How the Cosmos Works
Move beyond basic astronomy trivia to understand the real physics shaping our universe. Master the counter-intuitive rules of orbital mechanics, decode the lifecycles of stars, and explore the invisible forces driving cosmic expansion.
Like Duolingo, but for How the Cosmos Works. Tomo turns the whole topic into a game you play five minutes a day, until it actually sticks.
22 levels across 3 sections, about 44 minutes end to end, roughly 9 days at five minutes a day. It moves through Moving Through the Void, Decoding Worlds and Stars, and The Extreme and Invisible Universe. It assumes you already know the basics.
Free forever · No credit card · iPhone & Android
Key ideas in How the Cosmos Works
- Gravity in low Earth orbit remains roughly 90% as strong as on the ground.
- Weightlessness occurs because the spacecraft and crew are in continuous free-fall together.
- High horizontal speed ensures the falling craft curves around Earth without hitting it.
- A prograde burn adds orbital energy and raises altitude on the opposite side of the orbit.
- The burn location itself acts as a fixed pivot point that does not instantly change altitude.
- Firing prograde at periapsis raises the apoapsis without altering the periapsis altitude.
- Burning retrograde slows orbital speed, dropping the craft into a lower-altitude orbit.
- Lower orbits feature stronger gravitational pull and faster overall orbital velocities.
- Entering a lower orbit completes a revolution faster, allowing a craft to catch up to a target ahead.
- The initial prograde burn stretches the circular orbit into an elliptical transfer orbit.
- The craft coasts unpowered along the transfer ellipse until it reaches its new apoapsis.
- A second prograde burn at the apoapsis circularizes the orbit at the higher target altitude.
- Delta-v is the scalar total of velocity changes a spacecraft can perform with its fuel.
- Because fuel adds its own weight, propellant requirements scale exponentially via the rocket equation.
- Higher specific impulse or exhaust velocity yields more delta-v per kilogram of propellant.
- In the planet's reference frame, flyby entry and exit speeds are identical.
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 How the Cosmos Works 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.
Why do astronauts float inside their spaceship?
Get it right to open this lesson and 21 more in the app.
How to learn How the Cosmos Works, step by step
Go in order. 22 short levels across 3 sections, about 44 minutes in all, five minutes a day.
- 1
Moving Through the Void
- Navigating Orbital Mechanics
- Leveraging Gravity Wells and Sweet Spots
- 2
Decoding Worlds and Stars
- Assessing Planetary Environments
- Tracing Stellar Evolution and Nucleosynthesis
- 3
The Extreme and Invisible Universe
- Analyzing Extreme Spacetime Curvature
- Mapping Dark Matter and the Cosmic Web
- Investigating Origins and Cosmic Fate
3 sections · 7 units · 22 levels. Built to play, not to enroll.
Questions about How the Cosmos Works
How do I learn How the Cosmos Works?
Go in order: start with Moving Through the Void, then Decoding Worlds and Stars, then The Extreme and Invisible Universe. On Tomo that's 22 short levels, about 44 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 How the Cosmos Works?
Yes. Tomo works like Duolingo: short daily lessons, streaks and quick quizzes. How the Cosmos Works is one of its free courses, and you can type any other topic to get a course of your own.
Is the How the Cosmos Works course free?
Yes. How the Cosmos Works 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 How the Cosmos Works?
22 levels across 3 sections, about 44 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 How the Cosmos Works?
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
How the Cosmos Works is taught in the Explain Like I'm 5 style: no big words. promise.. 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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Start How the Cosmos Works today.
Download Tomo, search How the Cosmos Works, and play your first lesson in under a minute.