Week 08 · How Big: Sizes and Properties

Thursday

Reading the fact sheet: properties

// Reading the planets as a data table

⏱ about 20 min

Thursday: Reading the Fact Sheet: Properties

Raven spreads the full NASA fact sheet across the Sky Deck step. "Six rows today. Day length, year length, gravity, temperature, moons, rings."

Rocket reads the day row. "Jupiter spins in about ten hours. Venus takes 2802 hours. That is months!"

"What do you notice about temperature?" Raven asks.

"It drops as you go out. Except Venus. Venus is hotter than Mercury, and Mercury is closer to the Sun."

Nova hovers over the Venus column. "A thick blanket of air keeps heat in," she says. "A textbook explains it."

Rocket moves to the moon row and laughs. "Saturn: 274 moons. Earth: one." Raven smiles. "Patterns and surprises. Read on."

A table from NASA

The NASA Planetary Fact Sheet lists many properties for each world. Today you read six of them side by side.

Length of day is how many hours from one noon to the next. Orbital period is how many Earth days one trip around the Sun takes.

Mean temperature is in degrees Celsius. Surface gravity is in meters per second squared, as in week 5.

Planet	Day (hours)	Year (Earth days)	Gravity	Mean temp (C)	Moons	Rings?
Mercury	4222.6	88.0	3.7	167	0	No
Venus	2802.0	224.7	8.9	464	0	No
Earth	24.0	365.2	9.8	15	1	No
Mars	24.7	687.0	3.7	-65	2	No
Jupiter	9.9	4331	23.1	-110	95	Yes
Saturn	10.7	10,747	9.0	-140	274	Yes
Uranus	17.2	30,589	8.7	-195	28	Yes
Neptune	16.1	59,800	11.0	-200	16	Yes

What the rows show

Days: the giant planets spin fastest. NASA says Jupiter has the shortest day, 9.9 hours, and Saturn the second shortest, 10.7 hours.

Years: the farther from the Sun, the longer the year. Mercury needs 88 days. Neptune needs 59,800.

Temperature: it falls with distance from the Sun, with one exception. Venus is hotter than Mercury.

OpenStax Astronomy explains the exception. Venus's thick atmosphere acts like a giant greenhouse, keeping heat in and raising the temperature enormously.

Moons and rings: Mercury and Venus have no moons. All four giant planets have rings and many moons. Saturn has the most, 274.

READ THE ROWS

Read the question.
Tap your answer.

Which planet has the shortest day?

Venus is hotter than Mercury even though Mercury is closer to the Sun. Why?

Which planets have rings?

Saturn has ____ moons on the fact sheet.

The planet with the longest year in the table is ____.

Statement	True or false?
Mars has a day length close to Earth's.	?
Mercury has the hottest mean temperature in the table.	?
No terrestrial planet in the table has rings.	?
Uranus has more moons than Jupiter.	?

WHY THIS EXERCISEEach statement tests whether you can find and compare values in a real data table.

Try it

Cover the gravity column. Using what you learned in week 5, predict which planet has the strongest surface gravity.
Uncover and check. Write whether the giant planets all beat Earth, and which one did not.

Try this

Pick one planet. Write a short weather report for it using its day length, temperature and gravity from the table.
Read it aloud to someone. Ask them to guess the planet.

Draw the eight planets in a row. Above each, draw a small sun for a short day or a sleeping moon for a long one. Below each, write its moon count.

Describe the temperature pattern across the table and the one exception, using numbers.Rocket laughed at Saturn's 274 moons. Why might giant planets collect so many more moons than small ones? Write your idea.Write one new question the table makes you want to ask.

Sharp reading. Tomorrow you learn where all these numbers came from: telescopes on the ground, in space and spacecraft out there.

Grown-up checked my answers

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