I freeze in place and slowly look down, unsure of what I'm expecting to find. All I see at first are numbers flashing up at me in red: 18 LBS. It turns out I'm standing on top of a scale, which is built right into the floor. Ah ha! So they can build scales into the ground. I knew it!

"Wow," Lizzy says. "I knew you were skinny, but I didn't think you were that skinny!" I look around for an explanation of the scale, but I don't see one.

A man with wild white hair, a white lab coat, and big round gla.s.ses approaches. He has a little skip to his step. He reminds me of a poster of Albert Einstein my old science teacher had hung on the wall. To my surprise, James is with him.

The old man points down at the scale and says, "That's what you would weigh if you stood on the moon. Less gravitational pull."

My eyes widen. "Cool!"

"Let me try," Lizzy says, thrusting the telescope into my arms and stepping on the scale herself. "Seventeen pounds!" she announces.

"If you stood on the sun," the old man says, "you'd weigh over a ton."

"Wow," Lizzy says, nodding. "No one would mess with me then!"

James clears his throat. "This is Dr. Grady," he announces. "Dr. Grady, this is Jeremy Fink and Lizzy Muldoun. The good doctor apparently couldn't wait for us to get to his lab."

Dr. Grady smiles sheepishly. "You'll have to forgive my impatience. We scientists are a curious bunch. A man gets a cryptic call saying two young people have something that belongs to him, and, well, he can't just sit in his office and wait."

"You guys know the drill," James tells Lizzy and me. "I'll be waiting in the dinosaur exhibit. Come meet me when you're done."

"See ya, James," Lizzy replies. I don't say anything. I'm too busy staring at Dr. Grady in his white lab coat. A real scientist! The things he must know about the world!

"Is that it?" Dr. Grady asks.

I must look puzzled, because he reaches over and taps the telescope in my arms.

"Oh!" I exclaim, reddening. "Yes, this is it." I pa.s.s the telescope to him, and he sits on a nearby bench to unwrap it. He stops after uncovering the top half. To my surprise and horror, he drops his head in his hands and begins to weep. Lizzy's eyes look like they're about to pop out of her head.

"What do we do?" she whispers in a low voice.

I shake my head, at a total loss. The only time I'd seen a grown man cry was my dad during an episode of Antiques Roadshow, when the copper pot some guy bought at a yard sale turned out to have belonged to Benjamin Franklin.

This is very different.

With one final heave of his shoulders, Dr. Grady wipes his eyes with the back of his hand. "I'm sorry, children," he says. "I've always been a crier. The kids at school used to tease me mercilessly."

I hold the envelope out to Dr. Grady, and he slowly reaches up for it. The occasional whimper sneaks out of him as he reads the letter.

I blame my inability to comfort him on Mom not letting me have a real pet.

Dr. Grady tucks the letter in his coat pocket and turns his attention back to the telescope. "I never dreamed I'd see this again," he says, eyeing it lovingly. "You must tell me how it came to be in your possession."

I open my mouth to answer when Lizzy says, "We'll tell you on one condition."

I glare at her. What does she think she's doing?

Dr. Grady looks amused. "And what would that be?"

"That you tell us the meaning of life," she says plainly.

I shake my head at her.

"No, wait," she says. "I mean the purpose of life. That's what I mean, right?"

I shake my head again. Dr. Grady turns his head back and forth between us.

"Oh, right. Duh!" Lizzy says. "I mean, why are we here? That's what I want to know."

I sigh. "What she means to say is, how are we here? Why is there something instead of nothing? Mr. Oswald thought you might know."

His eyes widen. "Old Ozzy is still alive? Impossible! He was ancient when I was a boy!"

"No, no," I a.s.sure him. "Our Mr. Oswald is his grandson."

Dr. Grady pushes himself off the bench. "Well, that's a relief," he says. "For a second there I thought Old Ozzy fashioned himself a time machine."

My ears perk up. If anyone would know how to build a time machine, it would be Dr. Grady.

"Go on," Lizzy says, reading my mind as usual. "Ask him. You know you want to."

"Ask me what?" Dr. Grady says, carefully lifting the telescope. "Something more important than how we all got to this backwater edge of the Milky Way?"

I can't seem to make myself ask the question. All of a sudden, it just sounds silly.

"He wants to know how to build a time machine," Lizzy reveals. "He's been trying to do it for five years."

"Not trying, exactly," I hurry to explain. "Mostly reading about it. About going back in time, that is. Not to the future or anything like that. I don't think that's possible."

He smiles. "I'm sorry to say that time travel is still theoretical at this point. But you're right, all the known laws of physics indicate that travel to the future is likely impossible. Travel to the past though, well, I'm not writing that off. But since there would be no way to return to the future, there would be two of you in the past and none of you here in the present. Theoretically of course. Very messy. Quite impractical. Now why would a young man like yourself want to do such a thing?"

