life seems unlikely.
To support life, a planet’s temperature must be between 32 and 212 degrees Fahrenheit (0 and 100 degrees Celsius) to keep the water in liquid form.
A planet orbiting too close to its home star will receive so much light energy that it will heat up to scorching temperatures, boiling all the water into steam.
Planets too far from their star will receive very little light energy, keeping the planet so cold that any water will remain as ice. Indeed, Mars has its water trapped as ice at the north and south poles.
There is a certain distance from every star where a planet receives as much light as it emits heat. That energy balance serves as a thermostat, keeping the temperature lukewarm—just right to keep the water liquid in lakes and oceans. In this “Goldilocks Zone” around a star, any planets would stay warm and bathed in water for millions of years, allowing the chemistry of life to flourish.
Geoff
