Will the universe wear out?

Cold open

Daniel: Every cup of coffee you have ever made has gone cold.

Sofia: Every single one.

Daniel: Every one. You never once came back to the kitchen and found it hotter than you left it. The heat leaks out into the room, the room warms up a tiny bit, and it never, ever flows back into the cup on its own.

Sofia: And that one boring fact — the coffee going cold — turns out to be the law that decides how the entire universe ends.

Daniel: Now listen to a man who's having the worst year of his life, about three thousand years ago. Psalm one oh two. "Of old, you laid the foundation of the earth. The heavens are the work of your hands. They will perish, but you will endure. Yes, all of them will wear out like a garment." Wear out. Like your favorite jacket. The universe has an expiration date, and a grieving poet wrote it down long before anybody had a word for it.

Sofia: I can already tell I'm going to be arguing with you.

Daniel: I'm Daniel Voss. Joined by physicist Dr. Sofia Marchetti, this is Episode 11: A Garment Wearing Out.

The Text Itself

Daniel: Let me set it up properly, because the context is the whole point. Psalm one oh two has a heading. "A Prayer of the afflicted, when he is overwhelmed and pours out his complaint before Yahweh."

Sofia: Overwhelmed. Okay.

Daniel: And he means it. Verse three. "My days consume away like smoke. My bones are burned as a torch." Verse four, "My heart is blighted like grass, and withered, for I forget to eat my bread." This is a man who feels himself — wearing out. And then, in the middle of that, he looks up.

Sofia: At the sky.

Daniel: At the sky. "The heavens are the work of your hands. They will perish, but you will endure. Yes, all of them will wear out like a garment. You will change them like a cloak, and they will be changed. But you are the same. Your years will have no end."

Sofia: So he's not saying "the universe is falling apart, how sad." He's saying "I'm falling apart, and so is everything, and you're not."

Daniel: Exactly. That's exactly it. And the Hebrew is so physical. "Wear out" is "balah" — the word for old fabric going thin, fraying, falling apart. "Garment" is "beged," just ordinary clothing. And "change them" is "chalaph" — to swap out, to replace. Like taking off a coat.

Sofia: I'll stay out of the Hebrew. That's your lane. But I like that it's — it's not dramatic. Nothing explodes. It just gets old.

Daniel: Nothing explodes. And it's not the only place. Isaiah fifty-one, six. "The heavens will vanish away like smoke, and the earth will wear out like a garment." Isaiah thirty-four, "The sky will be rolled up like a scroll." And then the New Testament picks up Psalm one oh two word for word — Hebrews chapter one. "They will perish, but you continue. They all will grow old like a garment does. You will roll them up like a mantle, and they will be changed."

Sofia: "Roll them up." That's different from "change them."

Daniel: You caught that. The Greek of Hebrews says "helixeis" — you will roll them up, fold them. Like folding up an old coat when you're done with it. Which means — and I love this — the garment isn't just thrown on the floor. Somebody folds it.

Sofia: Hm. Somebody's holding it.

Daniel: Somebody's holding it.

Sofia: And who's the "you" in Hebrews? The same God as the psalm?

Daniel: That's the startling part. Hebrews introduces the quote with "But of the Son he says." The writer takes a psalm addressed to God the Creator and says it's about Jesus. The One who made the heavens, who'll fold them up, who stays the same. And then near the end of the same letter — Hebrews thirteen, eight — "Jesus Christ is the same yesterday, today, and forever."

Sofia: So the contrast is the whole point. Everything else gets old —

Daniel: — and one person doesn't. That's the claim. It's a big one. I'm making it on purpose.

The Law Nobody Can Break

Daniel: Okay, Sofia. Your turn. When did science figure out that things wear out? Not just coats. Everything.

Sofia: The eighteen-fifties. And it came out of steam engines, of all things. People were trying to build better engines and kept running into the same wall — you can never turn all of your heat into useful work. Some of it always leaks away as waste.

Daniel: Always.

Sofia: Always. And in eighteen fifty-two, William Thomson — later Lord Kelvin — stood up in front of the Royal Society of Edinburgh and gave a paper with a wonderful title. "On a Universal Tendency in Nature to the Dissipation of Mechanical Energy." And the key sentence is, quote, "There is at present in the material world a universal tendency to the dissipation of mechanical energy."

