How the Cosmos Works
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.
For the part of you with thirty open tabs that never became anything.
22 levels across 3 sections, about 44 minutes end to end, roughly 9 days at five minutes a day. It moves through Looking Up: Motion and Gravity in Action, Decoding Starlight and Dying Stars, and The Architecture and Scale of the Universe. It starts from scratch.
Free forever · No credit card · iPhone & Android
Key ideas in How the Cosmos Works
- Steady light is a reliable visual cue that you are looking at a planet rather than a star
- Stars are so distant they appear as razor-thin points of light easily distorted by shifting air
- Planets are close enough to appear as small disks, which averages out atmospheric turbulence
- The sky's daily movement is an illusion caused by Earth spinning on its axis
- Earth rotates eastward, making celestial objects appear to move westward
- Light travels at a fast but finite speed across space
- The light we see right now left distant stars years, centuries, or millennia ago
- Looking farther into space inherently means looking further back into past time
- Planets orbit the Sun alongside Earth on nearly the same flat plane
- Because planets are orbiting nearby, their positions slowly drift against the distant starry background
- Distant stars are so far away that their relative positions appear fixed to human eyes
- One half of the Moon is always lit by the Sun, regardless of phase
- Phases are simply our changing vantage point of that sunlit side as the Moon loops around Earth
- Earth's shadow only falls on the Moon during a rare lunar eclipse, not during ordinary phases
- Gravity pulls the satellite down while sideways speed carries it forward
- The satellite drops toward Earth at the exact same rate the planet's round surface curves away
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 distant stars twinkle when you look up at night?
Get it right to open this lesson and 21 more in the app.
Where How the Cosmos Works takes you
Unravel the mechanics of the universe from your own backyard to deep space. Discover why orbits work, how dying stars forged the elements in your blood, and what warped spacetime reveals about reality.
- 1
Looking Up: Motion and Gravity in Action
- Making Sense of the Night Sky
- Why Orbiting Things Don't Crash Down
- 2
Decoding Starlight and Dying Stars
- Reading the Secret Messages in Starlight
- How Stars Live and Die
- Extreme Gravity and Bent Space
- 3
The Architecture and Scale of the Universe
- Galaxies and the Hidden Web of Matter
- The Expanding Universe and Cosmic Time
3 sections · 7 units · 22 levels. Built to play, not to enroll.
You pick the voice
How the Cosmos Works is taught in the 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.
More Science on Tomo
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Astrophysics: The Life of the Cosmos
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The Physics of Space Exploration
Move beyond the names of planets and learn the invisible forces that govern how we navigate the void and how stars live and die.
Navigating the Cosmos
Move beyond the names of planets and dive into the mechanics of space travel, the life cycles of stars, and the strange behavior of time and gravity in the deep universe.
Start How the Cosmos Works today.
Download Tomo, search How the Cosmos Works, and play your first lesson in under a minute.