Cosmology: The Story of the Universe
Journey from the first fraction of a second to the heat death of the universe. Master the physics of expansion, the mystery of dark energy, and the mathematical models that define our reality.
Like Duolingo, but for Cosmology: The Story of the Universe. Tomo turns the whole topic into a game you play five minutes a day, until it actually sticks.
75 levels across 8 sections, about 150 minutes end to end, roughly 30 days at five minutes a day. It moves through Measuring the Infinite, The Geometry of Space-Time, The Dark Universe, The Early Universe, The Cosmic Microwave Background, Cosmic Dawn and Structure, The Inflationary Paradigm, and The Ultimate Destiny. It assumes you already know the basics.
Free forever · No credit card · iPhone & Android

Key ideas in Cosmology: The Story of the Universe
- Parallax is the only direct geometric distance measurement
- Luminosity is the total energy a star emits per second
- Earth's position shifts by 2 AU over six months
- Standard candles have a known 'wattage' regardless of location
- Closer stars show a larger angular shift than distant ones
- Apparent brightness decreases with the square of the distance
- How Earth's orbit creates the baseline for parallax measurements
- The relationship between apparent brightness and intrinsic luminosity
- Longer pulsation periods indicate higher absolute magnitude
- Leavitt's Law links timing directly to light output
- Cepheids are bright enough to be seen in nearby galaxies
- They all explode at the same mass limit (Chandrasekhar limit)
- Their extreme brightness makes them visible across billions of light-years
- Parallax anchors the entire system to physical units
- Using Cepheid pulsation to determine distance
- Each rung is calibrated using the distance from the previous one
You've tried the other tabs
Thirty open tabs. Four facts you actually kept.
You watched. You nodded. By Sunday it was gone.
One answer, then back to scrolling.
Eight weeks. You meant to finish. You didn't.
Tomo gives Cosmology: The Story of the Universe the Duolingo treatment: levels, streaks, and quick quizzes that test what you just learned. That game loop is what the tabs above never had, so it's the one you actually finish.
Here's what playing it feels like
A real question from this course. Take your best guess.
When astronomers talk about a star's luminosity, what are they actually measuring?
Get it right to open this lesson and 74 more in the app.
How to learn Cosmology: The Story of the Universe, step by step
Go in order. 75 short levels across 8 sections, about 2 hours 30 minutes in all, five minutes a day.
- 1
Measuring the Infinite
- The Cosmic Distance Ladder
- Redshift and Hubble’s Law
- 2
The Geometry of Space-Time
- The Friedmann Equations
- Curvature and Critical Density
- 3
The Dark Universe
- The Case for Dark Matter
- Dark Energy and Lambda
- 4
The Early Universe
- Big Bang Nucleosynthesis
- Baryogenesis and Asymmetry
- The Photon Epoch and Recombination
- 5
The Cosmic Microwave Background
- Anisotropies and the Power Spectrum
- Polarization and B-Modes
- 6
Cosmic Dawn and Structure
- Jeans Instability and Collapse
- The Cosmic Web
- Reionization
- 7
The Inflationary Paradigm
- The Horizon and Flatness Problems
- The Inflaton Field
- 8
The Ultimate Destiny
- The Big Freeze and Heat Death
- The Big Rip and Big Crunch
- The Multiverse and Eternal Inflation
8 sections · 19 units · 75 levels. Built to play, not to enroll.
Questions about Cosmology: The Story of the Universe
How do I learn Cosmology: The Story of the Universe?
Go in order: start with Measuring the Infinite, then The Geometry of Space-Time, then The Dark Universe, then The Early Universe, and 4 more sections after that. On Tomo that's 75 short levels, about 2 hours 30 minutes in all, played five minutes a day. Start free and play the first level in under a minute.
Is there a Duolingo-style app for Cosmology: The Story of the Universe?
Yes. Tomo works like Duolingo: short daily lessons, streaks and quick quizzes. Cosmology: The Story of the Universe is one of its free courses, and you can type any other topic to get a course of your own.
Is the Cosmology: The Story of the Universe course free?
Yes. Cosmology: The Story of the Universe is playable on Tomo's free plan, which doesn't expire. No credit card, no waitlist. Download the app and start your first lesson.
How long does it take to learn Cosmology: The Story of the Universe?
75 levels across 8 sections, about 2 hours 30 minutes of play in total. It's built for five minutes a day, so you finish it a little at a time instead of all at once.
Do I need any background to start Cosmology: The Story of the Universe?
No. It's pitched at an intermediate level, so it starts where you are and builds up. If you can tap a phone, you can start.
Tomo is in ChatGPT
Tomo is also a ChatGPT plugin: the same playable courses, built and played inside your chat.
Add Tomo to ChatGPT- What to ask
- “Make me a Tomo course on black holes.” “Turn this chat into a Tomo course.”
- What you get
- Quick questions with instant feedback, hearts and stars, ready to play in about a minute.
- Where it goes
- No sign-up to start. Connect your Tomo account and your streak carries on in the app.
You pick the voice
Cosmology: The Story of the Universe is taught in the Professor style: clear, structured, thorough. Want a different feel? In the app you can spin up the same topic in any of Tomo's teaching styles. Same facts, totally different vibe.
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Astrophysics: The Life of the Cosmos
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The Architecture of the Cosmos
Go beyond the basics of stargazing to master the mechanics of galactic structures, the physics of singularities, and the ultimate fate of the universe.
Astrophysics and the Cosmic Scale
Move beyond identifying constellations to understanding the mechanics of the universe. Explore the physics of stellar evolution, the evidence for dark matter, and the tools astronomers use to measure the edge of space.
Start Cosmology: The Story of the Universe today.
Download Tomo, search Cosmology: The Story of the Universe, and play your first lesson in under a minute.