Daddy, where did I come from?^[.md]

2025-11-16

Preface

I wrote this for my daughter.

I hope we get to talk about all of this together as she grows up — where she came from, where we came from, and how we think the whole universe came to be. But if something were to happen to me before she's old enough to ask these things, I want her to be able to have a record of how I understand the world.

This isn't a scientific paper or a philosophical argument. I'm just a father-to-be trying to explain some of life's biggest questions.

---

"Daddy, where did I come from?"

You came from Mommy and Daddy. You began as one tiny cell, half from her and half from me, multiplying and organizing until you became you.

"But where did you come from?"

I came from my parents, and they from theirs, and if you follow that chain back far enough, the people along it begin to look less and less like us.^[1]

"But where did people come from?"

Before humans were earlier hominins who walked upright but had smaller brains and simpler lives. Before them were ape-like ancestors in forests, then small primates in trees, then early mammals, and before that, creatures living entirely in the water.^[1:1]

"But where did the water come from?"

The water on Earth wasn't there all at once. A lot of it arrived when icy comets and water-filled rocks from space crashed into the young Earth. Some water also formed later, when hydrogen and oxygen combined during the planet's early history. Little by little, all that water collected into the oceans.^[2]

"But where did life come from?"

Life seems to have begun on early Earth, in its young oceans. The planet had water, heat, and the right chemicals, and in that mix some simple molecules found ways to copy themselves. Once copying began, tiny changes built up over millions of years, shaping cells, then simple creatures, and eventually all the life we know.^[3]

"But where did Earth come from?"

Earth formed from a spinning disc of dust and gas left over from the birth of the Sun. Gravity — the pull that every bit of matter has on every other bit, the same pull that makes things fall to the ground when you drop them — drew tiny grains together into pebbles, then rocks, then mountain-sized pieces, and eventually those pieces merged into a whole planet.^[4]

"But where did the Sun come from?"

The Sun is a star that formed when a huge cloud of gas collapsed under its own gravity, heated up, and sparked nuclear fusion in its core. That cloud itself came from older, massive stars that lived and died long before our solar system existed. When those stars exploded, they scattered the elements they had made into space — carbon, oxygen, iron — which mixed into new clouds. And the very first of those older stars formed when gravity pulled together the first giant clouds of hydrogen in the early universe.^[5]

"But where did the universe come from?"

We think that the universe began deep inside a black hole in another universe.^[6] A black hole forms when a very massive star collapses at the end of its life — so massive that when its fuel runs out, gravity crushes the core into an incredibly tiny, incredibly dense point where not even light can escape.^[7]

As that core collapses inward, it gets smaller and smaller until it reaches the smallest size that nature will allow. At that scale, the rules of normal gravity no longer work. Quantum gravity, which only shows up at these extreme conditions, won't allow the collapse to shrink past that bottom limit. Instead, the crushed core hits that limit and rebounds. That rebound begins an expansion on the inside of the black hole.^[8]

That expansion starts as an almost infinitesimal point growing hotter and denser for a moment, then cooling as it stretches. At those temperatures, energy can turn into tiny particles of matter and back again. As the expansion continues and things cool down, some of those particles stop disappearing — they stay. Those were the first building blocks of everything in our universe. After a long, long time, those particles form to make atoms, then stars, then planets — and everything else that follows.^[9]

"But what came before the universe?"

That's one of the biggest questions there is, and we don't know for sure.

When the universe first began, everything was packed into a point so tiny and so extreme that space and time didn't exist yet.^[10] In a place that small, there's no "before" or "after" — time only starts when the universe begins to grow.^[10:1] So the very first universe didn't need anything to come before it. It simply was, and then it expanded.^[10:2]

Much later, once that universe had stars, those stars could collapse and form black holes. And inside a collapsing star, conditions become almost as intense as that very first beginning. They squeeze matter and energy down to a point so small that spacetime disappears again. When that point rebounds and starts to expand, it forms a new universe with its own rules.^[6:1][8:1]

If every universe can create more universes this way, then universes with rules that make stars will naturally produce more black holes — and therefore more universes. Over many generations, the universes that can build structure, light, planets, and life may simply become the ones that last and multiply.^[11]

We live in one of those universes. One whose rules make stars possible, make planets possible, make life possible — and make you possible. If the rules were even slightly different, none of this could've happened, and you wouldn't be around to ask these questions.^[12]

But just like everything has a beginning, everything has an ending too, including the universe.

"But what happens when the universe ends?"

As the universe continues to expand the way it is now, it will simply fade. Over an incredibly long time, stars will burn out, new ones won't form, and everything will grow colder and emptier. Even black holes will eventually disappear. The universe won't end suddenly; it will just grow quiet, thin, and dark, stretching out forever until almost nothing remains.^[13][14]

"But when the universe ends, do we end too?"