My throat tightens. Thankfully Lizzy doesn't try to answer for me.

"Why don't you two wait here," Dr. Grady says kindly. "I'll run this back to my office and then I'll show you around. We can chat some more."

I nod mutely, and we sit down on the bench. I stare up at the huge metal ball hanging from the ceiling, with the words THE SUN printed on it. A tiny ball hangs beside it. THE EARTH. How did I miss those before? One snip of a chain and they would crush us. The sign hanging next to them says, MORE THAN ONE MILLION OF OUR EARTHS WOULD FIT INSIDE THE SUN.

I feel very small.

Chapter 14: Life, the Universe, and Everything.

"Are you okay?" Lizzy asks. "You look a little freaked out. More freaked out than usual, I mean. I hope you didn't mind me asking about the time machine. Did you understand all that mumbo-jumbo?"

I pull myself away from the models of the sun and earth and take a deep breath. "Basically, he told me that even if I found a way to go back in time to save my father, I couldn't really save him. I couldn't bring him back with me. And if I could never get back, then I'd be leaving my mom without both my dad and me."

"But, hey, there would be two Jeremy Finks in the past. That wouldn't be so bad, right?"

I shake my head. "One of me is plenty."

"But maybe the other Jeremy could do your math homework while you-the real Jeremy-hung out with me. Two Jeremys would mean there'd be one more person on earth who could stand to be around me."

"First off," I reply, "I like math. But thanks for trying to make me feel better. And I'm not the only person who likes you. Your dad, for one."

"He has to, I'm his daughter."

"Well, Samantha seems to like you."

Lizzy shrugs. "I heard her tell Rick she thinks I'm 'entertaining.' "

"Well, that doesn't sound so bad."

Lizzy makes a face. "Dogs are entertaining."

I shrug. "Not all of them."

Lizzy smiles. At that moment Dr. Grady appears. He has taken off his white lab coat, but still looks like Einstein. "Come on," Lizzy says, pulling me to my feet. "Let's go find out how we got to this-what did he call it?-backwater edge of the Milky Way."

"I have reconsidered your question, Mr. Fink," Dr. Grady says, clasping me on the shoulder. "There is, in fact, a way to see into the past whenever one wishes. I'm afraid it's not exactly what you're looking for, but it is as good a place as any to start finding the answer to your first question-how we came to be here, and may even answer why. Follow me and keep in mind, this is just the scientific explanation based on what we can observe and measure with our current equipment."

He leads us to the top of the winding ramp. Most people are going in the opposite direction, so we have to fight our way through. "You have heard of a light year I imagine?" he asks. I nod. Lizzy nods, too, but I think she would nod at anything if it meant not having to listen to an explanation. I don't think Dr. Grady is convinced either, since he explains, "If an object-a star, for instance, like our own sun-is eight hundred light years away from Earth, it would take light leaving that object eight hundred years until it reached our eyes. So when you look at that object, you are seeing it as it appeared eight hundred light years ago, not as it looks today. It might not even exist anymore.

"Every time you look up at the stars," Dr. Grady continues, "you are looking into the past."

He points to a map of the night sky, and I recognize some of the constellations we learned about in school. He catches sight of Lizzy checking her teeth in one of the shiny display cases. "I'm not boring you, am I? We could just check out the gift shop if you'd prefer."

I try to give Lizzy a kick, but she moves away too quickly. She nearly topples right into a model of the solar system. "Please, go on, Dr. Grady," I urge.

"Okay, then. Roll up your sleeves, and I'll give you a quick lesson in the history of the universe. Ready?"

"Um, we're wearing short sleeves," Lizzy points out.

"It's an expression, my dear. Like, 'It's the journey, not the destination.' Shall I continue?"

"What journey do you mean?" Lizzy asks.

"Why, life, of course."

"Oh," Lizzy says. "Right."

Dr. Grady takes a few steps down the ramp and points to a quote engraved on the wall. He reads it out loud: " 'The universe is queerer than we suppose, and queerer than we can suppose.' This brings us back to your original question-how did we come to be here in this strange, mostly unknowable place? For the answer to that, we have to start at the beginning. About thirteen-point-seven billion years ago, there was nothing that we can measure. No s.p.a.ce. No time. Then suddenly, there was something. This something is called a singularity-a point so dense and hot that it contained all the matter that will ever fill the universe. No one knows where it came from. Maybe a supreme being placed it there for all we know, or it came from some whole other universe we know nothing about. But we do know what came next."

Before I can stop myself, my hand shoots up in the air. Lizzy laughs, and I quickly lower it. "The Big Bang?"