Daniel: A universal tendency. Not just in engines.

Sofia: And here's a fun twist about Kelvin, because I don't want anyone thinking scientists get everything right. Ten years later, in eighteen sixty-two, he used the same kind of reasoning to work out how old the sun could be. He assumed the sun shines because it's slowly shrinking under its own gravity, and he got — somewhere between twenty and a hundred million years.

Daniel: And the real answer?

Sofia: About four and a half billion. He was off by a factor of fifty or more. Nobody knew about nuclear fusion yet. That only got worked out in the nineteen-thirties.

Daniel: So the most famous physicist in Britain was confidently wrong.

Sofia: Confidently wrong. And he used that number to argue the geologists — and Darwin — didn't have enough time. His math was fine. His assumption about what powers the sun was wrong. I tell my students that story every year.

Daniel: I like that you tell it on your own side.

Sofia: You have to. The second law itself held up, though. That part he got right.

Sofia: Not just in engines. Then two years later, in eighteen fifty-four, Hermann von Helmholtz gives a lecture in Königsberg and follows that thought all the way out. If this tendency is universal, then eventually everything evens out — one temperature everywhere — and nothing can happen anymore. He said the universe would be, quote, "condemned to a state of eternal rest."

Daniel: Eternal rest. That's — that's a funeral phrase.

Sofia: It is. Today we call it the heat death of the universe.

Daniel: And the word "entropy" — where's that from?

Sofia: Rudolf Clausius, eighteen sixty-five. He coined it. And he ended that paper with two sentences that are basically the whole of thermodynamics. In German — I'll spare everyone my accent —

Daniel: Please don't spare us.

Sofia: Fine. "Die Energie der Welt ist constant. Die Entropie der Welt strebt einem Maximum zu." The energy of the world is constant. The entropy of the world tends toward a maximum.

Daniel: The energy stays. But it — runs down.

Sofia: The amount stays the same. The usefulness runs out. That's the second law. And physicists take it more seriously than almost anything. Arthur Eddington, the great British astronomer, wrote in nineteen twenty-eight that if your theory contradicts some other law, maybe the law is wrong. But — and this is a real quote — "if your theory is found to be against the second law of thermodynamics I can give you no hope; there is nothing for it but to collapse in deepest humiliation."

Daniel: That's the most British threat I've ever heard.

Sofia: It really is. Eddington also gave us the phrase "time's arrow." The reason the past and the future feel different — why you remember yesterday and not tomorrow — physicists tie that to entropy going up.

What Is Entropy, Actually

Daniel: Okay, I need you to make this simple for me. What IS entropy? People say "disorder," and I nod, and I have no idea what they mean.

Sofia: Honestly, "disorder" is a little misleading. Here's the better picture. Take your garment. A sweater. All those threads are arranged in one very particular way — knit, interlocked, holding a shape. There are only a few arrangements of those threads that count as "a sweater."

Daniel: Okay.

Sofia: Now think of all the ways those same threads could be arranged that are NOT a sweater. Tangled, frayed, loose, a pile of lint. There are vastly, vastly more of those.

Daniel: So if things get shuffled around at random —

Sofia: — you almost always land in one of the not-sweater arrangements. Not because nature hates sweaters. Just because there are so many more ways to be a mess than to be a sweater. That's entropy. It's a count of how many ways the pieces could be arranged and still look the same from the outside.

Daniel: And Boltzmann —

Sofia: Ludwig Boltzmann. Austrian. He's the one who saw that. He wrote it as a formula — S equals k log W. Entropy is a constant times the logarithm of the number of arrangements. It's carved on his gravestone in Vienna.

Daniel: On his gravestone?

Sofia: On his gravestone. Just the equation. I've been there, actually. You walk past all these huge composers' monuments — Beethoven, Brahms, Strauss — and then there's this one with a formula on it.

Daniel: That's the most physicist thing I've ever heard.

Sofia: Some of us cried a little. I'm not saying who.

Daniel: So a garment wearing out is actually — perfect. It's the exact picture.

Sofia: I'll be honest, it's one of the best everyday pictures of entropy there is. Fabric doesn't spontaneously re-knit itself. Fraying only goes one way.

Daniel: Okay, but couldn't a really clever being cheat? Sort the threads back? Push it the other way?

