Planets

Tell a planet from a star, name it, and say where it will be next month.

6 guides · about 30 min

A line runs from a guide to the guides that build on it.

1. 1. Spotting the Planets 6 min How can you tell a planet from a star?

   You’ll be able to tell a planet from a star, and say which planet it is.

   Leads to

   Why Planets Loop, Mercury's Hide-and-Seek, The Lagrange Points

   Begin
2. 2. Why Planets Loop 5 min Why would a planet ever go backwards?

   You’ll be able to explain why Mars runs backwards for weeks at a time.

   Builds on

   • Spotting the Planets. It uses “ecliptic”, which Spotting the Planets explains.

   Begin
3. 3. Venus's Eight-Year Star 5 min How does Venus draw a five-pointed star every eight years?

   You’ll be able to tell whether Venus is an evening or a morning star, and when it will switch.

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4. 4. Mercury's Hide-and-Seek 5 min Why is Mercury so hard to catch, and when is it easiest?

   You’ll be able to say which evenings of the year give you your best chance at Mercury.

   Builds on

   • Spotting the Planets. It uses “ecliptic”, which Spotting the Planets explains.

   Begin
5. 5. Racing and Crawling 4 min Why does Halley’s Comet race past the Sun and crawl far from it?

   You’ll be able to explain why a comet races past the Sun and crawls at the far end of its orbit.

   Leads to

   The Lagrange Points, A Visitor from Another Star (Visitors)

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6. 6. The Lagrange Points 7 min Where can a spacecraft keep pace with the Earth around the Sun?

   You’ll be able to point to where the Lagrange points sit in your sky.

   Builds on

   • Spotting the Planets. It uses “ecliptic”, which Spotting the Planets explains.
   • Racing and Crawling. It uses “nearer the Sun is faster”, from Racing and Crawling.

   Begin