"Exactly!" Dr. Grady says, rubbing his hands together excitedly. "But don't think of it as a bang, or an explosion, it was actually a ma.s.sive expansion, like blowing up an unimaginably tiny balloon to an unimaginably huge balloon that is still expanding."

Dr. Grady pauses, running his hands through his hair. It doesn't do much good because it bounces right back up anyway. Lizzy begins to hum softly to herself. I elbow her in the ribs. She shoots me a dirty look, but stops humming. Dr. Grady doesn't seem to notice.

"All the matter and energy in the universe," he explains excitedly, "including us, are inside this balloon. The planets, the stars, you and I, we all came from the very same stuff, at the very same point in time, thirteen-point-seven billion years ago. The universe unfolded at many times the speed of light, spewing forth subatomic particles, and creating things like gravity and electromagnetism. Stars formed from ga.s.ses and dust clouds, and the debris and ice spun off to create the planets. With me so far?"

I nod, my brain spinning. So I wasn't really born twelve (almost thirteen) years ago? I was really born 13.7 billion years ago? Mom owes me a lot of birthday presents!

"Let's bring it closer to home now," Dr. Grady says happily. It's great watching someone who loves what he does. Dad was like that, at the comics store. Mom loves the library, and Lizzy's dad loves the post office. I wonder if I'll ever find something I love as much. I tune back in to hear Dr. Grady say, "Our own solar system was formed 4.5 billion years ago. It took about another billion years until the surface of the earth cooled. Pretty much as soon as life could begin, it did. Out of the primordial soup-some basic chemicals and ga.s.ses mixed with UV radiation and lightning-arose the building blocks of life: amino acids. These were followed by bacteria, then single-celled organisms, multicelled organisms, plants, invertebrates, vertebrates, reptiles, and mammals, all adapting to their ever-changing environment over billions of years."

A group of teenagers dressed in white lab coats approaches, trailing after an older woman who looks like the female version of Dr. Grady. The kids each carry a clipboard. Lizzy nudges me and whispers, "That's you in five years!"

"Very funny," I whisper back. But I stare at their faces as they file by. Their eyes look eager and bright. It wouldn't be so bad to look like that.

Dr. Grady waits for the group to pa.s.s and continues. "It may be not very appealing to think that we came from the same sludge that produced the amoeba, but we all have a common ancestor; our DNA shares the same chemical structure. You, I, and the fruit fly all have the same blueprint for life. All life on this planet is connected-some people can feel it more than others, on a spiritual level. If there is life on other planets, it will likely have evolved very differently from us. The chance of duplicating what happened here is close to zero."

"How come?" I can't help asking.

"Trust me," Dr. Grady says. "We are here because over billions of years, countless variables fell into place, any of which could have taken another path. We are essentially a beautiful fluke, as are the millions of other species with which we share this planet. Our cells are composed of atoms and dust particles from distant galaxies, and from the billions of living organisms that inhabited this planet before us."

He pauses here and wipes a little tear from his eye. To be polite, Lizzy and I look away.

"So now you know the scientific explanation of how we got here," Dr. Grady says, clearing his throat. "As you can see, it also answers the question of why we are here. Physics tells us we're here because gravity keeps us from floating away into s.p.a.ce. In the most basic biological terms, we're here because some of the earliest inhabitants of this planet-bacteria-allow us to be. Our bodies would not be able to function without the jobs they perform for us-in the air around us, on our skin, and inside our organs. We think we're the most powerful species on the planet, but we're far from it. We would not live for one day without them, but bacteria are so adaptable, they will be here when the sun burns out. Bacteria and c.o.c.kroaches!"

I look at Lizzy, who has started squirming. I have no doubt she's thinking about the bacteria living on her body. Somehow I thought the answer to why we're here would be a little more, I don't know, glamorous?

Lizzy begins scratching. Long red welts appear on her arms.

"I fear I have rambled too long," Dr. Grady says, consulting his watch. "I hope I didn't overwhelm you."

"No, it was great," I tell him honestly. I have a million questions to ask, but I'm pretty sure Lizzy will kill me if I do. "Oh," I say, suddenly remembering the bargain Lizzy made, "your telescope came from-"

He puts up his hand to cut me off. "I changed my mind. Let it be a mystery as to why it has returned to me after fifty years. I've spent my life trying to find rational explanations for life's mysteries."

"Okay," I say with a smile. Lowering my voice, I ask, "Maybe someday I could... come back?"

"Of course," he says, slapping me on the back and grinning. "And you won't even have to bring me anything."

We shake hands, and I turn to Lizzy. "Are you ready to go?"

She nods frantically.

"Are you all right, Lizzy?" Dr. Grady asks, his brow crinkling in concern.

Lizzy nods again. "I'll be okay as soon as I can get into a really hot shower."

He laughs. "Remember, bacteria are friendly, for the most part. You don't want to wash, or scratch, them all away."