Sofia: You just reinvented Maxwell's demon.

Daniel: I did?

Sofia: James Clerk Maxwell, in a letter to a friend in eighteen sixty-seven, and then in his book "Theory of Heat" in eighteen seventy-one. He imagined a tiny being guarding a little door between two boxes of gas. Fast molecules, it lets through one way. Slow ones, the other way. One side gets hot, one side gets cold, and it never seems to do any work. Entropy goes down. The second law looks broken.

Daniel: So did the demon win?

Sofia: For about a hundred years, people argued. The answer finally came from computing. In nineteen sixty-one, Rolf Landauer at IBM showed that erasing information always costs a minimum amount of heat. And in nineteen eighty-two, Charles Bennett showed what that means for the demon. To sort molecules, it has to remember what it saw. Its memory fills up. To keep going, it has to erase — and erasing dumps heat back into the world. More than it saved.

Daniel: So even the demon pays.

Sofia: Even the demon pays. No being inside the system gets to run the clock backwards for free.

Daniel: Inside the system. I'm going to come back to that phrase.

Sofia: I figured you would.

A Personal Detour

Daniel: Can I tell you about my dad's work jacket?

Sofia: Please.

Daniel: He worked construction for thirty-one years. And he had this canvas jacket — tan, heavy — and he wore it every winter for, I'm not kidding, about twenty of those years. By the end the elbows were basically gone. You could see his shirt through them. The cuffs were frayed into little strings. My mom bought him a new one three Christmases in a row —

Sofia: And he wouldn't wear it.

Daniel: He would not wear it! Still in the box. And when he retired, I asked him, "Dad, why'd you keep wearing that thing?" And he said, "Because it knows me." And I didn't get it then. I think I get it now. He'd worn it so long it was shaped like him. It had his shoulders.

Sofia: That's lovely.

Daniel: And when he got sick, near the end, he was in that jacket on the porch, and he looked — he looked like it. Worn thin. And I remember thinking of Psalm one oh two right then, the part people skip. "My days consume away like smoke." The man in the psalm isn't talking about the stars first. He's talking about himself.

Sofia: I have one too. Not a jacket. My father's watch.

Daniel: Tell me.

Sofia: An old mechanical watch, the kind you have to wind every morning. He wound it every day at breakfast, same time, for forty years. And when I was little I asked him why, and he said, "Because if I don't, it stops." I thought that was the stupidest answer.

Daniel: It's a perfect answer.

Sofia: It's the second law! A wound spring is ordered energy. The watch spends it, tick by tick, and turns it into a tiny bit of heat. And unless somebody puts energy back in from outside, it runs down. Every single morning he was — pushing back against entropy for one more day.

Daniel: And now?

Sofia: I wind it now. Every morning. Same time. My husband thinks I'm ridiculous.

Daniel: He's wrong.

Sofia: He's completely wrong.

The Expiration Date

Daniel: Okay. So the universe is a watch nobody's winding. When does it stop?

Sofia: Not soon. Let me give you the timeline, because the numbers are so big they stop meaning anything. First, something we learned in nineteen ninety-eight. Two teams, watching distant exploding stars, found that the expansion of the universe isn't slowing down. It's speeding up.

Daniel: Speeding up.

Sofia: Speeding up. That won the Nobel Prize in twenty eleven — Saul Perlmutter, Brian Schmidt, Adam Riess. And it matters for the ending, because a universe that keeps spreading out faster and faster gets colder and emptier forever.

Daniel: So not a crunch. A fade.

Sofia: A fade. In nineteen ninety-seven, two physicists, Fred Adams and Gregory Laughlin, wrote a famous paper called "A Dying Universe," walking through the far future. Roughly a hundred trillion years from now, galaxies run out of gas to make new stars. The last stars burn out. What's left is cold leftovers — dead stars, and black holes.

Daniel: And black holes last forever?

Sofia: Even they don't. Stephen Hawking showed in nineteen seventy-four that black holes slowly leak away. For the biggest ones, it takes something like a ten with a hundred zeros after it, in years.

Daniel: A googol of years.

Sofia: About a googol, yes. And after that — a thin, cold haze of particles, spreading out forever. Nothing warmer than anything else. No more differences, so nothing can happen. Helmholtz's "eternal rest."

