Explorer
Our place in space, the true scale of the solar system, days and years, seasons, phases and eclipses, and the night sky.
NASA
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Our place in space
- Our place in space · 10 min Completed
From your street to the edge of the Milky Way: where Earth sits, how far away things are, and how we measure it.
- Our place in space · 10 min Completed
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A walk from the Sun to Neptune
- A walk from the Sun to Neptune · 10 min Completed
Almost every picture of the solar system is wrong about scale. Walk it at true scale and feel how empty space really is.
- A walk from the Sun to Neptune · 10 min Completed
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Days and years on each world
- Days and years on each world · 10 min Completed
Venus takes longer to spin once than to go around the Sun, Jupiter spins in under ten hours, and Neptune's year is 165 of ours. Why?
- Days and years on each world · 10 min Completed
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Why we have seasons
- Why we have seasons · 12 min Completed
It is not about distance from the Sun. It is about tilt. See why summer days are long and winter noons are low.
- Why we have seasons · 12 min Completed
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Moon phases and eclipses
- Moon phases and eclipses · 12 min Completed
Why the Moon changes shape through the month, and why we do not get an eclipse every new and full Moon.
- Moon phases and eclipses · 12 min Completed
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The night sky and light pollution
- The night sky and light pollution · 10 min Completed
Most people alive today have never seen a truly dark sky. See how many stars light pollution hides, and what anyone can do about it.
- The night sky and light pollution · 10 min Completed
Tools and lessons use simplified models for learning only. They must not be used for navigation, mission planning or any operational decision. Certificates are free and non-accredited. Read the educational content disclaimer