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Earth and Space 6-8 / Week 08 / Sky Night
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Week 08 · How Big: Sizes and Properties

Sky Night

Sky Night: The size game
// Reading the planets as a data table
⏱ about 20 min

Sky Night: The Size Game

The crew gathers on the porch step at dusk with a grown-up and a bag of paper planets.

There is no Moon in the evening sky. Raven writes "not up" and the date in the Moon log. "What do you notice? It is past third quarter, so it rises after the middle of the night."

Rocket hands a younger cousin the paper Earth. "Now pick which one is Jupiter." The cousin reaches for the saucer.

"Bigger," Rocket says. The cousin picks up the plate. "That big? For real?"

Nova hovers above with her light on the step, never in anyone's eyes. "Now show them the Sun," she says.

Raven unrolls the string into a circle across the porch. Everyone sets their planets inside it and goes quiet.

  1. Diameter is the distance straight across a planet. Earth is 12,756 kilometers across; Jupiter is about 11 times wider.
  2. The Sun is about 1.4 million kilometers across, about 110 Earths wide. It would take 1.3 million Earths to fill it.
  3. The four inner planets are small, rocky and solid. The four outer planets are giants of gas and ice with no surface to stand on.
  4. The fact sheet shows the giants spin fastest, years grow longer with distance, and temperature falls with distance except on Venus.
  5. Mercury and Venus have no moons. All four giant planets have rings and many moons. Saturn has 274.
  6. Ground telescopes, space telescopes and spacecraft each add different data to the planet table.
◇ SKY NIGHT: MOON CHECK AND THE SIZE GAME
With a grown-up, go to your usual Sky Deck spot after dark. If the Moon is up, sketch it with the date. If not, write "not up" and the date.
Hand a family member the paper Earth. Ask them to pick the paper planet they think is Jupiter, then Mars, then Saturn.
Reveal the answers. Then lay out the string Sun and let everyone place the planets inside it.
Ask each person which fact from the week surprised them most. Write the answers down.
Cloudy night backup: the size game is the whole show. Sketch the Moon from your last clear night instead.
For a grown-up
Please go outside together. Use a flashlight for the path and point it at the ground, never at anyone's eyes.
Stay in a known spot in the yard, on the porch or at a window. No one crosses a road or climbs for a better view.
The string stays flat on the floor or porch, never around anyone, and is picked up when you finish.
Safety first
Night observation only with a grown-up, from the yard, a porch or a window.
String stays flat on the ground. Pick up paper planets afterward so no one slips.
SKY NIGHT CHECK
  • Read the question.
  • Tap your answer.
Which paper planet is Jupiter?
Why does the string Sun have to go on the floor instead of on paper?
Draw the Moon as you saw it tonight, or as you expect it from your log. Beside it, draw the string Sun with the eight planets inside.
For a grown-up
Optional: The Size of Space by Neal Agarwal scrolls from an astronaut out to huge stars. Type neal.fun/size-of-space into a browser.
Its privacy policy says the site is not meant for children under 13, so a grown-up opens it and explores alongside.

Well done, crew. Next week you leave the sky for a while and pick up a rock to find out how it got here.

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