Daniel: "All of them will wear out like a garment."

Sofia: Yeah. I'll — I'll admit that's a hard line to hear right after that timeline.

Daniel: But here's the part that gets me even more. If something is wearing out, it had to be new once.

Sofia: Oh, you're going to the beginning.

Daniel: I'm going to the beginning. Run the film backwards. Entropy keeps going up, so the further back you go, the lower it was. Which means the universe started in an incredibly ordered state.

Sofia: That's right. And it's one of the deepest puzzles in physics. Roger Penrose — the same Penrose from our consciousness episode, Episode Four — tried to put a number on how special that starting point was. His estimate, in his nineteen eighty-nine book "The Emperor's New Mind," was one chance in ten to the ten to the hundred and twenty-third.

Daniel: Say that again.

Sofia: Ten, to the power of ten, to the power of a hundred and twenty-three. You couldn't write that number out if you put a zero on every particle in the universe. It's not even close.

Daniel: So the garment didn't just happen to be new. It was made new. On purpose. "Of old, you laid the foundation of the earth. The heavens are the work of your hands." That's verse twenty-five, right before the garment line. The psalm doesn't just say it's wearing out. It says somebody made it.

Sofia: And that's where you and I are going to part ways. But I won't pretend the starting point isn't strange. It's very strange. We don't have an explanation for it.

Daniel: Remember the demon? You said no being INSIDE the system gets to run the clock backwards for free.

Sofia: I did say that.

Daniel: So who wound the clock to begin with? Not anyone inside it. The psalm's answer is someone outside it. "You laid the foundation." Not a demon sorting molecules in the box. The one who built the box.

Sofia: I can't give you a physics answer to "who." Physics describes what happens inside the box. The very beginning is exactly where our tools run out. Some colleagues would say there's a deeper physical explanation we just haven't found — a multiverse, a quantum origin, something.

Daniel: And some would say there's someone.

Sofia: And some would say there's someone. I'm honestly not sure physics gets to vote on that one.

Daniel: That's the most honest thing anyone's said on this show.

Okay, but let's be honest

Daniel: Okay. Hit me. Where am I overselling it?

Sofia: Let me start with the obvious one. Everybody in the ancient world watched clothes wear out. Watched people get old. Watched buildings crumble. A poet saying "the sky will get old like a coat" doesn't need any physics. It's an observation about life, stretched across the sky.

Daniel: Fair. I'll grant it's poetry first. But here's the thing — most ancient cultures stretched it the OTHER way. They looked up and said the heavens are eternal. Aristotle said the heavens were made of a perfect substance that never changes. For most of history, the smart money was that the sky lasts forever.

Sofia: That's — true, actually. The unchanging heavens were the scientific consensus for almost two thousand years.

Daniel: And this psalm says, no. They're wearing out. Only God doesn't.

Sofia: Okay, second one, and this one cuts against you inside your own book. Ecclesiastes one, verse four. "One generation goes, and another generation comes; but the earth remains forever."

Daniel: You did your homework.

Sofia: I had a week.

Daniel: Okay — the word there is "olam." It means a long age, as far as you can see. It's used for things that clearly end — the same word describes a servant serving "forever," meaning for life. Ecclesiastes is watching generations pass while the ground stays put. That's a contrast between us and the earth, not a physics claim about the end of time.

Sofia: Hm. I'll take that. Third one, and this is the big one. The Bible's ending isn't a heat death. Second Peter three — "the heavens will pass away with a great noise, and the elements will be dissolved with fervent heat." That's fire. Heat death is cold. Dark. Quiet. Those are opposites.

Daniel: That's a real point. And I want to be careful here. The Bible doesn't predict heat death. Heat death is what happens if nobody steps in — the watch nobody winds. What Scripture says is that God steps in first. "You will change them like a cloak." "Behold, I am making all things new." The garment doesn't just wear out to nothing. Somebody takes it off and puts on a new one.

Sofia: So you're saying physics describes the clock running down, and the Bible says the clockmaker comes back before it stops.

Daniel: That's — honestly, that's a better way to say it than I would have.

Sofia: Don't quote me on the clockmaker.

Daniel: Too late.