We won't be here when the universe reaches that stage, but even long before that, people don't last forever. Our bodies stop working one day, just like how stars eventually burn out.^[15]

But we don't just disappear. Every part of us becomes part of something new, and we keep going in another way too — the same way Mommy and I live on through you. If you choose to have children someday, a piece of you will continue in them, just like a little piece of us and every other generation before you continues in you.

"But what if I don't want things to end?"

It's hard sometimes to accept that I, that you, and that everything you know won't last forever, but the best thing we can do is make the most of the time that we have.

What also sometimes helps is remembering that, even if we can't control everything that happens, we can choose how we love and how we care. Feeling loved and giving love — that's what makes all of this worth it, even when it's scary to think about endings.

"But where did love come from?"

Love comes from us — from the way we care about each other and want to stay connected in a big universe that's always changing. Even though love isn't made of anything you can touch, it shows up in what we do and how we treat people.

And even when people and memories fade, love doesn't just vanish. When you love someone, it changes them a little, and they carry that change into the way they treat others. Those small changes keep spreading, person to person, long after the original feeling has passed.

Love doesn't have a body or a shape, so it isn't tied to space the way stars and planets are. Even if the universe someday goes cold and empty, love doesn't die with it. Once it exists, it stays — and nothing can make it go away.

So, remember, no matter what happens, your Mommy and I will always love you.

---

Footnotes

1. Tattersall, The Fossil Trail (1995); Zimmer, Evolution (2001); Smithsonian Human Origins, https://humanorigins.si.edu ↩︎ ↩︎

2. Alexander, "Origin of Inner Solar System Water" (2017), https://doi.org/10.1098/rsta.2015.0384; Wu et al., "Origin of Earth's Water" (2018), https://doi.org/10.1029/2018JE005698; Piani et al., "Earth's Water and Enstatite Chondrites" (2020), https://doi.org/10.1126/science.aba1948 ↩︎

3. Lane, The Vital Question (2015); Szostak, "Chemistry of the Origin of Life" (2017), https://doi.org/10.1002/anie.201701488; Le Vay et al., "RNA-Only Origin of Life" (2020), https://doi.org/10.1007/s00239-020-09934-4 ↩︎

4. Armitage, Astrophysics of Planet Formation (2010); Raymond & Morbidelli, "Planet Formation Models" (2020), https://arxiv.org/abs/2002.05756 ↩︎

5. Shu et al., "Star Formation in Molecular Clouds" (1987), https://doi.org/10.1146/annurev.aa.25.090187.000323; Lada & Shu, "Formation of Sunlike Stars" (1990), https://doi.org/10.1126/science.248.4955.564; Burbidge et al., "Synthesis of the Elements in Stars" (1957), https://doi.org/10.1103/RevModPhys.29.547 ↩︎

6. Popławski, "Cosmology with Torsion" (2010), https://doi.org/10.1016/j.physletb.2010.09.056; Popławski, "Universe in a Black Hole" (2014), https://arxiv.org/abs/1410.3881 ↩︎ ↩︎

7. Chandrasekhar, The Mathematical Theory of Black Holes (1983); Thorne, Black Holes and Time Warps (1994) ↩︎

8. Ashtekar et al., "Quantum Nature of the Big Bang" (2006), https://doi.org/10.1103/PhysRevD.73.124038; Smolin, "Status of Cosmological Natural Selection" (2006), https://arxiv.org/abs/hep-th/0612185 ↩︎ ↩︎

9. Planck Collaboration, "Cosmological Parameters" (2018), https://doi.org/10.1051/0004-6361/201833910; Peebles, Large-Scale Structure of the Universe (1980) ↩︎

10. Hartle & Hawking, "Wave Function of the Universe" (1983), https://doi.org/10.1103/PhysRevD.28.2960; Lehners, "Review of the No-Boundary Wave Function" (2023), https://doi.org/10.1016/j.physrep.2023.08.002 ↩︎ ↩︎ ↩︎

11. Smolin, "Did the Universe Evolve?" (1992), https://doi.org/10.1088/0264-9381/9/1/016; Smolin, The Life of the Cosmos (1997) ↩︎

12. Barrow & Tipler, Anthropic Cosmological Principle (1986); Carter, "Large Number Coincidences and the Anthropic Principle" (1974) ↩︎

13. Adams & Laughlin, "A Dying Universe" (1997), https://doi.org/10.1103/RevModPhys.69.337; NASA, "Fate of the Universe," https://map.gsfc.nasa.gov/universe/uni_fate.html ↩︎

14. Hawking, "Particle Creation by Black Holes" (1975), https://doi.org/10.1007/BF02345020 ↩︎

15. Prialnik, Stellar Structure and Evolution (2009) ↩︎