Sofia: Last one, and it's a warning for your side, not against it. I hear this from people sometimes — "evolution violates the second law, because life is more ordered." That's wrong. The second law is about closed systems. The earth isn't closed. We get a flood of energy from the sun every second. Local order — a snowflake, a tree, a baby — is perfectly allowed, as long as total entropy goes up somewhere else.

Daniel: And I agree with you. That argument should be retired. It's just bad physics. I'm not here to defend it.

Sofia: Thank you. I was ready for a fight.

Daniel: Actually, give me the picture of how that works. Where does the earth's order come from?

Sofia: Penrose has the best way of putting it. The sun doesn't really give us extra energy — the earth sends out about as much energy as it takes in, or we'd keep heating up forever. What the sun gives us is LOW-entropy energy. For every one photon of visible sunlight that comes in, the earth sends roughly twenty photons of infrared heat back out into space.

Daniel: Same energy, chopped into twenty pieces.

Sofia: Same energy, twenty times the entropy. Every leaf, every meal, every heartbeat is paid for by that trade. We live downstream of a very ordered sun.

Daniel: Which runs down too.

Sofia: Which runs down too. Everything's borrowing.

Daniel: Not on that one. But let me ask you this one back. There are people who think the universe never really ends — that it bounces, or starts over. Penrose has a version of that too, right?

Sofia: He does — conformal cyclic cosmology. The end of one universe becomes the beginning of the next. It's elegant. But honestly, it hasn't been accepted by most cosmologists, and there's no agreed evidence for it. The mainstream picture is still a slow fade.

Daniel: So the best science we have says the universe had a beginning, it was set up in an almost impossibly ordered state, and it's wearing out.

Sofia: Yes. That's — yes. That's a fair summary of where the science is. What it means is where we disagree.

What Do We Do With a Story Like This

Daniel: Let me try pulling it together, and you tell me where I'm overreaching.

Sofia: I'm ready.

Daniel: Actually — one thing first. When we told people this episode was coming, a listener wrote in with a question that's stuck with me all week. "If everything wears out anyway, the sun, the stars, all of it — why does anything I do matter?"

Sofia: That's the question underneath all of this, isn't it.

Daniel: It is. And I want to answer it honestly, not with a slogan. So first, the threads. One. A man three thousand years ago, at the bottom of his life, said the heavens would wear out like a garment — when almost every wise person on earth thought the heavens were eternal. Two. In the eighteen-fifties, physics discovered a universal tendency for everything to run down, and today the best picture of the future is a slow fade to cold. Three. Run the film backwards and the universe started incredibly ordered — one in ten to the ten to the hundred and twenty-third. A garment that's wearing out had to be new once. And four. The psalm doesn't stop at decay. "But you are the same. Your years will have no end."

Sofia: Where you overreach is the leap from "the starting point is improbable" to "someone set it." I don't know what set it. Nobody does. But I'll say this — the one thing I can't do as a physicist is tell you the universe is eternal and self-sustaining. It isn't. It's a watch running down.

Daniel: And that's where I land. Paul says it in Romans eight. "The creation was subjected to vanity... in hope that the creation itself also will be delivered from the bondage of decay." The Greek word for decay there is "phthora" — not a sudden smash, a slow rotting from the inside. That's entropy, Sofia. Paul calls it bondage. And he says it isn't the end of the story. "We know that the whole creation groans and travails in pain together until now."

Sofia: Groaning. Like a birth.

Daniel: Like a birth. Not a funeral. My dad's jacket is in a box in my closet now. I can't throw it out. But I don't need it to last forever, because he isn't in the jacket. And that's the psalm. The heavens can wear thin. The One who made them isn't wearing out.

Sofia: And your listener? "Why does anything matter if it all wears out?"

Daniel: Here's my answer. If the universe were the last word, then honestly — maybe it wouldn't. Everything would just be a longer or shorter fade. But the psalm doesn't say the heavens are the last word. It says, "But you are the same." What you do matters because it's done in front of Someone who doesn't wear out. Love doesn't go into the garment. It goes to the person wearing it.

Sofia: I don't know that I believe that. But I'd like to.

Daniel: That's a good place to start.

Sofia: I'll go wind my watch.

Daniel: Wind your watch.

Daniel: Somewhere tonight, a cup of coffee is going cold on a kitchen counter, and the universe is getting a tiny bit older with it. Let it. The heavens are a garment. Someone is holding the sleeve. We'll be back.